technical manual ht 25cd - 994 9569 002 ht 20cd -...

T.M. No. 888-2609-001

© 2007

Harris Corporation

All rights reserved

TECHNICAL MANUALHT 25CD - 994 9569 002HT 20CD - 994 9568 002

888-2609-001

Returns And ExchangesDamaged or undamaged equipment should not be returned unless written approval and aReturn Authorization is received from HARRIS CORPORATION, Broadcast Systems Divi-sion. Special shipping instructions and coding will be provided to assure proper handling.Complete details regarding circumstances and reasons for return are to be included in therequest for return. Custom equipment or special order equipment is not returnable. In thoseinstances where return or exchange of equipment is at the request of the customer, orconvenience of the customer, a restocking fee will be charged. All returns will be sentfreight prepaid and properly insured by the customer. When communicating with HARRISCORPORATION, Broadcast Systems Division, specify the HARRIS Order Number or In-voice Number.

UnpackingCarefully unpack the equipment and preform a visual inspection to determine that no appar-ent damage was incurred during shipment. Retain the shipping materials until it has beendetermined that all received equipment is not damaged. Locate and retain all PACKINGCHECK LISTs. Use the PACKING CHECK LIST to help locate and identify any componentsor assemblies which are removed for shipping and must be reinstalled. Also remove anyshipping supports, straps, and packing materials prior to initial turn on.

Technical AssistanceHARRIS Technical and Troubleshooting assistance is available from HARRIS Field Serviceduring normal business hours (8:00 AM - 5:00 PM Central Time). Emergency service isavailable 24 hours a day. Telephone 217/222-8200 to contact the Field Service Departmentor address correspondence to Field Service Department, HARRIS CORPORATION, Broad-cast Systems Division, P.O. Box 4290, Quincy, Illinois 62305-4290, USA. Technical Supportby e-mail: [email protected]. The HARRIS factory may also be contacted through a FAXfacility (217/221-7096).

Replaceable Parts ServiceReplacement parts are available 24 hours a day, seven days a week from the HARRISService Parts Department. Telephone 217/222-8200 to contact the service parts departmentor address correspondence to Service Parts Department, HARRIS CORPORATION, Broad-cast Systems Division, P.O. Box 4290, Quincy, Illinois 62305-4290, USA. The HARRIS fac-tory may also be contacted through a FAX facility (217/221-7096).

NOTE The # symbol used in the parts list means used with (e.g. #C001 = used with C001).

MANUAL REVISION HISTORY PAGE

REV # DATE ECN # PAGES AFFECTED

888-2609-001 MRH-1/MRH-2WARNING: Disconnect primary power prior to servicing.

Guide to Using Harris Parts List InformationThe Harris Replaceable Parts List Index portrays a tree structure with the major items being leftmost in the index.The example below shows the Transmitter as the highest item in the tree structure. If you were to look at the bill ofmaterials table for the Transmitter you would find the Control Cabinet, the PA Cabinet, and the Output Cabinet. Inthe Replaceable Parts List Index the Control Cabinet, PA Cabinet, and Output Cabinet show up one indentation levelbelow the Transmitter and implies that they are used in the Transmitter. The Controller Board is indented one levelbelow the Control Cabinet so it will show up in the bill of material for the Control Cabinet. The tree structure of thissame index is shown to the right of the table and shows indentation level versus tree structure level.

Example of Replaceable Parts List Index and equivalent tree structure:

The part number of the item is shown to the right of the description as is the page in the manual where the bill forthat part number starts.

Inside the actual tables, four main headings are used:

Table #-#. ITEM NAME - HARRIS PART NUMBER - this line gives the information that corresponds to theReplaceable Parts List Index entry;

HARRIS P/N column gives the ten digit Harris part number (usually in ascending order);

DESCRIPTION column gives a 25 character or less description of the part number;

REF. SYMBOLS/EXPLANATIONS column 1) gives the reference designators for the item (i.e., C001, R102,etc.) that corresponds to the number found in the schematics (C001 in a bill of material is equivalent to C1 on theschematic) or 2) gives added information or further explanation (i.e., “Used for 208V operation only,” or “Usedfor HT 10LS only,” etc.).

Inside the individual tables some standard conventions are used:

A # symbol in front of a component such as #C001 under the REF. SYMBOLS/EXPLANATIONS column meansthat this item is used on or with C001 and is not the actual part number for C001.

In the ten digit part numbers, if the last three numbers are 000, the item is a part that Harris has purchased andhas not manufactured or modified. If the last three numbers are other than 000, the item is either manufactured byHarris or is purchased from a vendor and modified for use in the Harris product.

The first three digits of the ten digit part number tell which family the part number belongs to - for example, allelectrolytic (can) capacitors will be in the same family (524 xxxx 000). If an electrolytic (can) capacitor is foundto have a 9xx xxxx xxx part number (a number outside of the normal family of numbers), it has probably beenmodified in some manner at the Harris factory and will therefore show up farther down into the individual partslist (because each table is normally sorted in ascending order). Most Harris made or modified assemblies willhave 9xx xxxx xxx numbers associated with them.

The term “SEE HIGHER LEVEL BILL” in the description column implies that the reference designated partnumber will show up in a bill that is higher in the tree structure. This is often the case for components that maybe frequency determinant or voltage determinant and are called out in a higher level bill structure that is morecustomer dependent than the bill at a lower level.

2-02-93

WARNING

THE CURRENTS AND VOLTAGES IN THIS EQUIPMENT ARE DANGEROUS. PER-SONNEL MUST AT ALL TIMES OBSERVE SAFETY WARNINGS, INSTRUCTIONSAND REGULATIONS.

This manual is intended as a general guide for trained and qualified personnel who are aware of the dangers inherent inhandling potentially hazardous electrical/electronic circuits. It is not intended to contain a complete statement of all safetyprecautions which should be observed by personnel in using this or other electronic equipment.

The installation, operation, maintenance and service of this equipment involves risks both to personnel and equipment, andmust be performed only by qualified personnel exercising due care. HARRIS CORPORATION shall not be responsible forinjury or damage resulting from improper procedures or from the use of improperly trained or inexperienced personnelperforming such tasks.

During installation and operation of this equipment, local building codes and fire protection standards must be observed.The following National Fire Protection Association (NFPA) standards are recommended as reference:

- Automatic Fire Detectors, No. 72E

- Installation, Maintenance, and Use of Portable Fire Extinguishers, No. 10

- Halogenated Fire Extinguishing Agent Systems, No. 12A

WARNING

ALWAYS DISCONNECT POWER BEFORE OPENING COVERS, DOORS, ENCLO-SURES, GATES, PANELS OR SHIELDS. ALWAYS USE GROUNDING STICKS ANDSHORT OUT HIGH VOLTAGE POINTS BEFORE SERVICING. NEVER MAKE IN-TERNAL ADJUSTMENTS, PERFORM MAINTENANCE OR SERVICE WHEN ALONEOR WHEN FATIGUED.

Do not remove, short-circuit or tamper with interlock switches on access covers, doors, enclosures, gates, panels or shields.Keep away from live circuits, know your equipment and don’t take chances.

WARNING

IN CASE OF EMERGENCY ENSURE THAT POWER HAS BEEN DISCONNECTED.

WARNING

IF OIL FILLED OR ELECTROLYTIC CAPACITORS ARE UTILIZED IN YOUREQUIPMENT, AND IF A LEAK OR BULGE IS APPARENT ON THE CAPACITORCASE WHEN THE UNIT IS OPENED FOR SERVICE OR MAINTENANCE, ALLOWTHE UNIT TO COOL DOWN BEFORE ATTEMPTING TO REMOVE THE DEFEC-TIVE CAPACITOR. DO NOT ATTEMPT TO SERVICE A DEFECTIVE CAPACITORWHILE IT IS HOT DUE TO THE POSSIBILITY OF A CASE RUPTURE AND SUB-SEQUENT INJURY.

888-2609-001 iWARNING: Disconnect primary power prior to servicing.

ii 888-2609-001WARNING: Disconnect primary power prior to servicing.

FIRST-AID

Personnel engaged in the installation, operation, maintenance or servicing of this equipment are urged to become familiarwith first-aid theory and practices. The following information is not intended to be complete first-aid procedures, it is abrief and is only to be used as a reference. It is the duty of all personnel using the equipment to be prepared to giveadequate Emergency First Aid and thereby prevent avoidable loss of life.

Treatment of Electrical Burns

1. Extensive burned and broken skin

a. Cover area with clean sheet or cloth. (Cleanest available cloth article.)

b. Do not break blisters, remove tissue, remove adhered particles of clothing, or apply any salve or ointment.

c. Treat victim for shock as required.

d. Arrange transportation to a hospital as quickly as possible.

e. If arms or legs are affected keep them elevated.

NOTEIf medical help will not be available within an hour and the victim isconscious and not vomiting, give him a weak solution of salt and soda:1 level teaspoonful of salt and 1/2 level teaspoonful of baking soda toeach quart of water (neither hot or cold). Allow victim to sip slowlyabout 4 ounces (a half of glass) over a period of 15 minutes. Discon-tinue fluid if vomiting occurs. (Do not give alcohol.)

2. Less severe burns - (1st & 2nd degree)

a. Apply cool (not ice cold) compresses using the cleanest available cloth article.

b. Do not break blisters, remove tissue, remove adhered particles of clothing, or apply salve or ointment.

c. Apply clean dry dressing if necessary.

d. Treat victim for shock as required.

e. Arrange transportation to a hospital as quickly as possible.

f. If arms or legs are affected keep them elevated.

REFERENCE:

ILLINOIS HEART ASSOCIATION

AMERICAN RED CROSS STANDARD FIRST AID AND PERSONAL SAFETY MANUAL (SEC-OND EDITION)

888-2609-001 iiiWARNING: Disconnect primary power prior to servicing.

TABLE OF CONTENTSSECTION I

GENERAL DESCRIPTIONINTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1EQUIPMENT PURPOSE . . . . . . . . . . . . . . . . . . . . . . . . . 1-1PHYSICAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . 1-1FUNCTIONAL DESCRIPTION. . . . . . . . . . . . . . . . . . . . 1-1

POWER SUPPLIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1FM EXCITER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1IPA STAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

OUTPUT CIRCUIT . . . . . . . . . . . . . . . . . . . . . . . . 1-3FLEXPatch™ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

PA STAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3OUTPUT CIRCUIT . . . . . . . . . . . . . . . . . . . . . . . . 1-3

CONTROL CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . 1-3INTERLOCK CIRCUITS . . . . . . . . . . . . . . . . . . . 1-3OVERLOAD CIRCUITS . . . . . . . . . . . . . . . . . . . . 1-3AUTOMATIC RF POWER CONTROL . . . . . . . 1-3OUTPUT VSWR FOLDBACK . . . . . . . . . . . . . . . 1-3AC POWER CONTROL . . . . . . . . . . . . . . . . . . . . 1-4REMOTE CONTROL . . . . . . . . . . . . . . . . . . . . . . 1-4

INDICATORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4SAFETY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

EQUIPMENT CHARACTERISTICS . . . . . . . . . . . . . . . 1-4ELECTRICAL CHARACTERISTICS . . . . . . . . . . . . 1-4MECHANICAL CHARACTERISTICS . . . . . . . . . . . 1-4

SECTION IIINSTALLATION

INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1UNPACKING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

RETURNS AND EXCHANGES . . . . . . . . . . . . . . . . . . 2-1INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

COOLING AIR REQUIREMENTS. . . . . . . . . . . . . . . 2-1TRANSMITTER PLACEMENT . . . . . . . . . . . . . . . . . 2-1COMPONENT INSTALLATION . . . . . . . . . . . . . . . . 2-1TRANSMITTER WIRING . . . . . . . . . . . . . . . . . . . . . . 2-2

TRANSMITTER CABINET TO HIGHVOLTAGE POWER SUPPLY CABINETWIRING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

FM EXCITER WIRING . . . . . . . . . . . . . . . . . . . . 2-2INPUT POWER CONNECTIONS . . . . . . . . . . . . 2-2OUTPUT COAXIAL LINE INSTALLA-TION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

MONITOR AND DIRECTIONAL COU-PLER CABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

REMOTE CONTROL AND EXTENDEDCONTROL CONNECTIONS. . . . . . . . . . . . . . . . 2-5

INITIAL PA TUBE INSTALLATION . . . . . . . . . . . . 2-6INITIAL TURN ON PROCEDURE . . . . . . . . . . . . . . 2-7

No Tap mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13IPA Power Supply Checkout . . . . . . . . . . . . . 2-14

Half-tap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-14Full-Tap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15AUTOMATIC POWER CONTROL SET-UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-16

REMOTE CONTROL SET-UP . . . . . . . . . . . . . 2-16TECHNICAL ASSISTANCE . . . . . . . . . . . . . . . . . . . . . 2-16

SECTION IIIOPERATION

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1CONTROLS AND INDICATORS . . . . . . . . . . . . . . . . . 3-1OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11

TRANSMITTER TURN ON . . . . . . . . . . . . . . . . . . . 3-11TRANSMITTER TURN OFF . . . . . . . . . . . . . . . . . . 3-11

OPERATION IN NON-STANDARD CONFIGU-RATIONS USING FLEXPatch™ . . . . . . . . . . . . . . . . 3-11

FLEXPatch™ OPERATION TO BYPASS INOP-ERATIVE IPA DRIVER STAGES . . . . . . . . . . . . . 3-12

FLEXPatch™ OPERATION TO BYPASS AN IN-OPERATIVE PA STAGE . . . . . . . . . . . . . . . . . . . . . 3-13

FLEXPatch™ OPERATION TO BYPASS INOP-ERATIVE IPA DRIVER AND PA STAGES . . . . . 3-14

SECTION IVPRINCIPLES OF OPERATION

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1FUNCTIONAL DESCRIPTION . . . . . . . . . . . . . . . . . . . 4-1

POWER SUPPLIES . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1HIGH VOLTAGE POWER SUPPLY . . . . . . . . 4-1

Primary Control Circuit . . . . . . . . . . . . . . . . . 4-1Plate Power Supply. . . . . . . . . . . . . . . . . . . . . . 4-1Screen Power Supply . . . . . . . . . . . . . . . . . . . . 4-1

IPA POWER SUPPLY . . . . . . . . . . . . . . . . . . . . . 4-2CONTROLLER POWER SUPPLY . . . . . . . . . . 4-2

RF CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2HARRIS FM EXCITER . . . . . . . . . . . . . . . . . . . . . . . . . 4-2IPA SECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2IPA MODULE ASSEMBLY . . . . . . . . . . . . . . . . . . . . 4-2

PURPOSE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2CIRCUIT DESCRIPTION . . . . . . . . . . . . . . . . . . 4-2LOW-PASS FILTER AND DIREC-TIONAL COUPLER . . . . . . . . . . . . . . . . . . . . . . 4-3

Low-Pass Filter . . . . . . . . . . . . . . . . . . . . . . . . . 4-3Directional Coupler . . . . . . . . . . . . . . . . . . . . . 4-3Forward Port . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3Reflected Port . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3

PA STAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3DIRECTIONAL COUPLER . . . . . . . . . . . . . . . . . . . . 4-3CONTROL CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . 4-4

CONTROL LOGIC . . . . . . . . . . . . . . . . . . . . . . . . 4-4Filament Turn-On. . . . . . . . . . . . . . . . . . . . . . . 4-4Plate Control . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4Overload Circuits . . . . . . . . . . . . . . . . . . . . . . . 4-5Interlocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5Filament Turn-Off . . . . . . . . . . . . . . . . . . . . . . 4-6AC Failure Circuits . . . . . . . . . . . . . . . . . . . . . 4-6Automatic Power Control . . . . . . . . . . . . . . . . 4-6

VSWR FOLDBACK CIRCUIT. . . . . . . . . . . . . . . . . . 4-7CIRCUIT OPERATION. . . . . . . . . . . . . . . . . . . . . . . . 4-7CIRCUIT DESCRIPTION . . . . . . . . . . . . . . . . . . . . . 4-10METERING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10

POWER METERING AND VSWROVERLOADS . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10

PLATE METERING AND CURRENTOVERLOADS . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12

iv 888-2609-001WARNING: Disconnect primary power prior to servicing.

MULTIMETER CIRCUITS. . . . . . . . . . . . . . . . 4-13Screen Circuits . . . . . . . . . . . . . . . . . . . . . . . . 4-13Bias Circuits. . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13Filament Circuits . . . . . . . . . . . . . . . . . . . . . . 4-13Driver Circuits . . . . . . . . . . . . . . . . . . . . . . . . 4-13

SECTION VMAINTENANCE

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1PURPOSE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1STATION RECORDS. . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

MAINTENANCE LOGBOOK . . . . . . . . . . . . . . . . . . 5-1SAFETY PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . 5-1

PREVENTIVE MAINTENANCE . . . . . . . . . . . . . . . . . . 5-1FILTER CLEANING . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2BLOWER MAINTENANCE . . . . . . . . . . . . . . . . . . . . 5-2MAINTENANCE OF COMPONENTS . . . . . . . . . . . 5-2

SEMICONDUCTORS . . . . . . . . . . . . . . . . . . . . . . 5-2CAPACITORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2FIXED RESISTORS . . . . . . . . . . . . . . . . . . . . . . . 5-2VARIABLE RESISTORS . . . . . . . . . . . . . . . . . . . 5-2TRANSFORMERS . . . . . . . . . . . . . . . . . . . . . . . . 5-2FUSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2METER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3RELAYS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3SWITCHES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3INDICATORS AND INDICATORSWITCHES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3

PRINTED-CIRCUIT BOARDS . . . . . . . . . . . . . . 5-3CORRECTIVE MAINTENANCE . . . . . . . . . . . . . . . . . 5-3

ADJUSTMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3AIR SWITCH ADJUSTMENT . . . . . . . . . . . . . . 5-3

COMPONENT REPLACEMENT . . . . . . . . . . . . . . . 5-4

SCREEN BLOCKER REPLACEMENT . . . . . . 5-4PLATE BLOCKER REPLACEMENT . . . . . . . . 5-5

TUBE REMOVAL AND INSTALLATION . . . . . . . . 5-6PA TUBE REMOVAL . . . . . . . . . . . . . . . . . . . . . . 5-6CAVITY CONTACT INSPECTION . . . . . . . . . . 5-9PA TUBE INSTALLATION . . . . . . . . . . . . . . . . . 5-9POWER AMPLIFIER NEUTRALIZA-TION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-11

Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-12CONTROL SETUP AND OPERATION OFVSWR FOLDBACK CIRCUIT . . . . . . . . . . . . . . . . . . 5-13

ANALOG BOARD VSWR FOLDBACK CON-TROLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-13

SECTION VITROUBLESHOOTING

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1PURPOSE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1TROUBLESHOOTING. . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1TECHNICAL ASSISTANCE . . . . . . . . . . . . . . . . . . . . . . 6-1

Section VIIParts List

7-1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-17-2 Replaceable Parts Service . . . . . . . . . . . . . . . . . . . . 7-1

SECTION VIIIDIAGRAMS

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1

APPENDIX AMANUFACTURERS DATA

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1

888-2609-001 vWARNING: Disconnect primary power prior to servicing.

vi 888-2609-001WARNING: Disconnect primary power prior to servicing.

SECTION IGENERAL DESCRIPTION

1.1 INTRODUCTIONThis technical manual contains information necessary toinstall, operate, maintain and service the HARRISHT 20/25CD FM BROADCAST TRANSMITTER. Sec-tions in this technical manual provide the following infor-mation.

SECTION I, GENERAL DESCRIPTION, provides adescription of equipment features, identifies the ma-jor components and lists operating parameters andspecifications.

SECTION II, INSTALLATION, provides unpacking,inspection and installation information, pre-opera-tional checks and power on checks to ensure correctoperation.

SECTION III, OPERATION, identifies controls andindicators and provides equipment and operationprocedures.

SECTION IV, PRINCIPLES OF OPERATION, pro-vides a functional description and detailed diagramswith theory of operation.

SECTION V, MAINTENANCE, provides preventiveand corrective maintenance information with instruc-tions for equipment servicing.

SECTION VI, TROUBLESHOOTING, providescharts to aid in locating equipment malfunctions.

SECTION VII, PARTS LIST, provides information forordering replacement components and assemblies.

SECTION VIII, DIAGRAMS, provides block, logic,schematic diagrams and other drawings required forequipment maintenance.

1.2 EQUIPMENT PURPOSEThe HARRIS HT 20/25CD FM BROADCAST TRANS-MITTER is a commercial FM Transmitter designed forcontinuous broadcast operation (Figure 1-1). The trans-mitter uses a HARRIS ™ FM Exciter, a solid-statedriver, and a single tube as a PA stage to provide reli-able and efficient operation in the 87.5 to 108 MHzcommercial FM Broadcast Band.

1.3 PHYSICAL DESCRIPTIONThe unit is contained in a single cabinet, with the ex-ception of the high voltage and screen power supplyenclosure. The cabinet size and the internal placementof the second harmonic filter ensures the transmitter willfit in the place of many older 20 to 25 kW FM Transmit-ters.

The high voltage and screen power supplies are lo-cated externally in a single enclosure cabinet whichprovides increased maintenance accessibility and work-ing room. The High Voltage Power Supply may be lo-cated next to the transmitter or placed in a remote loca-tion.

The main cabinet rear door is hinged and may be re-moved for maintenance access.

Required metering is provided by seven meters locatedon the equipment front panel. An arrangement of lightemitting diode (LED) status indicators provides visualindications of transmitter operation. All controls requiredfor normal operation are accessible in full view of allindicators.

1.4 FUNCTIONAL DESCRIPTION1.4.1 POWER SUPPLIESA three-wire source of three-phase 208 to 240 Vac at175-200 amperes per phase or a four-wire source of360 to 415 Vac at 125-100 amperes per phase is re-quired to operate the HT 20/25CD Transmitter HighVoltage Power Supply. Additionally, a separate single-phase input at 30 amperes per phase source is re-quired to operate the HT 20/25CD Transmitter Cabinetpower supplies. (See paragraph entitled INPUTPOWER CONNECTIONS in Section II to determine thecorrect size for your transmitter power level and ac linevoltage.) All power supplies are overload-protected andfull-wave rectified using solid-state diodes.

The following power supplies are contained within thetransmitter cabinet (Figure 1-2):

LET = IPA DRIVER: +48 Vdc at 24 amperes.CONTROL LOGIC: +/-18 Vdc at 1.0 amperes and+/-12 Vdc at 1.0 amperes.

CONTROL GRID BIAS: -500 Vdc at 0.1 amperes.

PA FILAMENT: 10 Vac at 150 amperes.

POWER ADJUST MOTOR: 24 Vac at 2.0 amperes.

RELAY AND SOLENOID SWITCHING: 115 Vac at2.0 amperes.

The following power supplies are contained within theHigh Voltage Power Supply cabinet.

1. PLATE: +9500 Vdc (+7800 Vdc for HT20CD) or +5400 Vdc at 4.0 amperes.

2. SCREEN GRID: +1050 Vdc at 0.4 amperes.Power for the IPA DRIVER module is supplied by aswitching power supply. A front panel control (IPA OUT-PUT PWR ADJ) adjusts a 1-5VDC external control volt-age to the power supply which adjust the Output of theIPA Power Supply from 10 – 48VDC.

1.4.2 FM EXCITERRefer to the Exciter Manual provided with the transmit-ter for Technical Information

1.4.3 IPA STAGEThe HT 20/25CD IPA stage consists of two an IPADRIVER module. This module provides the necessarygain to drive the PA stage to full output with a 10 to 15watt exciter source. In the event the transmitter must beoperated with the module inoperative, FLEXPatch™provides a quick and convenient method to accommo-date this mode of operation. See Section III for FLEX-Patch™ description.

888-2609-001 1-1WARNING: Disconnect primary power prior to servicing.

Figure 1-1. HARRIS HT 20/25CD FM BROADCAST TRANSMITTER

1-2 888-2609-001WARNING: Disconnect primary power prior to servicing.

The IPA Driver module is a single amplifier assemblythat has 700 watt output capability. Internally the ampli-fier consists of two 350 watt units operating in parallelwith an input power splitter and output power combinerbuilt in.

The module is operated from the adjustable 48Vdc sup-ply. The input and output impedances are each 50ohms.

1.4.3.1 OUTPUT CIRCUITThe IPA output circuit is complete on one printed-circuitboard, comprising a Low-Pass Filter and a DirectionalCoupler. The Directional Coupler is implemented withmicrostrip techniques and provides dc voltages repre-sentative of forward and reflected output power. The re-flected power signal is used by the control circuit to in-itiate amplifier shutdown in the event of excessive IPAVSWR. The placement of the Low-Pass Filter ensuresthe Directional Coupler will sense IPA stage VSWRonly.

1.4.3.2 FLEXPatch™The HARRIS FLEXPatch™ system, provides for the by-passing of any or all of the RF amplifier stages follow-ing the Exciter. An inoperative stage may be quicklyand easily bypassed. The transmitter may then be re-turned to operation at a reduced output level. Resolu-tion of the problem may then be done at a more con-venient time or when repair or replacement parts are onhand.

The use of FLEXPatch™ requires only minimal techni-cal knowledge. Using front panel meter readings andindicators, a determination is made of the problemstage to bypass. Using that information, detailed in-structions may be followed to bypass that stage andreturn the transmitter to operation.

See Section III of this technical manual for details ofFLEXPatch™ operation.

1.4.4 PA STAGEA single-ended 8990 tetrode is conservatively operatedin the transmitter as a class C RF Output Amplifier toproduce a 25 kW rf output from the IPA input.

Forced-air cooling ensures cool operation and long tubelife. The input impedance of the PA stage is 50 ohms.In the event of a total PA stage failure, the output of theIPA output circuit could be routed to the 50-ohm trans-mitter antenna load as an emergency back-up.

The quarter-wave-length cavity, used in the PA stage,ensures that a wide bandwidth is maintained throughthe PA stage. The tuning arrangement requires no slid-ing contacts within the cavity walls which could be dam-aged if moved across high-current points. The inductiveplate network provides dc isolation between the platecircuit and the output circuit. This is a safety featureand additionally provides some immunity to lightningdamage.

1.4.4.1 OUTPUT CIRCUITThe rf output to the antenna is coupled through a 2ndHarmonic Stub Filter, Low-Pass Filter, and a DirectionalCoupler arrangement. The 2nd Harmonic Filter oper-ates at dc ground potential for safety and further immu-

nity from lightning damage. Special provisions allowconnection of monitors directly to the transmission lineat the rf transmitter output.

1.4.5 CONTROL CIRCUITSThe majority of the control circuitry is located on twoplug-in printed-circuit boards. One circuit board is con-cerned with the logic and timing process and the sec-ond circuit board is concerned with analog interface.The control functions are divided into INTERLOCKSand OVERLOADS with corresponding front panel indi-cators for each function.

1.4.5.1 INTERLOCK CIRCUITSFive parameters are monitored by the interlock circuitry.They are AIR, FAULT, XMTR CAB, HV CAB, and EXT.Should any interlock circuit open, high voltage will beremoved from the transmitter and operation must bemanually restored. An external interlock provision al-lows interface of an external interlock (such as a coax-ial transfer switch) into the transmitter control circuitry.

1.4.5.2 OVERLOAD CIRCUITSSix parameters are monitored by the overload circuitry.The AFC overload circuit interfaces with the ExciterAFC interlock. Should the interlock be activated, thetransmitter will shut down to prevent off-frequencytransmission. The IPA VSWR and PA VSWR circuitsmonitor the reflected power levels present at the IPADRIVER and the PA stage outputs. Should a high re-flection develop at either point, the transmitter controllogic will remove both high and low voltages. The PASCRN and PA PLT indicators sense over-current condi-tions in the PA screen and the PA plate circuits. TheEXT overload circuit allows interface of an external sta-tion overload into the transmitter circuitry.

Operation of an overload circuit will cause the transmit-ter to momentarily interrupt operation and then automat-ically recycle and restore power to attempt to clear thefault. Jumper-plug programming of the control logic cir-cuit board allows the transmitter to recycle either onceor three times after an overload within 30 seconds be-fore complete shut-down occurs. When shut-down doesoccur, both the respective OVERLOAD indicator andthe FAULT INTERLOCK indicator will illuminate.

1.4.5.3 AUTOMATIC RF POWER CONTROLThe transmitter allows automatic control of rf power out-put as a standard feature. After the automatic circuit isactivated, the station can program the power control cir-cuit to automatically maintain an established rf poweroutput level within approximately 2 or 4 percent of aselected value.

1.4.5.4 OUTPUT VSWR FOLDBACKOperating as part of the Automatic Power Control cir-cuit, the VSWR Foldback feature will automatically re-duce forward output power under slowly rising VSWRconditions. This will keep the transmitter on the air atreduced power under antenna icing conditions. As theice builds up and the antenna VSWR begins to rise,forward output power will be reduced automatically tothe highest safe operating level. When the icing condi-tion begins to be reduced by warmer temperatures, theVSWR Foldback circuit will automatically raise thepower to the highest safe operating level until full output


power is again reached. A front panel indicator and aremote status output are activated when the VSWRFoldback circuit is in a power reduction mode.

1.4.5.5 AC POWER CONTROLIf a total power failure occurs during operation, the con-trol circuit will automatically restore the transmitter tooperation.

1.4.5.6 REMOTE CONTROLRemote control and remote monitoring of various trans-mitter parameters is allowed by connections to terminalboard TB1 (remote control command inputs), terminalboard TB2 (remote control metering outputs), jack J2(extended control panel connections), jack J3 (statusand overload indicator outputs), and terminal board TB2on remote direct screen control assembly 1A15. All re-mote control functions require a momentary contact be-tween a terminal or pin of the interface connectors andthe control circuit positive bus voltage. This arrange-ment removes the chance of the unintentional operationof a particular function by an accidental connection toground.

1.4.6 INDICATORSSeven meters, sixteen LED’s, and two switch/indicatorsprovide status indications of overall transmitter opera-tion.

Meters monitor plate voltage, plate current, transmitterforward and reflected power output, IPA forward and re-flected power, and filament hours of operation. A five-position PA multimeter switch selects the specific PAparameters to be displayed by the multimeter. The PA

multimeter will display PA filament voltage, PA controlgrid bias voltage and current, and PA screen grid volt-age and current. A two position IPA multimeter switchselects the specific parameter to be displayed by theIPA multimeter. The IPA multimeter will display IPA cur-rent and IPA voltage. There is also an AC LINE VOLT-AGE meter to display the single-phase AC input.

1.4.7 SAFETYThe transmitter design provides safety features whichensure that no voltage potentials are accessible to op-erational personnel from the front panel.

Additionally, no high voltage points are readily accessi-ble to maintenance personnel unless a cabinet door orpanel is opened. If a door or a power supply panel isopened when power is energized, interlocks will removehigh voltage from both cabinets and operation will haveto be manually restored.

1.5 EQUIPMENT CHARACTERISTICS1.5.1 ELECTRICAL CHARACTERISTICSTable 1-1 lists electrical operating characteristics andparameters of the HARRIS HT 20/25CD FM BROAD-CAST TRANSMITTER.

1.5.2 MECHANICAL CHARACTERISTICSTable 1-2 lists physical and environmental charac-teristics of the HARRIS HT 20/25CD FM BROADCASTTRANSMITTER.

NOTESpecifications subject to change without notice.


Figure 1-2. HT 20/25CD SIMPLIFIED BLOCK DIAGRAM


FUNCTION CHARACTERISTIC

PRIMARY POWER REQUIREMENTS:

HIGH VOLTAGE POWER SUPPLY 208/230 Vac, 3-phase, 50/60 Hz, 3-wire at 200 A perphase, above 230 Vac use 175 A. For 360/400 Vac, 3-phase, 50/60 Hz, 4-wire at 125 A per phase, above 400Vac use 100 A. Refer to paragraph entitled INPUTPOWER CONNECTIONS in Section II for correct powerdisconnect current rating.

TRANSMITTER CABINET 208/240 Vac, 1-phase, 50/60 Hz, 30A. Refer to paragraphentitled INPUT POWER CONNECTIONS in Section II forcorrect power disconnect current rating.

POWER CONSUMPTION 37.5 kW (Typical at 25 kW output - HT 25CD).

30.7 kW (Typical at 20kW output - HT 20CD).

POWER FACTOR 0.95, lagging

ALLOWABLE POWER LINE VARIATION +/-5%. (Slow variation).

RF POWER OUTPUT Continuously variable 0 to 25 kW - HT-25CD.

Continuously variable 0 to 20 kW - HT 20CD.

RF OUTPUT IMPEDANCE 50 ohms

RF FREQUENCY RANGE 87.5 to 108 MHz

MAXIMUM VSWR TUNING RANGE 1.7 to 1

RF OUTPUT TERMINATION 3.125-inch (7.94 cm) EIA flange

RF HARMONIC SUPPRESSION Meets FCC requirements

REMOTE CONTROL:

CONTROL FUNCTIONS Momentary 20 mA contact to common 12V positive dc bus.

STATUS INDICATOR OUTPUTS

CONTROL INDICATORS Open collector outputs (+20 volts maximum).

Table 1-1. Electrical Characteristics


FUNCTION CHARACTERISTIC

CABINET DIMENSIONS:

Transmitter: 33.4 inches (84.84 cm) wide.

72.0 inches (182.88 cm) high.

30.2 inches (76.71 cm) deep.

High Voltage Power Supply: 48.0 inches (121.92 cm) wide.

60.25 inches (153.04 cm) high.

24.13 inches (61.29 cm) deep.

WEIGHT:

PACKED

Domestic 2,700 pounds (1225 kg).

Export 3,000 pounds (1361 kg).

CUBAGE 150 cubic feet (4.25 cubic meters).

OPERATING TEMPERATURE RANGE -4° to 122°F (-20°C to +50°C). Maximum temperature atsea level, decreasing 3.6°F (2°C) per 1,000 feet (305 me-ters) to 86°F (30°C) maximum at 10,000 feet above sealevel.

MAXIMUM HUMIDITY 95%, Noncondensing.

MAXIMUM ALTITUDE 10,000 feet (3048 meters) above sea level.

COOLING AIR REQUIREMENTS:60Hz(50Hz)

Cabinet Flushing 335 (280)cubic feet/minute (9.49 (7.93) cubic meters/m-inute)

Amplifier 400 (350) cubic feet/minute (11.33 (9.91) cubic meters/m-inute)

High Voltage Power Supply 250 (250) cubic feet/minute (7.08 (7.08) cubic meters/m-inute)

AIR INLET SIZE

Main Cabinet 16.4 inches x 23.6 inches (41.66 cm x 59.95 cm) reardoor.

Total inlet air 735 (630) cubic feet/min (20.82 (17.85) cu-bic meters/minute)

High Voltage Power Supply 15.1 inches x 15.25 inches (38.35 cm x 38.74 cm)

AIR OUTLET SIZE

Main Cabinet 26.25 inches x 29.5 inches (66.68 cm x 74.93 cm) top ofcabinet

High Voltage Power Supply Louvers in front and sides of cabinet.

Table 1-2. Mechanical/Environmental Charateristics


SECTION IIINSTALLATION

2.1 INTRODUCTIONThis section contains information for installing the HAR-RIS HT 20/25CD FM BROADCAST TRANSMITTERand performing pre-operational checks.

2.2 UNPACKINGCarefully unpack the HT 20/25CD Transmitter and per-form a visual inspection to determine that no apparentdamage was incurred during shipment. Retain the ship-ping materials until it has been determined that the unitis not damaged.

The contents of the shipment should be as indicated onthe packing list. If the contents are incomplete or if theunit is damaged electrically or mechanically, notify thecarrier and HARRIS CORPORATION, Broadcast Divi-sion.

Items included for Emergency bypass should be set ina safe place after installation for future emergency situ-ations. Those items include; PA-bypass cable, extendercard and the aluminum plate used to cover the hole inthe air plenum when the pre-amp or IPA is removed.

2.2.1 RETURNS AND EXCHANGESDamaged or undamaged equipment should not be re-turned unless written approval and a Return Authoriza-tion is received from HARRIS CORPORATION, Broad-cast Division. Special shipping instructions and codingwill be provided to assure proper handling. Completedetails regarding circumstances and reasons for returnare to be included in the request for return. Customequipment or special order equipment is not returnable.In those instances where return or exchange of equip-ment is at the request of the customer, or convenienceof the customer, a restocking fee will be charged. Allreturns will be sent freight prepaid and properly insuredby the customer. When communicating with HARRISCORPORATION, Broadcast Division, specify the HAR-RIS Order Number or Invoice Number. Each transmitteris thoroughly checked out and operated before ship-ment and the test results logged on the factory TestData Sheets. These data sheets provide the user withspecific detailed measurements and instructions relativeonly to the specific equipment to which the sheets areattached. The sheets will be found attached to the up-per front panel of the transmitter. It is strongly sug-gested that these sheets are filed in the front of thismanual for future use. These sheets will be referencedthroughout the installation procedure for tuning instruc-tions and meter indications.

2.3 INSTALLATIONPrior to installation, this Technical Manual and the FMExciter Technical Manual should be carefully studied toobtain a thorough understanding of the principles of op-eration, circuitry and nomenclature.

This will facilitate proper installation and initial checkout.Installation is accomplished in four steps: (1) transmitterplacement, (2) component installation, (3) transmitterwiring, and (4) initial turn on.

2.3.1 COOLING AIR REQUIREMENTSHarris transmitters are always designed to operate in afree, unobstructed environment with a maximum inletair temperature of 50°C. This means that the transmitterair system is designed to supply sufficient air at the re-quired static pressure to cool the transmitter only. Anyadditional pressure losses introduced by air exhaustsystems & air supply systems must be satisfied bymeans other than the transmitter blower. These inlet &exhaust systems generally need to be fan driven.

When installing an exhaust system which removes thewarm air from the transmitter room or building, a re-placement air system which delivers at least the samevolume of air removed is mandatory. It is considered tobe good Engineering practice to allow a relief gap (6 to10 inches of space) above the exhaust plane at the topof the transmitter in order to minimize the likelihood ofintroducing undesired restrictions to air flow.

For specific transmitter air requirements refer to theOutline Drawing 839-7495-063.

2.3.2 TRANSMITTER PLACEMENTIn order to remove the transmitter from the shippingpallet, the rear door must be opened to gain access tothe shipping hardware. The transmitter rear door util-izes special latches that requires an Allen wrench toopen. An Allen wrench was shipped with the transmitterand is located with the miscellaneous items.

SPECIAL NOTEBEFORE PLACING THE TRANSMITTER IN APERMANENT POSITION, BE SURE ALL SHIP-PING BLOCKS AND HARDWARE ARE RE-MOVED. THE EXCEPTION SHOULD BE THEANODE BLOCKER RED SHIPPING BLOCKWHICH WILL BE REMOVED IN STEPS 2.3.5.c.& d.

Set the transmitter and High Voltage Power Supplycabinet in place on a smooth and level location nearpower and signal cables. The High Voltage Power Sup-ply cabinet must be placed within reach of the 40 foot(12.2 meter) interconnecting cables. Ensure adequatecable length is allowed for any vertical rises. The floormust be capable of supporting the 730 pound (331.13kg) weight of the transmitter and the 1325 pound(601.02 kg) weight of the High Voltage Power Supply.

The interconnecting cables may be trimmed to length ifdesired, using the additional hardware supplied with thecables.

2.3.3 COMPONENT INSTALLATIONSome components may be removed from the transmit-ter after final test for shipment. The removal of compo-nents varies due to the method and requirements ofshipment. Capacitors, connectors, cables, etc., areshipped in separate cartons. All removed items will betagged to permit reinstallation in the transmitter. Thetransmitter rear door should be removed and left off un-til the installation is complete.


Items such as interconnecting wires and cables, shockmounted devices and miscellaneous small parts maybe taped or tied in for shipment. Remove all tape, stringand packing material that has been used for this pur-pose.

Symbol numbers and descriptions are provided on eachremoved component corresponding to the schematicdiagram, parts list and packing list. Symbol numbersare also stenciled near the cabinet location of each re-moved item.

Terminals and wires carry tags with information tellinghow to reconnect each item. Mounting hardware will befound either in small bags attached to each removedcomponent or inserted in the tapped holes where eachcomponent mounts.

Arrange the removed components in separate groupsaccording to where each was removed. Re-install allcomponents in their proper locations. Parts in the inte-rior should be installed first. Specific instructions followfor the items listed below.

Do not install the Power Amplifier tube until the installa-tion and wiring are complete. Tube installation proce-dures are given in paragraph entitled INITIAL PA TUBEINSTALLATION in Section II.

2.3.4 TRANSMITTER WIRINGInterconnecting Wiring Figure 2-2 and Primary AC Wir-ing Figures 2-3 & 2-4 show the electrical connections tothe transmitter.

Transmitter Cabinet External Connection Points Figure2-5 and Power Supply External Connection Points Fig-ure 2-6 identify the physical location of the externalconnections.

NOTEThe HT 20/25CD Transmitter is designed to oper-ate from a closed-delta or WYE type powersource. If the service entrance to the transmitterbuilding is an open-delta or “V-V” configuration,the local power company should be contactedand the service changed to a closed-delta con-figuration for proper transmitter operation. Referto “Engineering Report, Susceptibility of theOpen-Delta Connection to Third Harmonic andTransient Disturbances” in the appendix of thismanual for a complete discussion.

Connect a two-inch wide, 0.020-inch (minimum) thickcopper ground strap (not supplied) between the groundblock in the transmitter cabinet and the ground stud in-side the lower front panel of the High Voltage PowerSupply cabinet. At a central point, bond the groundstrap directly to the station earth ground connectionpoint. It is also recommended that the customer fur-nished power disconnects also be bonded at some cen-tral point to the station earth ground.

2.3.4.1 TRANSMITTER CABINET TO HIGH VOLT-AGE POWER SUPPLY CABINET WIRING

The locations of the control cable and high voltage ca-ble connection points are shown in Figures 2-2, 2-5,and 2-6. If it is desired to use cables of shorter length,the cables may be cut to length and terminated with the

supplied crimp lugs. Connect the control and high volt-age wiring as follows:

a. Connect the control cable (Harris part number929 7804 001) from terminal board TB3 in thetransmitter cabinet to terminal board TB1 in theHigh Voltage Power Supply cabinet observingthe correct wire number to terminal number asshown in Figure 2-2.

b. Connect the center conductor of the RG-58 co-axial cable portion of the high voltage cable(Harris part number 929 7929 001) to terminalE3 in the transmitter cabinet.

c. Connect the center conductor of the RG-213 co-axial cable portion of the high voltage cable toterminal E2 in the transmitter cabinet.

d. Connect the shields from the RG-58 and RG-213 coaxial cables to ground stud E1.

e. Connect the shield of the RG-58 to the groundstud near resistor R9 in the High Voltage PowerSupply cabinet.

f. Connect the center conductor of the RG-58 tothe open end of resistor R9 in the High VoltagePower Supply cabinet.

g. Connect the shield of the RG-213 to the groundstud located near resistor R10 in the High Volt-age Power Supply cabinet.

h. Connect the center conductor of the RG-213 tothe open end of resistor R10 in the High VoltagePower Supply cabinet.

CAUTIONBE SURE AND CONNECT THE SHIELDS TOGROUND AS SHOWN IN FIGURE 2-2 ANDDRESS THE WIRES AWAY FROM HIGHVOLTAGE TERMINALS.

2.3.4.2 FM EXCITER WIRINGConnect the audio inputs and exciter remote cables tothe exciter as indicated in the FM Exciter TechnicalManual. Exciter RF mute, AFC overload, ground, andac power wiring has been completed at the factory andtested with the transmitter.

2.3.4.3 INPUT POWER CONNECTIONSRefer to Figures 2-3, 2-5, and 2-6 and complete theinput power connections as follows:


WARNINGENSURE THAT PRIMARY POWER TO THETRANSMITTER IS DISCONNECTED ANDLOCKED OUT WHILE COMPLETING THEFOLLOWING CONNECTIONS.

CAUTIONUNLESS INSTRUCTED TO THE CON-TRARY, OVERLOAD RELAYS K1 AND K2ARE OPERATED WITHOUT SILICONEFLUID INSTALLED IN THE DASHPOT CUP.THIS INSURES THE OVERLOAD RELAYSWILL OPERATE AT 100% VALUE OF OVER-LOAD CURRENT, MUCH LIKE A FASTBLOW FUSE. SEE MANUFACTURERSDATA SHEETS FOR DETAILED RELAY OP-ERATION.

a. Connect the three number 10 THHW wires fromthe 30A power disconnect to TB1-1, -2, -3 in thetransmitter cabinet.

b. For 25 kW transmitter power output, use 200-ampere service for voltages up to 230 volts and175-ampere service for voltages above 230volts. On 4-wire power systems, use 125-am-pere service for voltages up to 400 volts and100-ampere service for voltages over 400 volts.

NOTEA fused disconnect is recommended utilizingclass RK5 fuses. If fuses are not to be used, thena breaker that is set up to the same curve andamperage may be used.

c. For power output levels significantly less than25 kW, size the power service according to thepower consumption of the transmitter during fi-nal test. Multiply the final test line voltage by thehighest three-phase line current reading on thetest data sheet multiplied by 1.732. This will de-termine the kVA consumption. To obtain the linecurrent for the voltage, divide the kVA consump-tion by the line voltage times 1.732 Add to this30 percent for a safety margin.

d. Connect three number 1/0 THHW wires from thepower disconnect (refer to steps b. and c. forsize) to relays K1, K2, and K3 in the High Volt-age Power Supply cabinet.

NOTEIf copper ground straps were installed in proce-dure paragraph 2.3.4 steps e. and f. will alreadyhave been completed.

e. Use two-inch wide copper strap and connectground stud E1, in the transmitter cabinet, tostation earth ground.

f. Use two-inch wide copper strap and connect theground stud (located near L1) on the base ofthe High Voltage Power Supply cabinet to sta-tion earth ground. Refer to Figure 2-6.

CAUTIONBECAUSE LOW RESISTANCE IN THEGROUND SYSTEM IS ESSENTIAL TO PRO-VIDE MAXIMUM PROTECTION FOR THEEQUIPMENT, IT IS RECOMMENDED THATALL CONNECTIONS BETWEEN COPPERSTRAPS BE BOLTED TOGETHER ANDTHEN EITHER BE SOLDERED OR BRAZED.THIS WILL INSURE LONG TERM LOW RE-SISTANCE CONNECTIONS.

2.3.4.4 OUTPUT COAXIAL LINE INSTALLATIONUsing Figure 2-1 as an example (or any other stationlayout) proceed as follows:

CAUTIONTHE LOW-PASS FILTER AND ALL OUTPUTCOAXIAL LINE MUST BE SEPARATELYSUPPORTED PRIOR TO ATTACHMENT TOTHE TRANSMITTER RF OUTPUT PORTFLANGE. DAMAGE TO THE RF PORT CANRESULT IF THE OUTPUT COAXIAL LINE ISNOT SUPPORTED.

a. Connect the elbow assembly containing themonitor samples to the rf output port of thetransmitter. The elbow containing the monitorsamples should be installed closest to the trans-mitter using the supplied 3/8 inch hardware.

CAUTIONDO NOT SPLIT ANY FINGERS OF THE IN-NER CONDUCTOR TRANSMISSION LINEBULLETS WHEN INSERTING THE INNERCONDUCTOR.

b. Connect the ‘INPUT’ end of the Low Pass Filterto the open end of the elbow. BE SURE THEFILTER IS SEPARATELY SUPPORTED. ITSWEIGHT MUST NOT BE APPLIED TO THETRANSMITTER OUTPUT TRANSMISSIONLINE. Use the supplied 3/8 inch hardware.Carefully install the transmission line bullet inthe ‘OUTPUT’ end of the filter.

c. Connect the end of the Directional Coupler as-sembly marked ‘TRANSMITTER’ to the ‘OUT-PUT’ end of the Low Pass Filter. Use the 3/8inch hardware supplied.

d. Terminate the Directional Coupler assembly withthe station antenna or station dummy load.

The standard ouptut configuration for the HT-20/25transmitter is as follows. The elbow (w/monitor ports)connects to the output of the transmitter. The shortstraight section connects to this elbow followed by theplain elbow then low pass filter. Should you wish toeliminate an elbow, it must be replaced with a straightsection of equal length (about 7.5"). Contact Harrisservice parts (217) 221-7500 to confirm part numbers.

Outer 9287942022 TUBING ASSY (Flanged,3-1/8" X 7-5/8")

Inner 9398014012 TUBE, COAX1.315 X 5.72 LG

Bullet 6200544000 CONN, ANCHOR INS 3-1/8;50 Ohm (as needed)

12/6/2007 888-2609-001 2-3WARNING: Disconnect primary power prior to servicing.

Figure 2-1. Interconnecting Wiring

Figure 2-2. Primary AC Wiring, 3-Phase,380/415 Vac 4-Wire


CAUTIONFAILURE TO INSTALL THE ELBOWS,TRANSMISSION LINE SECTION, LOW PASSFILTER AND DIRECTIONAL COUPLER INTHIS EXACT STANDARD CONFIGURATIONMAY RESULT IN ABNORMAL TRANSMIT-TER OPERATION AND LOSS OF CALIBRA-TION OF OUTPUT POWER AND VSWR ME-TERING. FOR FURTHER INFORMATIONABOUT NON-STANDARD CONFIGURA-TIONS, CONTACT HARRIS FIELD SERVICE.

2.3.4.5 MONITOR AND DIRECTIONAL COUPLERCABLES

Connect the two Directional Coupler cables (167 and168) to the Directional Coupler. The red plug goes tothe red jack. The yellow plug goes to the yellow jack onthe assembly. Connect the other ends of cables 167and 168 to BNC connectors J5 and J4 respectively onthe top of transmitter cabinet. Two monitor jacks for sta-tion monitoring equipment are provided on the elbowassembly installed in paragraph entitled OUTPUT CO-AXIAL LINE INSTALLATION.

2.3.4.6 REMOTE CONTROL AND EXTENDEDCONTROL CONNECTIONS

Tables 2-1, 2-2, and 2-5 list the remote control circuitconnections. Tables 2-3 and 2-4 list the extended con-trol circuit connections. Figure 2-5 shows the physicallocation of the remote terminal boards and extendedjacks within the transmitter cabinet. A FAILSAFEjumper must be installed between TB1-5 and TB1-12for non-remote control operation.

Figure 2-3. Primary AC Wiring, 3-Phase, 208/240 Vac

Figure 2-4. Transmitter Cabinet External ConnectionPoints


2.3.5 INITIAL PA TUBE INSTALLATIONIt is recommended that the entire tube installation pro-cedure in this section and the TUBE REMOVAL ANDINSTALLATION instructions in Section V be studiedprior to attempting tube installation. It can not be overemphasized that improper tube installation can result indamage to the tube socket fingerstock. This is particu-larly important on a high frequency transmitter wherethe tube will not clear the plate blocking assembly andthe tube socket without proper installation sequence.The PA tube is installed in the following manner:

WARNINGDISCONNECT AND LOCK OUT PRIMARYPOWER TO THE TRANSMITTER. BE SUREALL AC POWER IS REMOVED FROM THETRANSMITTER AND HIGH-VOLTAGEPOWER SUPPLY.

a. Rotate the PA TUNE control to MAX position(extreme clockwise position).

NOTEUse the front panel control PA TUNE to place thetuning control in the maximum position.

b. Remove the PA access door held by 12 captivescrews.

WARNINGUSE THE GROUNDING STICK TO DISSI-PATE ALL RESIDUAL POTENTIALS FROMALL COMPONENTS BEFORE TOUCHINGTHEM.

NOTEDo not move the neutralization flag assembly.

c. Locate the red shipping block attached to thecavity sidewall and the plate blocking assembly.

CAUTIONPRIOR TO ATTEMPTING REMOVAL OF THESHIPPING BLOCK, ENSURE THE TOPCLAMP (SHOWN IN FIGURE 5-2) HOLDINGTHE PLATE BLOCKING ASSEMBLY IN THECAVITY SHORT IS TIGHT AND HOLDINGTHE BLOCKING ASSEMBLY SECURELY.WHEN REMOVING THE RED SHIPPINGBLOCK HOLDING THE ANODE BLOCKERASSEMBLY IN PLACE, BE SURE TO RE-MOVE THE ANGLE BRACKET THATHOLDS THE RED BLOCK TO THE CAVITYSIDE WALL. DO NOT LEAVE THE PIECEOF ANGLE IN THE CAVITY.

d. Remove the shipping block from inside the cav-ity.

e. Using an inspection mirror, examine the insideof the tube socket assembly for loose hardwareor damaged fingerstock.

Figure 2-5. Power Supply External Connection Points


NOTEThe next step will determine which sequencemust be used for installing the PA tube. On cer-tain higher frequencies, the sequence in para-graph entitled PA TUBE INSTALLATION step (c.)in Section V is the only way the tube can be in-stalled.

f. Refer to the top pictorial of Figure 5-2. On thetransmitter cavity back panel locate the hard-ware used to mount the cavity shorting deck.

Counting from the bottom set of mounting holes, deter-mine which set of holes is being used to support thecavity shorting deck.

NOTEIf the cavity shorting deck is mounted in one ofthe four bottom sets of mounting holes, the se-quence in paragraph entitled PA TUBE INSTAL-LATION step (c.) in Section V must be used toinstall the tube. If the shorting deck is supportedabove the four bottom sets of mounting holes, thesequence in the following step (h.) may be usedto install the tube.

g. The following sequence is to be used only if thecavity shorting deck is supported in mountingholes above the four bottom sets of mountingholes:

1. While holding the tube with both hands, care-fully position the tube inside the cavity be-tween the tube socket and the plate blockingassembly with the filament stem down.

2. Center the filament stem over the tubesocket.

3. Gently lower the tube into the socket.

CAUTION= DO NOT ROTATE OR ROCK THE TUBE AFTER ITIS INSTALLED IN THE SOCKET OR DAMAGE WILLOCCUR TO THE FINGERSTOCK.

4. Use both hands to push the tube straightdown until the tube is properly seated.

NOTEThe tube socket has built in stops. Ensure thetube is all the way down in the socket and level.

5. Loosen the anode clamp (fastened aroundthe anode of the tube for shipment). Slide theclamp down the tube and allow it to rest onthe screen blocker assembly.

6. Attach the high voltage lead to the anodecap.

CAUTIONBEFORE PROCEEDING, ENSURE THATTHE PLATE BLOCKING ASSEMBLY IS BE-ING HELD SECURELY PRIOR TO LOOSEN-ING THE TOP CLAMP.

7. Hold the plate blocking assembly in a securemanner while loosening the top clamp.

8. Lower the plate blocking assembly over thetube anode until the built-in stops prevent fur-ther downward movement.

9. Rotate the plate blocking assembly on thetube until the edge of the stationary tuningplate is parallel to the same cavity wall wherethe front panel adjustable tuning plate ismounted. Refer to Figure 5-2. DO NOTchange the position of the middle strap whichholds the stationary plate tuning paddle.

10. Ensure that the top clamp is over the finger-stock protruding from the cavity shortingplate.

11. Tighten the top clamp.12. Lift the anode clamp off the screen blocker

assembly and slide the clamp over thefingerstock at the bottom edge of the plateblocking assembly.

13. Tighten the anode clamp being sure that theclamp is securing the blocking assembly tothe tube anode.

h. Remove all loose hardware and shipping mate-rial from inside the cavity.

i. Thoroughly clean the interior of the cavity, trans-mitter cabinet and High Voltage Power Supplycabinet with a vacuum cleaner.

j. Install the PA access door, using the captivehardware. Install the rear door on the transmit-ter cabinet. Install the panels on the High Volt-age Power Supply cabinet.

This completes the installation of the components re-moved for shipment and the wiring of the transmitterand the High Voltage Power Supply.

2.3.6 INITIAL TURN ON PROCEDUREThe following procedure should be followed in se-quence for initial turn-on. Each step assumes the pre-ceding step has been successfully completed. If anyabnormalities are encountered in the following steps,stop the procedure, remove all power and troubleshootthe problem.

a. SET THE FOLLOWING CIRCUIT BREAK-ERS/SWITCHES TO THE OFF POSITION.

1. The high voltage service disconnect to theHigh Voltage Power Supply cabinet.

2. The transmitter cabinet service disconnect tothe transmitter cabinet.

3. The BLOWER and SCREEN breakers on theHigh Voltage Power Supply cabinet.

4. The five circuit breakers on the transmitterlower front panel; IPA, bias, control blowerand filament.

WARNINGDISCONNECT AND LOCK OUT PRIMARYPOWER TO THE TRANSMITTER CABINETAND TO THE HIGH VOLTAGE POWER SUP-PLY CABINET.

b. Ensure that all equipment removed from thetransmitter for shipment, including the poweramplifier tube, has been installed. Verify all wir-ing connections using the wiring diagrams.

NOTEVerify that all transformer primaries are tapped forthe correct ac line voltage.


REMOTE CONTROL TERMINAL BOARD COMMENTS

FUNCTIONS CONNECTION

PL OFF TB1-1 Requires momentary +12 volts toturn plate supply off.

PL ON TB1-2 Requires momentary +12 volts toturn plate supply on or start trans-mitter turn-on cycle.

FIL ON TB1-3 Requires momentary +12 volts toturn filament on.

FIL OFF TB1-4 Requires momentary +12 volts toturn filament off or start transmit-ter run-down cycle.

R/C TB1-5 +12 volts present for remote con-trol equipment when CONTROLswitch is in the NORMAL posi-tion.

EXT O.L. TB1-6 Requires momentary +12 voltsfor external overload input.

Interlock +12V (for dualtransmitters)

TB1-7 Supplies +12V to dual transmitterinterlock line.

Filament time delay (dualtransmitters)

TB1-8 Supplies +12V upon completionof filament time-delay for dualtransmitters.

Power Set RAISE command TB1-9 Requires continuous +12 volts toraise the APC power set point.

Power Set LOWER TB1-10 Requires continuous +12 volts tolower the APC power set point.

GND TB1-11 Provides ground to remote equip-ment.

F/S TB1-12 Requires +12 volts while remoteequipment is functioning prop-erly.

Table 2-1. Remote Control Command Input ConnectionsTB1



FUNCTIONS CONNECTIONS

EXT INTK TB2-1 Removes transmitter plate voltageand illuminates EXT INTER-LOCK indicator when ground ap-plied to terminal.

VSWR FOLDBACK TB2-2 Open collector transistor providesground potential through 570ohms for remote VSWR Fold-back active status.

TB2-3 Spare terminal available on ana-log board.

FAULT TB2-4 Low output signals a FAULT.


PL ON TB2-6 Open collector transistor providesground potential through 570ohms for remote PLATE ONstatus indicator.

FIL ON TB2-7 Open collector transistor providesground potential through 570ohms for remote FILAMENT ONstatus indicator.

PLATE I TB2-8 Provides approximately +5 voltsinto an open circuit for 5 amperesplate current (one volt per am-pere).

VSWR TB2-9 Provides less than 10 volts intoopen circuit for full scale PAVSWR reading.

PWR TB2-10 Provides less than 10 volts intoan open circuit for full scaleFORWARD POWER reading.

PL V TB2-11 Provides approximately +15 voltsinto an open circuit for 10 kVplate voltage.


Table 2-2. Remote Control Command Input ConnectionsTB2


EXTENDED CONTROLFUNCTION

JACK CONNECTION COMMENTS

FILAMENT ON J2-1 Open collector transistor provides ground potentialthrough 570 ohms for extended FILAMENT ONindicator.

Power Set RAISE command J2-2 Requires continuous +12 volts while raising theAPC set point.

J2-3 SpareFIL ON J2-4 Requires momentary +12 volts to turn filament onPA PF J2-5 Provides less than +10 volts into an open circuit

for full scale forward power metering.PLATE ON J2-6 Open collector transistor provides ground potential

through 570 ohms for extended PLATE ON indi-cator.

Power Set LOWER J2-7 Requires continuous +12 volts while lowering theAPC set point.

FILAMENT OFF J2-8 Requires momentary +10 volts to turn filament offor start transmitter rundown cycle.

PA Ip J2-9 Provides approximately +5 volts into open circuitfor 5 amperes plate current (one volt per ampere).

J2-10 SpareJ2-11 SpareJ2-12 SpareJ2-13 SpareJ2-14 SpareJ2-15 Spare

PLATE OFF J2-16 Requires momentary +12 volts to turn plate supplyoff.

J2-17 SpareJ2-18 Spare

PA Ep J2-19 Provides approximately +15 volts into an open cir-cuit for 10 kV plate voltage.

PLATE ON J2-20 Requires momentary +12 volts to turn plate supplyon or start transmitter turn-on cycle.

FAILSAFE J2-21 Requires +12 volts to signal extended controlequipment is functioning properly.

PA VSWR J2-22 Provides less than +10 volts into open circuit forfull scale PA VSWR reading.

FAULT INTLK J2-23 Low output signals a FAULT.GND J2-24 Provides ground to extended control equipment.

Table 2-3. Extended Control Connections J2




PA SCREEN OVERLOADindicator

J3-1 Provides ground potential through1000 ohms for extended PASCREEN OVERLOAD indicator.

IPA VSWR OVERLOAD in-dicator

J3-2 Provides ground potential through1000 ohms for extended IPAVSWR OVERLOAD indicator.

PA VSWR OVERLOAD in-dicator

J3-3 Provides ground potential through1000 ohms for extended PAVSWR OVERLOAD indicator.

Failsafe J3-4 Requires +12 volts while ex-tended equipment functioningproperly.

PA PLATE OVERLOAD in-dicator

J3-5 Provides ground potential through1000 ohms for extended PAPLATE OVERLOAD indicator.

EXTERNAL OVERLOADindicator

J3-6 Provides ground potential through1000 ohms for extended EXTER-NAL OVERLOAD indicator.

J3-7 Spare

Ground J3-8 Provides ground to extendedequipment.

AFC OVERLOAD indicator J3-9 Provides ground potential through1000 ohms for extended OVER-LOAD indicator.

PLATE ON indicator J3-10 Provides ground potential through570 ohms for extended PLATEON indicator.

J3-11 Spare

J3-12 Spare

Table 2-4. Extended Control Connections J3




FILAMENT ON indicator J3-13 Provides ground potential through570 ohms for extended FILA-MENT ON indicator.

J3-14 Requires momentary +12 volts toextinguish LOCAL/EXTENDEDOVERLOAD indicators.

J3-15 Spare

OVERLOAD COMMON J3-16 Provides +12 volts through resettransistor to common side (anodeof LED) of extended OVER-LOAD indicators.

J3-17 Spare

J3-18 Spare

J3-19 Spare

FAULT INTERLOCK indica-tor

J3-20 Provides ground for extendedFAULT STATUS indicator.

J3-21 Spare

J3-22 Spare



Table 2.4. Extended Control Connections J3 (Continued)


c. Ensure that all grounding hooks are in theirproper holders.

d. Ensure that the transmitter rf output is termi-nated into the station antenna or a load with aknown good VSWR.

e. Ensure that all remote control and extendedcontrol equipment is disconnected or in a stand-by mode to prevent accidental operation.

f. On the transmitter front panel, set the CON-TROL switch to the LOCAL ONLY position.

2.3.6.1 No Tap modea. Remove the High Voltage Power Supply cabinet

lower front panel.

WARNINGUSE THE GROUNDING STICK TO DISSI-PATE ALL RESIDUAL POTENTIALS FROMALL COMPONENTS AND TERMINALBOARD TERMINALS BEFORE TOUCHINGTHEM.

b. In the High Voltage Power Supply cabinet, lo-cate the HIGH/LOW plate voltage switch. (Re-fer to Figure 3-3 for the physical location of theswitch.) Place the switch in the neutral (center)position. This will allow application of primarypower to the High Voltage Power Supply cabinetto check the control circuitry without applyingplate voltage to the transmitter.

c. Replace the High Voltage Power Supply cabinetlower front panel. Temporarily fasten withenough screws to hold it in place. The panel willbe removed again later in the procedure.

d. Open the transmitter cabinet rear doore. Apply primary power to the transmitter cabinet.

WARNINGAC LINE VOLTAGE IS NOW PRESENT INTHE TRANSMITTER CABINET AND THE HVPOWER SUPPLY CABINET CONTROL CIR-CUITRY.

f. On the lower front of the transmitter cabinet lo-cate the AC line voltmeter (M7). Verify that theline voltage is correct. If the voltage is not cor-rect, investigate and correct before proceeding.

g. Set the BIAS circuit breaker to ON and verifythe following indicators are illuminated.

1. REG DC +12V and -12V.2. CONTROL LOCAL ONLY.3. AIR INTERLOCK.4. Possibly the FAULT INTERLOCK.

h. Set the BLOWER, CABINET FAN and FILA-MENT circuit breakers to ON and press Fila-ment ON. The blower speed should build upand the AIR INTERLOCK indicator should extin-guish.

i. Verify that the exciter is operating.


FUNCTION CONNECTIONS

AUTO TB2-1 Requires momentary +12 volts toswitch Power Control to AUTOMode

MANUAL TB2-2 Requires momentary +12 volts toswitch Power Control to MAN-UAL Mode

POWER RAISE TB2-3 Requires continuous +12 volts toraise power

POWER LOWER TB2-4 Requires continuous +12 volts tolower power

AUTO STATUS TB2-9 Provides +12 volts through a 1Kohm resistor for AUTO STATUS

MANUAL STATUS TB2-10 Provides +12 volts through a 1Kohm resistor for MANUALSTATUS

Table 2-5. Remote Control Command Input Connections1A15 Terminal Board TB2


j. Lower the exciter power output to zero using theexciter front panel controls.

k. If the AIR INTERLOCK indicator fails to extin-guish, refer to paragraph entitled AIR SWITCHADJUSTMENT in Section V to properly set theair switch.

l. When the AIR INTERLOCK indicator extin-guishes the filament contactor should be heardenergizing and the FILAMENT ON switchshould illuminate.

m. Rotate the PA MULTIMETER switch to theFILAMENT VOLTAGE position and verify thepresence of filament voltage.

n. Adjust the FILAMENT ADJ control until the PAMULTIMETER indicates the same voltage as re-corded on the factory Test Data sheets.

o. Rotate the PA MULTIMETER switch to the BIASVOLTAGE position and verify the presence ofgrid bias voltage.

p. At this point in the checkout the bias voltagereading should be the same as the value re-corded on the factory Test Data sheets with thePLATE OFF. Adjustment to the bias voltageshould only be made at this point if it does notagree with the factory Test Data sheets. Adjust-ment is made using the transmitter front panelGRID VOLTS ADJ control.

q. Depress the FILAMENT OFF switch. The fila-ment contactor should be heard de-energizingand the FILAMENT ON switch should extin-guish.

r. Verify that the blower continues to rotate for ap-proximately three minutes and then automat-ically turns off.

s. Apply primary power to the High Voltage PowerSupply cabinet. Depress the FILAMENT ONswitch. The shorting solenoids in the High Volt-age Power Supply should be heard energizingat this time.

t. After approximately 20 seconds, depress thePLATE ON switch. The contactors in the HighVoltage Power Supply cabinet should be heardenergizing and the PLATE ON switch should il-luminate.

u. Open the transmitter cabinet door and verify thatthe blower stops, the FILAMENT ON andPLATE ON switches extinguish, the contactorsand shorting solenoids in the High VoltagePower Supply cabinet de-energize, and theXMTR CAB INTERLOCK indicator illuminates.

v. Close the transmitter cabinet door. The XMTRCAB INTERLOCK indicator should extinguish,the blower should start, and the FILAMENT ONswitch should illuminate.

NOTEPLATE ON switch should not illuminate again un-til the PLATE ON switch is depressed.

w. Remove the upper front panel from the HighVoltage Power Supply cabinet.

x. The HV CAB INTERLOCK indicator should illu-minate

WARNINGAC VOLTAGE IS PRESENT IN THE HIGHVOLTAGE POWER SUPPLY CABINET. DONOT TOUCH ANY COMPONENTS WITHOUTFIRST REMOVING PRIMARY POWER FROMTHE TRANSMITTER CABINET AND HIGHVOLTAGE POWER SUPPLY CABINET ANDGROUNDING ALL COMPONENTS WITHTHE GROUNDING HOOK.

y. Depress the PLATE ON switch. The PLATE ONswitch should remain extinguished.

z. Remove the grounding hook in the upper com-partment of the High Voltage Power Supplycabinet and allow it to rest away from any po-tential voltage. Temporarily replace the upperfront panel.

aa. Depress the PLATE ON switch. The PLATE ONswitch should not illuminate, and the high volt-age contactor and shorting solenoids should re-main in a de-energized condition.

ab. Replace the grounding hook and secure the up-per front panel on the High Voltage Power Sup-ply cabinet.

ac. Repeat the six previous steps (z. through ae.)using the High Voltage Power Supply cabinetlower front panel.

ad. Operate any external interlock to ensure properoperation. Verify that the EXT INTERLOCK indi-cator illuminates and the PLATE ON switch re-mains extinguished when the PLATE ON switchis depressed.

2.3.6.1.1 IPA Power Supply Checkouta. Verify Exciter power is at 0 watts.b. Set the IPA circuit breaker to ON.c. On the IPA MULTIMETER, select the IPA

VOLTAGE position.d. Rotate the IPA OUTPUT PWR ADJ control fully

counter-clockwisee. Depress the FILAMENT ON switch.f. After approximately 20 seconds depress the

PLATE ON switch. Confirm a reading of ap-proximately +10 Vdc on the IPA multimeter.

g. Rotate the IPA OUTPUT PWR ADJ control fullyclockwise and confirm that the multimeter nowindicates approximately +48Vdc. Rotate the IPAOUTPUT PWR ADJ control fully counterclock-wise.

h. Depress the PLATE OFF switch. The PLATEON switch should extinguish.

i. Depress the FILAMENT OFF switch. The FILA-MENT ON switch should extinguish.

2.3.6.2 Half-tapa. Remove primary power from the transmitter

cabinet and from the High Voltage Power Sup-ply cabinet.


WARNINGLOCK OUT PRIMARY POWER TO THETRANSMITTER CABINET AND TO THEHIGH VOLTAGE POWER SUPPLY CABI-NET.

b. Remove the lower front panel of the High Volt-age Power Supply cabinet.

WARNINGUSE THE SHORTING STICK TO GROUNDALL CAPACITORS AND TERMINALS BE-FORE OPERATING THE HIGH/LOW VOLT-AGE SWITCH.

c. Set the HIGH/LOW plate voltage switch to theLOW voltage position.

d. Install the lower front panel of the High VoltagePower Supply cabinet.

e. Apply primary power to the transmitter cabinetand High Voltage Power Supply cabinet.

f. Select the MANUAL power control mode withthe POWER OUT AUTO/MANUAL switch on thefront of the transmitter.

g. Set the PA TUNE, PA LOAD, GRID TUNE, andINPUT TUNE controls to the values indicated onthe factory Test Data sheets.

h. Set the BLOWER and SCREEN circuit breakerson the High Voltage Power Supply cabinet toON.

i. Rotate the PA MULTIMETER switch to theSCREEN VOLTAGE position.

j. Depress the FILAMENT ON switch.k. After approximately 20 seconds depress the

PLATE ON switch. Verify that the PLATE VOLT-AGE meter indicates approximately one-half thenormal reading recorded on the factory TestData sheets. The PLATE CURRENT metershould have no indication, and the PA MUL-TIMETER should indicate screen voltage pre-sent.

NOTEThe screen voltage should be approximately thesame as on the factory Test Data sheets. Be-cause the Plate Voltage is at half tap, as RF driveis increased, screen voltage may have to be low-ered to prevent a Screen Current Overload.Screen voltage is adjusted by using the POWEROUT RAISE/LOWER control.

l. Select FWD PWR on the exciter multimeter.m. Raise the exciter power output, using the exciter

front panel controls until the exciter multimeterindicates the value listed on the factory TestData sheets. Rotate the IPA POWER OUTPUTADJ control clockwise until the IPA POWERmeter reads 50 watts in the FORWARD posi-tion.

n. Rotate the IPA POWER meter switch to the RE-FLECTED POWER position and adjust the IN-PUT TUNE and the GRID TUNE controls forminimum indication on the IPA POWER meter.

o. Rotate the POWER meter switch to the FOR-WARD position and adjust the PA TUNE andthe PA LOAD controls for maximum power indi-cation on the POWER meter.

p. Momentarily rotate the POWER meter switch tothe REFLECTED position and verify a lowVSWR indication, then return the switch to theFORWARD position.

q. Rotate the IPA OUTPUT ADJ control in smallincrements until the IPA FORWARD POWER in-dicates 100 watts. With each increase in IPAFORWARD POWER, adjust the INPUT TUNEand GRID TUNE for minimum IPA REFLECTEDPOWER and the PA TUNE and PA LOAD con-trols for maximum FORWARD power on thePOWER meter.

NOTEWith the power supply at half-tap the maximumpower out of the PA tube will be approximately30%. The maximum PLATE CURRENT will beapproximately 2.5 amps.

r. Depress the PLATE OFF switch.s. Depress the FILAMENT OFF switch and allow

the transmitter to complete its cool-down cycle.FILAMENT ON switch should extinguish.

2.3.6.3 Full-Tapa. Remove primary power from the High Voltage

Power Supply cabinet and the transmitter cabi-net.

WARNINGLOCK OUT PRIMARY POWER TO THETRANSMITTER CABINET AND TO THEHIGH VOLTAGE POWER SUPPLY CABI-NET.

b. Remove the lower front panel of the High Volt-age Power Supply cabinet.

WARNINGUSE THE SHORTING HOOK TO GROUNDALL CAPACITORS AND TERMINALS BE-FORE OPERATING THE HIGH/LOW VOLT-AGE SWITCH.

c. While grounding the HIGH/LOW VOLTAGEswitch with the shorting hook, change the switchto the HIGH position.

d. Replace the shorting hook in its holder and re-place the lower front panel of the High VoltagePower Supply cabinet.

e. Apply primary power to the High Voltage PowerSupply cabinet and the Transmitter cabinet.

f. Rotate the IPA OUTPUT PWR ADJ control to itsextreme counterclockwise position.

g. Depress the FILAMENT ON switch. After ap-proximately 20 seconds, depress the PLATEON switch. Verify that the PLATE VOLTAGEmeter indicates the value recorded on the fac-tory Test Data sheets and that the PLATE CUR-RENT meter has a low indication.


h. Using the RAISE/LOWER POWER OUT switch,adjust the PA MULTIMETER SCREEN VOLT-AGE indication to the same as recorded on thefactory test data sheets.

NOTEDuring the high power tune-up procedure, thescreen voltage may have to be readjusted asmore power is produced by the transmitter.

i. Rotate the IPA OUTPUT ADJ control in smallincrements until the IPA FORWARD POWER in-dicates the value recorded on the factory TestData sheets. With each increase in IPA FOR-WARD POWER, adjust the INPUT TUNE andGRID TUNE for minimum IPA REFLECTEDPOWER and the PA TUNE and PA LOAD con-trols for maximum FORWARD power on thePOWER meter. Compare the final operating pa-rameters to the factory Test Data sheets.

j. Depress the PLATE OFF switch.k. Depress the FILAMENT OFF switch and allow

the transmitter to complete its cool-down cycle.l. This completes the Initial Turn On Procedure.

2.3.6.4 AUTOMATIC POWER CONTROL SET-UPThe Automatic Power Control in the HT 20/25CD trans-mitter may be set up in the following manner:

a. Bring the transmitter up to full operating power.b. Observe the AUTO PWR RAISE and LOWER

indicators.c. Use the POWER SET RAISE/LOWER control to

extinguish both the AUTO POWERRAISE/LOWER indicators.

NOTEIf the AUTO POWER RAISE indicator is illumi-nated, depress the POWER SET control to theLOWER position until the RAISE indicator is ex-tinguished. Conversely if the AUTO POWERLOWER indicator is illuminated, depress thePOWER SET control to the RAISE position untilthe LOWER indicator is extinguished.

d. When both the AUTO POWER RAISE and theAUTO POWER LOWER indicators are extin-guished select the AUTO power control modeusing the AUTO/MANUAL switch.

e. This completes the Automatic Power Controlset-up.

2.3.6.5 REMOTE CONTROL SET-UPThe HARRIS HT 20/25CD FM BROADCAST TRANS-MITTER is compatible with most modern remote controlsystems. The user is referred to the appropriate vendorinstruction manual for installation and operating instruc-tions.

2.4 TECHNICAL ASSISTANCEHARRIS Technical and Troubleshooting assistance isavailable from HARRIS Field Service during normalbusiness hours (8:00 AM - 5:00 PM Central Time).Emergency service is available 24 hours a day. Tele-phone 217/222-8200 to contact the Field Service De-partment or address correspondence to Field ServiceDepartment, HARRIS CORPORATION, Broadcast Divi-sion, P.O. Box 4290, Quincy, Illinois 62305-4290, USA.The HARRIS factory may also be contacted through aFAX facility (217-222-7041) or a TELEX service (650-372-2976).

NOTETO OPTIMIZE TUBE PERFORMANCE ANDLIFE EXPECTANCY, REFER TO THE EIMACBULLETIN ENTITLED “EXTENDING TRANS-MITTER TUBE LIFE” IN VENDOR SECTION OFTHIS MANUAL BEFORE BEGINNING NORMALOPERATION OF THE TRANSMITTER.


SECTION IIIOPERATION

3.1 INTRODUCTIONThis section contains operation procedures and infor-mation pertaining to identification, location, and functionof the controls and indicators on the HARRISHT 20/25CD FM BROADCAST TRANSMITTER.

3.2 CONTROLS AND INDICATORSFigures 3-1 through 3-3 show the location of allHT 20/25CD Transmitter controls and indicators. Tables

3-1 through 3-3 list all controls and indicators with thefunction of each item listed.

Controls and indicators for the FM Exciter are describedin the FM Exciter Technical Manual.


Figure 3-1. Front Controls and Indicators


REF. CONTROL/INDICATOR FUNCTION

1 PLATE VOLTAGE ME-TER Meter M4

Displays PA plate voltage.

2 PLATE CURRENT ME-TER Meter M5

Displays the PA stage plate current.

3 POWER METER MeterM6

Displays VSWR or transmitter rf output as selected by the FORWARD/RE-FLECTED POWER switch.

4 FORWARD/RE-FLECTED POWERswitch Switch S11

Selects between a POWER meter display of VSWR or transmitter rf output.

5 FILAMENT ON SwitchS1

Applies power to all circuits except the IPA, PA plate and PA screen powersupplies. Indicator illuminates when command signal is applied to the fila-ment contactor.

6 FILAMENT OFF SwitchS4

Turns off all rf power related circuits. Blower rundown cycle initiates.

7 PLATE OFF Switch S3 Turns the IPA, PA plate and PA screen power supplies off.

8 PLATE ON Switch S2 Energizes the IPA, PA plate and PA screen power supplies. Indicator illumi-nates when the command signal is applied to plate contactor.

37 FWD PA PWR CAL Po-tentiometer R4

Allows calibration of the POWER meter when the POWER switch is in theFORWARD position (FACTORY CALIBRATED).

38 REFLD PA PWR CALPotentiometer R5

Allows calibration of the POWER meter when the POWER switch is in theREFLECTED position (FACTORY CALIBRATED).

10 POWER OUTAUTO/MANUAL SwitchS1

Allows selection of either manual or automatic control of the transmitter rfoutput level.

12 POWER OUTRAISE/LOWER SwitchS2

When transmitter is in MANUAL POWER CONTROL, adjusts the transmit-ter rf output by controlling the motorized screen variac.

35 REFLD IPA PWR CALPotentiometer R3

Allows calibration of the IPA POWER meter reflected power indication(FACTORY CALIBRATED).

36 FWD IPA PWR CAL Po-tentiometer R2

Allows calibration of the IPA POWER meter forward power indication (FAC-TORY CALIBRATED).

14 PA LOAD Capacitor C16 Adjusts coupling of the PA CAVITY RF output to the antenna.

13 PA TUNE MIN/MAXControl (Mech Part)

Adjusts tuning of the PA CAVITY plate circuit.

15 GRID TUNE Control L4(Mech Part)

Adjusts tuning of the PA stage grid circuit.

16 INPUT TUNE MIN/MAXCapacitor C9

Adjusts coupling of the IPA rf output to the PA stage.

18 FILAMENT CircuitBreaker CB1

Provides control and overload protectection for the PA filament supply.

19 BIAS Circuit BreakerCB2

Provides control and overload protection for the DIGIT™ FM Exciter, con-trol grid power supplies, the logic power supply, and the 115 Vac controlcircuits.

20 IPA Circuit Breaker CB3 Provides control and overload protection for the IPA power supply.

21 BLOWER CircuitBreaker CB4

Provides control and overload protection for the blower circuitry.

22 FILAMENT ADJ Trans-former T2

Adjusts the PA filament voltage.

Table 3-1. Front Controls and Indicators



23 FILAMENT HRS MeterM1

Indicates hours of PA filament operation.

27 PA Multimeter SwitchS10

Selects between a MULTIMETER indication of filament voltage, bias volt-age, bias current, screen voltage, or screen current.

29 PA MULTIMETER (M2)Meter M2

Indicates filament voltage, bias voltage, bias current, screen voltage, orscreen current as selected by the multimeter switch.

28 BIAS VOLTS ADJ Rheo-stat R8

Adjusts the bias voltage applied to the PA tube control grid.

30 HUM NULL RheostatR33

Adjusts the ac signal placed on the PA tube control grid to balance outhum caused by filament emission.

31 IPA REFLECTEDPOWER/FORWARDPOWER Switch S12

Selects between an IPA power meter display of IPA stage forward or re-flected power.

33 IPA POWER Meter M3 Displays IPA stage forward or reflected power.

34 IPA OUTPUT PWRADJ Potentiometer R31

Adjusts the rf output of the IPA stage.

48 PWR SETRAISE/LOWER SwitchS2

Adjusts the rf power output reference level when operating in automaticcontrol.

49 AUTO PWRLOWER/VSWR FBKLED Indicator DS14

See Note below

NOTEWhen illuminated steady green, indicates that the rf power must be lowered to equalize the transmitter rfpower output with the reference level established with the PWR SET RAISE/ LOWER switch. When alter-nately flashing red and green, indicates that RF power must be lowered due to high OUTPUT REF PWRreading and that all automatic OUTPUT PWR RAISE functions are inhibited (VSWR Foldback condition).When flashing only red, indicates OUTPUT REF PWR is high but that lowering of the RF power is notpresently required and that all automatic OUTPUT PWR RAISE functions are inhibited (VSWR Foldbackcondition). These functions will be completely automatic if the transmitter is operating in the Auto PowerControl mode as indicated by LED 1A11DS1.

50 AUTO PWR RAISELED Indicator DS13

When illuminated, indicates that the rf power must be raised to equalize thetransmitter rf power output with the reference level established with thePWR SET RAISE/LOWER switch. This function will be completely automat-ic if the transmitter is operating in the Auto Power Control mode as indi-cated by LED 1A11DS1.

51 EXT OVERLOAD LEDIndicator DS11

When illuminated, indicates that the external overload has triggered theexternal overload circuit.

52 PA PLT OVERLOADLED Indicator DS10

When illuminated, indicates that excessive PA plate current has triggeredthe PA plate overload circuit.

53 PA SCRN OVERLOADLED Indicator DS9

When illuminated, indicates that excessive PA screen current has triggeredthe PA screen overload circuit.

54 PA VSWR OVERLOADLED Indicator DS8

When illuminated, indicates that excessive antenna VSWR has triggeredthe PA VSWR overload circuit.

55 IPA VSWR OVERLOADLED Indicator DS7

When illuminated, indicates that excessive PA grid circuit VSWR has trig-gered the IPA VSWR overload circuit.

56 AFC OVERLOAD LEDIndicator DS6

When illuminated, indicates that the exciter AFC has faulted. For theDIGIT™ exciter, AFC stands for Automatic Fault Control and is an exciterfault interlock not a PLL out of lock fault.

57 OVERLOAD IND RE-SET Switch S1

When depressed, resets the overload indicators.

Table 3-1. Front Controls and Indicators (Continued)



39 AIR INTERLOCK LEDIndicator DS1

When illuminated, indicates that the air interlock switch is open.

40 FAULT INTERLOCKLED Indicator DS2

When illuminated, indicates that an overload has occurred repeatedly andactivated the transmitter fault circuit.

41 XMTR CAB INTER-LOCK LED IndicatorDS3

When illuminated, indicates that a transmitter cabinet door is open.

42 HV CAB INTERLOCKLED Indicator DS4

When illuminated, indicates that the High Voltage Power Supply cabinetrear or front panel is open, or that one of the grounding sticks is not in itsholder.

43 EXT INTERLOCK LEDIndicator DS5

When illuminated, indicates that the external station interlock is open.

44 +12V REG DC LED Indi-cator DS15

When illuminated, indicates an active output from the 12 Vdc regulator inthe control circuit.

45 -12V REG DC LED Indi-cator DS16

When illuminated, indicates an active output from the -12 Vdc regulator inthe control circuit.

46 LOCAL ONLY CON-TROL LED IndicatorDS12

When illuminated, indicates that local control has been selected and thatthe remote control command inputs are inactive.

47 LOCAL ONLY/NORMCONTROL Switch S3

Selects between local or remote transmitter operation.

58 IPA VSWR Potentiome-ter R24

Adjusts the overload trip point of IPA reflected power (FACTORY CALI-BRATED).

59 PA VSWR Potentiome-ter R25

Adjusts the overload trip point of PA reflected power (FACTORY CALI-BRATED).

60 PA SCREEN Potenti-ometer R26

Adjusts the overload trip point of PA screen current (FACTORY CALI-BRATED).

61 PA Potentiometer R27 Adjusts the overload trip point of PA plate current (FACTORY CALI-BRATED).

26 IPA Multimeter SwitchS1

Selects IPA current, IPA voltage for IPA.

32 IPA Multimeter MeterM1

Indicates the parameter selected by IPA Multimeter Switch S1.

11 MANUAL LED 1A11DS2 When illuminated, indicates manual control of power adjustment.

9 AUTO LED 1A11DS1 When illuminated, indicates automatic control of power adjustment.

17 Cabinet Fan CircuitBreaker CB5

Provides control and overload protection for the cabinet flushing fan.

25 AC VOLTAGE Meter M7 Indicates AC voltage.

62 CIRCUIT BOARDGROUND Test PointTP1

Provides test probe connection point to circuit ground.

63 VSWR FOLDBACKON/OFF Switch S1

Enables the VSWR Foldback function when in the ON position (righthand).

64 VSWR FOLDBACKSET POINT 1 Thresh-old Adjust Potentiome-ter R117

Allows calibration of VSWR Foldback set point 1.




65 VSWR FOLDBACKSET POINT 1 VoltageSample Test Point TP4

Provides test probe connection point to measure set point 1 voltage.

66 VSWR FOLDBACKSET POINT 2 VoltageSample Test Point TP3

Provides test probe connection point to measure set point 2 voltage.

67 VSWR FOLDBACK RE-FLECTED POWERSAMPLE VOLTAGETest Point TP2

Provides test probe connection point to measure the reflected power sam-ple voltage.

68 VSWR FOLDBACKSET POINT 2 Thresh-old Adjust Potentiome-ter R118

Allows calibration of VSWR Foldback set point 2.



Figure 3-2. Rear Controls and Indicators



1 SECOND HARMONICNOTCH FILTER AD-JUSTMENT AdjustmentFL2

Adjusts the quarter-wave stub to the 2nd Harmonic frequency of the PA.

2 IPA MATCHING Capaci-tor C3

Adjusts the coupling of the IPA stage to the PA grid circuit.

3 IPA Tuning CapacitorC1

Adjusts the tuning of the IPA stage.

4 Second HarmonicNotch Adjustment Ca-pacitor C2

Tunes the IPA stage Low-Pass Filter to the 2nd Harmonic frequency.

5 Directional Coupler NullAdjustments CapacitorC12, Potentiometer R2

Adjusts IPA stage Directional Coupler for a null in reflected power.

6 Filament Meter Cali-brate Potentiometer R9

Calibrates the MULTIMETER filament voltage display.

7 PA Neutralizing Capaci-tor (Mech Part)

Adjusts the PA stage neutralization at the fundamental frequency.

8 AIR PRESSURESWITCH ADJUST-MENT S9, Switch S9

Adjusts the air pressure switch dropout point.

Table 3-2. Rear Controls and Indicators


Figure 3-3. High Voltage Power SupplyControls and Indicators



1 BLOWER CircuitBreaker CB2

Provides control and overload protection for the High Voltage Power Supplyflushing fan.

2 SCREEN CircuitBreaker CB1

Provides control and overload protection for the screen power supply.

WARNINGTHE FULL PA PLATE VOLTAGE EXISTS ON THE ELEMENTS OF THE HIGH/LOW PLATE VOLT-AGE SWITCH. NEVER ATTEMPT ADJUSTMENT OF SWITCH S8 UNLESS ALL POWER IS DEEN-ERGIZED AND THE SWITCH IS GROUNDED.

3 HIGH/LOW PLATEVOLTAGE Switch S8

Allows a 50% reduction in the PA supply output voltage for tuning. (This isa test feature and is not intended to be a method of power reduction exceptfor test or emergency situations. Operation in the lower output voltagemode may result in degraded audio performance.)

Table 3-3. High Voltage Power SupplyControls and Indicators


3.3 OPERATIONThe following operational procedure is presented for theHT 20/25CD Transmitter under the assumption that thetransmitter has been thoroughly and properly alignedand is free of any discrepancies. Also, that the transmit-ter cabinet has been inspected to ensure that no for-eign objects are inside, all parts and components areproperly installed, all connectors are secure, and all in-terlocks are closed.

3.3.1 TRANSMITTER TURN ONActivate station power to the transmitter and the highvoltage power supply.

Depress the PLATE ON pushbutton switch. The excitershould come on (the RF MUTE light will extinguish) andthe AIR INTERLOCK indicator will remain illuminated.

As the main blower comes up to speed, the AIR IN-TERLOCK indicator will extinguish and the FILAMENTON pushbutton will illuminate.

Operate the multimeter switch to the FILAMENT VOLT-AGE position and adjust the FILAMENT ADJ control asrequired to obtain the correct filament voltage indica-tion.

After a delay of approximately 20 seconds, to allow thePA filament to heat, the PLATE ON pushbutton will illu-minate.

Note the PLATE CURRENT meter indication to ensurethe PA plate circuit is correctly resonated.

Operate the FORWARD/REFLECTED switch to FOR-WARD. Note the transmitter rf output power. If adjust-ment is required, proceed as follows:

Operate the IPA REFLECTED POWER/FORWARDPOWER switch to FORWARD POWER. If required,adjust the IPA OUTPUT POWER ADJ control to es-tablish the correct IPA stage power output.

Operate the FORWARD/REFLECTED POWERswitch to FORWARD. Select the MANUAL powercontrol mode by using the POWER OUTAUTO/MANUAL switch. Adjust the transmitter outputpower by tuning and loading to achieve the ratedoutput power. If necessary, adjust PA screen voltageusing the MANUAL POWER RAISE/LOWER control.

Using the POWER OUT AUTO/MANUAL switch, se-lect the AUTO power control mode.

Operate the FORWARD/REFLECTED POWER switchto the REFLECTED position and note the VSWR. Thetransmitter will operate into a 1.7:1 maximum mismatch.

However, the antenna VSWR should be kept to a mini-mum level. If a high VSWR is present, the cavity maynot be brought to resonance with only the PLATETUNE control. If cavity resonance cannot be achieved,the PLATE TUNE control will be at either extreme (MINor MAX). COARSE tuning of the cavity must be made.If the PLATE TUNE control is at MAX, the COARSEtuning short of the cavity needs to be lowered. If thePLATE TUNE control is at MIN, the COARSE tuningshort of the cavity needs to raised. (NOTE: If theVSWR condition causing the cavity detuning is tempo-rary [i.e. antenna icing] operation at reduced power maybe preferable to relocating the coarse tuning plate. Op-eration at reduced power may be accomplished manu-ally or be allowed to occur automatically by selectingthe APC power control mode and enabling the VSWRfoldback feature.)

The IPA stage power output is equal to the IPAPOWER meter indication minus the IPA POWER meterreflected power indication. Table 3-4 lists VSWR levelscorresponding to various reflected power levels. The in-dex of the table is obtained by dividing the IPA stagereflected power indication in watts by the IPA stage for-ward power indication in watts.

3.3.2 TRANSMITTER TURN OFFDepress the PLATE OFF pushbutton switch and after acool-off period depress the FILAMENT OFF pushbuttonswitch. Operation of the transmitter will cease.

However, the blower will operate for approximately 3.5minutes to insure adequate cooling of the PA stage.

3.4 OPERATION IN NON-STANDARDCONFIGURATIONS USINGFLEXPatch™

FLEXPatch™ allows transmitter operation in any of sev-eral configurations that permit an inoperative rf stage to

INDEX = REF PWR RETURN LOSS VSWRFWD PWR

0.00 dB 1.0:1

.002 26.9 dB 1.1:1

.008 20.9 dB 1.2:1

.017 17.7 dB 1.3:1

.028 15.5 dB 1.4:1

.040 13.9 dB 1.5:1

.065 11.8 dB 1.75:1

.111 9.5 dB 2.0:1

.183 7.3 dB 2.5:1

.25 6.0 dB 3.0:1

.36 4.4 dB 4.0:1

VSWR may be calculated by:

PREF = Power Reflected in Watts

PFWD = Power Forward in Watts

VSWR =

1 + PREF

PFWD

1 - PREF

PFWD

Table 3-4. Power/VSWR Conversion


be easily bypassed. Transmitter operation in any ofthese bypass modes will be at a reduced output powerlevel.

STANDARD configuration can be seen in overall draw-ing 8529163008.

FLEXPatch™ consist of two bypass cables which areprovided with the Transmitter. PA bypass cable9220446033 and IPA Bypass cable labeled FLEX-PATCH.

All of the bypass modes may be configured by simplyconnecting these coaxial jumpers. If an inoperative PAcavity is to be bypassed, an additional change must bemade inside the cavity assembly to effect a connectionto the output transmission line center conductor. Alsoan external coaxial cable connection to the cavity willhave to be changed in any PA by-pass mode.

After determining which rf stage is inoperative, termi-nate transmitter operation by depressing the FILAMENTOFF pushbutton. Following completion of the filamentcool down period, the main cabinet blower will ceaserunning. At this time, disconnect station power to thetransmitter.

WARNINGDISCONNECT AND LOCK OUT STATIONPRIMARY POWER TO THE TRANSMITTERCABINET AND TO THE HIGH VOLTAGEPOWER SUPPLY CABINET.

Open the transmitter cabinet rear door.

WARNINGUSE THE GROUNDING STICK TO DISSI-PATE ALL RESIDUAL POTENTIALS FROMALL COMPONENTS AND TERMINALBOARDS BEFORE TOUCHING THEM.

Having determined which stage(s) needs to be by-passed, find the appropriate FLEXPatch™ cable/s. Pro-ceed to the paragraph indicated in Table 3-5. Figures3-5 through 3-11 show the FLEXPatch™ configurationsto accomplish the various bypass modes.

3.4.1 FLEXPatch™ OPERATION TO BYPASSINOPERATIVE IPA DRIVER STAGES

Locate the IPA Emergency Bypass cable labeled Flex-patch which was provided with the Transmitter accesso-ries. This cable should have a BNC connector on oneend and an N-type connector on the other. Open therear door and locate cable 265 connected to J1 on thePA cavity. Remove this cable and connect the Flex-patch cable with the N-type connector to J1. Now routethis cable up to the front of the cabinet to the Exciter.Remove cable 256 on the RF output of the Exciter andconnect the BNC end of the Flexpatch Cable to the RFOutput of the Exciter.

Close the rear door on the Transmitter cabinet. Reapplystation power to the Transmitter cabinet and to the HighVoltage Power Supply cabinet.

Depress the FILAMENT ON pushbutton. Release andconfirm that the FILAMENT ON pushbutton remains illu-

minated and that the blower is running. Lower the ex-citer power output, using the exciter front panel con-trols, until the power output is zero.

After the twenty second warm up period, depress thePLATE ON pushbutton. The PLATE VOLTAGE metershould read upscale to the normal voltage. The PLATECURRENT and output POWER meters should remainat a 0 reading.

Select the FWD PWR Multimeter position on the exciterfront panel. raise the exciter power output until the ex-citer multimeter indicates 15 watts.

NOTEWith the IPA bypassed, the front panel IPAPOWER control has no effect on IPA RF outputpower.

The IPA FORWARD POWER should read at or near 0watts. Select the REF PWR position on the exciter frontpanel multimeter. Carefully adjust the INPUT TUNE andGRID TUNE controls for a minimum reading on excitermultimeter.

Select the SCREEN VOLTAGE position on the multime-ter. Using the MANUAL POWER RAISE and POWERLOWER toggle switch, set the screen voltage to 1000V.

Observe the PLATE CURRENT meter reads slightly up-scale (about 0.3 Amperes).

However the output POWER meter may not indicate aforward power reading. Move the PA TUNE control fullyclockwise. Power output from the PA cavity is now inthe range of 250 watts. Continue to operate in thismode as long as necessary.

When it is desired to return to the normal transmitterconfiguration, first reduce the power output of the ex-citer to the value recorded on the factory final test datasheet.

Reduce the PA screen voltage to that value recorded inthe factory final test data sheets.

Terminate transmitter operation by depressing the FILA-MENT OFF pushbutton.

CONFIGURATION SEE PARAGRAPH

TO BYPASS NO.

IPA 3.4.1

PA 3.4.2

IPA and PA 3.4.3Notes * An additional change must be made withinthe PA cavity as well as an external coaxial cableconnection to the PA cavity to facilitate thesemodes.

** If either the IPA removed from the air duct, acover plate (HARRIS P/N 839 7822 005 suppliedwith transmitter) must be placed over hole wheremodule was removed from to maintain proper airflow through remainder of transmitter.

Table 3-5. FLEXPatch™ Bypass Configurations


After the three minute blower run-down period haselapsed, disconnect station power to the Transmittercabinet and to the High Voltage Power Supply cabinet.




Replace and/or repair the failed unit(s).

Return the cabling to their normal configuration as seenin drawing 8529163008.

Close the Transmitter cabinet rear door and secure allaccess panels. Return the HT 20/25CD Transmitter tonormal operation by following the turn on procedure asdescribed beginning in paragraph entitled TRANSMIT-TER TURN ON in Section III.

3.4.2 FLEXPatch™ OPERATION TO BYPASS ANINOPERATIVE PA STAGE

chWARNING = WARNING

ENSURE THAT ALL POWER IS REMOVEDFROM THE TRANSMITTER BEFORE PER-FORMING THE FOLLOWING STEPS. AL-WAYS USE A GROUNDING STICK TO EN-SURE THAT THERE ARE NO RESIDUALVOLTAGES PRESENT.

Open the rear door and disconnect the cable from J1and reconnect it to the auxiliary input connector J2 lo-cated just above J1 on the side of the PA Cavity.

Remove the PA Cavity access panel. Remove the PAtube according to the instructions in paragraph entitledTUBE REMOVAL AND INSTALLATION in Section V.Locate the inductive output loop connected between theOUTPUT LOAD capacitor (C16) and the center conduc-tor of the output transmission line.

Note the loop orientation for future reference. Unboltand remove the loop and retain for future use. Locatethe PA Cavity Emergency bypass input connector (J2).Locate the PA Emergency bypass cable (HARRIS partnumber 922 0446 033) that was packed with the trans-mitter accessories. Install the cable in the cavity by firstconnecting the type N connector to the bypass inputconnector. Attach the lugged end of the center conduc-tor to the center conductor of the output transmissionline. Do so by placing the lug under the bolt that goesinto the center conductor and tightening gently butfirmly.

Notice now that the lug attached to the outside shield ofthe cable falls directly over one of the bolts that holdsthe outer conductor of the transmission line to the cav-

ity wall. Remove that bolt. Run it through the lug andreinstall it. Tighten gently but firmly. Check to makesure all connections are tight. Reinstall the PA tube ac-cording to the instructions in paragraph entitled TUBEREMOVAL AND INSTALLATION in Section V. Replacethe cavity access panel.

NOTEThe PA tube and the access panel must be inplace to prevent the blower motor from drawingtoo much current.

On TB3 add a jumper to connect TB3-13 and TB3-14together. This will supply the closure needed to activatethe IPA with the Main Power Supply Cabinet de-ener-gized.

Turn the IPA POWER control fully counterclockwise.

Close the rear door of the Transmitter cabinet. Applystation power to the Transmitter cabinet ONLY.

WARNINGDO NOT APPLY STATION POWER TO THEHIGH VOLTAGE POWER SUPPLY CABI-NET.

Depress the FILAMENT ON pushbutton. Release andconfirm that the FILAMENT ON pushbutton remains illu-minated and that the blower is running. After 20 sec-onds, depress the PLATE ON pushbutton. It should re-main illuminated.

Advance the IPA multimeter to the IPA VOLTAGE posi-tion. The reading should be approximately 10V.

Advance the IPA POWER control until the IPA FOR-WARD POWER meter indicates 500 watts of RF power.Note that the IPA REFLECTED POWER meter may in-dicate some value of reflected power depending on theantenna VSWR. This is normal. As the IPA is drivingthe antenna directly, there are no controls to match theIPA to this load. The output POWER meter may indi-cate upscale slightly due to the 500 watts of outputpower. Continue to operate in this mode as necessary.

Note that in this PA BYPASS mode no station power isreconnected to the High Voltage Power Supply.

When it is desired to return to the normal transmitterconfiguration, first readjust the IPA POWER control sothat the IPA FWD power reading on the multimeterreads the same as that on the factory final test datasheet.

Depress the FILAMENT OFF pushbutton. Allow theblower run-down period to elapse.

Disconnect station power to the Transmitter cabinet andto the High Voltage Power Supply cabinet.





Replace and/or repair the failed unit(s).

Disconnect cable #265 from J2 on the PA Cavity andreconnect it to J1 just below J2.

Remove the access panel on the PA cavity. Removethe PA tube according to the instructions in paragraphentitled TUBE REMOVAL AND INSTALLATION in Sec-tion V. Remove the emergency PA bypass cable andstore it for future use.

Reinstall the output inductive loop using the originalhardware. Be sure it is in the same orientation as itoriginally was before it was removed. Firmly tighten allhardware. Replace the PA tube according to the in-structions in paragraph entitled TUBE REMOVAL ANDINSTALLATION in Section V. Replace the PA cavity ac-cess panel and tighten the hardware that secures it.


3.4.3 FLEXPatch™ OPERATION TO BYPASSINOPERATIVE IPA DRIVER AND PASTAGES

Locate the IPA Emergency Bypass cable labeled Flex-patch which was provided with the Transmitter accesso-ries. This cable should have a BNC connector on oneend and an N-type connector on the other. Open therear door and locate N-type connector J2 on the PAcavity. Connect the Flexpatch cable with the N-typeconnector going to J2. Now route this cable up to thefront of the cabinet to the Exciter. Remove cable 256on the RF output of the Exciter and connect the BNCend of the Flexpatch Cable to the RF Output of the Ex-citer.

WARNINGENSURE THAT ALL POWER IS REMOVEDFROM THE TRANSMITTER BEFORE PER-FORMING THE FOLLOWING STEPS. AL-WAYS USE A GROUNDING STICK TO EN-SURE THAT THERE ARE NO RESIDUALVOLTAGES PRESENT.

Remove the PA Cavity access panel. Remove the PAtube according to the instructions in paragraph entitledTUBE REMOVAL AND INSTALLATION in Section V.Locate the inductive output loop connected between theOUTPUT LOAD capacitor (C16) and the center conduc-tor of the output transmission line.

Note the loop orientation for future reference. Unboltand remove the loop and retain for future use. Locatethe PA Cavity Emergency bypass input connector (J2).Locate the PA Emergency bypass cable (HARRIS partnumber 922 0446 033) that was packed with the trans-mitter accessories. Install the cable in the cavity by first

connecting the type N connector to the bypass inputconnector. Attach the lugged end of the center conduc-tor to the center conductor of the output transmissionline. Do so by placing the lug under the bolt that goesinto the center conductor and tightening gently butfirmly.

Notice now that the lug attached to the outside shield ofthe cable falls directly over one of the bolts that holdsthe outer conductor of the transmission line to the cav-ity wall. Remove that bolt. Run it through the lug andreinstall it. Tighten gently but firmly. Check to makesure all connections are tight. Reinstall the PA tube ac-cording to the instructions in paragraph entitled TUBEREMOVAL AND INSTALLATION in Section V. Replacethe cavity access panel.

NOTEThe PA tube and the access panel must be inplace to prevent the blower motor from drawingtoo much current.

Locate and unplug the ac power connector on the rearof the exciter. This may be done by pulling the exciterout on its extender rails. Unplug the multipin plug thatprovides ac power from the transmitter wiring and con-trol circuits. Locate the standard line cord that is placedwith the transmitter accessories. Plug this into the ex-citer and route the line cord out of the cabinet throughthe rear door. Do not plug the cord into an ac outputyet.

WARNINGDO NOT APPLY STATION POWER TOEITHER THE HIGH VOLTAGE POWER SUP-PLY CABINET OR TO THE TRANSMITTERCABINET.

Open the top cover on the exciter. Locate JP6 on theRegulator board which is located directly behind the ex-citer front panel. Place the jumper in the 60W positionor pins 1-2. This raises the exciter maximum power out-put to at least 55W.

Close and secure the top cover on the exciter.

Plug the line cord into a source of 120 Vac.

Select the FWD PWR multimeter position on the exciterfront panel. Raise the exciter power output until the ex-citer multimeter indicates 55 watts.

Operate in this mode as necessary.

When it is desired to return to the normal transmitterconfiguration, lower the exciter power output to zero us-ing the exciter front panel controls, the remove allpower to the exciter and open the top cover. Move thePWR RANGE SELECT jumper JP6 on the regulatorboard back to the 20W position or pins 2-3. The exciteroutput is now limited to 20W max. rf output. Reapplypower and readjust the exciter power output so that theexciter multimeter indicates the FWD PWR reading re-corded on the factory final test data sheet. Remove thetemporary test ac cord from the exciter and plug theexciter in using the normal ac cord in the transmitter.


Remove the FLEXPatch™ cables and return cables totheir normal configuration as shown in drawing852916308.

Remove the access panel on the PA cavity. Removethe PA tube according to the instructions in paragraphentitled TUBE REMOVAL AND INSTALLATION in Sec-tion V. Remove the emergency PA bypass cable andstore it for future use.

Reinstall the output inductive loop using the originalhardware. Be sure it is in the same orientation as it

originally was before it was removed. Firmly tighten allhardware. Replace the PA tube according to the in-structions in paragraph entitled TUBE REMOVAL ANDINSTALLATION in Section V. Replace the PA cavity ac-cess panel and tighten the hardware that secures it.



SECTION IVPRINCIPLES OF OPERATION

4.1 INTRODUCTIONThis section presents detailed principles of operation forthe HARRIS HT 20/25CD BROADCAST TRANSMIT-TER with supporting diagrams.

4.2 FUNCTIONAL DESCRIPTION4.2.1 POWER SUPPLIESThe following text describes the power supply circuitryof the HT 20/25CD Transmitter. Refer to drawings 839-7822-017 or 839-7822-016 for the folloing discussion.

4.2.1.1 HIGH VOLTAGE POWER SUPPLYThe HARRIS HT 20/25CD Transmitter High VoltagePower Supply produces the proper plate and screenvoltages for operation of the HT 20/25CD Transmitterover its entire rated output power range. The primary ofthe supply is designed to operate from a 208/240 Vac,50/60 Hz, 3 phase, three-wire source or a 360/415 Vac,50/60 Hz, 30, four-wire source. A fan in the High Volt-age Power Supply cabinet ensures cool and depend-able operation. The BLOWER circuit breaker providescontrol and overload protection for the fan.

4.2.1.1.1 Primary Control CircuitAssuming all transmitter interlocks are closed, the HighVoltage Power Supply primary circuit overloads areclosed, and the PA filament heating-delay cycle has ex-pired, a ground from the AC Control module (1A12) inthe control circuit, will energize step/start relay K4.Power will be applied to the transformers in the HighVoltage Power Supply through resistors which limit theinitial inrush of current. After a short mechanical delay,high-voltage contactor K3 will close and bypass thestep/start resistors to apply full line voltage to the plateand screen supplies. The step/start arrangement allowsthe supplies to gradually increase output which resultsin longer component life. If an interlock should openwhile the High Voltage Power Supply is energized, bothrelays K3 and K4 will open and deenergize the primarycircuit of transformer T1. In addition, high-voltage short-

ing switches L1 and L2 will discharge the plate supplyto ground.

4.2.1.1.2 Plate Power SupplyThe Plate Power Supply primary is connected in aclosed-delta configuration for 208/240 VRMS mains(Figure 4-1). A half-voltage supply is provided from thetransformer center tap. Due to the physical constructionof the transformer, each secondary phase will lead orlag its respective primary phase by 60 degrees in-phase. The secondary phase separation (60 degrees)divided into one cycle of primary phase rotation (360degrees) will equal six secondary phases. The six-phase circuit used in the HT 20/25CD Transformer re-quires little filtering as four percent ripple is approachedwithout using a filter (refer to Table 4-1).

A requirement of all multiphase supplies is that thethree-phase primary line voltage must be balanced towithin the percentage of ripple voltage which is to beobtained from the power supply. The principle outputripple frequency will equal to the primary line frequencytimes the secondary phases. Line unbalance will showup as ripple in the rectifier circuit and produce approxi-mately three percent peak ripple in the secondary cir-cuit into a resistive or inductive load at twice the powerline frequency.

Constant primary line unbalance can be corrected bythe use of primary taps or a tapped three-phase autotransformer.

4.2.1.1.3 Screen Power SupplyThe Screen Power Supply is a single phase full wavebridge-rectified supply with a two-section filter. The pri-mary circuit is connected across two phases of thethree-phase primary input to the High Voltage PowerSupply.

The SCREEN circuit breaker provides control and over-load protection.

Figure 4-1. Six-Phase Circuit


One leg of the screen power supply transformer is con-nected to the primary source through a variable trans-former-motor arrangement (B2-T2) which controls thepower supply output. Power for the motor is obtainedfrom a 115 Vac winding on the control grid bias trans-former. If MANUAL OUTPUT POWER CONTROL is se-lected, the POWER OUT RAISE/LOWER switch will de-termine the direction of motor rotation which in turn de-termines the supply output potential. If the POWEROUTPUT switch is operated to LOWER, the direction ofrotation will lower the PA screen potential. If the switchis operated to RAISE, the direction of rotation will raisethe PA screen potential. If AUTOMATIC OUTPUTPOWER CONTROL is selected, adjustment of thescreen control motor is determined automatically bypreset limits and predetermined levels of the control cir-cuitry.

4.2.1.2 IPA POWER SUPPLYThe IPA Power Supply provides a positive 48 Vdc po-tential at a maximum 24 amperes to operate the IPADRIVER module. The supply consists of a single phaseinput, and a separate bleeder resistance. The output ofthe supply is applied to the IPA module through currentmetering resistor R35. The IPA power supply is control-led by an external DC voltage (1-5VDC) which is ad-justable by the IPA OUTPUT POWER ADJ Potentiome-ter.

The IPA DRIVER module operates directly from theoutput of the IPA power supply. The voltage developedacross resistor R35 is proportional to the current drawnby the module. This voltage is applied to the IPA CUR-RENT position of the IPA MULTIMETER which is cali-brated to read in amperes.

The output voltage of the Power supply is varied by theIPA OUTPUT PWR ADJ control. The 1-5VDC controlvoltage from the IPA OUTPUT POWER ADJ deter-mines the output of the Power supply from 10 – 48VDCwhich then changes the RF output level of the transmit-ter.

4.2.1.3 CONTROLLER POWER SUPPLYThe transmitter control logic is powered by +/-18 Vdcpotentials obtained from a single-phase power supplyconsisting of transformer T5, positive and negative full-wave rectifiers, and two single-element filters. A sepa-rate single-phase transformer (T7) supplies 24 Vac to

the automatic power adjust circuit and relays in the con-troller section.

The +18 Vdc potential is applied to the AC ControlModule and the -18 Vdc potential is applied to both theAC Control Module and the Controller Assembly. Regu-lators in each unit establish stable sources of positiveand negative 12 Vdc. The various logic potentials aredistributed throughout the control circuitry as required tooperate the transmitter control logic.

4.2.2 RF CIRCUITSThe following text describes the RF Circuitry of theHT 20/25CD Transmitter.

4.2.3 HARRIS FM EXCITERFor information on the FM Exciter refer to the FM Ex-citer Technical Manual.

4.2.4 IPA SECTIONThe IPA Section of the HT 20/25CD consists of a RFIPA Driver module and an IPA Multimeter.

4.2.5 IPA MODULE ASSEMBLY4.2.5.1 PURPOSEThe purpose of the IPA Module is to amplify the outputof the FM Exciter to the level required to drive the PAamplifier stage to the desired level.

4.2.5.2 CIRCUIT DESCRIPTIONThe 700 watt output IPA unit consists of two 350 wattassemblies. An input power splitter provides equal drivelevels to each amplifier section from the common input.An output power combiner sums the outputs of the twosections to the common output.

The IPA is fused for DC overload protection.

The amplifier unit is operable with only one side func-tioning. However, the RF output will be reduced accord-ingly.

The input and output impedances are each 50 ohmsand the unit is rated for operation at +50 Vdc input. Inthe HT 20/25CD the typical supply voltage is +43 Vdcat the normal 400 watt operating output for 25 kW TPO.

Figure 4-2 is a simplified diagram of the RF Amplifier.

As the unit is difficult to troubleshoot and repair in thefield, it is recommended that it be returned to the HAR-RIS factory for repair.

SECONDARY PRIMARY SINGLE SECTION FILTER RIPPLE VOLTAGE

PHASES LINE (Resistive or Inductive Load)

POWER

FACTOR PEAK-TO-PEAK RMS

3 (half-wave) 0.83 50% 18%

6 (full-wave) 0.96 11% 4%

Table 4-1. Multiphase Supply Principle RippleCharacteristics


4.2.5.3 LOW-PASS FILTER AND DIRECTIONALCOUPLER

The output circuit includes a Low-Pass Filter and a Di-rectional Coupler complete on one printed-circuit board.

4.2.5.3.1 Low-Pass FilterA PI section Low-Pass Filter consisting of capacitor C3which functions as an IPA tuning control, inductors L2and L4, and capacitor C3 which functions as an IPAloading control. Additional components function as asecond harmonic notch filter. Capacitor C2 provides asecond harmonic notch filter adjustment.

4.2.5.3.2 Directional CouplerThe output circuit includes a Directional Coupler pro-duced in printed-circuit form with microstrip techniquesusing the principle that adjacent sections of microstriptransmission line share common inductive and capaci-tive coupling. The Directional Coupler provides two dcsignals, each obtained by rectifying a voltage sampleobtained from the transmission line circuitry. Because ofthe difference in directivity of the two samples, one out-put will be proportional to the forward traveling waveand the other sample will be proportional to the re-flected traveling wave.

4.2.5.3.3 Forward PortThe forward port of the Directional Coupler develops arectified rf voltage through diode CR2 produced alongthe sensing line which is terminated by the resistanceof resistor R3. The resultant dc is filtered by capacitorsC5, C6, C7, and inductor L6 and then applied to theforward power amplifier in the controller.

4.2.5.3.4 Reflected PortThe Reflected Port of the Directional Coupler is termi-nated by the resistance of R1 and R2 and nulled by thecombination of capacitor C12, inductor L7, and variableresistor R2. The rf sample developed by the ReflectedCoupler is then filtered to remove harmonic compo-nents. The single section pi filter consists of capacitorsC8, C9, and inductor L5. The filtered rf sample thenappears across resistor R4. The filtered sample is thenrectified by diode CR1, developing a negative voltageacross a resistive voltage divider formed by R5 and R6.Capacitor C10 removes any remaining rf energy fromthe sample voltage. This negative sample voltage isthen applied to the reflected power amplifier in the con-trol circuitry.

4.2.6 PA STAGEA single 8990 tetrode operated as a class C amplifier ina quarter-wave cavity functions as the RF OutputStage. The quarter-wave cavity design ensures a widebandwidth is maintained from the exciter output to thetransmitter rf output (refer to Figure 4-3). Forced aircooling ensures cool PA stage operation and long PAtube life.

The rf drive from the IPA stage is applied to the PAinput circuit which is tuned for optimum matching by acoil-capacitor combination. The control grid bias is ap-plied through a hum-null control to the grid circuit whichcancels filament emission hum from amplitude modulat-ing the rf signal.

The control grid-blocking capacitor, the screen grid-by-pass capacitor, and the plate circuit-blocking capacitor

employ a thin film of Kapton material as insulation. Thisprovides good isolation and stability at the close toler-ances required in the PA cavity.

Output coupling is accomplished by capacity tuning andloading controls. A dc blocking capacitor ensures thatthe PA TUNE control and the cavity both operate at dcground potential. The rf output is coupled to the an-tenna through a second harmonic filter, Low-Pass Filterarrangement, and a Directional Coupler. The rf couplingloops in the elbow assembly provide a means to moni-tor the transmitter rf output.

4.2.7 DIRECTIONAL COUPLERThe Directional Coupler senses the rf output and pro-vides two dc signals, each obtained by rectifying a volt-age sample obtained from the transmission line. Be-cause of the directivity of the two samples, one outputwill be proportional to the forward traveling wave andthe other sample will be proportional to the reflectedtraveling wave. The two dc voltages are applied to am-plifiers in the controller section for display by the meter-ing circuit.

Figure 4-2. Simplified Diagram RF Amplifier

Figure 4-3. RF Bandwidth for 25 kW Operation


4.2.8 CONTROL CIRCUITSThe following text describes the control circuitry of theHT 20/25CD Transmitter. Refer to applicable drawingsin the external Drawing Package.

4.2.8.1 CONTROL LOGICThe Control Logic for the HT 20/25CD Transmitter con-sists of three main boards.

The digital board contains the actual control circuits,timers, and overload circuitry. The analog board pro-vides interfacing between the digital board, statusboard, and the actual transmitter. The status board con-tains the indicators and controls associated with theControl Logic.

4.2.8.1.1 Filament Turn-OnA filament on command from remote control equipment,from extended control equipment, or from the local FILON pushbutton switch is applied to an OR gate. Thesignal from the OR gate operates the filament latch re-lay, opening its contact, and operates the blower latchrelay, closing its contact. The signal also resets theblower run-down timer, the blower flip-flop, and thethermal overloads of blower contactor K1. When theblower latch contact is closed, solid state relay K4 isactivated, which applies voltage to the primary of trans-former T1. One secondary of transformer T1 providesstepped-up voltage to the bias supply.

The second secondary functions as an isolation trans-former, providing 120 Vac to energize blower contactorK1. It also provides 120 Vac through interlock switchesto energize the drop solenoid assembly. When the fila-ment latch relay contacts open, one of the two inputs ofthe following filament gate is completed. When blowerair has increased enough to close the air interlock, thesecond gate input goes HIGH and the entire filamentgate input is satisfied. The filament gate is now acti-vated and supplies a signal via a buffer and an inverterto the gate of a triac controlling the filament contactor.The filament contactor will energize by conductingthrough the triac to ground applying voltage to the fila-ment transformer.

If the control signal on the triac’s gate is removed, thefilament contactor will deenergize when the triac ceasesconduction on the first zero-crossing of the 120 Vac ap-plied to the contactor. The FILAMENT ON indicator, ex-tended filament status circuit, and remote filamentstatus circuit also receive a positive control signal fromthe filament gate. The filament gate output supplies atriggering signal to the filament warm-up timer and areset pulse to the filament flip-flop. Note that there is aplug with two possible positions associated with the fila-ment warm-up timer. This plug (P2) is used to chooseeither a 20-second or a 3-minute filament warm-uptime. At the end of the warm-up timer a positive-goingclock pulse is applied to the input of the filament flip-flop. This clock pulse sets the Q output of the flip-flopHIGH and Q* flip-flop output LOW. The Q output com-pletes one input of the plate gate.

4.2.8.1.2 Plate ControlFour inputs to the plate gate must be satisfied beforethe plate can be turned on. One of the three remaining

inputs is the external interlock. A representation of anexternal interlock closure is shown on the diagram.

This closure could be a load water interlock or anyother interlock for which it is desired that the plate re-turn to ON condition as soon as the interlock is re-leased without further commands. The transmitter isequipped with an indicator LED to indicate the occur-rence of an external interlock.

The third input to the plate gate comes from the over-load circuit. Under normal conditions without any over-loads present the output from the overload circuit isHIGH. Thus, three of the four inputs to the plate gateare now HIGH. The fourth input to the plate gate comesdirectly from the plate latching relay A1K3. This relay isactivated by the local PLATE ON pushbutton switch orany PLATE ON remote commands, and is OR gateddirectly to the plate latching relay. This command opensthe plate latching relay contacts supplying the fourthHIGH input to allow completion of the plate gate. Theoutput of the plate on input OR gate is also connectedto an input of the filament on input OR gate. All of thepreceding operations can be initiated by entering aPLATE ON command. As shown in the logic diagram,the PLATE ON command from the plate on OR gate isapplied through diode A1CR4 to the filament on ORgate. In this manner, a PLATE ON command will initiatethe entire turn-on sequence of the transmitter. This isreferred to as a one-button start.

The LOW output of the plate gate is inverted and usedto enable the AFC overload input to permit an exciterfault condition to remove the transmitter from the aironce the transmitter is in operation. @NOTE = Note

When using the Exciter, the term AFC stands for Auto-matic Fault Control, not Automatic Frequency Control.In the audio is not applied to a VCO to create the FMsignal but is generated digitally and then converted toanalog. The AFC fault is a general exciter fault outputwhich covers several possible exciter faults. For moreinformation, refer to the FM Exciter Technical Manual.

The LOW is also applied to one input of the failsafe ORgate. As long as one of the two inputs to the failsafeOR gate is HIGH the output will be HIGH, preventingthe plate voltage from being energized. The second in-put to the failsafe OR gate comes from a NOR gatewhose output is HIGH until one of its two inputs is pre-sented with a HIGH. When the front panel NOR-MAL/LOCAL switch is in the LOCAL position a HIGH isapplied to one input of the failsafe NOR gate causing itsoutput to go LOW enabling the failsafe OR gate. If theNORMAL/LOCAL switch is in the NORMAL position+12 volts is furnished to the remote equipment, whichprovides a contact closure returning the +12 volts to thefailsafe NOR gate as a HIGH. In the event that the re-mote equipment fails the closure opens presenting aLOW to the NOR gate disabling the failsafe OR gateand removing the transmitter plate voltage. The LOWoutput from the failsafe OR gate is inverted to illuminatethe PLATE ON indicator and to drive the remote indica-tor circuits. A second inverter applies the plate on sig-nal to the base of transistor A12Q1 biasing it into con-duction and energizing relay A12K2 through normallyclosed contacts of relay A12K1. The closure of a set of


contacts on the relay A12K2 in turn energizes the step-start contactor in the power supply applying voltage tothe plate transformer primary through surge resistors.

A set of contacts on the step-start contactor energizesthe main contactor which bypasses the current limitingresistors and applies full voltage to the primary. An ad-ditional set of contacts on the main contactor connectsrelay A12K1 to the collector of transistor A12Q1. Be-cause transistor A12Q1 is biased into conduction by theplate on signal, relay A12K1 will energize applying +Vto the triac controlling the IPA contactor and at thesame time remove +V from relay A12K2. Another set ofcontacts on relay A12K1 supplies the 120 Vac return tothe main contactor keeping it energized when the step-start contactor opens due to the removal of its 120 Vacreturn by relay A12K2.

Delayed plate on signals are provided by capacitorA2C8 discharging through resistor A2R93 to the exciterrf mute circuit and by capacitor A2C7 dischargingthrough resistor A2R94 to the automatic power enablecircuit.

These delayed signals allow the plate voltage to reachfull potential and stabilize prior to application of rf driveand automatic power control.

Plate turn off is accomplished either from the localPLATE OFF pushbutton switch or remote plate off com-mands. The plate off commands are OR gated and ap-plied directly to the contact close coil of the plate latch-ing relay.

The closed contact applies a LOW to one of the plategate inputs, turning transistor A12Q1 off thus removingplate voltage.

4.2.8.1.3 Overload CircuitsWhen an overload occurs, an SCR associated with thatoverload input signal is triggered, resulting in illumina-tion of an LED indicator on the front panel of the trans-mitter. That same overload input is applied to an ORgate input, the output of which triggers an overloadtimer and a fault timer.

The overload timer produces a three-second pulsewhich is inverted and becomes a LOW plate gate inputsignal. This pulse shuts off the plate for approximatelythree seconds. This same inverted signal is applied totwo fault flip-flops and the overload AND gate. The endof the negative pulse becomes a positive-going clockpulse causing the first flip-flop to change state such thatthe Q output becomes HIGH. The second flip-flop doesnot change state from this initial pulse because its datainput line has been LOW. However, the first flip-flop Qoutput has now changed the second flip-flop data inputline to a HIGH. If a second overload occurs, the over-load signal is again applied to the OR gate and triggersthe overload timer. The timer produces a three-secondpulse which is inverted. This pulse shuts off the platefor three seconds and clocks the second flip-flop caus-ing the Q output to go HIGH. If a third overload occurs,it also is applied to the OR gate and triggers the over-load timer.

This time, however, the overload timer output pulse af-ter being inverted, along with the Q output of the sec-

ond flip-flop completes the overload AND gate. The out-put of the overload AND gate becomes a plate off com-mand applied to the plate off OR gate. The plate off ORgate output opens the plate latch relay contacts andturns off the transmitter plate voltage. The transmitterwill not return to the plate on condition until a plate oncommand occurs. The output of the overload AND gatealso operates a fault latch relay which illuminates theFAULT indicator. The operator then has an indicationthat three overloads have turned off the transmitter.Note that the plate on command resets the fault latchrelay.

As mentioned previously, the fault timer is triggeredfrom the initial overload. It produces a pulse of approxi-mately 30 seconds. If two additional overloads have notoccurred within this 30-second period, the end of the30-second pulse produces reset pulses for both faultflip-flops. The result of this action is that three over-loads must occur within 30 seconds to set the transmit-ter to a condition where reapplication of the plate volt-age requires an operator plate on command. Note thata plate on command will terminate the 30-second pulseby resetting the timer. Jumper plug P3, after the secondflip-flop, allows the transmitter to be operated in a modesuch that any single overload will require an operatoron command to reestablish plate voltage.

As previously described, the devices that illuminate theoverload LED’s are silicon controlled rectifiers (SCR).Because an SCR will allow current flow after its triggeris removed, the SCR acts as a memory device main-taining the overload LED illumination even after theoverload trigger signal has been removed. The overloadLED’s are extinguished by applying a positive voltage tothe base of A2Q17 biasing it off thus removing conduc-tion through the LED’s and SCR’s.

4.2.8.1.4 InterlocksAs is shown in the logic diagram, interlock circuitry isconnected to the plate-off input OR gate to shut offtransmitter plate voltage when the interlock violation oc-curs. The interlock switch provides a LOW to illuminatethe appropriate LED indicator. When these interlocksare released, an operator plate on command must begiven to reestablish plate voltage. When an external in-terlock is activated and released, an operator plate oncommand is not required because the external interlockis applied directly to the plate AND gate.

The HT 20/25CD Transmitter is also provided with a setof 120 Vac interlocks that consist of the other half of thecontroller interlock switches. The 120 Vac interlockswitches are connected in a series loop providing 120Vac to the drop solenoids, L1 and L2, in the High Volt-age Power Supply cabinet.

When an interlock in the Transmitter Cabinet or HighVoltage Power Supply is opened, two events occur si-multaneously, 1) one-half of the interlock switch sendsa plate off command to the controller which illuminatesthe proper interlock indicator and deenergizes the platecircuits, and 2) the other half of the interlock switch re-moves 120 Vac from the drop solenoids which deener-gize and short the plate voltage line to ground through100 ohms.


4.2.8.1.5 Filament Turn-OffFilament off is accomplished by applying a filament offcommand to the filament off input OR gate either viathe transmitter front panel control or the remote filamentoff controls. The output of the filament off OR gate com-mands the filament latching relay to the contact closeposition, applies a plate off command through the plateOR gate, resets the filament warm-up timer, and initi-ates the blower run-down timer. After the filaments andplates of the transmitter have been turned off theblower run-down timer allows the blower to cool downthe power tube for approximately three minutes beforeshutting off the blower. The signal from the filament offOR gate triggers the timer, the output of which is athree-minute width pulse applied to an inverter. The endof the pulse produces a clock signal which triggers theblower flip-flop. Its Q output then goes LOW. This signalis inverted, resets the blower latch relay, and removesthe voltage from the solid-state blower relay and theblower contactor, shutting off the blower.

The filament off signal from the filament off OR gatealso resets the filament warm-up timer. Thus assuresthe filament warm-up timer is prepared to accept thenext filament on trigger signal.

4.2.8.1.6 AC Failure CircuitsThe filament, blower, plate, and fault circuits areequipped with latching relays which inherently havememory capability independent of ac power failures. Af-ter an ac power failure, these devices will remain in thestate they were in before the failure. Another device as-sociated with ac power failure is the ac fail gate. Thisdevice, with its associated capacitor and resistor, timesthe ac power failure and modifies the filament warm-uptime accordingly when power returns. During normaloperation the capacitor shown on the input of the ac failgate is charged via the Q output from the filament flip-flop. During an ac power failure the capacitor dis-charges through the resistor A1R32. If the power failurehas been brief, the capacitor will not fully discharge.When power returns, the charge on the capacitor pre-sents a HIGH to the input of the ac fail gate and thefilament warm-up timer will begin timing again, produc-ing a HIGH which is applied to the second input of theac fail gate. Also, when power has been applied, V+ isnow present at the third input of the ac fail gate. Underthese conditions the output of the ac fail gate will beHIGH and applied to the input of the OR gate associ-ated with the reset input on the filament warm-up timer.The output of the OR gate generates a reset commandwhich will immediately terminate the timing pulse at theoutput of the timer. This action will trigger the filamentflip-flop and turn the transmitter back on. The precedingevents will occur after an ac power failure up to 10 sec-onds. After 10 seconds, the capacitor on the input ofthe ac fail gate will have been very nearly discharged.Therefore, when ac power is reapplied the input to theac fail gate from the capacitor is LOW. The ac fail gateoutput will then be LOW and the reset command intothe filament warm-up timer will not occur. The filamentwarm-up timer will complete its full time-out before platevoltage is reapplied. Jumper P1, on the output of the acfail gate, allows the operator to force a full warm-upperiod after any ac power failure. This may be desired

in some installations, especially where tube life is ofprime concern.

The last device, associated with ac power failure, is acapacitor on the trigger input of the blower run-downtimer. During the blower run-down cycle, the filamentlatch relay contacts are closed discharging this capaci-tor. The purpose of this capacitor is to reset the blowerrun-down timer in the event of an ac power failure dur-ing the blower run-down cycle.

If an ac power failure occurs, the discharged capacitorcauses a LOW trigger input signal to the blower run-down timer when power is restored. This will restart thefull blower run-down timing cycle to ensure proper cool-down.

4.2.8.1.7 Automatic Power ControlThe HT 20/25CD Transmitter control logic contains cir-cuitry used to maintain the transmitter output powerwithin approximately two or four percent (selected) ofthe operator set power level.

Refer to drawing 839-7618-001 - Simplified SchematicAutomatic Power Control for the following discussion.

Power out of the transmitter can be controlled by rais-ing or lowering the screen voltage. Motor driven vari-able transformer T2, connected to the primary of screentransformer T3, will vary the dc screen voltage from ap-proximately 100 volts to 1000 volts. This, in turn, willvary the transmitter power from approximately eightpercent above 25 kW to a lower limit of approximately75 percent below 25kW. The lower limit will be depend-ent upon how quickly the IPA reflected rises as a resultof the change in PA tube input impedance changes asa result of the greatly lowered screen voltage. This mis-match condition may be corrected by retuning of the PAgrid input circuit. Without this retuning, the lower powerlimit will be the point at which the IPA reflected powerreaches the preset overload level.

Front panel POWER OUT AUTO/MANUAL switch S1will allow Remote Direct Screen relay 1A15K1 to switchbetween auto and manual control of motor B2. Whenthe relay is in the Manual position POWER OUTRAISE/LOWER switch S2 provides the return line tooperate the motor. In the AUTO position the return linefor the motor is provided by triacs. In either the Auto orthe Manual power control modes, limit switches removethe return line if transformer T2 reaches the end of itsrange.

As previously stated, when the transmitter is in theAutomatic power control mode, the return line for themotor is provided by triacs. The control signals for thetriacs are generated by the over-power and under-power comparators. As shown in the simplified sche-matic the reference voltage for both comparators is de-rived from power-set potentiometer R1, which acts as avariable voltage divider. The reference voltage is di-rectly applied to the noninverted input of the under-power comparator. Reference voltage for the over-power comparator is applied through an operationalamplifier used as a non-inverting summing amplifier.The voltage from the power-set potentiometer is addedto a voltage derived from a fixed voltage divider consist-ing of resistors R52, R53, R5D, and R5E. Jumper plug


P1 allows selection of one of two fixed voltages to beadded. In this manner the reference voltage applied tothe inverted input of the over-power comparator isslightly higher than the reference voltage applied to theunder-power comparator. This difference in referencevoltages sets the “window” of the automatic power con-trol range. Changing the jumper increases or decreasesthe width of the “window” by increasing or decreasingthe volt age added to the reference voltage of the over-power comparator.

Transmitter forward power metering voltage is sampledand applied through a buffer to the non-inverted input ofthe over power comparator and the inverted input of theunder power comparator. If the transmitter power outdecreases causing the forward metering sample voltageto decrease below the reference voltage “window”, theunder power comparator output will go HIGH and beapplied to the enable gate. Assuming the delayed plateon command is HIGH, the enable gate will output aHIGH to the power raise gate. The second input to thepower-raise gate will also be HIGH from the invertedoutput of the power-lower gate. With both inputs satis-fied, the power-raise gate HIGH output is inverted twiceand applied to the gate of the triac controlling thepower-raise return line of motor B2. When the transmit-ter power increases, the metering sample voltage willreturn to within the “window”. As this happens the un-der-power comparator output will return to LOW revers-ing the above sequence and removing the control sig-nal from the triac gate. On the other extreme if thetransmitter output power increases causing the meter-ing sample voltage to increase above the “window”, theover-power comparator output will go HIGH and be ap-plied to the enable gate. The output of the enable gateis gated through the power-lower gate, inverted twice,and applied to the triac gate controlling the power-lowerreturn of B2. The outputs of the power-raise and power-lower gates are also connected to LED’s to indicate thepresence of a control signal.

A small amount of positive feedback or hysteresis isadded to both comparators to ensure positive switchingand minimize hunting. The feedback of over-powercomparator integrated circuit U7B is to the forwardpower metering voltage input. When the forward powermetering voltage (output of integrated circuit U7A) isless positive than the reference input voltage, the out-put of the comparator is low or ground. In this case,R55 and R56 form a voltage divider to ground so thatthe actual input to the comparator is one percent lessthan the output of buffer integrated circuit U7A. As theforward power metering voltage increases, it must goone percent above the reference voltage before thecomparator will switch and its output goes high. When itdoes switch, the resistive divider (resistors R55 andR56) is no longer referenced to ground, but to the posi-tive output voltage. This causes the actual voltage atthe forward metering input to be equal to or greaterthan one percent higher than the output of buffer inte-grated circuit U7A. As the auto power control systemlowers the transmitter output power and the meteringvoltage decreases, it must go one percent below thereference before the comparator will switch to a lowoutput. When it does, the voltage divider is again refer-

enced to ground. The under-power comparator (inte-grated circuit U7C) operates in the same manner ex-cept the one percent hysteresis, rather than modifyingthe forward power metering voltage, acts upon the ref-erence voltage through the resistive divider formed byresistors R5H and R57.

The PWR SET potentiometer, which controls the refer-ence voltage for the comparators, is a motorized poten-tiometer. Remote commands, extended commands,and local commands from the LOCAL PWR SETRAISE/LOWER switch are OR gated, inverted, andthen applied to the triacs controlling the motorized PWRSET potentiometer.

4.2.9 VSWR FOLDBACK CIRCUITThe VSWR FOLDBACK CIRCUIT is intended to providea slow reduction of the HT 20/25CD RF power outputas the antenna load VSWR increases. This feature al-lows the HT 20/25CD to stay on the air to maintainservice continuity, even though the antenna VSWR mayexceed normal operating values due to the gradualbuild up of ice, the typical cause of high VSWR.

The control circuitry will automatically reduce the RFoutput power to a safe operating level for VSWR valuesabove a preset point. The foldback circuit will automat-ically track the increase or decrease of the load VSWRand will correspondingly increase or decrease the out-put power over a wide range as the icing conditionchanges. When the icing condition has subsided andnormal VSWR values are obtained, the VSWR foldbackcircuit will restore the RF PA stage back to its normaloperating power automatically with no operator controlrequired.

A quick reference drawing illustrating foldback circuitoperation is shown in Figure 4-4, while descriptive textdiscussing important points about foldback operationfollows.

4.2.10 CIRCUIT OPERATIONThe foldback circuit is designed to follow gradualchanges in load VSWR due to antenna icing in the gen-eral case, but other causes of load VSWR, for example,moisture accumulation in the antenna feed lines, powerdividers or the main transmission will also activate thefoldback circuit. The control initiation is aimed at track-ing gradual VSWR changes and will automatically ad-just the RF output to accommodate the load changesbut an abrupt change due to a momentary open orshort circuit caused by an RF arc or intermittent trans-mission line connection will activate the standardHT 20/25CD fast acting VSWR overload trip circuits.The foldback circuit operates in parallel with the stand-ard VSWR protection circuits so that a sudden changein the load VSWR will trip the transmitter in the usualmanner while gradual changes in VSWR will be sensedand controlled by the foldback circuit.

The foldback circuit adjusts the RF output by adjustingthe PA stage screen voltage. The speed of response offoldback action will be equal to the time required to runthe motor driven screen control potentiometer.

Typically, the motor driven potentiometer will take about30 to 40 seconds to run the screen voltage over a


Figure 4-4. VSWR Foldback Operation


range from 1000 volts down to about 100 volts andsubsequently will reduce the RF output from 25 kWdown to about 5 kW. The actual output power and con-trol range will vary according to the normal transmitterTPO.

The foldback circuit also operates in parallel with theautomatic power control circuit which maintains con-stant power output over a selected range (+/-4% or +/-2%) and drives the same screen control motor potenti-ometer.

Since the foldback circuit operates in conjunction withthe automatic power control circuit, the auto power con-trol circuit must be switched ON (remote or front panelselectable) to obtain the benefits of both the auto powercontrol and VSWR foldback features. When the autopower circuit is switched to the manual position, boththe auto power and foldback circuits are switched off.Under these conditions, the transmitter output powercan be adjusted manually from the front panel by tog-gling the raise and lower switch (a front panel momen-tary up or down, center-off switch).

NOTETouch up tuning of the transmitter should alwaysbe done in the manual position.

If it is desired, the foldback circuit can be switched OFFindependently leaving only the auto power control cir-cuit activated. The foldback ON/OFF switch S-1 is lo-cated on the analog control board behind the frontpanel access door (refer to the set-up and operationsection).

The foldback circuit continuously monitors the reflectedpower from a directional coupler sample that drives thetransmitter VSWR meter circuit.

Foldback action can be initiated by setting a trip point tothe desired VSWR level that will begin power foldback,however, two set points are provided.

The reason for this is to provide the operator withenough adjustments to handle the wide variations ofload impedance that may be expected in the field andto safely operate the HT 20/25CD while running in theauto power mode. The first threshold set point (R117) isnormally set to a VSWR value below the point wherepower foldback is desired to begin. The first set point isused to flash a red LED warning indication on the frontpanel to alert the operator of a high VSWR conditionand to inhibit the auto power system from attempting toincrease the RF output power in response to the loadchange. This is shown as condition A in Figure 4-4. Aremote VSWR foldback indication is also activated atthis time.

The basic intent of the first set point is to flash a redLED warning indicator and to inhibit the auto powersystem, but in addition, the first set point is selected toprevent the PA stage plate and screen currents fromrising to overload values when the PA stage is detuneddue to the changing antenna load. Under detuned con-ditions, the PA stage RF output will decrease and theplate and screen currents will increase. The auto powersystem sensing low RF output power will then attemptto raise the output power back to normal causing an

additional increase in plate and screen currents. Thefirst set point is used to inhibit this action and to providethe operator with a field adjustment to safely limit oper-ating current values for the applied VSWR. Normally,the first set point is factory set to 1.3:1 VSWR which willsatisfy most field conditions and will limit the plate andscreen currents to levels well below their respectiveoverload points. It should be noted that detuning effectsof the PA stage under higher than normal VSWR is tobe expected and is the normal course of events forwhich the first set point is intended to take into account.

The second set point (R118) is intended to be adjustedto a VSWR value slightly above the first value, typically1.35:1. This is also factory set. When the load VSWRincreases to this value, then power foldback begins.This is shown as condition B in Figure 4-4. This is indi-cated by a alternating green and red flashing LED onthe front panel. At this time the PA stage screen volt-age is lowered by operating the motor driven PA screenpotentiometer. The flashing green LED is alternatedwith the red flashing LED previously activated by SETPOINT 1. The foldback LED indicator is a single pack-age, dual red/green LED to provide a distinctive indica-tion set apart from the other red and green LED indica-tors on the front panel. The green LED will continue toflash alternately with the red LED until the RF outputpower is reduced to a point where the reflected powerproduces a voltage sample below the second set point.The flashing green LED then stops but the red LEDcontinues to flash to alert the operator that the reasonfor the power reduction is a VSWR foldback condition.The red LED indicator will continue to flash as long asthe foldback condition persists due to high VSWR. Thisserves to assist the operator in identifying the cause ofreduced power output which may result from otherproblems, for example, low drive, low PA tube emis-sion, power supply faults, etc. When a power reductioncondition occurs that is not the result of high VSWR butis due to other causes, then the red/green LED flashingindicator will not illuminate.

The foldback circuit will continue to monitor the VSWRcondition and will effectively track VSWR changes forboth increasing and decreasing values.

For further VSWR increases after the first onset of fold-back, the process repeats. When the VSWR sampledvoltage again exceeds the second set point, the PApower output will be further reduced, the green LED in-dicator will flash alternately with the red section to indi-cate foldback action is taking place. The process stopsagain with only a red flashing indicator after the VSWRvoltage sample again drops below the second set point.This circuit action will continue until the PA screen volt-age is brought near to the bottom of its range, approxi-mately 100 volts. The VSWR at this point may be ashigh as 4 to 1. The PA stage plate and screen current,however, will be very low and the RF output power willbe less than 20% of full output. The PA stage underthese conditions is just idling with very little dissipationbut with enough output power to maintain primary serv-ice coverage.

If at any time during a foldback condition the VSWRdecreases, then the red flashing LED will stop and the


green power raise LED (same BI-LED indicator) will illu-minate to indicate that the power output is being raisedup to the next safe power level for the VSWR presenton the line. If the VSWR condition returns to normal,the foldback circuit will track the change so as to re-store PA stage to full operating power automatically.During the power raise procedure, the red flashing LEDwill stop, the auto power system will be activated toraise the power, illuminating the steady green LEDraise indicator, and the remote foldback indicator will beturned off.

4.2.11 CIRCUIT DESCRIPTIONRefer to drawing 839-7617-001, Simplified VSWR Fold-back Schematic for the following discussion. TheVSWR voltage sample from the metering circuit is ap-plied to the inverting inputs of voltage comparatorsU11C and U11D. The adjustable voltage reference tooperate comparator U11C is obtained from SET POINT1, R117. When the input VSWR sample exceeds theSET POINT 1 voltage, comparator U11C output willtoggle from a normal low to a high condition turning onQ22 to inhibit the auto power raise circuit and Q23 toprovide a remote indication to alert the operator that ahigh VSWR now exists. In addition, the high outputfrom U11C will activate the foldback flasher circuit con-sisting of U11A and Q24, LED drivers, to flash the redsegment of the BI-LED indicator on the transmitter frontpanel. At this time the following conditions prevail.

The VSWR level has exceeded the first set point.

The auto power circuit has been inhibited to preventany further attempt to raise the transmitter outputpower.

The red segment on the transmitter front panel nowflashes to warn the operator of a high VSWR condi-tion.

The remote status indicator will alert the remote op-erator with a steady, holding closure to ground that ahigh VSWR condition exists.

The actual foldback of the transmitter output power hasnot yet begun. The first set point level is used as aninhibit and warning function normally set to a VSWRlevel slightly above the normal operating value, typically1.3:1. The transmitter will stay in this condition as longas the VSWR sample stays above SET POINT 1 andbelow SET POINT 2. If the VSWR sample increasesfurther to a point that exceeds SET POINT 2, then theoutput of voltage comparator U11D will toggle from anormal low to a high condition activating the auto powerlower circuits. The auto power control circuit then acti-vates the motor driven screen voltage potentiometer toreduce the screen voltage until the RF output powerhas been correspondingly reduced to a point where theVSWR voltage sample falls back to a level below SETPOINT 2. The foldback flasher circuit activates U11A,used as a logic gate, through Q2, to provide a highoutput for the green LED driver Q25. The flasher circuitconsisting of U11B, R119 and C31 will oscillate with asquare output to effectively drive the green and redsegments of the BI-LED through Q24 and Q25. The netresult is an alternating red and green flashing indicatoron the transmitter front panel. This serves to alert theoperator that the transmitter RF output power is being

reduced. The green flashing will stop when the VSWRsample voltage drops below SET POINT 2.

The red LED segment of the BI-LED will continue toflash. This serves to alert the operator that the reasonfor the low transmitter output power is due to action ofthe VSWR foldback circuit and not due to other faults inthe transmitter. During the time that SET POINT 2 isexceeded the following conditions exist.

1. The auto power lower circuit is activated.

2. The motor driver screen voltage potentiometeris activated.

3. The BI-LED front panel indicator will alter-nately flash red and green.

The above foldback process will continue for each in-crease in VSWR until the screen voltage is reduced tonear 100 volts with a resultant transmitter output powerof approximately 15% to 20%. This level still maintainsprimary area coverage without going off the air.

When VSWR falls back to its normal value and theVSWR voltage sample drops below SET POINT 1, thenthe high outputs of U11C and U11D toggle to a lowstate shutting down the flasher circuit and activating theauto power raise circuit. At this time the following condi-tions exist.

1. The red and green flashing stops.

2. The auto power raise function is activated.

3. The green LED raise indicator is illuminated.

The above raise procedure will continue to raise the RFoutput power back to normal operating values or untilSET POINT 1 is again exceeded. This may occur dur-ing the power raise procedure where the VSWR maynot have returned to normal but is at an intermediatepoint. In this case, the foldback will increase RF outputto the highest safe operating level where SET POINT 2is not exceeded. In this manner, the foldback circuit willautomatically track VSWR values as they increase ordecrease.

Refer to the drawing 839-7816-001 for a functional viewof how the VSWR circuit is integrated into the autopower control circuit.

4.2.12 METERINGThe following text describes the metering circuitry usedto monitor the various operating parameters of theHT 20/25CD Transmitter.

4.2.12.1 POWER METERING AND VSWR OVER-LOADS

The analog circuit board of the control logic containsforward and reflected metering circuits for the poweramplifier and the intermediate power amplifier. Becausethe circuits operate in an identical manner, only thepower amplifier circuits will be discussed. Refer to Fig-ure 4-5 for following discussion.

Figure 4-5 shows the relationship of the DirectionalCoupler, the meter, and the associated circuitry. Thenegative voltage from the Directional Coupler forwardsample is applied through the forward calibration poten-tiometer to the inverting input of an amplifier. The out-put of this amplifier is again amplified, without inversion,


Figure 4-5. Simplified Power Metering


and applied through the FORWARD/REFLECTEDPOWER switch to the positive terminal of the POWERmeter.

The negative terminal of the POWER meter is atground potential. Remote and extended metering is pro-vided by amplifying the output of the inverting amplifier.The reflected power is monitored in a similar manner.An additional output of the reflected inverting amplifieris applied to the noninverted input of a VSWR compara-tor. PA VSWR OVLD SET potentiometer R25 acts as avoltage divider and supplies the reference voltage tothe VSWR comparator. When the meter voltage ex-ceeds the preset reference voltage the comparator out-put goes HIGH. This HIGH is applied to the overloadcircuitry discussed in paragraph entitled OVERLOADCIRCUITS. The forward metering voltage of the poweramplifier is applied to the automatic power control cir-cuitry described in paragraph entitled AUTOMATICPOWER CONTROL.

Refer to Figure 4-6 Simplified Plate Current Overloads.The plate overload circuit consists of a fixed comparatorand a variable comparator OR gated to the plate cur-rent overload SCR. When plate voltage is initially ap-plied, the plate current sample is applied to the nega-tive input of the fixed comparator. The positive input isfrom a voltage divider consisting of resistors A2R41 andA2R42. If initial plate current exceeds nine amperes

(determined by resistors A2R41 and A2R42) the com-parator output goes HIGH and is applied through theOR gate to the appropriate SCR. The plate currentsample is also applied to the negative input to the vari-able comparator.

The positive input to the variable comparator is derivedfrom the voltage divider containing the PA PLT OVLDSET potentiometer, which is normally set for an over-load of four amperes at 25 kW output. If the transmitterplate current exceeds the pre-set trip point the compa-rator output goes HIGH and is applied to the plate cur-rent overload enable gate. The second HIGH input tothe enable gate is the delayed plate-on signal. If thedelay time has elapsed, the overload signal is appliedto the appropriate SCR through the plate overload ORgate. The enable gate prevents any initial turn-on surgeof plate current from tripping the plate overload circuits.

4.2.12.2 PLATE METERING AND CURRENT OVER-LOADS

Plate voltage and current are monitored by meters M4and M5 respectfully.

Resistors R20 and R21 (transmitter cabinet) are metermultipliers for the plate voltage meter. Resistors R11through R15 (transmitter cabinet) act as parallel metershunts for the plate current meter which is in the nega-tive lead of the plate power supply. Resistors R17

Figure 4-6. Simplified Plate Current Overload


through R19 (transmitter cabinet) are used as metermultipliers. Resistor R19 is selected for proper meterindication in factory test as the value may vary fromtransmitter to transmitter. Zener diode CR7 providesprotection to the plate current meter. Resistors R12through R16 (located in the High Voltage Power Supplycabinet) provide the top leg of a voltage divider used forextended and remote plate voltage metering. A poweramplifier plate current sample is provided through resis-tor R16 (located in the transmitter cabinet) to the con-trol logic overload circuits.

The screen overload circuits operate in an identicalmanner as the plate overload, with the fixed comparatorset to have an output at 900 mA screen current.

4.2.12.3 MULTIMETER CIRCUITSMultimeter M2 monitors screen voltage and current, gridbias voltage and current, or filament voltage.

4.2.12.3.1 Screen CircuitsResistors R22 and R23 are used as meter multipliersand resistor R26 as a shunt for the multimeter in theSCREEN VOLTAGE switch position. In the SCREENCURRENT switch position, resistor R23 is used as amultiplier for the meter, while diode CR1 provides meterprotection. The meter is used to monitor current in thenegative lead of the screen power supply. A sample forthe screen current overload circuit is provided throughresistor R20.

4.2.12.3.2 Bias CircuitsThe BIAS VOLTAGE switch position monitors grid biasvoltage at the center tap of transformer T6. ResistorR24 is a meter multiplier and resistor R25 is the metershunt. Resistor R1 and R10 serve as the same func-tions respectfully when the switch indicates BIAS CUR-RENT.

4.2.12.3.3 Filament CircuitsWhen the multimeter switch is in the FILAMENT VOLT-AGE position the multimeter is connected in series withthe V output of integrated circuit U1 and an offset volt-age. The offset voltage gives the meter an expandedscale of 7 to 12 volts ac. The output voltage of inte-grated circuit U1 is a dc voltage, which corresponds tothe true RMS voltage input of integrated circuit U1 re-gardless of the waveform shape. Input voltage for inte-grated circuit U1 is developed across the voltage di-vider consisting of resistor R1 in the transmitter cabinetand resistor R2 on the AC Control Board. It should benoted that the return lead of resistor R2, integrated cir-cuit U1, and other components associated with the fila-ment voltage meter circuit are connected to the groundpotential side of the power amplifier tube cathode. Inthis manner the dc voltage out of the integrated circuitrepresents the true RMS voltage of the filament. Resis-tors R5 and R6 are a voltage divider furnishing -V tointegrated circuit U1, while the divider (resistors R7 andR8) provide +V to the integrated circuit. The offset volt-age is present whenever the filament voltage is present.

Meter M1 of the IPA multimeter assembly monitors IPAcurrent and IPA power supply voltage. In Figure 4-14,the IPA multimeter is shown as it electrically appears inthe circuit with the parameter measured listed next tothe meter. The multimeter is not in the circuit unless theIPA multimeter switch indicates that position.

4.2.12.3.4 Driver CircuitsResistor R34 is used as a current shunt, resistor R35as a current limiting resistor, and R1 as a meter multi-plier to measure Driver module current. To measureIPA voltage, R3 is used as a current limiting resistorand R2 is used as a meter multiplier.

Figure 4-7. Simplified Metering (IPA)


SECTION VMAINTENANCE

5.1 INTRODUCTIONThis section provides preventive maintenance checks,cleaning, and corrective maintenance information forthe HARRIS HT 20/25CD FM BROADCAST TRANS-MITTER.

5.2 PURPOSEThe information contained in this section is intended toprovide guidance to establish a comprehensive mainte-nance program to promote operational readiness andeliminate down time. Particular emphasis is placed onpreventive maintenance and record keeping functions.

5.3 STATION RECORDSThe importance of keeping station performance recordscannot be over emphasized. Separate logbooks shouldbe maintained by operation and maintenance activities.These records can provide data for predicting potentialproblem areas and analyzing equipment malfunctions.

= TRANSMITTER LOGBOOK

As a minimum performance characteristics, the trans-mitter should be monitored (using front panel indicators)and the results recorded in the transmitter logbook ateach shift change or at least once per day.

5.3.1 MAINTENANCE LOGBOOKThe maintenance logbook should contain a completedescription of all maintenance activities required tokeep the transmitter operational. A list of maintenanceinformation to be recorded and analyzed to provide adata base for a failure reporting system is as follows:

DISCREPANCY

Describe the nature of the malfunction. Includeall observable symptoms and performance char-acteristics.

CORRECTIVE ACTION

Describe the repair procedure used to correct themalfunction.

DEFECTIVE PART(S)

List all parts and components replaced or re-paired. Include the following:

a. COMPONENT TIME IN USE

b. COMPONENT PART NUMBER

c. COMPONENT SCHEMATIC NUMBER

d. COMPONENT ASSEMBLY NUMBER

e. COMPONENT REFERENCE DESIGNATOR

SYSTEM ELAPSED TIME

Total transmitter time on.

NAME OF REPAIR PERSON

Person who actually made the repair.

STATION ENGINEER

Indicates chief engineer noted and approved thetransmitter repair.

5.3.2 SAFETY PRECAUTIONSIt is very dangerous to attempt to make measurementsor replace components with power on. The design ofthe transmitter provides safety features such that if thecabinet is opened while power is applied, an interlockswitch will remove all transmitter and exciter primary acpotentials. However, ac line potentials exist within thechassis even if the interlock operates. Therefore, theprimary ac disconnect should be opened prior to servic-ing the unit.

Do not short out or bypass interlock switches as amaintenance short cut.

Module removal or replacement with power energized isnot recommended.

5.4 PREVENTIVE MAINTENANCEPreventive maintenance is a systematic series of opera-tions performed periodically on equipment. As theseprocedures cannot be applied indiscriminately, specificinstructions are necessary.

a. Visual inspection is the most important preven-tive maintenance operation because it deter-mines the necessity for the others. Becomethoroughly acquainted with normal operationconditions in order to recognize and identify ab-normal conditions readily. The remedy for mostvisible defects is obvious, however care must betaken if heat damaged components are located.Overheating is usually a symptom of trouble. Itis essential to determine the actual cause ofoverheating before the heat damaged compo-nent is replaced, otherwise the damage may berepeated. Inspect for:

1. Overheating, indicated by discoloration, bulg-ing parts and peculiar odors.

2. Leakage of grease and oil.3. Oxidation.4. Dirt, corrosion, rust, mildew and fungus

growth.b. Check parts for overheating, especially rotation

parts such as the blower motor. The need forlubrication, the lack of proper ventilation, or theexistence of some defect can be detected andcorrected before serious trouble occurs. Be-come familiar with operating temperatures in or-der to recognize deviations from the normalrange.

c. Tighten loose screws, bolts, and nuts. Do nottighten indiscriminately as fittings that are tight-ened beyond the pressure for which they aredesigned may be damaged or broken.

d. Clean parts when inspection shows that clean-ing is required.

e. Make adjustments when inspection shows thatadjustments are necessary to maintain normaloperation.

f. Lubricate meshing mechanical surfaces atspecified intervals with specified lubricants toprevent mechanical wear and keep the equip-ment operating normally. Do not over lubricate.


g. Paint surfaces with the original type of paint(use prime coat if necessary) when inspectionshows rust, worn or broken paint film.

5.4.1 FILTER CLEANINGOne filter is provided in the back of the HT 20/25CDTransmitter cabinet. Clean each filter periodically withwarm water and a mild detergent with replacementdone on an as-needed basis. Additional filters may beordered from HARRIS to assist in maintenance (HAR-RIS Part No. 922\0446\018).

CAUTIONchCAUTIONTEXT = DO NOT OIL THE FILTER. THEFILTER WILL CLOG IF OILED. THE AIR FILTER ISTO BE INSTALLED DRY.

5.4.2 BLOWER MAINTENANCEInspect the blower for dust accumulation periodically.Remove the dust with a vacuum cleaner and brush.Check the impeller for wear. The motor bearings aresealed and lubricated for approximately 25,000 hours ofoperation in an environment of 120°F (50°C). A blowerthat is noisy or shows wear will require bearing replace-ment or unit replacement. The blower mounting boltsshould be checked for tightness.

Each blower motor is cooled by the air passing over themotor. If the ambient air temperature is too high or theair flow is restricted, then the lubricant will gradually bevaporized from the motor bearings and bearing failurewill occur. If very dirty air passes over the motor, theaccumulation must be wiped from the motor and thedust must be blown out of the motor before the collec-tion of dust impairs the motor cooling.

If the unit is operated in very dusty air, the concaveside of the impeller blades will collect this dust and thematerial will build up on the surface.

If this happens, the performance will be reduced andunbalance will result with a possibility of damage to themotor.

5.4.3 MAINTENANCE OF COMPONENTSThe following paragraphs provide information for com-ponent maintenance.

5.4.3.1 SEMICONDUCTORSRoutine checking of semiconductors used in theHT 20/25CD Transmitter is not required. The bestcheck of semiconductor performance is actual operationin the transmitter. When semiconductors are replaced,check circuitry operation which may be affected. Re-placement semiconductors should be of the originaltype or a recommended direct replacement. Preventivemaintenance of transistors is accomplished by perform-ing the following steps:

a. Inspect the semiconductors and surroundingarea as accumulations of dirt or dust could formleakage paths.

b. Examine all semiconductors for loose connec-tions or corrosion.

5.4.3.2 CAPACITORSPreventive maintenance of capacitors is accomplishedas follows:

a. Examine all capacitor terminals for loose con-nections or corrosion.

b. Ensure that component mountings are tight.c. Examine the body of each capacitor for swelling,

discoloration, or other evidence of breakdown.d. Inspect oil-filled and electrolytic capacitors for

leakage signs.e. Use standard practices to repair poor solder

connections with a low-wattage soldering iron.f. Clean cases and bodies of all capacitors.

5.4.3.3 FIXED RESISTORSPreventive maintenance of fixed resistors is accom-plished by the following steps:

a. When inspecting a chassis, printed-circuit board,or discrete component assembly, examine resis-tors for dirt or signs of overheating. Discolored,bulging, cracked, or chipped components indi-cate a possible overload.

b. When replacing a resistor ensure the replace-ment value corresponds to the component des-ignated by the schematic diagram.

c. Clean dirty resistors with a small brush.

5.4.3.4 VARIABLE RESISTORSPreventive maintenance of variable resistors follows:

a. Inspect and tighten all loose mountings, connec-tions and control knob setscrews (do not disturbknob alignment).

b. If necessary, clean components with a dry brushor cloth.

c. When dirt is difficult to remove, clean with acloth moistened with an approved cleaning sol-vent.

5.4.3.5 TRANSFORMERSPreventive maintenance of transformers is accom-plished by performing the following:

a. Feel each transformer soon after power removalfor signs of overheating.

b. Inspect each transformer for dirt, loose mountingbrackets and rivets, loose terminal connections,and insecure connecting lugs. Dust, dirt or mois-ture between terminals may cause flashovers.Insulating compound or oil around the base of atransformer indicates overheating or leakage.

c. Tighten loose mounting lugs, terminals, or rivets.d. Clean with a dry cloth. Use an approved clean-

ing solvent if required.e. Clean corroded contacts or connections with

crocus cloth.f. Replace defective transformers.

5.4.3.6 FUSESPreventive maintenance with reference to fuses is ac-complished as follows:

a. When a fuse blows, determine the cause beforeinstalling a replacement.

b. Inspect fuse caps and mounts for charring andcorrosion.

c. Examine fuse clips for dirt, improper tension,and loose connections.

d. If necessary tighten fuse clips and connectionsto the clips. The tension of the fuse clips maybe increased by carefully pressing the clip sidestogether.


e. Dust fuses and clips with a small brush.

5.4.3.7 METERPreventive maintenance of the meter is accomplishedas follows:

a. Inspect meters for loose, dirty, or corrodedmountings and connections.

b. Examine leads for frayed insulation and brokenstrands.

c. Check for cracked or broken plastic cases andcover glasses.

d. Tighten loose mountings or connections. Sincemeter cases are made of plastic, exercise careto prevent breakage.

e. Clean meter cases and glass cover with a drycloth.

f. Remove dirt from mountings and connectionswith a stiff brush.

g. Remove corrosion with crocus cloth.

5.4.3.8 RELAYSReplace hermetically sealed relays if defective. Non-hermetically sealed relays are considered normal if:

a. The relay is mounted securely.b. Connecting leads are not frayed and the insula-

tion is not damaged.c. Terminal connections are tight and clean.d. Moving parts travel freely.e. Spring tension is correct.f. Contacts are clean, adjusted properly and make

good contact.g. The coil shows no signs of overheating.h. The assembly parts are clean and not corroded.

5.4.3.9 SWITCHESPreventive maintenance of switches is accomplished bychecking the following:

a. Inspect switches for defective mechanical actionor looseness of mounting and connections.

b. Examine cases for chips or cracks. Do not dis-assemble switches.

c. Inspect accessible contact switches for dirt, cor-rosion, looseness of mountings and connec-tions.

d. Check contacts for pitting, corrosion, or wear.e. Operate the switches to determine if each

moves freely and is positive in action. In gangand wafer switches, the rotor should make goodcontact with the stationary member.

f. Tighten all loose connections and mountings.g. Adjust contact tension.h. Clean any dirty or corroded terminal connec-

tions or switch section with crocus cloth.i. Replace defective switches.

5.4.3.10 INDICATORS AND INDICATOR SWITCHESPreventive maintenance of indicator lamps and indicatorswitches is accomplished by checking the following:

a. Examine indicator sockets for corrosion andloose hardware.

b. Inspect indicator assemblies for broken orcracked covers, loose envelopes, loose mount-ing screws, and loose or dirty connections.

c. Tighten loose mounting screws and solder looseconnections. If connections are dirty or cor-roded, clean with crocus cloth before soldering.

d. Clean indicators with a dry cloth.e. Clean corroded socket contacts and connec-

tions with crocus cloth. Low-operating voltagesrequire clean contacts and connections.

5.4.3.11 PRINTED-CIRCUIT BOARDSPreventive maintenance of printed-circuit boards is ac-complished by checking the following:

a. Inspect the printed-circuit boards for cracks orbreaks.

b. Inspect the wiring for open circuits or raised foil.c. Check components for breakage or discoloration

due to overheating.d. Clean off dust and dirt with a vacuum cleaner

and a brush.e. Use standard practices to repair solder connec-

tions with a low-wattage soldering iron.

5.5 CORRECTIVE MAINTENANCECorrective maintenance for the transmitter is limited bythe objective of minimum down time. Maintainability andcare are considerably simplified for operation and main-tenance personnel as the transmitter is designed andbuilt with modular circuitry to minimize down time.

The controller extender board (HARRIS part number992 5646 001) may be used to extend the analog orthe digital circuit boards from the equipment for mainte-nance as required. Even though low dc potentials areused on the HT 20/25CD printedcircuit boards, servic-ing equipment with power energized is always hazard-ous and is therefore not recommended.

5.5.1 ADJUSTMENTSTable 5-1 provides an adjustment procedure for all con-trols which are not described in Section II, Installation.

5.5.1.1 AIR SWITCH ADJUSTMENTAir switch S9 is adjusted for proper operation as fol-lows:

WARNINGDISCONNECT AND LOCK OUT STATIONPRIMARY POWER TO THE TRANSMITTERAND HIGH VOLTAGE POWER SUPPLY.

a. Set the following circuit breakers and switchesto OFF.

1. Station power distribution breaker to the HighVoltage Power Supply.

2. Station power distribution breaker to thetransmitter cabinet.

3. Both circuit breakers on the High VoltagePower Supply.

4. All circuit breakers on the transmitter frontpanel.

b. Open the transmitter cabinet rear door and lo-cate air switch S9 (reference 8 in Figure 3-2).


WARNINGUSE THE GROUNDING STICK AND DISSI-PATE RESIDUAL POTENTIALS FROM ALLCOMPONENTS BEFORE TOUCHING THEM.

c. Rotate the adjustment screw on air switch S9 tothe extreme counterclockwise position.

d. Rotate the adjustment screw on air switch S9one complete turn in the clockwise direction.

e. Loosen the captive retaining hardware on thebottom one-half of the PA tube access door.

f. Close the transmitter cabinet rear door.g. Apply station power to the transmitter.h. Set the following circuit breakers and switches

to ON.1. Station power distribution breaker to the

transmitter cabinet.2. All circuit breakers on the transmitter front

panel.

WARNING230 VAC IS NOW PRESENT IN THE TRANS-MITTER CABINET AND THE CONTROLSECTION OF THE HIGH VOLTAGE POWERSUPPLY.

i. Set the BIAS and BLOWER circuit breakers toON.

j. Depress the FILAMENT ON pushbutton switch.Let the blower build up speed. Verify the AIRINTERLOCK indicator is extinguished.

k. Depress the FILAMENT OFF pushbutton switch.


l. Open the transmitter cabinet rear door.


m. Rotate the adjustment screw on air switch S9one-quarter turn clockwise and the close trans-mitter cabinet rear door.

n. Apply station power to the transmitter.o. Repeat steps i. through m. until the AIR INTER-

LOCK indicator illuminates with the blower oper-ating at full speed.


p. Open the transmitter cabinet rear door and se-cure the captive retaining hardware on the PAaccess door loosened in step e.

chWARNING = WARNING

USE THE GROUNDING STICK AND DISSI-PATE RESIDUAL POTENTIALS FROM ALLCOMPONENTS BEFORE TOUCHING THEM.

q. Close the transmitter cabinet rear door and de-press the FILAMENT ON pushbutton.

r. Verify the AIR INTERLOCK indicator is extin-guished after the blower builds up speed.

s. This completes the air switch adjustment proce-dure.

5.5.2 COMPONENT REPLACEMENTFigures 5-3 through 5-11 identify the components onthe circuit boards by symbol number. Figure 5-12 identi-fies the components on the Plate Blocker Assembly,and Figure 5-13 identifies the components mounted be-neath the tube socket deck. The circuit boards used inthe HT 20/25CD Transmitter are of the double-sidedplated-through type. This means that there are traceson both sides of the board and the through-holes con-tain a metallic plating. Because of the plated-throughholes, solder creeps up into the hole. This requires amore sophisticated technique for component removal inorder to avoid damage to the traces on the board. Ex-cessive heat of any point on the board will cause dam-age.

To remove a component from a double-sided board, theleads of the defective component should be cut fromthe body while the leads are still soldered to the board.The component is then discarded and each lead isheated independently and pulled out of the hole. Eachhole may then be cleared of solder by carefully heatingwith a low wattage iron and removing the residual sol-der with a solder vacuum tool.

The new component is installed in the usual way andsoldered from the bottom side of the board. If no dam-age has been done to the plated-through hole, solder-ing on the top side is not required. However, if the re-moval procedure did not progress smoothly, each leadshould be soldered at the top side to prevent potentialintermittent problems.

After soldering, remove residual flux. Solvents are avail-able in electronic supply houses which are useful. Theboard should then be checked to ensure the defluxingoperation has removed the flux and not just smeared itabout so that it is less visible. While rosin flux is notnormally corrosive, it will absorb moisture and becomeconductive enough to cause deterioration in specifica-tions over a period of time.

5.5.2.1 SCREEN BLOCKER REPLACEMENTThe Screen Blocker may be field replaced as follows:



a. Remove the power amplifier tube following theprocedure in paragraph entitled TUBE RE-MOVAL AND INSTALLATION in this section.

CAUTIONDO NOT DAMAGE THE TUBE SOCKET FIN-GER STOCK DURING TUBE REMOVAL.

b. Remove the power amplifier cavity rear panel(27 screws with captive nuts).


c. On the underside of the tube socket deck, re-move the screen dc connection from left rearfeed through insulator.

d. Remove the cap nuts and associated hardwarefrom all four corners of the screen bypass plate.

NOTEThe hardware associated with the screen dc con-nection is threaded into the screen bypass plateand must be removed from the underneath side.

e. Remove the screen bypass plate being carefulnot to damage the screen fingerstock.

f. Remove the Kapton screen insulator.g. Be sure the PA tube socket deck is clean and

free of foreign matter. (This point can not beover-emphasized.)

h. Replace the Kapton screen insulator (3 mil). Theinsulator should be clean and free of foreignmatter.

i. Be sure that the bottom side of the screen by-pass plate is clean. Set the screen bypass platein position over the insulator.

j. Replace the corner screen bypass plate mount-ing hardware finger tight. (The screen bypassplate should be free to move.) Do not connect toscreen dc lead at this time.

k. Carefully insert the PA tube following the in-structions of paragraph entitled PA TUBE IN-STALLATION in this section. The tube will actas a gauge and align the screen bypass plate inthe correct position.

l. Tighten the corner mounting hardware on thescreen bypass plate and install the cap nuts.

m. Using a volt/ohm meter (VOM) set to the RX100scale and verify that the screen bypass plate isnot shorted to ground.

n. Reconnect the screen dc lead to the left rearcorner.

o. Reinstall the cavity rear panel using the originalhardware.

p. This completes the screen blocker replacement.

5.5.2.2 PLATE BLOCKER REPLACEMENTMaintenance personnel should use their own judgmentin repairing the plate blocker assembly. The placementof the “Kapton” polymide film is highly critical. The up-most care and proper handling should be observed. It isrecommended that the maintenance person familiarizehimself with the physical properties of “Kapton” bystudying the appropriate service bulletins in the appen-dix of this book. The plate blocking assembly (HARRISpart number 929 4129 001) is an entire assembly thatcan be obtained from the HARRIS Service Parts De-partment. If plate blocker assembly repair is required itcan be accomplished in the following manner:


a. Remove the power amplifier tube following theinstructions in paragraph entitled TUBE RE-MOVAL AND INSTALLATION in this section.


b. Remove the PA cavity back panel held by 27screws with captive nuts.

NOTEBe sure to mark the set of holes holding theshorting deck in the next step so that the deckcan be replaced in the same position.

c. While supporting the cavity shorting deck so thatit doesn’t fall, remove the 15 screws securingthe shorting deck to the cavity sides.

d. Carefully remove the plate blocking assemblyand shorting deck from the cavity.

e. Place the removed assembly on a clean workbench.

f. Loosen the clamp holding the plate blocking as-sembly to the shorting deck.

g. Slide the blocking assembly out of the shortingdeck.

NOTEIn the following steps refer to Figure 5-12.

h. Loosen the clamp assembly holding the innerand outer tubes.

i. Remove the six sets of mounting hardware onthe strap connecting the outer tube halves.

j. Carefully slide the inner and outer tubes apart.k. Remove the old “Kapton” from the inner tube.l. Wrap five turns of new “Kapton” (HARRIS part

number 033 4010 010) around the inner tube,being sure that the edge of the “Kapton” is 0.81inches from the edge of the inner tube as shown


in Figure 5-12. Also be sure no air pockets existbetween layers.

m. Being careful not to damage the “Kapton”, slidethe outer tube over the inner tube until the edgeof the outer tube is 1.8 inches from the edge ofthe inner tube.

n. Temporarily slide the clamp assembly up 4.5inches from the edge of the assembly andtighten the clamp.

o. Install the strap removed in step i. and tightenthe hardware.

p. Loosen the clamp from its temporary position;slide it down to the end of the outer tube andtighten.

q. Verify the dimensions on the plate blocking as-sembly as shown in Figure 5-12.

r. Use a volt/ohm meter (VOM) set to the resis-tance scale and verify that the two tubes are notshorted electrically.

NOTEIf a HI-POT machine is available, the plateblocker should be tested at 15 kV dc for two min-utes.

s. Slide the plate blocking assembly into the short-ing deck; secure the clamp.

t. Install the deck assembly into the cavity, beingsure to use the same mounting holes. Securewith the proper hardware.

u. Replace the back cover of the cavity using thecorrect hardware.

v. Install the tube following the instructions of para-graph entitled PA TUBE INSTALLATION in thissection.

5.5.3 TUBE REMOVAL AND INSTALLATIONThe following paragraphs provide information for properPA tube removal and installation. Refer to Figure 5-1.

5.5.3.1 PA TUBE REMOVALPrior to PA tube removal it is recommended that per-sonnel read and study the entire procedure before at-tempting tube removal. In instances where the transmit-ter is operating on a higher frequency, it can not beover emphasized that the proper removal sequencemust be followed in order to prevent damage to thetube or the tube socket fingerstock. The PA tube maybe removed in the following manner:


a. Be sure all power is removed from the transmit-ter.

b. Rotate the PA TUNE control to the MAX posi-tion (extreme clockwise position).

NOTEAlways use the front panel control PA TUNE toplace the tuning control in the maximum position.

c. Open the transmitter cabinet rear door.


d. Remove the PA access door held by 12 cap-tive screws.


NOTEThe next step will determine which sequencemust be used in removing the tube. On certainhigher frequencies, the sequence in step (f.) isthe only way the tube can be removed.

e. Refer to the top pictorial of Figure 5-1. On thetransmitter cavity back panel locate the hard-ware used to mount the cavity shorting deck.Counting from the bottom set of mounting holes,determine which set of holes is being used tosupport the cavity shorting deck.

NOTEIf the cavity shorting deck is supported in one ofthe four bottom sets of mounting holes, the se-quence in step (f.) must be used to remove thetube. If the shorting deck is supported above thefour bottom sets of mounting holes, the sequencein step (g.) may be used for tube removal.

f. The following sequence is to be used if the cav-ity shorting deck is supported in the bottom foursets of mounting holes:

CAUTIONPRIOR TO LOOSENING ANY OF THECLAMPS STUDY THE TOP PICTORIAL OFFIGURE 5-1. UNDER NO CIRCUMSTANCESSHOULD THE STATIONARY PLATE CLAMPBE LOOSENED.

NOTERefer to Figure 5-1. The sequence numbers onthe pictorials coincide with the steps in the follow-ing sequence.

1. Loosen the anode clamp; slide the clampdown resting it on the screen blocker assem-bly.

2. Loosen the top clamp; slide the clamp downallowing it to rest on the stationary tuningplate.

3. Raise the plate blocking assembly until thestationary tuning plate prevents the blockingassembly from sliding any further into thecavity short; hold the blocking assembly inthe raised position.


Figure 5-1. PA Tube Removal


CAUTIONIN THE FOLLOWING STEP, BE SURE THETOP CLAMP IS TIGHT AND WILL PREVENTTHE BLOCKING ASSEMBLY FROM SLID-ING DOWN AND CAUSING DAMAGE.

4. While holding the plate blocking assembly inthe raised position, slide the top clamp upover the fingerstock protruding from the cav-ity short and tighten. Be sure the clamp isholding the plate blocking assembly in theshort.

5. Remove the high voltage connector from thetube anode cap. Allow the lead to hang freeinside the blocking assembly.

6. Place both hands beneath the anode of thetube. (Be careful not to place thumbs on thetop of the tube.) Rest elbows on the tubesocket deck and exert an upward force onthe tube until the tube is free of the socket.

CAUTIONDO NOT ROCK OR ROTATE THE TUBEWHILE THE TUBE IS ENGAGED IN THESOCKET OR DAMAGE WILL OCCUR TOTHE FINGERSTOCK.

7. Lift the tube until the filament stem is clear ofthe socket assembly.

CAUTIONIN THE FOLLOWING STEPS BE SURETHAT THE TUBE DOES NOT DROP INTOTHE SOCKET ASSEMBLY AND DAMAGETHE FINGERSTOCK.

8. Rotate the filament stem towards the accessopening being sure that the stem does notdamage the fingerstock.

9. Continue rotating the tube until the filamentstem is pointing directly to the access open-ing. The anode cap must clear the far edgeplate blocking assembly.

NOTEThe tube should now have been turned 90 de-grees from its original position.

10. While maintaining the tube positioned overthe tube socket, rotate the filament stem to-wards the top of the cavity. Guide the anodepast the far edge of the blocking assemblyand the filament stem past the near edge ofthe blocking assembly into the blocking as-sembly.

NOTEDepending on the height of the cavity shortingdeck, the anode may dip into tube socket duringthis turn. Be careful not to damage the exposedfingerstock.

NOTEThe tube should now have been turned 180 de-grees from its original position. The filament stemwill be inside the blocking assembly with the tubeinverted over the tube socket.

11. While holding the tube in the inverted posi-tion, lift it up and towards the access door.The junction of the anode and the tube stemshould be touching the edge of the plateblocking assembly nearest the access door.

12. Using the position obtained in step 11. as apivot point, rotate the anode of the tube to-wards the access door; ensure the anodeclears the socket assembly.

13. Continue rotating the tube until it is 90 de-grees from the inverted position. At this timethe anode of the tube should be located inthe space between the access door and theplate blocking assembly.

14. Carefully guide the tube through the accessdoor and out of the cavity.

g. The following sequence is to be used if the cav-ity shorting deck is supported in mounting holesabove the four bottom sets of mounting holes:

CAUTIONPRIOR TO LOOSENING ANY OF THECLAMPS STUDY THE TOP PICTORIAL OFFIGURE 5-1. UNDER NO CIRCUMSTANCESSHOULD THE STATIONARY PLATE CLAMPBE LOOSENED.

1. Loosen the anode clamp and slide the clampdown, resting it on the screen blocker as-sembly.

2. Loosen the top clamp and slide the clampdown, allowing it to rest on the stationary tun-ing plate.

3. Raise the plate blocking assembly until thestationary tuning plate is above the top edgeof the front panel adjustable tuning plate.Hold the blocking assembly in the raised po-sition.

CAUTIONIN THE FOLLOWING STEP, BE SURE THATTHE TOP CLAMP IS TIGHT AND WILL PRE-VENT THE BLOCKING ASSEMBLY FROMSLIDING DOWN AND CAUSING DAMAGE.

4. While holding the plate blocking assembly inthe raised position, slide the top clamp upand over the fingerstock protruding from thecavity short and tighten. Be sure that theclamp is holding the plate blocking assemblyin the short.

5. Remove the high voltage connector from thetube anode cap. Allow the leads to hang freeinside the blocking assembly.

6. Place both hands beneath the anode of thetube. (Be careful not to place thumbs on thetop of the tube.) Rest elbows on the tubesocket deck and exert an upward force onthe tube until the tube is free of the socket.

CAUTIONDO NOT ROCK OR ROTATE THE TUBEWHILE THE TUBE IS ENGAGED IN THESOCKET OR DAMAGE WILL OCCUR TOTHE FINGERSTOCK.

7. Lift the tube until the filament stem is clear ofthe socket assembly.


CAUTIONBE CAREFUL NOT TO ALLOW THE TUBETO DROP INTO THE SOCKET ASSEMBLYAND DAMAGE THE FINGERSTOCK.

8. Carefully guide the tube through the accessdoor and out of the cavity.

5.5.3.2 CAVITY CONTACT INSPECTIONIt is always good practice whenever a tube has beenremoved from a socket to inspect the contact fingers inthe socket for proper tension, cleanliness, and for bro-ken or bent contact fingers. If a contact finger is miss-ing inspect to insure that the missing finger is not lo-cated in such a place as to cause shorting or arcingunder normal operations. If a contact finger is slightlybent, carefully bend it to the proper position and ten-sion. If a contact finger is badly bend and cannot bestraightened, it should be removed from the cavity sothat it doesn’t break and fall into an electrical circuit. Ifmore than four adjacent contact fingers or more than 30percent of the total number of contact fingers are miss-ing, the entire contact ring should be replaced.

5.5.3.3 PA TUBE INSTALLATIONPrior to PA tube installation it is recommended that per-sonnel read and study the entire procedure before at-tempting to install the tube. In instances where thetransmitter is operating on a higher frequency, it cannot be over emphasized that the proper installation se-quence must be followed in order to prevent damage tothe tube or the tube socket fingerstock. The PA tubemay be installed in the following manner:

NOTETO OPTIMIZE TUBE PERFORMANCE AND LIFEEXPECTANCY, REFER TO THE EIMAC BULLE-TIN ENTITLED “EXTENDING TRANSMITTERTUBE LIFE” IN VENDOR SECTION OF THISMANUAL.

NOTEThe following sequence of instructions assumethat maintenance personnel have removed thetube. If this is not the case or if it is an initial tubeinstallation perform steps (a.) through (f. or g.) ofparagraph entitled PA TUBE REMOVAL in thissection before proceeding.


a. Use a volt/ohm meter (VOM), set to the resis-tance scale, and check the tube to be installedfor elements shorted together or open filaments.


b. Refer to the top pictorial of Figure 5-2. On thetransmitter cavity back panel locate the hard-ware used to mount the cavity shorting deck.Counting from the bottom set of mounting holes,determine which set of holes is being used tosupport the cavity shorting deck.

NOTEIf the cavity shorting deck is supported in one ofthe four bottom sets of mounting holes, the se-quence in step (c.) must be used to install thetube. If the shorting deck is supported above thefour bottom sets of mounting holes, the sequencein step (d.) may be used for tube installation.

c. The following sequence is to be used if the cav-ity shorting deck is supported in the bottom foursets of mounting holes:

CAUTIONPRIOR TO INSTALLING THE TUBE ENSURETHAT THE TOP CLAMP IS TIGHT ANDHOLDING THE PLATE BLOCKING ASSEM-BLY SECURELY.

NOTERefer to Figure 5-2. The sequence numbers onthe pictorials coincide with the steps in the follow-ing sequence.

1. While holding the tube anode with bothhands, guide the tube through the PA accessdoor with the filament stem entering the cav-ity first.

2. While supporting the tube above the tubesocket deck, raise the tube up so that thejunction of the anode and the stem is touch-ing the near bottom edge of the plate block-ing assembly.

3. Using the position obtained in step (2.) as apivot point, rotate the filament stem towardsthe top of the cavity and inside the plateblocking assembly, being sure that the anodecap clears the tube socket.

NOTEThe tube should now be inverted over the tubesocket with the filament stem inside the plateblocking assembly. DO NOT ALLOW THE TUBETO DROP INTO THE SOCKET AND DAMAGETHE FINGERSTOCK.

4. While supporting the tube over the socket,rotate the filament towards the access open-ing and guide the stem past the near edge ofthe blocking assembly and the anode pastthe far edge of the blocking assembly.


Figure 5-2. Tube Installation


NOTEDepending on the height of the cavity shortingdeck, the anode may dip into the tube socket dur-ing this turn. BE CAREFUL NOT TO DAMAGETHE EXPOSED FINGERSTOCK.

NOTESteps (5.) and (6.) are to be completed simultane-ously. BE SURE THE STEM DOES NOT DAM-AGE THE FINGERSTOCK AD THE ANODESWING INTO THE BLOCKING ASSEMBLY.

5. Rotate the filament stem towards the socket.6. Guide the anode cap past the far edge of the

blocking assembly.

NOTEThe tube should now be in the proper position forinsertion, with the anode cap inside the plateblocking assembly.

7. Center the tube over the tube socket.8. Carefully lower the tube into the socket.

CAUTIONDO NOT ROTATE OR ROCK THE TUBE AF-TER IT IS INSTALLED IN THE SOCKET ORDAMAGE WILL OCCUR TO THE FINGER-STOCK.

9. Using both hands, push the tube straightdown until the tube is properly seated.

NOTEThe tube socket has built in stops. Be sure thetube is all the way down in the socket and level.

10. Place the high voltage connector on the an-ode cap.

CAUTIONIN THE FOLLOWING STEP BE SURE THEPLATE BLOCKING ASSEMBLY IS BEINGHELD SECURELY PRIOR TO LOOSENINGTHE TOP CLAMP.

11. Hold the plate blocking assembly securelywhile loosening the top clamp.

12. Lower the plate blocking assembly over thetube anode until the built in stops prevent fur-ther downward motion.

13. Refer to the top pictorial of Figure 5-2. Rotatethe plate blocking assembly on the tube untilthe edge of the stationary tuning plate is par-allel to the same cavity wall where the frontpanel adjustable tuning plate is mounted.

14. After making sure the clamp is up over thefingerstock protruding from the cavity short,tighten the top clamp.

15. Lift the anode clamp off the screen blockerassembly and slide the clamp over thefingerstock at the bottom edge of the plateblocking assembly.

16. Tighten the anode clamp, being sure that theclamp is securing the blocking assembly tothe tube anode.

17. Proceed to step (e.) to complete the tube in-stallation.

d. The following sequence is only used if the cavityshorting deck is supported in mounting holesabove the four bottom sets of mounting holes:

1. While holding the tube with both hands, care-fully position the tube inside the cavity be-tween the tube socket and the plate blockingassembly with the filament stem down.

2. Center the filament stem over the tubesocket.

3. Carefully lower the tube into the socket.

CAUTIONDO NOT ROTATE OR ROCK THE TUBE AF-TER IT IS INSTALLED IN THE SOCKET ORDAMAGE WILL OCCUR TO THE FINGER-STOCK.

4. Using both hands push the tube straightdown until the tube is properly seated.

NOTEThe tube socket has built in stops. Ensure thetube is all the way down in the socket and level.

5. Place the anode clamp (included in installa-tion material) over the anode of the tube andslide the clamp down the tube and allow it torest on the screen blocker assembly.

6. Attach the high voltage lead to the anodecap.

CAUTIONIN THE FOLLOWING STEP BE SURE THEPLATE BLOCKING ASSEMBLY IS BEINGHELD SECURELY PRIOR TO LOOSENINGTHE TOP CLAMP.

7. Hold the plate blocking assembly in a securemanner while loosening the top clamp.

8. Lower the plate blocking assembly over thetube anode until the built in stops prevent fur-ther downward motion.

9. Refer to Figure 5-2. Rotate the plate blockingassembly on the tube until the edge of thestationary tuning plate is parallel to the samecavity wall where the front panel adjustabletuning plate is mounted.

10. Be sure the top clamp is up over the finger-stock protruding from the cavity short.

11. Tighten the top clamp.12. Lift the anode clamp off the screen blocker

assembly and slide the clamp over thefingerstock at the bottom edge of the plateblocking assembly.

13. Tighten the anode clamp ensuring the clampis securing the blocking assembly to the tubeanode.

e. Remove all loose hardware from inside the cav-ity.

f. Install the PA access door using the captivehardware.

5.5.3.4 POWER AMPLIFIER NEUTRALIZATIONThe HT 20/25CD Transmitter requires neutralizationwith NO POWER applied. An rf indicator device of


some type is required. The following list of test equip-ment is in order of preference, but neutralization maybe accomplished using any one of the devices listed.

a. RF Spectrum Analyzerb. RF Voltmeterc. 100 MHz Oscilloscoped. VTVM with RF probe

5.5.3.4.1 ProcedureSelect one of the listed pieces of test equipment andneutralize the power amplifier as follows:

a. Set the FM Exciter power output to zero usingthe exciter front panel controls.

b. Set the station power distribution breaker to theHigh Voltage Power Supply to OFF.

c. Set the station power distribution breaker to thetransmitter cabinet to OFF.

d. Open the transmitter cabinet rear door.


e. Locate the IPA Emergency Bypass cable la-beled Flexpatch which was provided with theTransmitter accessories. This cable should havea BNC connector on one end and an N-typeconnector on the other.

f. Open the rear door and locate cable 265 con-nected to J1 on the PA cavity. Remove this ca-ble and connect the Flexpatch cable with the N-type connector to J1.

g. Now route this cable up to the front of the cabi-net to the Exciter. Remove cable 256 on the RFoutput of the Exciter and connect the BNC endof the Flexpatch Cable to the RF Output of theExciter.

h. Close the rear door on the Transmitter cabinet.Reapply station power to the Transmitter cabinetand to the High Voltage Power Supply cabinet.

i. Disconnect the ac power plug from the FM Ex-citer AC POWER jack on the rear of the exciter.

j. Connect the exciter ac test cord into the exciter,but do not plug in to the ac outlet yet.

k. Loosen the 12 captive screws on the PA accesspanel and remove the panel.


l. Using Figure 5-3 as a reference connect a tem-porary short of copper strap or jumper wire be-tween the bottom of the rod supporting the neu-tralizing flag and the PA deck.

m. Connect the selected rf indicating device to oneof the monitor samples located on the swivel el-bow on the top of the transmitter.

n. Plug the exciter ac test cord into a 110 Vacsource.

o. Depress the Exciter MULTIMETER FWD PWRpushbutton switch.

p. Increase the exciter power output until the ex-citer multimeter indicates 10 watts.

q. Depress the REF PWR exciter pushbuttonswitch and adjust the power amplifier INPUTTUNE and GRID TUNE controls for minimum in-dication on the exciter multimeter.

r. Monitor the rf sampling device connected in stepn. and adjust the power amplifier PA LOAD andPA TUNE controls for maximum indication.

s. Temporarily place the PA access door over theaccess port as shown by the dotted lines in Fig-ure 5-3.

t. Remove the temporary short from the neutraliz-ing flag and adjust the INPUT TUNE and GRIDTUNE controls for minimum indication on theexciter multimeter.

NOTEIf the rf indicating device displays the rf signaldown by -30 dB or more with the short removedas compared to with the short in place, no furtheradjustment is required. If the signal is not -30 dBdown further adjustment is required.

u. Adjust the neutralizing flag for minimum indica-tion on the rf indicating device.

NOTEAs shown in Figure 5-3 the neutralizing flag maybe adjusted in three planes. The nuts holding theflag must be loosened prior to movement of theflag. The transmitter has been neutralized at thefactory with the tube that was shipped with thetransmitter. Initial adjustment should only requiremovement of the flag within the adjustment slot.

v. Replace the PA access door in the normal posi-tion and secure with the 12 captive screws.

w. Lower the exciter power output to zero.x. Disconnect the Exciter ac test cord and recon-

nect the original cable to AC POWER jack onthe back of the exciter.

y. Return all cables to their normal configuration asshown in drawing 8529163008.

z. Close the Transmitter cabinet rear door and se-cure all access panels.

aa. Return the HT 20/25CD Transmitter to normaloperation by following the turn on procedure asdescribed beginning in paragraph entitledTRANSMITTER TURN ON in Section III.

ab. Disconnect the rf indicator device from the moni-tor sample. This completes the neutralizationprocedure.

This page deleted in 888-2384-001 Rev. B


5.6 CONTROL SETUP AND OPERATIONOF VSWR FOLDBACK CIRCUIT

The VSWR foldback feature is an automatic systemthat is factory adjusted and calibrated and does not nor-mally require any day-to-day adjustment. The VSWRfoldback feature is essentially a monitor system that isactivated only when necessary during a high VSWRcondition. Several setup controls and test points areprovided, however, for field adjustment under mainte-nance conditions.

The HT 20/25CD front panel layout with the VSWRfoldback feature is shown in Figure 5-14. It should benoted there are no VSWR foldback controls on the frontpanel, only a special LED indicator (red/green BI-LED)to show when the VSWR foldback system is in opera-tion as described in the Section II, Circuit Operation.For field adjustment, 4 test points, 2 threshold potenti-ometers and one ON/OFF control switch are providedand are located on the analog control board behind thefront panel hinged access door. These are maintenancelevel controls that are easy to set up but should only be

adjusted when really necessary, i.e., after recalibratingthe VSWR meter circuit, after a component failure inVSWR foldback circuit or to compensate for a new setof VSWR conditions. Refer to Figure 5-15 for a view ofthe analog printed-circuit board with the VSWR foldbackcontrols. The following describes the test point and con-trol functions.

5.7 ANALOG BOARD VSWR FOLDBACKCONTROLS

a. S1 switches the VSWR foldback circuit ON orOFF.

NOTESwitching S1 ON or OFF enables or disables thefoldback circuit and does not affect any other cir-cuit in the transmitter. When S1 is switched OFF,the red/green LED indicator is still active to warnof a high VSWR condition but no control action istaken. This serves to provide an indication whileadjusting the threshold set points when the trans-mitter is operating under maintenance conditions.

b. R117 lower threshold set point 1 sets the firstthreshold point to a voltage corresponding to aVSWR of approximately 1.30:1.

c. R118 upper threshold set point 2 sets the sec-ond threshold point to a voltage correspondingto a VSWR of approximately 1.35:1.

d. TP-1 is a test probe ground point.e. TP-2 monitors reflected voltage from the power

meter circuit and bridges the input to the fold-back voltage comparators. Typical values rangefrom +.2 to +.3 dc volts (VSWR 1.1:1 to 1.25:1).Refer to Figure 5-15.

f. TP-3 monitors upper threshold set point 2. Typi-cal values range from +.4 to +.45 dc volts corre-sponding to 1.35:1 VSWR.

g. TP-4 monitors lower threshold set point 1. Typi-cal values range from +.35 to +.4 dc volts corre-sponding to 1.30:1 VSWR.

Figure 5-16 shows the typical voltages obtained at TP-2for various VSWR values and the typical adjustment setpoints for R117 (set point 1) and R118 (set point 2).The point where the steady red LED indicator illumi-nates and the point where the alternating red/green illu-mination begins is also shown.

Figure 5-3. Transmitter Neutralizing Flag


CIRCUIT PURPOSE VARIABILITY

CAVITY COARSE Tuning Provides shorted coax to resonatecavity.

Raising shorting plate will lowerthe cavity resonate frequency.Hole patterns in walls and short-ing plate give l/4-inch incre-ments.

PA TUNE (Cavity Fine Tun-ing)

Tunes the cavity to resonance forlimited range of antenna VSWRs.

The cavity will tune over +/-1MHz range with a 50-ohm load.Rotating front panel adjustmentPA TUNE clockwise will tunethe cavity higher in frequency. Aplate “dip” can be observed andthe “efficient side” of resonanceshould be used.

PA LOAD (C16) Presents the tube with correct im-pedance to produce the TPO. Alsomatches the antenna VSWR.

Clockwise rotation for properlytuned cavity will load the cavityheavier and causes more platecurrent to be drawn.

INPUT TUNE Matches grid to 50 ohms; capaci-tor trimmer.

When used simultaneously with“Grid Tune”, matches the gridimpedance to the 50-ohm outputimpedance of the IPA.

GRID TUNE (L4) Matches grid to 50 ohms; induc-tive tuning.

When used with “Input Tune”,matches the grid impedance tothe 50-ohm output impedance ofthe IPA. Coarse adjust madeseparately (L7).

IPA OUTPUT POWER ADJ(R31)

Varies the supply voltage to the rfamplifier assembly in the IPAmodule. The IPA power then var-ies accordingly.

Range of voltage from 10 volts toover 40 volts. Power can be var-ied from near 20 watts to over400 watts. Clockwise rotation in-creases IPA power.

GRID VOLTS ADJ (BiasVoltage)

Sets the dc voltage on the grid ofthe PA tube.

Range is from below 250 volts toover 450 volts. Clockwise rota-tion gives a more negative poten-tial

HUM NULL (R33) Adds a small amount of ac linevoltage to the PA grid. Nulls theresidual line hum of other circuits.AM noise reduction.

To be set while observing AMNoise without FM modulation.

POWER OUT- AUTO/MAN-UAL (1A11S1)

Places the rf power output in con-trol of the operator or under auto-matic control.

Maintain RF Output power towithin +/-2% or +/-4%.

Table 5-1. RF Circuit Adjustments


CIRCUIT PURPOSE VARIABILITY

POWER OUT-RAISE/LOWER (1A11S2)

Lower or raises the screen dc volt-age.

Range of at least 100 Vdc to1000 Vdc. Will vary outputpower of transmitter +5% to ap-proximately -80% when properlyadjusted.

PA PWR CAL(FWD/REFLD) (1A11R4)

Adjusts loop resistance to cali-brated rf output of Tx. Requirescalorimeter.

Range of 10 kW to 25 kW outputpower.

PA REFLECTED POWERCAL (1A11R5)

Adjust loop resistance to calibratedscale to read VSWR. Use voltageof PA forward coupling to set.

Range of 10 kW to 25 kW outputpower.

IPA PWR CAL FWD(1A11R2)

Adjusts loop resistance to cali-brated rf output of IPA. Requiresaccurate indicating load.

Range scale of 500W maximum.

IPA PWR CAL REFLD(1A11R3)

Adjusts loop resistance for IPA re-flected power. Use known mis-match power.

Range scale of 50W maximum.

FILAMENT (Voltage) AD-JUST (T2)

Adjust filament voltage to 8990.See manufacturers data sheet on8990.

Range of +/-10% or greater. Tapsextend this range.

Table 5-1. RF Circuit Adjustments (Continued)


Figure 5-4. IPA Low-Pass Filter/Directional CouplerBoard Component Locator


Figure 5-5. AC Control Circuit Board Component Locator


Figure 5-6. Control Logic RFI Board Component Locator


Figure 5-7. Status Circuit Board Component Locator


Figure 5-8. Analog Circuit Board with VSWR FoldbackComponent Locator


Figure 5-9. Digital Circuit Board Component Locator


Figure 5-10. Motherboard Component Locator


Figure 5-11. Plate Blocker Assembly


Figure 5-12. Lower Side Tube Socket Deck


Figure 5-13. Front Panel Layout


Figure 5-14. Analog PC Board w/VSWR Foldback Controls

Figure 5-15. VSWR Versus TP-2 +VDC


SECTION VITROUBLESHOOTING

6.1 INTRODUCTIONThis section provides troubleshooting charts and gen-eral troubleshooting information for the HARRIS HT20/25 FM BROADCAST TRANSMITTER.

6.2 PURPOSEThe information in this section is intended to aid main-tenance personnel in isolating problems in the HT 20/25Transmitter with minimum down time. The charts serveas an aid to the repairman in locating a particular prob-lem area. When the problem has been identified referto Section V for adjustments, component identification,and replacement information.

6.3 TROUBLESHOOTINGMost troubleshooting consists of visual checks. Be-cause of the voltages and high dc currents in the trans-mitter, it is not safe to work with power energized. Themeters, indicators, and fuses should be used to deter-mine which stage is malfunctioning.

In event of problems, isolate the trouble area to one ofthe following with the meters and indicators for eachsection (see Tables 6-1 and 6-2).

Antenna and Feedline

Power Supplies

Control and Metering

IPA DRIVER Module

Exciter

Power AmplifierWhen the trouble is isolated to a specific area, refer tothe theory section of this manual for circuit discussionto aid in problem resolution. Table 6-3 lists typicaltrouble symptoms pertaining to the overall transmitteroperation with references to fault isolation diagrams list-ing probable causes and corrective actions. A correctiveaction given for a trouble symptom is not necessarilythe only answer to a problem, it only tends to lead therepairman to the area that may be causing the trouble.

Prior to starting a troubleshooting procedure check allswitches, power cord connections, connecting cables,and power fuses.

6.4 TECHNICAL ASSISTANCESee Technical Assistance clause on back of Title Page.


SWITCH POSITION METER INDICATION @25kW (@20kW)

PA Stage Multime-ter switch

Filament Voltage PA Multimeter 10.0 Volts

Bias Voltage PA Multimeter -310 Volts (-335 Volts)

Bias Current PA Multimeter 43 mA (50 mA)

Screen Voltage PA Multimeter 870 Volts (590 Volts)

Screen Current PA Multimeter 160 mA (135 mA)

IPA Stage RE-FLECTEDPOWER/FOR-WARD PowerSwitch

Reflected Power IPA Power Meter 1 Watt

Forward Power IPA Power Meter 400 Watts

Transmitter PowerSwitch

Forward Power Meter 100% Power [25 kW] (20kW)

Reflected Power Meter 1.09 VSWR

Plate Voltage 9.25 Kilo Volts (8.08 Kilo Volts)

Plate Current 3.51 Amperes (3.08 Amperes)

PA EFFICIENCY - 77.0% (79.0%)

PA PLATE DISSIPATION - 7.467 kW (4.870 kW)

AC LINE FREQUENCY - 60 Hz

AC LINE VOLTAGE - 235/235/235 Volts (230,230,230 Volts)

AC LINE CURRENT - 88/91/89 Amperes (68/71/71 Amperes)

*Always refer to the factory test data sheet sent with the transmitter.

Table 6-1. Typical Operating Parameters *


TRANSMITTERPARAMETER

POWER 1 POWER 2 POWER 3

Power Output 10.17 kW 15.57 kW 20.2 kW

Plate Voltage 9.39 kV 9.25 kV 9.2 kV

Plate Current 1.50 A 2.20 A 2.80 A

Screen Voltage 750 V 740 V 738 V

Screen Current 90 mA 105 mA 110 mA

Grid Voltage -235 V -250 V -300 V

Grid Current (-) 1 mA 34 mA

IPA Voltage 10 V 12 V 16 V

PA Efficiency 72.5 % 76.5 % 78.4 %

PA Plate Dissipation 3.85 kW 4.78 kW 5.56 kW

Table 6-2. Meter Indications with Varying Power Levels

SYMPTOM DEFECT/REFERENCE

NO TRANSMITTER RF OUTPUT POWER Refer to Figure 6-1

LOW RF OUTPUT Refer to Figure 6-2

LOW OR NO DRIVER MODULE OUTPUT Refer to Figure 6-3

deleted Figure 6-4

CONTROL CIRCUIT INOPERATIVE

FILAMENT ON SEQUENCE Refer to Figure 6-5

FILAMENT OFF SEQUENCE Refer to Figure 6-6

PLATE ON SEQUENCE Refer to Figure 6-7 (2 sheets)

PLATE OFF SEQUENCE Refer to Figure 6-8

Table 6-3. Symptom Index


Figure 6-1. No Transmitter RF Output


Figure 6-2. Low RF Output


Figure 6-3. Low or No Driver Module Output


Figure 6-4. Deleted


N O T E S


FIGURE 6-5. CONTROL CIRCUIT INOPERATIVE(FILAMENT ON SEQUENCE)

1859-496-9/6-10

FIGURE 6-6. CONTROL CIRCUIT INOPERATIVE(FILAMENT OFF SEQUENCE)

1859-566-11/6-12

FIGURE 6-7. CONTROL CIRCUIT INOPERATIVE(PLATE ON SEQUENCE) (SHEET 1 OF 2)

1859-576-13/6-14

FIGURE 6-7. CONTROL CIRCUIT INOPERATIVE(PLATE ON SEQUENCE) (SHEET 2 OF 2)

1859-576-15/6-16

FIGURE 6-8. CONTROL CIRCUIT INOPERATIVE(PLATE OFF SEQUENCE)

1859-586-17/6-18


Replaceable Parts List Index

Table 7-1. XMTR, HT-20, 20KW . . . . . . . . . . . . . . . . . . . . . 994 9568 002 (A) 7-2Table 7-2. XMTR, HT-25, 25KW . . . . . . . . . . . . . . . . . . . . . 994 9569 002 (A) 7-2Table 7-3. R-SK-FM25K2/HT-25/HT-20 . . . . . . . . . . . . . . . . . 990 1081 001 (J) 7-3Table 7-4. BASIC PS, HT20/25 . . . . . . . . . . . . . . . . . . . . . . 992 5428 001 (BR) 7-4Table 7-5. *RECT ASSY, HV . . . . . . . . . . . . . . . . . . . . . . 992 9156 001 (C1) 7-6Table 7-6. KIT, 4 WIRE “Y” XMTR MOD . . . . . . . . . . . . . . . . . 992 6812 002 (A) 7-7Table 7-7. *KIT FIL REG 60HZ HT20/25FM/CD . . . . . . . . . . . . . 992 8093 003 (C) 7-7Table 7-8. *KIT FIL REG 50HZ HT20/25FM/CD . . . . . . . . . . . . . 992 8093 004 (A) 7-7Table 7-9. MOD KIT-HT25FM PA TUNING . . . . . . . . . . . . . . . . 992 8362 001 (D) 7-7Table 7-10. R-BK-FM25K2/HT-25/HT-20 . . . . . . . . . . . . . . . . . 994 9102 002 (A) 7-8Table 7-11. R-PK-FM25K2/HT-25/HT-20 . . . . . . . . . . . . . . . . . 994 9125 001 (G) 7-8Table 7-12. KIT, EXTENDED COOLING 1PH . . . . . . . . . . . . . . . 994 9129 002 (A) 7-8Table 7-13. XMTR, BASIC, HT-20/25FM . . . . . . . . . . . . . . . . . 994 9138 004 (D) 7-9Table 7-14. AC CONTROL PC BD . . . . . . . . . . . . . . . . . . . . 992 5439 002 (C) 7-13Table 7-15. DIR COUPLER ASSY . . . . . . . . . . . . . . . . . . . . 992 5620 001 (R) 7-14Table 7-16. PANEL, IPA MULTIMETER . . . . . . . . . . . . . . . . . 992 6751 004 (B) 7-15Table 7-17. PWB, RMT SCREEN CTL LOGIC . . . . . . . . . . . . . . 992 6761 002 (C) 7-15Table 7-18. TRANSMITTER CONTROLLER . . . . . . . . . . . . . . . 992 9862 001 (B) 7-15Table 7-19. *DIGITAL LOGIC PC ASSY . . . . . . . . . . . . . . . 992 5433 001 (AA) 7-16Table 7-20. PWB, ANALOG, W/VSWR FB . . . . . . . . . . . . . . 992 5434 002 (AM) 7-17Table 7-21. RF1 PC BD ASSY . . . . . . . . . . . . . . . . . . . . 992 5435 001 (D) 7-19Table 7-22. STATUS PC BD ASSY . . . . . . . . . . . . . . . . . . 992 5437 001 (H) 7-20Table 7-23. PWB, MOTOR POT INTERFACE . . . . . . . . . . . . 992 6576 001 (D) 7-20Table 7-24. PA CAVITY, . . . . . . . . . . . . . . . . . . . . . . . . . 992 9864 001 (B) 7-20Table 7-25. SOCKET & INPUT CKT ASSY . . . . . . . . . . . . . . 992 5567 002 (W) 7-22

Section VIIParts List

7-1 IntroductionThis section provides a description, reference designator, and order number for replaceable electrical parts, assemblies,and selected mechanical parts necessary for proper maintenance of the HARRIS HT 20/25CD FM BROADCASTTRANSMITTER. Below is the replaceable parts list index for all assemblies and subassemblies in the transmitter.

7-2 Replaceable Parts ServiceSee Replaceable Parts Service clause on back of manual title page for information on ordering parts.


Table 7-1. XMTR, HT-20, 20KW - 994 9568 002 (A)Harris PN Description QTY UM Reference Designators000 0000 009. . . . . . PACKING CHECK LIST . . . . . . . . . . . . . . . . 0 DWG344 0091 000. . . . . . SCREW, SET 6-32 X 3/8 . . . . . . . . . . . . . . . . . 0 EA374 0151 000. . . . . . TUBE, 8990 . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA V001472 1657 000. . . . . . XFMR, PLATE 29KVA . . . . . . . . . . . . . . . . . . . 1 EA646 1353 000. . . . . . NAMEPLATE, XMTR EQUIPMENT . . . . . . . . . 1 EA646 1662 001. . . . . . NAMEPLATE, HT20CD . . . . . . . . . . . . . . . . . . 0 EA646 1662 002. . . . . . NAMEPLATE, HT20FM . . . . . . . . . . . . . . . . . . 0 EA822 0608 001. . . . . . SLUG, END . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 EA829 3899 002. . . . . . INDUCTOR. . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 EA829 3899 003. . . . . . INDUCTOR. . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 EA829 3899 004. . . . . . INDUCTOR. . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 EA829 3899 005. . . . . . INDUCTOR. . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 EA829 3899 006. . . . . . INDUCTOR. . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 EA829 3899 007. . . . . . INDUCTOR. . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 EA829 3899 008. . . . . . INDUCTOR. . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 EA829 3899 009. . . . . . INDUCTOR. . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 EA829 9839 001. . . . . . SHIELD, LOADING STRAP . . . . . . . . . . . . . . . 0 EA839 7495 063. . . . . . CABINET OUTLINE DRAWING. . . . . . . . . . 0 DWG839 7822 015. . . . . . FAMILY TREE, HT-25FM. . . . . . . . . . . . . . . 0 DWG929 3899 010. . . . . . INDUCTOR. . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 EA929 3899 011. . . . . . INDUCTOR. . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 EA988 2609 001. . . . . . DP HT 20/25 XMTR . . . . . . . . . . . . . . . . . . . . . 0 EA990 1081 001. . . . . . R-SK-FM25K2/HT-25/HT-20 . . . . . . . . . . . . . . 0 EA992 5428 001. . . . . . BASIC PS, HT20/25 . . . . . . . . . . . . . . . . . . . . . 1 EA992 6812 002. . . . . . KIT, 4 WIRE “Y” XMTR MOD . . . . . . . . . . . . . . 0 EA992 8093 003. . . . . . *KIT FIL REG 60HZ HT20/25FM/CD . . . . . . . . 0 EA T008992 8093 004. . . . . . *KIT FIL REG 50HZ HT20/25FM/CD . . . . . . . . 0 EA T008992 9854 006. . . . . . TRAY, RACK MOUNTING . . . . . . . . . . . . . . . . 0 EA994 9102 002. . . . . . R-BK-FM25K2/HT-25/HT-20 . . . . . . . . . . . . . . 0 EA994 9125 001. . . . . . R-PK-FM25K2/HT-25/HT-20 . . . . . . . . . . . . . . 0 EA994 9129 002. . . . . . KIT, EXTENDED COOLING 1PH. . . . . . . . . . . 0 EA994 9138 004. . . . . . XMTR, BASIC, HT-20/25FM . . . . . . . . . . . . . . 1 EA994 9410 004. . . . . . EXCITER, DIGIT CD FM, BASIC . . . . . . . . . . . 0 EA994 9425 003. . . . . . MODULE, ANALOG I/O . . . . . . . . . . . . . . . . . . 0 EA994 9530 002. . . . . . DGTL STEREO INTERFACE MODULE . . . . . 0 EA994 9678 001. . . . . . EXCITER, BASIC, SUPERCITER . . . . . . . . . . 0 EA995 0012 001. . . . . . FLEXSTAR EXCITER . . . . . . . . . . . . . . . . . . . 0 EA

Table 7-2. XMTR, HT-25, 25KW - 994 9569 002 (A)Harris PN Description QTY UM Reference Designators000 0000 009. . . . . . PACKING CHECK LIST . . . . . . . . . . . . . . . . 0 DWG344 0091 000. . . . . . SCREW, SET 6-32 X 3/8 . . . . . . . . . . . . . . . . . 0 EA374 0151 000. . . . . . TUBE, 8990 . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA V001472 1219 000. . . . . . XFMR, PLT, . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA646 1353 000. . . . . . NAMEPLATE, XMTR EQUIPMENT . . . . . . . . . 1 EA646 1662 003. . . . . . NAMEPLATE, HT25CD . . . . . . . . . . . . . . . . . . 0 EA646 1662 004. . . . . . NAMEPLATE, HT25FM . . . . . . . . . . . . . . . . . . 0 EA822 0608 001. . . . . . SLUG, END . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 EA829 3899 002. . . . . . INDUCTOR. . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 EA


829 3899 003 . . . . . INDUCTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 EA829 3899 004 . . . . . INDUCTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 EA829 3899 005 . . . . . INDUCTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 EA829 3899 006 . . . . . INDUCTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 EA829 3899 007 . . . . . INDUCTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 EA829 3899 008 . . . . . INDUCTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 EA829 3899 009 . . . . . INDUCTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 EA829 9839 001 . . . . . SHIELD, LOADING STRAP. . . . . . . . . . . . . . . 0 EA839 7495 063 . . . . . CABINET OUTLINE DRAWING . . . . . . . . . 0 DWG839 7822 015 . . . . . FAMILY TREE, HT-25FM . . . . . . . . . . . . . . 0 DWG929 3899 010 . . . . . INDUCTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 EA929 3899 011 . . . . . INDUCTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 EA988 2609 001 . . . . . DP HT 20/25 XMTR. . . . . . . . . . . . . . . . . . . . . 0 EA990 1081 001 . . . . . R-SK-FM25K2/HT-25/HT-20 . . . . . . . . . . . . . . 0 EA992 5428 001 . . . . . BASIC PS, HT20/25 . . . . . . . . . . . . . . . . . . . 1 EA992 6812 002 . . . . . KIT, 4 WIRE “Y” XMTR MOD . . . . . . . . . . . . . 0 EA992 8093 003 . . . . . *KIT FIL REG 60HZ HT20/25FM/CD. . . . . . . 0 EA T008992 8093 004 . . . . . *KIT FIL REG 50HZ HT20/25FM/CD. . . . . . . 0 EA T008992 8362 001 . . . . . MOD KIT-HT25FM PA TUNING . . . . . . . . . . 0 EA992 9854 006 . . . . . TRAY, RACK MOUNTING. . . . . . . . . . . . . . . 0 EA994 9102 002 . . . . . R-BK-FM25K2/HT-25/HT-20 . . . . . . . . . . . . . . 0 EA994 9125 001 . . . . . R-PK-FM25K2/HT-25/HT-20 . . . . . . . . . . . . . 0 EA994 9129 002 . . . . . KIT, EXTENDED COOLING 1PH . . . . . . . . . 0 EA994 9138 004 . . . . . XMTR, BASIC, HT-20/25FM . . . . . . . . . . . . . 1 EA994 9410 004 . . . . . EXCITER, DIGIT CD FM, BASIC . . . . . . . . . 0 EA994 9425 003 . . . . . MODULE, ANALOG I/O. . . . . . . . . . . . . . . . . . 0 EA994 9530 002 . . . . . DGTL STEREO INTERFACE MODULE . . . . . 0 EA994 9678 001 . . . . . EXCITER, BASIC, SUPERCITER . . . . . . . . . . 0 EA995 0012 001 . . . . . FLEXSTAR EXCITER . . . . . . . . . . . . . . . . . . 0 EA

Table 7-3. R-SK-FM25K2/HT-25/HT-20 - 990 1081 001 (J)Harris PN Description QTY UM Reference Designators335 0274 000 . . . . . BUSHING, NYLON . . . . . . . . . . . . . . . . . . . . . 1 EA380 0125 000 . . . . . XSTR, NPN 2N4401 ESD. . . . . . . . . . . . . . . . 2 EA380 0126 000 . . . . . XSTR, PNP 2N4403 ESD. . . . . . . . . . . . . . . . 1 EA380 0189 000 . . . . . XSTR, NPN 2N3904 ESD. . . . . . . . . . . . . . . 10 EA380 0190 000 . . . . . XSTR, PNP 2N3906 ESD. . . . . . . . . . . . . . . . 4 EA380 0590 000 . . . . . XSTR, NPN, 2N6294 ESD| . . . . . . . . . . . . . 1 EA380 0614 000 . . . . . XSTR, NPN MJ11028 ESD . . . . . . . . . . . . . . 1 EA382 0260 000 . . . . . IC, 555 ESD . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA382 0367 000 . . . . . IC, 4049/14049 ESD . . . . . . . . . . . . . . . . . . . 1 EA382 0371 000 . . . . . IC, MC7912CT ESD . . . . . . . . . . . . . . . . . . . . 1 EA382 0379 000 . . . . . IC, 723C ESD . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA382 0415 000 . . . . . IC, 324 ESD . . . . . . . . . . . . . . . . . . . . 1 EA382 0428 000 . . . . . IC, LM358 ESD. . . . . . . . . . . . . . . . . . . 1 EA382 0475 000 . . . . . IC, 317 ESD . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA382 0553 000 . . . . . IC 4012 ESD. . . . . . . . . . . . . . . . . . . . . 1 EA382 0618 000 . . . . . IC, 4081/14081 ESD . . . . . . . . . . . . . . . . . 1 EA382 0619 000 . . . . . IC, CD4050/MC14050 ESD. . . . . . . . . . . . . . 1 EA382 0631 000 . . . . . IC, AD536AJD ESD. . . . . . . . . . . . . . 1 EA382 0662 000 . . . . . IC, MC14013BCP CMOS ESD. . . . . . . . . . . . 1 EA382 0719 000 . . . . . IC LM324AN ESD . . . . . . . . . . . . . . . . . 1 EA382 0954 000 . . . . . IC, 4001B/14001B ESD. . . . . . . . . . . . . 1 EA384 0167 000 . . . . . RECT, .35 AMP 5KV PIV ESD . . . . . . . . . . . . 2 EA


384 0205 000. . . . . . DIODE SILICON 1N914/4148 ESD. . . . . . . . . 7 EA384 0316 000. . . . . . RECT SIL CTL 2N5060 ESD. . . . . . . . . . . . . . 2 EA384 0321 000. . . . . . *DIODE 5082-2800 ESD . . . . . . . . . . . . . . . . . 1 EA384 0431 000. . . . . . RECT. 1N4001 ESD . . . . . . . . . . . . . . . . . . . 16 EA384 0610 000. . . . . . * LED, GREEN T-1 3/4 ESD. . . . . . . . . . . . 2 EA384 0611 000. . . . . . *LED, RED T1-3/4 ESD . . . . . . . . . . . . . 6 EA384 0614 000. . . . . . RECT 70HF40 . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA384 0674 000. . . . . . RECTIFIER 70A 400 PIV ESD . . . . . . . . . . . . 1 EA384 0684 000. . . . . . TRIAC TIC206A 100V 3AMP ESD . . . . . . . . . 1 EA384 0694 000. . . . . . LED RED CART 12V . . . . . . . . . . . . . . . . . . . . 1 EA384 0695 000. . . . . . LED GREEN CART 12V ESD . . . . . . . . . . . . . 1 EA384 0702 000. . . . . . RECT FW BRIDGE 600V 35A ESD . . . . . . . . 1 EA384 0736 000. . . . . . RECT,HIGH CURRENT GI/MR751 ESD . . . . . 1 EA384 0806 000. . . . . . LED, BI-COLOR RED/GREEN ESD . . . . . . . . 1 EA384 0844 000. . . . . . RECT BCR5AM/BT136-500 ESD . . . . . . . . . . 3 EA386 0078 000. . . . . . ZENER, 1N4734A 5.6V ESD. . . . . . . . . . . . . . 1 EA386 0082 000. . . . . . ZENER, 1N4744A 15V 1W 5% ESD. . . . . . . . 1 EA386 0083 000. . . . . . ZENER, 1N4742A 12V ESD . . . . . . . . . . . . . . 1 EA386 0135 000. . . . . . ZENER, 1N4733A 5.1V ESD. . . . . . . . . . . . . . 1 EA386 0137 000. . . . . . ZENER, 1N4746A 18V ESD . . . . . . . . . . . . . . 1 EA386 0169 000. . . . . . ZENER, 1N5352A 15V ESD . . . . . . . . . . . . . . 1 EA386 0394 000. . . . . . ZENER, 1N5231A(B) 5.1V.5W ESD . . . . . . . . 1 EA386 0405 000. . . . . . ZENER, 1N5242B 12V ESD . . . . . . . . . . . . . . 1 EA386 0430 000. . . . . . ZENER 1N5365B 36V 2W 5% ESD . . . . . . . . 1 EA398 0011 000. . . . . . FUSE,FAST CART .250A 250V . . . . . . . . . . . . 5 EA398 0138 000. . . . . . FUSE, FAST CART 10A 250V . . . . . . . . . . . . . 5 EA410 0417 000. . . . . . INSULATOR, MICA . . . . . . . . . . . . . . . . . . . . . 1 EA560 0049 000. . . . . . MOV, 275WVAC, 75J, 14MM DISC . . . . . . . . . 1 EA917 2256 021. . . . . . XSTR, MODIFIED, MJE271 . . . . . . . . . . . . . . . 1 EA

Table 7-4. BASIC PS, HT20/25 - 992 5428 001 (BR)Harris PN Description QTY UM Reference Designators000 0000 002. . . . . . APPEARS ON A HIGHER LEVEL . . . . . . . . 0 DWG T001055 0121 020. . . . . . NIPPLE, CLOSE 2 IN. . . . . . . . . . . . . . . . . . . . 1 EA055 0121 021. . . . . . CONDUIT LOCKNUT 2 IN . . . . . . . . . . . . . . . . 2 EA055 0121 022. . . . . . BUSHING, INSULATED 2 IN. . . . . . . . . . . . . . 2 EA335 0007 000. . . . . . WASHER NYLON .175 ID . . . . . . . . . . . . . . . . 2 EA335 0012 000. . . . . . WASHER NYLON .195 ID . . . . . . . . . . . . . . . 60 EA335 0017 000. . . . . . WASHER NYLON .261 ID . . . . . . . . . . . . . . . . 6 EA356 0004 000. . . . . . CABLE CLAMP 1/4 D. . . . . . . . . . . . . . . . . . . . 6 EA357 0071 000. . . . . . SCREW 10-32 X 1/2. . . . . . . . . . . . . . . . . . . . . 3 EA358 0003 000. . . . . . BRACKET RESISTOR MTG . . . . . . . . . . . . . 10 EA #R001,#R002,#R003,#R007,#R011358 0004 000. . . . . . BRACKET RESISTOR MTG . . . . . . . . . . . . . . 6 EA #R008,#R009,#R018358 0416 000. . . . . . SPACER, ROLLED #8 X 1/2LG . . . . . . . . . . . . 4 EA #T002358 2598 000. . . . . . CABLE TIE MOUNT, 4-WAY . . . . . . . . . . . . . . 4 EA358 2628 000. . . . . . CABLE PUSH MOUNT. . . . . . . . . . . . . . . . . . . 2 EA358 3136 000. . . . . . STUD, BRS 1/4-20 X 2-1/4. . . . . . . . . . . . . . . . 3 EA384 0167 000. . . . . . RECT, .35 AMP 5KV PIV ESD . . . . . . . . . . . . 4 EA398 0454 000. . . . . . FUSE, TIME-DELAY, 5 AMP 500V . . . . . . . . . 2 EA402 0001 000. . . . . . CLIP, FUSE 1.062 60A 600V . . . . . . . . . . . . . . 8 EA402 0107 000. . . . . . CLIP, FUSE 9/16 . . . . . . . . . . . . . . . . . . . . . . . 6 EA402 0177 000. . . . . . FUSE BLOCK, 2 POLE, 600V . . . . . . . . . . . . . 1 EA410 0010 000. . . . . . INSULATOR ROUND NS5W 0208 . . . . . . . . . 1 EA #C001410 0018 000. . . . . . INSULATOR ROUND NS5W 0312 . . . . . . . . . 8 EA


410 0019 000 . . . . . INSULATOR ROUND NS5W 0316 . . . . . . . . . 9 EA #R013,#R016410 0020 000 . . . . . INSULATOR ROUND NS5W 0320 . . . . . . . . . 3 EA410 0021 000 . . . . . INSULATOR ROUND NS5W 0324 . . . . . . . . . 6 EA #R012,#R014,#R015410 0027 000 . . . . . INSULATOR ROUND NS5W 0424 . . . . . . . . . 3 EA #S008410 0061 000 . . . . . INSULATOR SQ NS5W 1212 . . . . . . . . . . . . . 2 EA410 0064 000 . . . . . INSULATOR SQ NS5W 1224 . . . . . . . . . . . . . 6 EA424 0003 000 . . . . . GROMMET 1/2 MTG DIA . . . . . . . . . . . . . . . . 1 EA424 0009 000 . . . . . GROMMET 1-3/8 MTG DI . . . . . . . . . . . . . . . . 3 EA424 0017 000 . . . . . GROMMET 5/16 MTG DIA . . . . . . . . . . . . . . . 5 EA424 0032 000 . . . . . GROMMET 2-1/2 MTG D. . . . . . . . . . . . . . . . . 1 EA430 0031 000 . . . . . FAN CARAVEL CL3T2/020191. . . . . . . . . . . . 1 EA430 0190 000 . . . . . FAN GUARD 10" . . . . . . . . . . . . . . . . . . . . . . . 1 EA436 0273 000 . . . . . MOTOR, SYNCH 1/2 RPM . . . . . . . . . . . . . . . 1 EA B002448 0224 000 . . . . . HANDLE ALUM . . . . . . . . . . . . . . . . . . . . . . . . 1 EA448 0256 000 . . . . . FILTER 15X15 X 1.785 . . . . . . . . . . . . . . . . . . 1 EA472 1216 000 . . . . . XFMR, PWR, 817-0333-001 . . . . . . . . . . . . . . 1 EA472 1246 000 . . . . . XFMR, CTL, F-215U, P-8619 . . . . . . . . . . . . . 1 EA474 0055 000 . . . . . *XFMR, VAR, POWER . . . . . . . . . . . . . . . . . . 1 EA T002476 0270 000 . . . . . REACTOR 814-2067-001 . . . . . . . . . . . . . . . . 1 EA476 0296 000 . . . . . REACTOR, FILTER 10HY 5KV. . . . . . . . . . . . 2 EA508 0534 000 . . . . . CAP 0.02 UF 30KVDC 10% . . . . . . . . . . . . . . 1 EA508 0535 000 . . . . . CAP 0.10 UF 3KVDC 10% . . . . . . . . . . . . . . . 1 EA510 0471 000 . . . . . CAP 5.5UF 15KV 10% . . . . . . . . . . . . . . . . . . 1 EA510 0560 000 . . . . . CAP 12UF 2KV 10% . . . . . . . . . . . . . . . . . . . . 3 EA C2,C3,C7540 0837 000 . . . . . RES 250.0 OHM 275W 10% . . . . . . . . . . . . . . 2 EA R19540 1167 000 . . . . . RES 5.0 OHM 275W 10% . . . . . . . . . . . . . . . . 1 EA R10540 1200 000 . . . . . RES 110.0 OHM 50W 10% . . . . . . . . . . . . . . . 1 EA542 0169 000 . . . . . * RES 25 OHM 5% 25W . . . . . . . . . . . . . . . . . 2 EA R21542 0282 000 . . . . . RES 1 OHM 5% 100W . . . . . . . . . . . . . . . . . . 3 EA542 0305 000 . . . . . RES 20K OHM 5% 100W . . . . . . . . . . . . . . . . 2 EA R11542 0325 000 . . . . . RES 1K OHM 5% 175W . . . . . . . . . . . . . . . . . 1 EA542 0354 000 . . . . . RES 50 OHM 5% 225W . . . . . . . . . . . . . . . . . 1 EA542 0356 000 . . . . . RES 100 OHM 5% 225W . . . . . . . . . . . . . . . . 1 EA R18542 1604 000 . . . . . RES 100K OHM 160W 5% . . . . . . . . . . . . . . . 5 EA R012,R013,R014,R015,R016560 0036 000 . . . . . MOV, 150WVAC, 80J, 20MM DISC . . . . . . . . 1 EA RV001570 0256 000 . . . . . CNTOR 200A 120VAC 3P. . . . . . . . . . . . . . . . 1 EA K003570 0366 000 . . . . . CNTOR 40A, 4P 50/60HZ 110-120V. . . . . . . . 1 EA K004574 0154 000 . . . . . RELAY 115V 50/60HZ. . . . . . . . . . . . . . . . . . . 4 EA K005,K006,K007,K008582 0034 000 . . . . . RELAY MAG OVERLOAD. . . . . . . . . . . . . . . . 2 EA604 0624 001 . . . . . SW, SIMLTD ROLLER, SPDT, 11A . . . . . . . . 2 EA S12,S13606 0552 000 . . . . . CB 3A 250AC/65DC 50/60HZ . . . . . . . . . . . . . 1 EA CB2606 0579 000 . . . . . CB, 2 POLE, 10 AMP 250VAC . . . . . . . . . . . . 1 EA CB1614 0003 000 . . . . . TERM BD 3 TERM . . . . . . . . . . . . . . . . . . . . . 1 EA TB3614 0058 000 . . . . . TERM BD 14 TERM . . . . . . . . . . . . . . . . . . . . 1 EA TB1614 0438 000 . . . . . TERM, STANDOFF . . . . . . . . . . . . . . . . . . . . . 2 EA E001,E008810 2264 001 . . . . . LOCKING PLATE . . . . . . . . . . . . . . . . . . . . . . 8 EA810 8733 001 . . . . . (S7) LINK SWITCH . . . . . . . . . . . . . . . . . . . . . 1 EA813 5012 053 . . . . . STDOFF 10-32X2-3/4 RD . . . . . . . . . . . . . . . . 1 EA813 5013 060 . . . . . STDOFF 1/4-20X1/4 1 RD. . . . . . . . . . . . . . . . 3 EA813 5051 026 . . . . . STDOFF 1/4-20 X 2, 1 RD. . . . . . . . . . . . . . . . 1 EA813 5605 027 . . . . . STUD BRS 8-32 X 3 . . . . . . . . . . . . . . . . . . . . 2 EA #R006,#R021814 3570 001 . . . . . STRAP COND TERM . . . . . . . . . . . . . . . . . . . 2 EA814 7796 002 . . . . . HANDLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 EA814 7917 001 . . . . . HOOK, 1/2IN RADIUS. . . . . . . . . . . . . . . . . . . 2 EA815 0742 001 . . . . . TERMINATION, CONT . . . . . . . . . . . . . . . . . . 6 EA


816 6141 002. . . . . . SUPPORT,6.8 IN. LG. . . . . . . . . . . . . . . . . . . . 4 EA #T002816 6215 001. . . . . . COUPLING,STEP DOWN . . . . . . . . . . . . . . . . 1 EA817 0548 001. . . . . . RUNNING SHEETS . . . . . . . . . . . . . . . . . . . 0 DWG817 1059 001. . . . . . SPACER, LOCKNUT . . . . . . . . . . . . . . . . . . . . 2 EA817 1292 001. . . . . . STDOFF 1" DIA X 3" L . . . . . . . . . . . . . . . . . . 12 EA817 1335 161. . . . . . COLLAR, STOP LIMIT SW . . . . . . . . . . . . . . . 1 EA #T002827 7267 001. . . . . . CLAMP, FILTER. . . . . . . . . . . . . . . . . . . . . . . . 1 EA827 7368 003. . . . . . BRACKET, GRD. HOOK MT . . . . . . . . . . . . . . 1 EA828 8800 002. . . . . . SPACER, CLIP. . . . . . . . . . . . . . . . . . . . . . . . . 2 EA #S008829 1026 001. . . . . . ANGLE, SPARK GAP ADJ. . . . . . . . . . . . . . . . 1 EA829 1027 002. . . . . . ANGLE, SPARK GAP . . . . . . . . . . . . . . . . . . . 1 EA829 1028 002. . . . . . BOARD, SPARK GAP . . . . . . . . . . . . . . . . . . . 1 EA829 4879 001. . . . . . BRACKET, CAPACITOR . . . . . . . . . . . . . . . . . 2 EA #C006829 4911 001. . . . . . STRAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA829 4912 001. . . . . . STRAP, DIVIDER SHELF . . . . . . . . . . . . . . . . 1 EA829 4913 001. . . . . . STRAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 EA829 4915 001. . . . . . STRAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA829 7781 001. . . . . . CHASSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA #T002829 8858 001. . . . . . PLATE, MOTOR. . . . . . . . . . . . . . . . . . . . . . . . 1 EA839 4737 002. . . . . . PANEL, CONTACTOR. . . . . . . . . . . . . . . . . . . 1 EA839 5569 001. . . . . . STRAP, GND . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA842 6366 001. . . . . . DUCT INTAKE FLUSH. . . . . . . . . . . . . . . . . . . 1 EA852 9163 007. . . . . . SCHEM, MAIN CABINET. . . . . . . . . . . . . . . 0 DWG916 7150 001. . . . . . COIL CLIP . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 EA #S008916 7503 001. . . . . . REAR COVER ASSY . . . . . . . . . . . . . . . . . . . . 1 EA917 2037 001. . . . . . SWITCH, INTERLOCK. . . . . . . . . . . . . . . . . . . 5 EA S001,S002,S003,S004,S005917 2244 001. . . . . . SPACER, 1.0 LG .75 DIA. . . . . . . . . . . . . . . . . 3 EA928 9349 001. . . . . . LOWER FRT CVR ASSY . . . . . . . . . . . . . . . . . 1 EA929 4867 001. . . . . . SUPPORT, CONT PNL . . . . . . . . . . . . . . . . . . 1 EA929 4871 001. . . . . . ANGLE, CONT PNL . . . . . . . . . . . . . . . . . . . . . 1 EA929 7553 001. . . . . . CABLE ASSY PWR SUP . . . . . . . . . . . . . . . . . 1 EA929 7733 001. . . . . . RES/DIODE PC BD ASSY . . . . . . . . . . . . . . . . 1 EA939 4733 001. . . . . . COVER, UPPER FRONT. . . . . . . . . . . . . . . . . 1 EA939 4739 001. . . . . . SHELF, DIVIDER . . . . . . . . . . . . . . . . . . . . . . . 1 EA952 8703 001. . . . . . CABINET ASSY, FM25 . . . . . . . . . . . . . . . . . . 1 EA992 5480 001. . . . . . H.V. SHORTING ASSY . . . . . . . . . . . . . . . . . . 1 EA992 9156 001. . . . . . *RECT ASSY, HV. . . . . . . . . . . . . . . . . . . . . . . 3 EA

Table 7-5. *RECT ASSY, HV - 992 9156 001 (C1)Harris PN Description QTY UM Reference Designators2540004000A . . . . . *WIRE, BUS CU 16AWG . . . . . . . . . . . . . . . . . 2 FT354 0713 000. . . . . . SOLDER TERMINAL, SWAGE . . . . . . . . . . 104 EA354 0838 000. . . . . . TERMINAL LUG RING 10 . . . . . . . . . . . . . . . . 2 EA354 0839 000. . . . . . TERMINAL LUG RING 6 . . . . . . . . . . . . . . . . . 2 EA358 3476 000. . . . . . SPADEBOLT 10-32 THREAD . . . . . . . . . . . . . 2 EA384 0933 000. . . . . . RECTIFIER DIODE 1KV 6A. . . . . . . . . . . . . . 52 EA516 0063 000. . . . . . *CAP, DISC 0.002UF 1KV 20% . . . . . . . . . . . 52 EA540 1600 601. . . . . . RES 1MEG OHM 3W 5%. . . . . . . . . . . . . . . . 52 EA839 8169 002. . . . . . ASSY INSTR, HV RECTIFIER . . . . . . . . . . . 0 DWG929 8305 286. . . . . . STANDOFF 10-32 X 0.40 LG. . . . . . . . . . . . . . 2 EA939 8169 001. . . . . . BOARD, HV RECTIFIER . . . . . . . . . . . . . . . . . 1 EA


Table 7-6. KIT, 4 WIRE “Y” XMTR MOD - 992 6812 002 (A)Harris PN Description QTY UM Reference Designators354 0760 000 . . . . . TAB ADAPTOR 250 SERIES . . . . . . . . . . . . . 3 EA358 0003 000 . . . . . BRACKET RESISTOR MTG . . . . . . . . . . . . . . 2 EA358 3131 000 . . . . . STUD, BRS 1/4-20 X 1 . . . . . . . . . . . . . . . . . . 1 EA358 3135 000 . . . . . STUD, BRS 1/4-20 X 2 . . . . . . . . . . . . . . . . . . 1 EA358 3137 000 . . . . . STUD, BRS 1/4-20 X 2-1/2 . . . . . . . . . . . . . . . 1 EA398 0368 000 . . . . . FUSE, CART 2A 600V . . . . . . . . . . . . . . . . . . 3 EA402 0130 000 . . . . . FUSE HOLDER, 3 POLE. . . . . . . . . . . . . . . . . 1 EA410 0016 000 . . . . . INSULATOR ROUND NS5W 0308 . . . . . . . . . 3 EA410 0027 000 . . . . . INSULATOR ROUND NS5W 0424 . . . . . . . . . 1 EA410 0173 000 . . . . . INSULATOR ROUND . . . . . . . . . . . . . . . . . . . 1 EA426 0077 000 . . . . . ISOLATION MOUNT . . . . . . . . . . . . . . . . . . . . 4 EA510 0574 000 . . . . . CAP 30UF 370VAC 50/60HZ . . . . . . . . . . . . . 3 EA542 1586 000 . . . . . RES 2.0 OHM 180W 10% . . . . . . . . . . . . . . . . 1 EA636 0037 000 . . . . . METER, ELAPSED TIME 50HZ . . . . . . . . . . . 1 EA740 0837 000 . . . . . MON, PH 350-440V 3 PH . . . . . . . . . . . . . . . . 1 EA815 0742 001 . . . . . TERMINATION, CONT . . . . . . . . . . . . . . . . . . 4 EA829 7223 002 . . . . . PLATE, CAP MTG. . . . . . . . . . . . . . . . . . . . . . 1 EA917 2408 001 . . . . . CABLE, 50HZ KIT . . . . . . . . . . . . . . . . . . . . . . 1 EA929 7222 001 . . . . . CAP MTG, UNIVERSAL CLAMP . . . . . . . . . . 3 EA

Table 7-7. *KIT FIL REG 60HZ HT20/25FM/CD - 992 8093 003 (C)Harris PN Description QTY UM Reference Designators472 1250 000 . . . . . XFMR,CONSTVOLT,23-23-2308 . . . . . . . . . . 1 EA817 2501 018 . . . . . RUN LIST, V REG KIT HT-20/25HT . . . . . . 0 DWG817 2501 019 . . . . . MOD INSTR,V REG KIT,HT-20/25FM. . . . . 0 DWG917 1335 262 . . . . . CABLE, VOLT REG KIT . . . . . . . . . . . . . . . . . 1 EA

Table 7-8. *KIT FIL REG 50HZ HT20/25FM/CD - 992 8093 004 (A)Harris PN Description QTY UM Reference Designators472 1252 000 . . . . . XFMR, CV, 3KVA 50HZ 1PH . . . . . . . . . . . . . 1 EA817 2501 018 . . . . . RUN LIST, V REG KIT HT-20/25HT . . . . . . 0 DWG817 2501 019 . . . . . MOD INSTR,V REG KIT,HT-20/25FM. . . . . 0 DWG917 1335 262 . . . . . CABLE, VOLT REG KIT . . . . . . . . . . . . . . . . . 1 EA

Table 7-9. MOD KIT-HT25FM PA TUNING - 992 8362 001 (D)Harris PN Description QTY UM Reference Designators302 0108 000 . . . . . SCR, 6-32 X 1/2. . . . . . . . . . . . . . . . . . . . . . . . 2 EA302 0385 000 . . . . . SCR, 6-32 X 1/2. . . . . . . . . . . . . . . . . . . . . . . . 2 EA302 0588 000 . . . . . SCR, 10-32 X 1/2. . . . . . . . . . . . . . . . . . . . . . . 1 EA306 0006 000 . . . . . NUT, HEX 10-32 . . . . . . . . . . . . . . . . . . . . . . . 1 EA310 0009 000 . . . . . WASHER, FLAT 1/4 . . . . . . . . . . . . . . . . . . . . 1 EA310 0017 000 . . . . . WASHER FLAT #6 . . . . . . . . . . . . . . . . . . . . . 2 EA310 0040 000 . . . . . WASHER, FLAT #10 . . . . . . . . . . . . . . . . . . . . 1 EA312 0075 000 . . . . . WASHER, SPRING 1/4 . . . . . . . . . . . . . . . . . . 1 EA314 0005 000 . . . . . WASHER, SPLIT-LOCK 6. . . . . . . . . . . . . . . . 2 EA314 0006 000 . . . . . WASHER, SPLIT-LOCK 8. . . . . . . . . . . . . . . . 4 EA314 0007 000 . . . . . WASHER, SPLIT-LOCK 10. . . . . . . . . . . . . . . 1 EA344 0003 000 . . . . . SCREW, SET 6-32 X 1/8. . . . . . . . . . . . . . . . . 1 EA


344 0005 000. . . . . . SCREW, SET 6-32 X 1/4 . . . . . . . . . . . . . . . . . 1 EA358 1165 000. . . . . . COLLAR 1/4 HOLE . . . . . . . . . . . . . . . . . . . . . 1 EA452 0125 000. . . . . . CLAMP, GEAR. . . . . . . . . . . . . . . . . . . . . . . . . 1 EA452 0126 000. . . . . . GEAR, SPUR SPLIT HUB . . . . . . . . . . . . . . . . 1 EA452 0128 000. . . . . . GEAR, SEGMENT . . . . . . . . . . . . . . . . . . . . . . 1 EA817 1335 235. . . . . . POST, GEAR MTG. . . . . . . . . . . . . . . . . . . . . . 2 EA922 0446 092. . . . . . DRILL TEMPLATE-HT25FM . . . . . . . . . . . . . . 1 EA922 0446 093. . . . . . COVER PLATE-HT25FM PA . . . . . . . . . . . . . . 1 EA922 1067 001. . . . . . BLOCK, BEARING . . . . . . . . . . . . . . . . . . . . . . 1 EA922 1067 002. . . . . . PLATE, BEARING . . . . . . . . . . . . . . . . . . . . . . 1 EA922 1067 005. . . . . . SHAFT, PA TUNING . . . . . . . . . . . . . . . . . . . . 1 EA922 1067 006. . . . . . SHAFT, PA TUNING . . . . . . . . . . . . . . . . . . . . 1 EA988 9045 392. . . . . . INSTALLATION INSTRUCTIONS . . . . . . . . . . 1 EA

Table 7-10. R-BK-FM25K2/HT-25/HT-20 - 994 9102 002 (A)Harris PN Description QTY UM Reference Designators740 1223 000. . . . . . *AMP MODULE 700W 86-108MHZ . . . . . . . . . 1 EA992 5433 001. . . . . . *DIGITAL LOGIC PC ASSY . . . . . . . . . . . . . . . 1 EA992 5434 002. . . . . . PWB, ANALOG, W/VSWR FB . . . . . . . . . . . . . 1 EA992 5439 002. . . . . . AC CONTROL PC BD . . . . . . . . . . . . . . . . . . . 1 EA992 5620 001. . . . . . DIR COUPLER ASSY . . . . . . . . . . . . . . . . . . . 1 EA

Table 7-11. R-PK-FM25K2/HT-25/HT-20 - 994 9125 001 (G)Harris PN Description QTY UM Reference Designators396 0183 000. . . . . . LAMP, 14V .08A 382 . . . . . . . . . . . . . . . . . . . . 5 EA410 0152 000. . . . . . INSULATOR BSHG NS5W-4103 . . . . . . . . . . . 1 EA410 0156 000. . . . . . INSULATOR BSHG NS5W-4203 . . . . . . . . . . . 1 EA424 0162 000. . . . . . BELT NO-SLIP 95 T. . . . . . . . . . . . . . . . . . . . . 1 EA432 0364 000. . . . . . WHEEL, BLOWER CW ROTATION. . . . . . . . . 1 EA436 0273 000. . . . . . MOTOR, SYNCH 1/2 RPM. . . . . . . . . . . . . . . . 1 EA436 0289 000. . . . . . MOTOR, 1/3HP 50/60 HZ 3PH . . . . . . . . . . . . 1 EA448 0256 000. . . . . . FILTER 15X15 X 1.785 . . . . . . . . . . . . . . . . . . 1 EA472 1217 000. . . . . . XFMR, PWR, 817-0332-001. . . . . . . . . . . . . . . 1 EA494 0004 000. . . . . . CHOKE RF 7UH. . . . . . . . . . . . . . . . . . . . . . . . 1 EA510 0471 000. . . . . . CAP 5.5UF 15KV 10% . . . . . . . . . . . . . . . . . . . 1 EA516 0402 000. . . . . . CAP 4800 PF 20KV . . . . . . . . . . . . . . . . . . . . . 1 EA574 0351 000. . . . . . * RELAY, REED SPST 6VDC . . . . . . . . . . . . . 1 EA574 0437 000. . . . . . RELAY, SS SPST 25A 240VAC. . . . . . . . . . . . 1 EA582 0034 000. . . . . . RELAY MAG OVERLOAD . . . . . . . . . . . . . . . . 1 EA590 0037 000. . . . . . SOLENOID 220V, 60HZ. . . . . . . . . . . . . . . . . . 1 EA604 0397 000. . . . . . SW, PRESS. . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA829 9745 009. . . . . . BLOCKER . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA839 5741 004. . . . . . SCREEN BLOCKER . . . . . . . . . . . . . . . . . . . . 1 EA

Table 7-12. KIT, EXTENDED COOLING 1PH - 994 9129 002 (A)Harris PN Description QTY UM Reference Designators306 0007 000. . . . . . NUT, HEX 1/4-20 . . . . . . . . . . . . . . . . . . . . . . . 8 EA310 0009 000. . . . . . WASHER, FLAT 1/4. . . . . . . . . . . . . . . . . . . . . 8 EA314 0009 000. . . . . . WASHER, SPLIT-LOCK 1/4. . . . . . . . . . . . . . . 8 EA432 0239 000. . . . . . WHEEL, BLOWER CW ROTATION. . . . . . . . . 1 EA BW1436 0264 000. . . . . . MOTOR 2HP 220/240V 1 PH. . . . . . . . . . . . . . 1 EA B1


604 0912 000 . . . . . SW, DIFF PRESS.. . . . . . . . . . . . . . . . . . . . . . 1 EA606 0581 000 . . . . . CB, 3 POLE, 20 AMP 250VAC . . . . . . . . . . . . 1 EA CB4939 8220 544 . . . . . PLATE, MOTOR MTG. . . . . . . . . . . . . . . . . . . 1 EA939 8220 545 . . . . . TEMPLATE, MOTOR MTG. . . . . . . . . . . . . . . 1 EA

Table 7-13. XMTR, BASIC, HT-20/25FM - 994 9138 004 (D)Harris PN Description QTY UM Reference Designators043 6110 010 . . . . . PLSTC FOAM 2" X 24" . . . . . . . . . . . . . . . 0.174 SF051 0001 017 . . . . . *ADHESIVE, LIQUID NAILS . . . . . . . . . . . . . . 0 EA055 0120 004 . . . . . CONDUIT LKNUT .5 . . . . . . . . . . . . . . . . . . . . 1 EA #S009350 0037 000 . . . . . RIVET POP .125X.265 . . . . . . . . . . . . . . . . . 76 EA354 0003 000 . . . . . LUG #10 RING RED 22-18AWG. . . . . . . . . . 30 EA #TB1354 0197 000 . . . . . CONNECTOR SET SCREW TYPE. . . . . . . . . 4 EA354 0627 000 . . . . . CONTACT, SOCKET. . . . . . . . . . . . . . . . . . . 50 EA354 0760 000 . . . . . TAB ADAPTOR 250 SERIES . . . . . . . . . . . . . 1 EA #Z001358 0002 000 . . . . . *BRACKET RESISTOR MTG . . . . . . . . . . . . . 6 EA #R002,#R003,#R003A358 0003 000 . . . . . BRACKET RESISTOR MTG . . . . . . . . . . . . . . 2 EA #R005358 0411 000 . . . . . RING RETAINING .250 . . . . . . . . . . . . . . . . . . 2 EA358 0473 000 . . . . . CLAMP, HOSE DIA 1.313 MIN 2.25 MAX| . . . 1 EA358 1165 000 . . . . . COLLAR 1/4 HOLE . . . . . . . . . . . . . . . . . . . . . 4 EA358 1171 000 . . . . . WRENCH, 5/16 HEX . . . . . . . . . . . . . . . . . . . . 1 EA358 1307 000 . . . . . COUPLING, OFFSET . . . . . . . . . . . . . . . . . . . 1 EA358 2034 000 . . . . . GROMMET, ADAPTING . . . . . . . . . . . . . . . . . 2 EA358 2073 000 . . . . . BUSHING, CHASSIS. . . . . . . . . . . . . . . . . . . . 1 EA358 2262 000 . . . . . STRAIN RELIEF, 24 CKT . . . . . . . . . . . . . . . . 2 EA358 2635 000 . . . . . CABLE TIE, PUSH MOUNT SNAP IN. . . . . . . 8 EA358 2917 000 . . . . . PLUG BUTTON 7/16 HOLE BLK. . . . . . . . . . . 1 EA358 2995 000 . . . . . END PLATE, 261 TERM BD . . . . . . . . . . . . . . 1 EA #TB10358 3072 000 . . . . . PLUG, BLK .75" DIA HOLE . . . . . . . . . . . . . . . 4 EA358 3109 000 . . . . . STUD, BRS 8-32 X 1. . . . . . . . . . . . . . . . . . . . 4 EA #E004,#E005,#R020,R021358 3135 000 . . . . . STUD, BRS 1/4-20 X 2 . . . . . . . . . . . . . . . . . . 2 EA359 0179 000 . . . . . CONNECTOR MALE 268-N . . . . . . . . . . . . . . 2 EA #S009384 0167 000 . . . . . RECT, .35 AMP 5KV PIV ESD . . . . . . . . . . . . 2 EA Z002,Z003384 0702 000 . . . . . RECT FW BRIDGE 600V 35A ESD . . . . . . . . 1 EA Z001384 0720 000 . . . . . TRANSZORB 1N6377 15V 5W ESD . . . . . . . 1 EA CR008386 0078 000 . . . . . ZENER, 1N4734A 5.6V ESD . . . . . . . . . . . . . 1 EA CR007396 0183 000 . . . . . LAMP, 14V .08A 382 . . . . . . . . . . . . . . . . . . . . 2 EA DS001,DS002398 0011 000 . . . . . FUSE,FAST CART .250A 250V . . . . . . . . . . . 2 EA F001,F002402 0107 000 . . . . . CLIP, FUSE 9/16 . . . . . . . . . . . . . . . . . . . . . . . 2 EA402 0192 000 . . . . . FUSEBLOCK 3P . . . . . . . . . . . . . . . . . . . . . . . 1 EA XF001,XF002,XF003406 0491 000 . . . . . PLUG WIRING FOR LED CART . . . . . . . . . . . 2 EA410 0004 000 . . . . . INSULATOR ROUND NS5W 0108 . . . . . . . . . 5 EA410 0013 000 . . . . . INSULATOR ROUND NS5W 0216 . . . . . . . . . 2 EA E004,E005410 0015 000 . . . . . INSULATOR ROUND NS5W 0224 . . . . . . . . . 4 EA #R020,#R021,#TB008410 0021 000 . . . . . INSULATOR ROUND NS5W 0324 . . . . . . . . . 3 EA #R034,#R035410 0027 000 . . . . . INSULATOR ROUND NS5W 0424 . . . . . . . . . 2 EA E002,E003424 0025 000 . . . . . GROMMET 9/16 MTG DIA . . . . . . . . . . . . . . . 4 EA #B001424 0162 000 . . . . . BELT NO-SLIP 95 T . . . . . . . . . . . . . . . . . . . . 1 EA430 0039 000 . . . . . FAN TARZAN 230VAC 50/60HZ. . . . . . . . . . . 1 EA430 0241 000 . . . . . FAN GUARD . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA432 0364 000 . . . . . WHEEL, BLOWER CW ROTATION . . . . . . . . 1 EA #B001436 0304 000 . . . . . MOTOR 1/2HP 1PH 1725/1425 RPM . . . . . . . 1 EA B001438 0039 000 . . . . . PULLEY, NO-SLIP . . . . . . . . . . . . . . . . . . . . . 2 EA448 0865 000 . . . . . LATCH, TOOL-OPERATED . . . . . . . . . . . . . . 3 EA


448 0941 001. . . . . . HINGE, FREE SWINGING TYPE. . . . . . . . . . . 3 EA452 0025 000. . . . . . GEAR, MITER 16 TEETH . . . . . . . . . . . . . . . . 2 EA452 0026 000. . . . . . GEAR, MITER 16 TEETH . . . . . . . . . . . . . . . . 2 EA472 0622 000. . . . . . XFMR CTL 115/230V 50/60HZ . . . . . . . . . . . . 2 EA T005,T007472 0709 000. . . . . . XFMR, ISO, . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA T006472 1217 000. . . . . . XFMR, PWR, 817-0332-001. . . . . . . . . . . . . . . 1 EA T001472 1218 000. . . . . . XFMR, FIL . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA T004474 0090 000. . . . . . * XFMR, VAR, VT8LN . . . . . . . . . . . . . . . . . . . 1 EA T002476 0304 000. . . . . . REACTOR FLTR 10HY . . . . . . . . . . . . . . . . . . 1 EA L001500 0833 000. . . . . . CAP, MICA, 390PF 500V 5%. . . . . . . . . . . . . . 3 EA C008,C009,C011522 0245 000. . . . . . CAP 75 UF 25V . . . . . . . . . . . . . . . . . . . . . . . . 1 EA C006522 0529 000. . . . . . CAP 470UF 50V 20%. . . . . . . . . . . . . . . . . . . . 1 EA C001524 0155 000. . . . . . CAP 220UF 450V. . . . . . . . . . . . . . . . . . . . . . . 2 EA C002,C003524 0322 000. . . . . . CAP 15000UF 100WVDC -10, +75%. . . . . . . . 1 EA C005530 0088 000. . . . . . BRACKET, CAP, 2" ID . . . . . . . . . . . . . . . . . . . 2 EA #C002,#C003530 0092 000. . . . . . BRACKET, CAP, 3" ID . . . . . . . . . . . . . . . . . . . 1 EA #C005540 1600 222. . . . . . RES 750 OHM 3W 5% . . . . . . . . . . . . . . . . . . . 1 EA R004540 1600 510. . . . . . RES 240K OHM 3W 5%. . . . . . . . . . . . . . . . . . 2 EA R006,R007542 0180 000. . . . . . RES 1K OHM 5% 25W. . . . . . . . . . . . . . . . . . . 1 EA R002542 0219 000. . . . . . RES 5K OHM 5% 50W. . . . . . . . . . . . . . . . . . . 2 EA R003,R003A542 0289 000. . . . . . RES 50 OHM 5% 100W . . . . . . . . . . . . . . . . . . 1 EA R005548 0373 000. . . . . . RES 249K OHM 3/4W 1% . . . . . . . . . . . . . . . . 2 EA R035,R036548 1173 000. . . . . . RES 49.9 OHM 3W 1% . . . . . . . . . . . . . . . . . . 1 EA R010548 1502 000. . . . . . RES 5.0 OHM 10W 1% . . . . . . . . . . . . . . . . . . 5 EA R011,R012,R013,R014,R015548 1539 000. . . . . . RES 5 MEGOHM 10W 1%. . . . . . . . . . . . . . . . 1 EA R020548 2178 000. . . . . . RES 500K OHM 3W 1%. . . . . . . . . . . . . . . . . . 3 EA548 2208 000. . . . . . RES 4.5 MEGOHM 10W 1% . . . . . . . . . . . . . . 1 EA R021548 2400 330. . . . . . RES 2K OHM 1/2W 1% . . . . . . . . . . . . . . . . . . 1 EA R016548 2400 339. . . . . . RES 2.49K OHM 1/2W 1%. . . . . . . . . . . . . . . . 2 EA R017,R102548 2400 343. . . . . . RES 2.74K OHM 1/2W 1%. . . . . . . . . . . . . . . . 1 EA R018548 2400 368. . . . . . RES 4.99K OHM 1/2W 1%. . . . . . . . . . . . . . . . 1 EA R001548 2400 401. . . . . . RES 10K OHM 1/2W 1% . . . . . . . . . . . . . . . . . 4 EA R025,R026,R035,R039548 2400 418. . . . . . RES 15K OHM 1/2W 1% . . . . . . . . . . . . . . . . . 1 EA R101560 0049 000. . . . . . MOV, 275WVAC, 75J, 14MM DISC . . . . . . . . . 9 EA RV001,RV002,RV003,RV004,RV005,RV006,RV007,RV008,RV009570 0279 000. . . . . . CNTOR 40A 600V 3P. . . . . . . . . . . . . . . . . . . . 1 EA K001570 0366 000. . . . . . CNTOR 40A, 4P 50/60HZ 110-120V . . . . . . . . 1 EA K002574 0395 000. . . . . . RELAY 120VAC 30A DPST-NO. . . . . . . . . . . . 1 EA K003574 0437 000. . . . . . RELAY, SS SPST 25A 240VAC. . . . . . . . . . . . 1 EA K004576 0095 000. . . . . . RELAY TIME DELAY ADJ . . . . . . . . . . . . . . . . 1 EA K007598 0169 000. . . . . . SWITCH CAP, PB, RED. . . . . . . . . . . . . . . . . . 2 EA598 0170 000. . . . . . SWITCH CAP, PB, GR. . . . . . . . . . . . . . . . . . . 2 EA598 0188 000. . . . . . *SW, SPST-NO, PUSH BUTTON. . . . . . . . . . . 4 EA S001,S002,S003,S004604 0397 000. . . . . . SW, PRESS. . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA S009606 0579 000. . . . . . CB, 2 POLE, 10 AMP 250VAC. . . . . . . . . . . . . 1 EA CB004606 0790 000. . . . . . CB, 2 POLE, 2.5 AMP 250VAC . . . . . . . . . . . . 1 EA CB005606 0806 000. . . . . . CB, 2 POLE, 15 AMP 250VAC. . . . . . . . . . . . . 2 EA CB001,CB003606 0827 000. . . . . . CB, 2 POLE, 5 AMP 250VAC. . . . . . . . . . . . . . 1 EA CB002612 0942 000. . . . . . HOUSING, SOCKET 24 CKT. . . . . . . . . . . . . . 2 EA614 0050 000. . . . . . TERM BD 6 TERM . . . . . . . . . . . . . . . . . . . . . . 3 EA TB005,TB007,TB008614 0058 000. . . . . . TERM BD 14 TERM . . . . . . . . . . . . . . . . . . . . . 2 EA TB002,TB003614 0401 000. . . . . . TERM, INSULATED . . . . . . . . . . . . . . . . . . . . . 7 EA E008,E009,E010,E011,E012,E013,E016614 0693 000. . . . . . TERM BD 4 TERM . . . . . . . . . . . . . . . . . . . . . . 1 EA TB001614 0718 000. . . . . . JUMPER MODEL 601-J/141J . . . . . . . . . . . . . 2 EA #TB7-1,#TB7-3614 0786 000. . . . . . TERM BD, 2C MODULAR 261. . . . . . . . . . . . . 5 EA TB010620 0122 000. . . . . . ADAPTER, N-PLUG/N-JACK, RT ANG . . . . . . 1 EA


620 0455 000 . . . . . ADPT BNC UG492A/U . . . . . . . . . . . . . . . . . . 3 EA J004,J005620 0499 000 . . . . . COUPLING, STRAIGHT 3-1/8. . . . . . . . . . . . . 1 EA620 0544 000 . . . . . CONN, ANCHOR INS 3-1/8; 50 OHM . . . . . . . 1 EA620 0581 000 . . . . . COUPLING, SLEEVE, 3-1/8 . . . . . . . . . . . . . . 1 EA620 0918 000 . . . . . CONNECTOR, INNER COND 3-1/8 . . . . . . . . 2 EA620 1893 000 . . . . . ELBOW 90 DEG 3-1/8. . . . . . . . . . . . . . . . . . . 1 EA620 2275 000 . . . . . ELBOW, EQUAL, 3-1/8, 90 DEG . . . . . . . . . . 2 EA630 0186 000 . . . . . VOLTMETER, 0-300VAC, 3.5",[S] . . . . . . . . . 1 EA M007632 1114 000 . . . . . AMMETER, 0-5ADC, 4.5",[S] . . . . . . . . . . . . . 1 EA M005632 1116 000 . . . . . METER, %PWR/VSWR, 4.5",[S] . . . . . . . . . . . 1 EA M006632 1117 000 . . . . . VOLTMETER, 0-10KVDC, 4.5",[S] . . . . . . . . . 1 EA M004636 0036 000 . . . . . METER, ELAPSED TIME 60HZ . . . . . . . . . . . 1 EA M001646 1250 000 . . . . . LABEL SAFETY INSTR. . . . . . . . . . . . . . . . . . 1 EA646 1483 000 . . . . . HARRIS NAMEPLATE . . . . . . . . . . . . . . . . . . 1 EA648 0051 000 . . . . . * COUNTER, CCW ROTATION . . . . . . . . . . . 2 EA650 0021 000 . . . . . KNOB RD SKIRT .911" DIA . . . . . . . . . . . . . . 1 EA650 0028 000 . . . . . KNOB RD SKIRT 1.135" DIA . . . . . . . . . . . . . 1 EA #S011650 0102 000 . . . . . KNOB LOCK KL1251G . . . . . . . . . . . . . . . . . . 1 EA650 0147 000 . . . . . KNOB CRANK 1.25" DIA. . . . . . . . . . . . . . . . . 2 EA650 0148 000 . . . . . KNOB ROUND . . . . . . . . . . . . . . . . . . . . . . . . 1 EA650 0279 000 . . . . . KNOB CONTROL 1.25" DIA . . . . . . . . . . . . . . 1 EA736 0387 000 . . . . . PWR SUPPLY, 48VDC @ 24A . . . . . . . . . . . . 1 EA740 1223 000 . . . . . *AMP MODULE 700W 86-108MHZ. . . . . . . . . 1 EA813 5000 007 . . . . . STDOFF 6-32X1/2 5/16 HEX . . . . . . . . . . . . . 4 EA813 5000 013 . . . . . STDOFF 6-32X1-1/2 5/16 H . . . . . . . . . . . . . . 2 EA #TB1813 5000 027 . . . . . STDOFF 8-32X5/8 5/16 HEX . . . . . . . . . . . . . 4 EA #M007813 5604 011 . . . . . STUD BRS 6-32 X 1 . . . . . . . . . . . . . . . . . . . . 1 EA #E14813 5606 015 . . . . . STUD BRS 10-32 X 1-1/4 . . . . . . . . . . . . . . . . 3 EA #R034815 0644 001 . . . . . TERMINAL, SOLDER . . . . . . . . . . . . . . . . . . . 1 EA #E007817 0084 001 . . . . . SPACER BUSHING PLATE . . . . . . . . . . . . . . 8 EA817 0091 001 . . . . . SHAFT KNOB . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA817 0097 001 . . . . . SPACER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 EA817 2067 011 . . . . . PIN, INTERLOCK . . . . . . . . . . . . . . . . . . . . . . 1 EA817 2067 018 . . . . . RUNNING SHEET, MAIN CAB . . . . . . . . . . 0 DWG822 0446 008 . . . . . SPACER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA822 0446 049 . . . . . PLATE, METER MOUNTING . . . . . . . . . . . . . 1 EA #M007822 0446 081 . . . . . HINGE, BREAKER PANEL . . . . . . . . . . . . . . . 1 EA822 0446 090 . . . . . STRAP, CAP GROUND . . . . . . . . . . . . . . . . . 1 EA #C004829 4386 001 . . . . . SCREEN BLOWER . . . . . . . . . . . . . . . . . . . . . 1 EA #B001829 4404 001 . . . . . SUPPORT STRAP . . . . . . . . . . . . . . . . . . . . . 2 EA829 7438 001 . . . . . BRACKET SWITCH . . . . . . . . . . . . . . . . . . . . 1 EA829 8312 001 . . . . . WINDOW METER . . . . . . . . . . . . . . . . . . . . . . 1 EA #M007829 9023 013 . . . . . BRACKET, SWITCH . . . . . . . . . . . . . . . . . . . . 2 EA #S010,#S011839 7495 045 . . . . . ANGLE SUPPORT DOOR . . . . . . . . . . . . . . . 1 EA839 7822 005 . . . . . COVER PLATE, DUCT . . . . . . . . . . . . . . . . . . 1 EA839 7822 006 . . . . . CLAMP, RADIATION SCREEN. . . . . . . . . . . . 2 EA839 7822 007 . . . . . PWR DISTRIBUTION . . . . . . . . . . . . . . . . . 0 DWG839 7822 008 . . . . . PWR DISTRIBUTION . . . . . . . . . . . . . . . . . 0 DWG852 9163 008 . . . . . SCHEMATIC, OVERALL HT20/25 . . . . . . . 0 DWG913 5001 124 . . . . . STANDOFF HEX 4.75 LG . . . . . . . . . . . . . . . . 4 EA915 1842 008 . . . . . STUD TERMINAL . . . . . . . . . . . . . . . . . . . . . . 2 EA #TB1,#TB2,#TB3,#TB4915 1842 009 . . . . . STUD TERMINAL . . . . . . . . . . . . . . . . . . . . . . 2 EA #TB1,#TB2917 0083 001 . . . . . BLOCK ASSY . . . . . . . . . . . . . . . . . . . . . . . . . 2 EA917 0085 001 . . . . . PLATE ASSY. . . . . . . . . . . . . . . . . . . . . . . . . . 2 EA917 0092 001 . . . . . SHAFT ASSY . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA


917 0724 001. . . . . . SWITCH MODIFICATION . . . . . . . . . . . . . . . . 1 EA S011917 1335 064. . . . . . RESISTOR, .05 OHM. . . . . . . . . . . . . . . . . . . . 1 EA R034917 1895 018. . . . . . SHAFT, GRID TUNE/PA LOAD . . . . . . . . . . . . 2 EA917 2033 001. . . . . . SWITCH, INTERLOCK. . . . . . . . . . . . . . . . . . . 3 EA S005,S010,S011917 2213 001. . . . . . STRAP, GROUND . . . . . . . . . . . . . . . . . . . . . . 1 EA #TB1917 2511 003. . . . . . CABLE, MAIN. . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA922 0446 003. . . . . . BRKT, SWITCH MTG. . . . . . . . . . . . . . . . . . . . 1 EA #S005922 0446 006. . . . . . INSULATION . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA922 0446 017. . . . . . SCREEN, RADIATION. . . . . . . . . . . . . . . . . . . 1 EA922 0446 018. . . . . . FILTER, REAR DOOR . . . . . . . . . . . . . . . . . . . 1 EA922 0446 019. . . . . . SEAL, AIR INTAKE . . . . . . . . . . . . . . . . . . . . . 1 EA922 0446 027. . . . . . SHIELD, BRKR PANEL . . . . . . . . . . . . . . . . . . 1 EA922 0446 028. . . . . . SPACER, IPA DOOR . . . . . . . . . . . . . . . . . . . . 1 EA922 0446 030. . . . . . PLATE, EXICTER MOUNTING . . . . . . . . . . . . 1 EA922 0446 047. . . . . . DIRECTIONAL CPLR & CABLE. . . . . . . . . . . . 1 EA922 0729 001. . . . . . LOW PASS FILTER, ASSY . . . . . . . . . . . . . . . 1 EA922 0829 001. . . . . . PLATE, FAN MTG . . . . . . . . . . . . . . . . . . . . . . 1 EA922 0829 003. . . . . . ELBOW ASSY, AIR . . . . . . . . . . . . . . . . . . . . . 1 EA922 1074 002. . . . . . COVER, 1TB1 . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA #TB1922 1205 029. . . . . . BRKT, EXCITER MTG. . . . . . . . . . . . . . . . . . . 2 EA922 1298 001. . . . . . ANGLE, METER MTG.. . . . . . . . . . . . . . . . . . . 6 EA922 1298 002. . . . . . ELBOW, MODIFIED. . . . . . . . . . . . . . . . . . . . . 1 EA922 1298 008. . . . . . TUBE, AIR . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA922 1298 011. . . . . . SHIELD, XMSN LINE . . . . . . . . . . . . . . . . . . . . 2 EA929 7399 001. . . . . . SUPPORT ASSY . . . . . . . . . . . . . . . . . . . . . . . 1 EA929 7399 002. . . . . . SUPPORT ASSY . . . . . . . . . . . . . . . . . . . . . . . 1 EA929 7804 001. . . . . . CABLE ASSY INTERCONNECT . . . . . . . . . . . 1 EA929 7814 002. . . . . . CABLE ASSY . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA W265929 7814 005. . . . . . CABLE, COAX . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA W257929 7819 003. . . . . . CABLE, E2 TO 1A10 C13, HI VOLTAGE. . . . . 1 EA #1A10E1,#E002929 7881 001. . . . . . COVER ASSY . . . . . . . . . . . . . . . . . . . . . . . . . 2 EA #TB002,#TB003929 7929 001. . . . . . CABLE ASSY . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA929 9135 309. . . . . . SPACER, INNER CONDUCTOR . . . . . . . . . . . 4 EA929 9135 494. . . . . . PLATE, HINGE SPACER. . . . . . . . . . . . . . . . . 3 EA938 4203 004. . . . . . GROUND STICK ASSY . . . . . . . . . . . . . . . . . . 1 EA938 5850 090. . . . . . XMISSION LINE 3-1/8 . . . . . . . . . . . . . . . . . . . 1 EA939 4040 001. . . . . . FLANGED SHIELD ASSY . . . . . . . . . . . . . . . . 1 EA939 6337 232. . . . . . COVER, XFMR BRKR PNL . . . . . . . . . . . . . . . 1 EA939 7495 026. . . . . . SIDE, AIR DUCT . . . . . . . . . . . . . . . . . . . . . . . 2 EA939 7495 027. . . . . . DIVIDER, AIR DUCT . . . . . . . . . . . . . . . . . . . . 1 EA939 7495 034. . . . . . STUB FILTER ASSY . . . . . . . . . . . . . . . . . . . . 1 EA939 7495 068. . . . . . LABEL, FLEXPATCH . . . . . . . . . . . . . . . . . . . . 1 EA939 7964 001. . . . . . VENTURI, INLET CONE . . . . . . . . . . . . . . . . . 1 EA #B001939 7964 002. . . . . . VENTURI, INLET RING . . . . . . . . . . . . . . . . . . 1 EA #B001939 8208 007. . . . . . MOTOR MTG. . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA939 8208 008. . . . . . SUPPORT, CAVITY . . . . . . . . . . . . . . . . . . . . . 2 EA939 8208 010. . . . . . COVER, AC CTLR BD . . . . . . . . . . . . . . . . . . . 1 EA939 8208 016. . . . . . COVER, AC METERING . . . . . . . . . . . . . . . . . 1 EA943 4114 154. . . . . . COVER, CIRCUIT BREAKER . . . . . . . . . . . . . 1 EA943 4754 003. . . . . . COVER, TOP . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA943 4754 006. . . . . . DOOR, REAR. . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA943 4827 014. . . . . . BLANK, PNL 6.97 X 19 . . . . . . . . . . . . . . . . . . 1 EA943 4968 006. . . . . . AIR DUCT, FM25K2. . . . . . . . . . . . . . . . . . . . . 1 EA943 4972 005. . . . . . DUCT REAR DOOR. . . . . . . . . . . . . . . . . . . . . 1 EA943 4972 006. . . . . . PNL, REAR DOOR. . . . . . . . . . . . . . . . . . . . . . 1 EA


943 5215 601 . . . . . BRACKET, POWER SUPPLY. . . . . . . . . . . . . 1 EA943 5501 003 . . . . . ENCLOSURE, METER . . . . . . . . . . . . . . . . . . 1 EA943 5501 004 . . . . . PANEL, METER FACE . . . . . . . . . . . . . . . . . . 1 EA943 5501 005 . . . . . PANEL, METER TRIM . . . . . . . . . . . . . . . . . . 1 EA943 5501 008 . . . . . PANEL, TUNING . . . . . . . . . . . . . . . . . . . . . . . 1 EA943 5501 009 . . . . . PANEL, CIRCUIT BREAKER . . . . . . . . . . . . . 1 EA943 5501 011 . . . . . PANEL, INNER RIGHT . . . . . . . . . . . . . . . . . . 1 EA943 5501 015 . . . . . PANEL, INNER LEFT . . . . . . . . . . . . . . . . . . . 1 EA943 5501 016 . . . . . PANEL, AC METERING . . . . . . . . . . . . . . . . . 1 EA952 9216 001 . . . . . ASSY, CABINET . . . . . . . . . . . . . . . . . . . . . . . 1 EA992 5439 002 . . . . . AC CONTROL PC BD . . . . . . . . . . . . . . . . . . . 1 EA992 5620 001 . . . . . DIR COUPLER ASSY . . . . . . . . . . . . . . . . . . 1 EA992 5646 001 . . . . . EXTENDER CARD ASSY . . . . . . . . . . . . . . . 1 EA992 6751 004 . . . . . PANEL, IPA MULTIMETER. . . . . . . . . . . . . . . 1 EA992 6761 002 . . . . . PWB, RMT SCREEN CTL LOGIC. . . . . . . . . 1 EA992 6880 001 . . . . . RF MONITOR COUPLING UNIT. . . . . . . . . . 1 EA992 9862 001 . . . . . TRANSMITTER CONTROLLER . . . . . . . . . . . 1 EA992 9864 001 . . . . . PA CAVITY, . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA999 2459 003 . . . . . HARDWARE LIST, XMTR. . . . . . . . . . . . . . . . 1 EA999 2460 003 . . . . . WIRE/TUBING LIST, XMTR . . . . . . . . . . . . . . 1 EA

Table 7-14. AC CONTROL PC BD - 992 5439 002 (C)Harris PN Description QTY UM Reference Designators254 0001 000 . . . . . WIRE, BUS CU 22AWG . . . . . . . . . . . . . 0.1667 FT R29,R31380 0125 000 . . . . . XSTR, NPN 2N4401 ESD. . . . . . . . . . . . . . . . 1 EA Q7380 0126 000 . . . . . XSTR, PNP 2N4403 ESD. . . . . . . . . . . . . . . . 1 EA Q8548 2400 258 . . . . . RES 392 OHM 1/2W 1% . . . . . . . . . . . . . . . . . 2 EA R021,R027843 5400 791 . . . . . SCH, AC CONTROL BOARD . . . . . . . . . . . 0 DWG843 5400 793 . . . . . PWB, AC CONTROL BOARD . . . . . . . . . . . . . 1 EA500 0754 000 . . . . . CAP, MICA, 220PF 500V 5% . . . . . . . . . . . . . 4 EA C4,C6,C22,C25522 0529 000 . . . . . CAP 470UF 50V 20% . . . . . . . . . . . . . . . . . . . 1 EA C002526 0048 000 . . . . . CAP 10UF 20V 20% . . . . . . . . . . . . . . . . . . . . 2 EA C3,C20516 0453 000 . . . . . CAP .1UF 100V 20% X7R. . . . . . . . . . . . . . . . 5 EA C1,C5,C23,C26,C27522 0531 000 . . . . . CAP 1UF 50V 20% . . . . . . . . . . . . . . . . . . . . . 2 EA C7,C8516 0084 000 . . . . . CAP, 0.020UF 500V -20/+80% . . . . . . . . . . . . 6 EA C9,C10,C12,C14,C16,C18516 0419 000 . . . . . CAP .05 UF 500V . . . . . . . . . . . . . . . . . . . . . . 5 EA C11,C13,C15,C17,C19526 0359 000 . . . . . CAP 47UF 25V 10% . . . . . . . . . . . . . . . . . . . . 1 EA C021386 0394 000 . . . . . ZENER, 1N5231A(B) 5.1V.5W ESD . . . . . . . 1 EA CR2384 0431 000 . . . . . RECT. 1N4001 ESD. . . . . . . . . . . . . . . . . . . . 3 EA CR3,CR4,CR5574 0156 000 . . . . . RELAY 12VDC 4PDT . . . . . . . . . . . . . . . . . . . 2 EA K1,K2494 0218 000 . . . . . CHOKE, WIDE BAND 2.5 TURN. . . . . . . . . . 10 EA L1,L2,L3,L4,L5,L6,L7,L8,L9,L10380 0590 000 . . . . . XSTR, NPN, 2N6294 ESD| . . . . . . . . . . . . . 1 EA Q1384 0844 000 . . . . . RECT BCR5AM/BT136-500 ESD. . . . . . . . . . 5 EA Q2,Q3,Q4,Q5,Q6548 2400 369 . . . . . RES 5.11K OHM 1/2W 1% . . . . . . . . . . . . . . . 2 EA R5,R8548 2400 276 . . . . . RES 604 OHM 1/2W 1% . . . . . . . . . . . . . . . . . 1 EA R2548 2400 311 . . . . . RES 1.27K OHM 1/2W 1% . . . . . . . . . . . . . . . 2 EA R3,R4548 2400 366 . . . . . RES 4.75K OHM 1/2W 1% . . . . . . . . . . . . . . . 1 EA R26548 2400 301 . . . . . RES 1K OHM 1/2W 1%. . . . . . . . . . . . . . . . . . 1 EA R6548 2400 289 . . . . . RES 825 OHM 1/2W 1% . . . . . . . . . . . . . . . . . 1 EA R7550 0812 000 . . . . . POT 100 OHM 1/2W 10% . . . . . . . . . . . . . . . . 1 EA R9548 2400 254 . . . . . RES 357 OHM 1/2W 1% . . . . . . . . . . . . . . . . . 1 EA R10548 2400 234 . . . . . RES 221 OHM 1/2W 1% . . . . . . . . . . . . . . . . . 6 EA R11,R16,R17,R18,R19,R20548 2400 239 . . . . . RES 249 OHM 1/2W 1% . . . . . . . . . . . . . . . . . 1 EA R12548 2400 330 . . . . . RES 2K OHM 1/2W 1%. . . . . . . . . . . . . . . . . . 2 EA R015,R024


548 2400 401. . . . . . RES 10K OHM 1/2W 1% . . . . . . . . . . . . . . . . . 6 EA R1,R014,R23,R025,R30,R32548 2400 266. . . . . . RES 475 OHM 1/2W 1% . . . . . . . . . . . . . . . . . 1 EA R022548 2400 332. . . . . . RES 2.1K OHM 1/2W 1%. . . . . . . . . . . . . . . . . 1 EA R013548 2400 101. . . . . . RES 10 OHM 1/2W 1% . . . . . . . . . . . . . . . . . . 1 EA R028610 1389 000. . . . . . HDR, 10C 1 ROW VERTICAL . . . . . . . . . . . . . 2 EA TB1,TB2610 1366 000. . . . . . HDR, 5C 1 ROW VERTICAL . . . . . . . . . . . . . . 1 EA TB3382 0631 000. . . . . . IC, AD536AJD ESD . . . . . . . . . . . . . . 1 EA U1382 0475 000. . . . . . IC, 317 ESD. . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA U2358 1726 000. . . . . . SPRING, HOLD DOWN . . . . . . . . . . . . . . . . . . 2 EA404 0161 000. . . . . . SOCKET RELAY 9KH2 . . . . . . . . . . . . . . . . . . 2 EA XK1,XK2404 0674 000. . . . . . SOCKET, DIP, 14 PIN (DL) . . . . . . . . . . . . . . . 1 EA XU1404 0498 000. . . . . . HEAT SINK FOR CASE TO-3 . . . . . . . . . . . . . 1 EA999 1897 001. . . . . . HARDWARE LIST . . . . . . . . . . . . . . . . . . . . . . 1 EA

Table 7-15. DIR COUPLER ASSY - 992 5620 001 (R)Harris PN Description QTY UM Reference Designators540 1600 118. . . . . . RES 51 OHM 3W 5% . . . . . . . . . . . . . . . . . . . . 1 EA R001540 1600 201. . . . . . RES 100 OHM 3W 5% . . . . . . . . . . . . . . . . . . . 1 EA R003839 5303 001. . . . . . SCHEM, LOW PASS FILTER . . . . . . . . . . . 0 DWG839 5156 001. . . . . . PWB, LPF/DIRECT COUPLER . . . . . . . . . . . . 1 EA813 4999 043. . . . . . STDOFF 4-40X.295 1/4 HEX . . . . . . . . . . . . . . 8 EA829 7210 001. . . . . . REF DWG., COIL HEIGHT. . . . . . . . . . . . . . 0 DWG517 0053 000. . . . . . CAP TRIMMER 0.8-23.0 PF. . . . . . . . . . . . . . . 2 EA C001,C003517 0052 000. . . . . . CAP TRIMMER 0.8-11.0PF . . . . . . . . . . . . . . . 1 EA500 0817 000. . . . . . CAP, MICA, 47PF 500V 5%. . . . . . . . . . . . . . . 1 EA C005500 0833 000. . . . . . CAP, MICA, 390PF 500V 5%. . . . . . . . . . . . . . 1 EA C006500 0842 000. . . . . . CAP, MICA, 820PF 300V 5%. . . . . . . . . . . . . . 2 EA C10518 0104 000. . . . . . CAP, VAR 5.5-18PF. . . . . . . . . . . . . . . . . . . . . 1 EA C12516 0235 000. . . . . . CAP FEED-THRU 1000PF. . . . . . . . . . . . . . . . 3 EA C13,C14,C15384 0321 000. . . . . . *DIODE 5082-2800 ESD . . . . . . . . . . . . . . . . . 2 EA CR1,CR2612 0233 000. . . . . . RECEPTACLE N UG-58A/U . . . . . . . . . . . . . . 2 EA829 7108 001. . . . . . INDUCTOR, 2-1/2 TURN . . . . . . . . . . . . . . . . . 3 EA829 7108 002. . . . . . INDUCTOR, 1-1/2 TURN . . . . . . . . . . . . . . . . . 1 EA494 0376 000. . . . . . CHOKE RF 0.22UH . . . . . . . . . . . . . . . . . . . . . 2 EA494 0377 000. . . . . . CHOKE RF 0.27UH . . . . . . . . . . . . . . . . . . . . . 1 EA550 0621 000. . . . . . POT, 200 OHM .5W 10% . . . . . . . . . . . . . . . . . 1 EA R002843 3817 001. . . . . . COVER LPF / DIR COUPLER . . . . . . . . . . . . . 1 EA813 4999 024. . . . . . STDOFF 6-32X3/8 1/4 HEX . . . . . . . . . . . . . . . 6 EA999 2107 001. . . . . . WIRE LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA500 1320 000. . . . . . CAP 10PF 500V 10%. . . . . . . . . . . . . . . . . . . . 2 EA C004,C011526 0097 000. . . . . . CAP 47UF 35V 20%. . . . . . . . . . . . . . . . . . . . . 2 EA C016,C017500 0807 000. . . . . . CAP, MICA, 18PF 500V 5%. . . . . . . . . . . . . . . 1 EA C009548 2400 258. . . . . . RES 392 OHM 1/2W 1% . . . . . . . . . . . . . . . . . 1 EA R004548 2400 318. . . . . . RES 1.5K OHM 1/2W 1%. . . . . . . . . . . . . . . . . 1 EA R005548 2400 285. . . . . . RES 750 OHM 1/2W 1% . . . . . . . . . . . . . . . . . 1 EA R006999 1902 001. . . . . . HARDWARE LIST . . . . . . . . . . . . . . . . . . . . . . 1 EA300 2108 000. . . . . . SCR, 6-32 X 1 . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA917 2162 001. . . . . . SPACER. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA404 0250 000. . . . . . HEAT SINK FOR TO-5 CASE . . . . . . . . . . . . . 1 EA500 0811 000. . . . . . CAP, MICA, 27PF 500V 5%. . . . . . . . . . . . . . . 1 EA C008494 0375 000. . . . . . CHOKE RF 0.18UH . . . . . . . . . . . . . . . . . . . . . 1 EA L008500 1346 000. . . . . . CAP 43PF 5% 250V. . . . . . . . . . . . . . . . . . . . . 1 EA C018


Table 7-16. PANEL, IPA MULTIMETER - 992 6751 004 (B)Harris PN Description QTY UM Reference Designators358 0437 000 . . . . . BUSHING PANEL .252 ID. . . . . . . . . . . . . . . . 1 EA #1A14410 0010 000 . . . . . INSULATOR ROUND NS5W 0208 . . . . . . . . . 8 EA500 0833 000 . . . . . CAP, MICA, 390PF 500V 5% . . . . . . . . . . . . . 3 EA C007,C010,C012550 0067 000 . . . . . POT 10K OHM 2W 10% . . . . . . . . . . . . . . . . . 1 EA R031552 0984 000 . . . . . RHEO 1500 OHM 25 W. . . . . . . . . . . . . . . . . . 1 EA R008552 0985 000 . . . . . RHEO 100 OHM 25 W. . . . . . . . . . . . . . . . . . . 1 EA R033632 1115 000 . . . . . AMMETER, 0-100UADC, 3.5",[S] . . . . . . . . . . 1 EA M001632 1118 000 . . . . . WATTMETER, DUALSCALE, 3.5",[S]. . . . . . . 1 EA M003632 1119 000 . . . . . MULTIMETER, TRISCALE, 3.5",[S] . . . . . . . . 1 EA M002650 0021 000 . . . . . KNOB RD SKIRT .911" DIA . . . . . . . . . . . . . . 3 EA #1A14,#S10,#S12810 2753 016 . . . . . COUPLING . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA #1A14813 5000 027 . . . . . STDOFF 8-32X5/8 5/16 HEX . . . . . . . . . . . . . 4 EA813 5631 094 . . . . . SHAFT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA #1A14829 3967 001 . . . . . SUPPORT METER . . . . . . . . . . . . . . . . . . . . . 2 EA829 8312 001 . . . . . WINDOW METER . . . . . . . . . . . . . . . . . . . . . . 3 EA917 0725 001 . . . . . SWITCH MODIFICATION . . . . . . . . . . . . . . . . 2 EA S010,S012922 0446 016 . . . . . HINGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA922 0446 029 . . . . . PLATE, RESISTOR MOUNTING . . . . . . . . . . 1 EA939 5629 002 . . . . . BRKT. METER MTG. . . . . . . . . . . . . . . . . . . . 1 EA939 8208 014 . . . . . COVER, IPA MULTIMETER . . . . . . . . . . . . . . 1 EA #M003,#R031939 8208 015 . . . . . COVER, IPA/PA METERS . . . . . . . . . . . . . . . 1 EA #1A14,#M001943 5501 014 . . . . . DOOR, IPA MULTIMETER . . . . . . . . . . . . . . . 1 EA992 6925 002 . . . . . IPA MULTIMETER BD . . . . . . . . . . . . . . . . . . 1 EA #1A14

Table 7-17. PWB, RMT SCREEN CTL LOGIC - 992 6761 002 (C)Harris PN Description QTY UM Reference Designators354 0309 000 . . . . . TERM SOLDER. . . . . . . . . . . . . . . . . . . . . . . 15 EA516 0533 000 . . . . . CAP .01UF 10% 50V X7R. . . . . . . . . . . . . . . . 1 EA C009540 1600 310 . . . . . RES 2.4K OHM 3W 5%. . . . . . . . . . . . . . . . . . 4 EA R005,R006,R007,R008542 0084 000 . . . . . RES 3K OHM 5% 12W . . . . . . . . . . . . . . . . . . 2 EA R014,R015548 2400 401 . . . . . RES 10K OHM 1/2W 1%. . . . . . . . . . . . . . . . . 4 EA R010,R011,R012,R013839 7227 002 . . . . . SCHEM, REMOTE SCREEN CTRL . . . . . . 0 DWG843 4603 002 . . . . . PCB, REMOTE SCREEN CONTROL . . . . . . . 1 EA384 0844 000 . . . . . RECT BCR5AM/BT136-500 ESD. . . . . . . . . . 4 EA Q001,Q002,Q003,Q004494 0218 000 . . . . . CHOKE, WIDE BAND 2.5 TURN. . . . . . . . . . . 4 EA L001,L002,L003,L004516 0074 000 . . . . . CAP, DISC .005UF 1KV 20% . . . . . . . . . . . . . 4 EA C005,C006,C007,C008516 0084 000 . . . . . CAP, 0.020UF 500V -20/+80% . . . . . . . . . . . . 4 EA C001,C002,C003,C004548 2400 258 . . . . . RES 392 OHM 1/2W 1% . . . . . . . . . . . . . . . . . 4 EA R001,R002,R003,R004548 2400 301 . . . . . RES 1K OHM 1/2W 1%. . . . . . . . . . . . . . . . . . 1 EA R009574 0062 000 . . . . . RELAY LATCHING 4 PDT. . . . . . . . . . . . . . . . 1 EA K001610 1389 000 . . . . . HDR, 10C 1 ROW VERTICAL. . . . . . . . . . . . . 2 EA J1,J2999 2410 001 . . . . . WIRE LIST. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA999 2411 001 . . . . . HARDWARE LIST . . . . . . . . . . . . . . . . . . . . . . 1 EA

Table 7-18. TRANSMITTER CONTROLLER - 992 9862 001 (B)Harris PN Description QTY UM Reference Designators358 2105 000 . . . . . CARD GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . 4 EA384 0694 000 . . . . . LED RED CART 12V. . . . . . . . . . . . . . . . . . . . 1 EA384 0695 000 . . . . . LED GREEN CART 12V ESD . . . . . . . . . . . . 1 EA550 0067 000 . . . . . POT 10K OHM 2W 10% . . . . . . . . . . . . . . . . . 4 EA R002,R003,R004,R005


550 1112 000. . . . . . *POT, MOTORIZED 1K OHM 12VDC . . . . . . . 1 EA R001604 0911 000. . . . . . SW, TGL SPDT . . . . . . . . . . . . . . . . . . . . . . . . 2 EA813 4999 026. . . . . . STDOFF 6-32X1/2 1/4 HEX . . . . . . . . . . . . . . . 4 EA813 4999 027. . . . . . STDOFF 6-32X5/8 1/4 HEX . . . . . . . . . . . . . . . 9 EA829 4336 001. . . . . . HINGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA839 7440 001. . . . . . SCHEM, XMTR CTRL BOARDS . . . . . . . . . 0 DWG839 7617 001. . . . . . SCHEM, SIMPLIFIED VSWR. . . . . . . . . . . . 0 DWG839 7618 001. . . . . . SCHEM, SIMPLIFIED AUTO PW. . . . . . . . . 0 DWG917 2470 001. . . . . . PLATE, LED PANEL STOP . . . . . . . . . . . . . . . 1 EA922 1298 003. . . . . . PANEL, CTLR TOP . . . . . . . . . . . . . . . . . . . . . 1 EA922 1298 004. . . . . . ANGLE, MTHBD SUPPORT . . . . . . . . . . . . . . 2 EA922 1298 005. . . . . . ANGLE, MOTOR POT MTG. . . . . . . . . . . . . . . 1 EA922 1298 006. . . . . . ANGLE, CTLR TOP SUPPORT . . . . . . . . . . . . 1 EA929 7186 001. . . . . . CABLE ASSY . . . . . . . . . . . . . . . . . . . . . . . . . . 2 EA929 7187 001. . . . . . CABLE ASSY . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA929 9820 001. . . . . . CABLE ASSY MOTORIZED POT . . . . . . . . . . 1 EA939 8208 009. . . . . . BRACKET, SWTICH/POT MTG. . . . . . . . . . . . 1 EA939 8208 011. . . . . . PANEL, CONTROLLER FRONT . . . . . . . . . . . 1 EA939 8208 012. . . . . . CHASSIS, CONTROLLER . . . . . . . . . . . . . . . . 1 EA939 8208 013. . . . . . DIVIDER, CONTROLLER . . . . . . . . . . . . . . . . 1 EA939 8208 018. . . . . . PANEL, CONTROLLER LED . . . . . . . . . . . . . . 1 EA992 5433 001. . . . . . *DIGITAL LOGIC PC ASSY . . . . . . . . . . . . . . . 1 EA A001992 5434 002. . . . . . PWB, ANALOG, W/VSWR FB . . . . . . . . . . . . 1 EA A002992 5435 001. . . . . . RF1 PC BD ASSY . . . . . . . . . . . . . . . . . . . . . 1 EA A003992 5436 002. . . . . . MOTHER BD ASSY . . . . . . . . . . . . . . . . . . . . 1 EA A004992 5437 001. . . . . . STATUS PC BD ASSY. . . . . . . . . . . . . . . . . . . 1 EA A005992 6576 001. . . . . . PWB, MOTOR POT INTERFACE . . . . . . . . . 1 EA A006

Table 7-19. *DIGITAL LOGIC PC ASSY - 992 5433 001 (AA)Harris PN Description QTY UM Reference Designators354 0309 000. . . . . . TERM SOLDER . . . . . . . . . . . . . . . . . . . . . . . 23 EA TP001,TP002,TP003,TP004,TP005,TP006,TP007,TP008,TP009,TP010,TP

011,TP012,TP013,TP014,TP015,TP016,TP017,TP018,TP019,TP020,TP021,TP022,TP023

358 0958 000. . . . . . CARD EJECTOR, NYLON . . . . . . . . . . . . . . . . 2 EA380 0125 000. . . . . . XSTR, NPN 2N4401 ESD . . . . . . . . . . . . . . . . 2 EA Q002,Q009380 0189 000. . . . . . XSTR, NPN 2N3904 ESD . . . . . . . . . . . . . . . 11 EA Q001,Q003,Q004,Q005,Q007,Q013,Q014,Q015,Q022,Q023,Q024380 0190 000. . . . . . XSTR, PNP 2N3906 ESD . . . . . . . . . . . . . . . . 4 EA Q006,Q008,Q010,Q012382 0260 000. . . . . . IC, 555 ESD. . . . . . . . . . . . . . . . . . . . . . . . . . . 4 EA U001,U002,U006,U007382 0553 000. . . . . . IC 4012 ESD . . . . . . . . . . . . . . . . . . . . . 1 EA U004382 0662 000. . . . . . IC, MC14013BCP CMOS ESD . . . . . . . . . . . . 2 EA U003,U005382 0954 000. . . . . . IC, 4001B/14001B ESD . . . . . . . . . . . . . 1 EA U008384 0316 000. . . . . . RECT SIL CTL 2N5060 ESD. . . . . . . . . . . . . . 6 EA Q016,Q017,Q018,Q019,Q020,Q021384 0321 000. . . . . . *DIODE 5082-2800 ESD . . . . . . . . . . . . . . . . . 1 EA CR044384 0431 000. . . . . . RECT. 1N4001 ESD . . . . . . . . . . . . . . . . . . . 50 EA CR001,CR002,CR003,CR004,CR005,CR006,CR007,CR008,CR009,CR010

,CR011,CR012,CR013,CR014,CR015,CR016,CR017,CR019,CR020,CR021,CR022,CR023,CR024,CR025,CR026,CR028,CR029,CR030,CR031,CR032,CR033,CR034,CR035,CR036,CR037,CR038,CR040,CR041,CR042,CR045,CR047,CR048,CR049,CR050,CR051,CR052,CR054,CR055,CR056,CR057

386 0135 000. . . . . . ZENER, 1N4733A 5.1V ESD. . . . . . . . . . . . . . 3 EA CR018,CR027,CR043404 0673 000. . . . . . SOCKET, DIP, 8 PIN (DL) . . . . . . . . . . . . . . . . 4 EA XU001,XU002,XU006,XU007404 0674 000. . . . . . SOCKET, DIP, 14 PIN (DL) . . . . . . . . . . . . . . . 4 EA XU003,XU004,XU005,XU008516 0375 000. . . . . . CAP 0.01UF 50V -20/+80% Z5U . . . . . . . . . . 11 EA C007,C015,C032,C036,C047,C048,C049,C050,C051,C052,C054516 0453 000. . . . . . CAP .1UF 100V 20% X7R . . . . . . . . . . . . . . . . 4 EA C005,C013,C030,C034


522 0531 000 . . . . . CAP 1UF 50V 20% . . . . . . . . . . . . . . . . . . . . . 7 EA C004,C008,C012,C020,C028,C029,C033522 0538 000 . . . . . CAP 220 UF 50V 20%. . . . . . . . . . . . . . . . . . . 2 EA SEND TO TEST526 0048 000 . . . . . CAP 10UF 20V 20% . . . . . . . . . . . . . . . . . . . . 1 EA C016526 0050 000 . . . . . CAP 1UF 35V 20% . . . . . . . . . . . . . . . . . . . . 21 EA C001,C002,C003,C011,C017,C022,C023,C024,C025,C026,C027,C038,C03

9,C040,C041,C042,C043,C044,C045,C046,C053526 0057 000 . . . . . CAP 100UF 20V 20% . . . . . . . . . . . . . . . . . . . 2 EA C009,C018526 0093 000 . . . . . CAP 15UF 35V 20% . . . . . . . . . . . . . . . . . . . . 1 EA C055526 0097 000 . . . . . CAP 47UF 35V 20% . . . . . . . . . . . . . . . . . . . . 1 EA C010526 0318 000 . . . . . CAP 10UF 35V 20% . . . . . . . . . . . . . . . . . . . . 1 EA C021526 0360 000 . . . . . CAP 220 UF 15V 10%. . . . . . . . . . . . . . . . . . . 5 EA C006,C014,C019,C031,C035548 2400 201 . . . . . RES 100 OHM 1/2W 1% . . . . . . . . . . . . . . . . . 3 EA R021,R060,R093548 2400 209 . . . . . RES 121 OHM 1/2W 1% . . . . . . . . . . . . . . . . . 2 EA R002,R041548 2400 277 . . . . . RES 619 OHM 1/2W 1% . . . . . . . . . . . . . . . . . 1 EA R042548 2400 301 . . . . . RES 1K OHM 1/2W 1%. . . . . . . . . . . . . . . . . 10 EA R001,R003,R008,R017,R028,R030,R033,R046,R048,R055548 2400 318 . . . . . RES 1.5K OHM 1/2W 1% . . . . . . . . . . . . . . . . 7 EA R051,R084,R085,R086,R087,R088,R089548 2400 330 . . . . . RES 2K OHM 1/2W 1%. . . . . . . . . . . . . . . . . . 6 EA R066,R067,R068,R069,R070,R071548 2400 342 . . . . . RES 2.67K OHM 1/2W 1% . . . . . . . . . . . . . . . 1 EA R072548 2400 347 . . . . . RES 3.01K OHM 1/2W 1% . . . . . . . . . . . . . . . 6 EA R016,R020,R023,R040,R043,R062548 2400 369 . . . . . RES 5.11K OHM 1/2W 1% . . . . . . . . . . . . . . . 1 EA R065548 2400 373 . . . . . RES 5.62K OHM 1/2W 1% . . . . . . . . . . . . . . . 1 EA R095548 2400 377 . . . . . RES 6.19K OHM 1/2W 1% . . . . . . . . . . . . . . . 6 EA R075,R076,R077,R078,R079,R080548 2400 381 . . . . . RES 6.81K OHM 1/2W 1% . . . . . . . . . . . . . . . 1 EA SEND TO TEST548 2400 385 . . . . . RES 7.5K OHM 1/2W 1% . . . . . . . . . . . . . . . . 1 EA R039548 2400 389 . . . . . RES 8.25K OHM 1/2W 1% . . . . . . . . . . . . . . . 1 EA R054548 2400 401 . . . . . RES 10K OHM 1/2W 1%. . . . . . . . . . . . . . . . 27 EA R005,R006,R010,R011,R012,R014,R015,R018,R019,R022,R024,R025,R02

9,R035,R036,R038,R044,R049,R053,R056,R057,R061,R074,R081,R083,R090,R094

548 2400 418 . . . . . RES 15K OHM 1/2W 1%. . . . . . . . . . . . . . . . . 1 EA R031548 2400 426 . . . . . RES 18.2K OHM 1/2W 1% . . . . . . . . . . . . . . . 1 EA R052548 2400 430 . . . . . RES 20K OHM 1/2W 1%. . . . . . . . . . . . . . . . . 4 EA R050,R073,R082,R097548 2400 437 . . . . . RES 23.7K OHM 1/2W 1% . . . . . . . . . . . . . . . 1 EA R091548 2400 451 . . . . . RES 33.2K OHM 1/2W 1% . . . . . . . . . . . . . . . 1 EA R092548 2400 454 . . . . . RES 35.7K OHM 1/2W 1% . . . . . . . . . . . . . . . 1 EA R032548 2400 466 . . . . . RES 47.5K OHM 1/2W 1% . . . . . . . . . . . . . . . 7 EA R004,R009,R013,R034,R037,R045,R058548 2400 489 . . . . . RES 82.5K OHM 1/2W 1% . . . . . . . . . . . . . . . 1 EA R026548 2400 501 . . . . . RES 100K OHM 1/2W 1%. . . . . . . . . . . . . . . . 1 EA R096548 2400 509 . . . . . RES 121K OHM 1/2W 1%. . . . . . . . . . . . . . . . 1 EA R059548 2400 569 . . . . . RES 511K OHM 1/2W 1%. . . . . . . . . . . . . . . . 1 EA R027548 2400 589 . . . . . RES 825K OHM 1/2W 1%. . . . . . . . . . . . . . . . 1 EA R007574 0351 000 . . . . . * RELAY, REED SPST 6VDC . . . . . . . . . . . . . 4 EA K001,K002,K003,K004610 0679 000 . . . . . PLUG, SHORTING, .25" CTRS. . . . . . . . . . . . 5 EA P001,P002,P003,P004,P005612 0775 000 . . . . . JACK, PC MT, .040 PINS . . . . . . . . . . . . . . . 16 EA J001,J002,J003,J004,J005,J006,J007,J008,J009,J010,J011,J012,J013,J014

,J015,J016839 7440 001 . . . . . SCHEM, XMTR CTRL BOARDS. . . . . . . . . 0 DWG843 3311 001 . . . . . PWB, DIGITAL LOGIC . . . . . . . . . . . . . . . . . . 1 EA

Table 7-20. PWB, ANALOG, W/VSWR FB - 992 5434 002 (AM)Harris PN Description QTY UM Reference Designators358 0958 000 . . . . . CARD EJECTOR, NYLON . . . . . . . . . . . . . . . 2 EA380 0125 000 . . . . . XSTR, NPN 2N4401 ESD. . . . . . . . . . . . . . . . 9 EA Q002,Q010,Q011,Q012,Q013,Q021,Q022,Q023,Q024380 0126 000 . . . . . XSTR, PNP 2N4403 ESD. . . . . . . . . . . . . . . . 1 EA Q025380 0189 000 . . . . . XSTR, NPN 2N3904 ESD. . . . . . . . . . . . . . . . 3 EA Q009,Q015,Q016380 0190 000 . . . . . XSTR, PNP 2N3906 ESD. . . . . . . . . . . . . . . . 8 EA Q001,Q003,Q004,Q005,Q006,Q007,Q008,Q018380 0785 000 . . . . . XSTR, PNP DARL MJE271 ESD . . . . . . . . 1 EA Q017


382 0367 000. . . . . . IC, 4049/14049 ESD. . . . . . . . . . . . . . . . . . . . 1 EA U009382 0371 000. . . . . . IC, MC7912CT ESD . . . . . . . . . . . . . . . . . . . . 1 EA U010382 0415 000. . . . . . IC, 324 ESD. . . . . . . . . . . . . . . . . . . . . 4 EA U003,U004,U007,U011382 0618 000. . . . . . IC, 4081/14081 ESD. . . . . . . . . . . . . . . . . . 2 EA U006,U008382 0619 000. . . . . . IC, CD4050/MC14050 ESD . . . . . . . . . . . . . . 1 EA U005382 0719 000. . . . . . IC LM324AN ESD. . . . . . . . . . . . . . . . . . 2 EA U001,U002384 0205 000. . . . . . DIODE SILICON 1N914/4148 ESD. . . . . . . . 30 EA CR001,CR002,CR004,CR005,CR006,CR007,CR008,CR009,CR010,CR011

,CR012,CR013,CR014,CR015,CR019,CR022,CR023,CR024,CR025,CR026,CR027,CR031,CR032,CR033,CR034,CR035,CR036,CR037,CR038,CR039

384 0431 000. . . . . . RECT. 1N4001 ESD . . . . . . . . . . . . . . . . . . . . 1 EA CR018384 0684 000. . . . . . TRIAC TIC206A 100V 3AMP ESD . . . . . . . . . 2 EA Q019,Q020386 0082 000. . . . . . ZENER, 1N4744A 15V 1W 5% ESD. . . . . . . . 3 EA CR003,CR020,CR030386 0137 000. . . . . . ZENER, 1N4746A 18V ESD . . . . . . . . . . . . . . 2 EA CR016,CR017386 0405 000. . . . . . ZENER, 1N5242B 12V ESD . . . . . . . . . . . . . . 1 EA CR021404 0674 000. . . . . . SOCKET, DIP, 14 PIN (DL) . . . . . . . . . . . . . . . 8 EA XU001,XU002,XU003,XU004,XU006,XU007,XU008,XU011404 0675 000. . . . . . SOCKET, DIP, 16 PIN (DL) . . . . . . . . . . . . . . 10 EA XR001,XR002,XR003,XR004,XR005,XR100,XR120,XR127,XU005,XU009516 0375 000. . . . . . CAP 0.01UF 50V -20/+80% Z5U . . . . . . . . . . 14 EA C011,C014,C017,C018,C019,C020,C021,C022,C024,C025,C026,C027,C02

8,C029516 0411 000. . . . . . CAP .1UF 50V DISC . . . . . . . . . . . . . . . . . . . . 2 EA C015,C016516 0453 000. . . . . . CAP .1UF 100V 20% X7R . . . . . . . . . . . . . . . . 9 EA C023,C032,C033,C034,C035,C038,C039,C040,C041522 0548 000. . . . . . CAP 10UF 50V 20%. . . . . . . . . . . . . . . . . . . . . 2 EA C006,C036522 0570 000. . . . . . CAP 2.2UF 50V 20% . . . . . . . . . . . . . . . . . . . . 3 EA C009,C012,C013522 0591 000. . . . . . CAP 47UF 25V 20%. . . . . . . . . . . . . . . . . . . . . 1 EA C037526 0050 000. . . . . . CAP 1UF 35V 20%. . . . . . . . . . . . . . . . . . . . . . 7 EA C002,C003,C004,C005,C008,C030,C042526 0057 000. . . . . . CAP 100UF 20V 20%. . . . . . . . . . . . . . . . . . . . 1 EA C010526 0238 000. . . . . . CAP 33UF 35V 20%. . . . . . . . . . . . . . . . . . . . . 1 EA C001526 0311 000. . . . . . CAP 2.2UF 35V 10% . . . . . . . . . . . . . . . . . . . . 1 EA C031526 0358 000. . . . . . CAP 22UF 35V 10%. . . . . . . . . . . . . . . . . . . . . 1 EA C007540 1353 000. . . . . . RES NETWORK 4700 OHM 2% . . . . . . . . . . . 1 EA R127540 1356 000. . . . . . RES NETWORK 10K OHM 2% . . . . . . . . . . . . 6 EA R001,R002,R003,R004,R005,R120540 1359 000. . . . . . RES NETWORK 3300 OHM . . . . . . . . . . . . . . 1 EA R100540 1600 101. . . . . . RES 10 OHM 3W 5% . . . . . . . . . . . . . . . . . . . . 2 EA R079,R082548 2400 201. . . . . . RES 100 OHM 1/2W 1% . . . . . . . . . . . . . . . . . 3 EA R052,R070,R075548 2400 209. . . . . . RES 121 OHM 1/2W 1% . . . . . . . . . . . . . . . . . 1 EA R096548 2400 230. . . . . . RES 200 OHM 1/2W 1% . . . . . . . . . . . . . . . . . 1 EA R053548 2400 242. . . . . . RES 267 OHM 1/2W 1% . . . . . . . . . . . . . . . . . 3 EA R061,R065,R076548 2400 266. . . . . . RES 475 OHM 1/2W 1% . . . . . . . . . . . . . . . . . 7 EA R062,R063,R113,R114,R115,R116,R138548 2400 277. . . . . . RES 619 OHM 1/2W 1% . . . . . . . . . . . . . . . . . 3 EA R059,R106,R108548 2400 301. . . . . . RES 1K OHM 1/2W 1% . . . . . . . . . . . . . . . . . 14 EA R007,R015,R016,R018,R021,R030,R031,R038,R054,R055,R069,R074,R10

5,R128548 2400 309. . . . . . RES 1.21K OHM 1/2W 1%. . . . . . . . . . . . . . . . 1 EA R080548 2400 318. . . . . . RES 1.5K OHM 1/2W 1%. . . . . . . . . . . . . . . . . 1 EA R098548 2400 330. . . . . . RES 2K OHM 1/2W 1% . . . . . . . . . . . . . . . . . . 5 EA R008,R011,R019,R022,R092548 2400 334. . . . . . RES 2.21K OHM 1/2W 1%. . . . . . . . . . . . . . . 12 EA R042,R043,R067,R068,R072,R073,R084,R085,R086,R087,R090,R101548 2400 337. . . . . . RES 2.37K OHM 1/2W 1%. . . . . . . . . . . . . . . . 1 EA R089548 2400 351. . . . . . RES 3.32K OHM 1/2W 1%. . . . . . . . . . . . . . . . 1 EA R137548 2400 362. . . . . . RES 4.32K OHM 1/2W 1%. . . . . . . . . . . . . . . . 2 EA R036,R037548 2400 366. . . . . . RES 4.75K OHM 1/2W 1%. . . . . . . . . . . . . . . . 4 EA R058,R078,R081,R083548 2400 369. . . . . . RES 5.11K OHM 1/2W 1%. . . . . . . . . . . . . . . . 1 EA R102548 2400 373. . . . . . RES 5.62K OHM 1/2W 1%. . . . . . . . . . . . . . . . 1 EA R047548 2400 381. . . . . . RES 6.81K OHM 1/2W 1%. . . . . . . . . . . . . . . . 2 EA R041,R044548 2400 385. . . . . . RES 7.5K OHM 1/2W 1%. . . . . . . . . . . . . . . . . 2 EA R134,R135548 2400 389. . . . . . RES 8.25K OHM 1/2W 1%. . . . . . . . . . . . . . . . 2 EA R097,R107548 2400 392. . . . . . RES 8.87K OHM 1/2W 1%. . . . . . . . . . . . . . . . 5 EA R010,R012,R013,R023,R024


548 2400 401 . . . . . RES 10K OHM 1/2W 1%. . . . . . . . . . . . . . . . 13 EA R027,R029,R032,R066,R071,R088,R112,R121,R122,R123,R124,R125,R126

548 2400 430 . . . . . RES 20K OHM 1/2W 1%. . . . . . . . . . . . . . . . . 2 EA R060,R064548 2400 434 . . . . . RES 22.1K OHM 1/2W 1% . . . . . . . . . . . . . . . 7 EA R026,R033,R048,R049,R050,R051,R091548 2400 451 . . . . . RES 33.2K OHM 1/2W 1% . . . . . . . . . . . . . . . 1 EA R014548 2400 466 . . . . . RES 47.5K OHM 1/2W 1% . . . . . . . . . . . . . . . 7 EA R009,R020,R077,R095,R109,R111,R129548 2400 481 . . . . . RES 68.1K OHM 1/2W 1% . . . . . . . . . . . . . . . 1 EA R136548 2400 491 . . . . . RES 86.6K OHM 1/2W 1% . . . . . . . . . . . . . . . 1 EA R028548 2400 493 . . . . . RES 90.9K OHM 1/2W 1% . . . . . . . . . . . . . . . 1 EA R119548 2400 501 . . . . . RES 100K OHM 1/2W 1%. . . . . . . . . . . . . . . . 8 EA R035,R093,R094,R099,R103,R104,R110,R139548 2400 547 . . . . . RES 301K OHM 1/2W 1%. . . . . . . . . . . . . . . . 2 EA R006,R017548 2400 601 . . . . . RES 1MEG OHM 1/2W 1% . . . . . . . . . . . . . . . 3 EA R130,R131,R132548 2400 634 . . . . . RES 2.21MEG OHM 1/2W 1% . . . . . . . . . . . . 1 EA R057548 2400 701 . . . . . RES 10MEG OHM 1/2W 1% . . . . . . . . . . . . . . 7 EA R025,R034,R039,R040,R045,R046,R056550 0955 000 . . . . . TRIMPOT 5K OHM 1/2W 10% . . . . . . . . . . . . 2 EA R117,R118604 0859 000 . . . . . SW, TGL DPDT . . . . . . . . . . . . . . . . . . . . . . . . 1 EA S001610 0750 000 . . . . . TEST PROBE, TYPE C. . . . . . . . . . . . . . . . . . 4 EA TP001,TP002,TP003,TP004610 0900 000 . . . . . HEADER 3 CKT STRAIGHT . . . . . . . . . . . . . . 1 EA J001612 1184 000 . . . . . SHUNT JUMPER 0.1" CENTERS . . . . . . . . . . 1 EA P001839 7440 001 . . . . . SCHEM, XMTR CTRL BOARDS. . . . . . . . . 0 DWG843 4735 001 . . . . . PWB, ANALOG . . . . . . . . . . . . . . . . . . . . . . . . 1 EA

Table 7-21. RF1 PC BD ASSY - 992 5435 001 (D)Harris PN Description QTY UM Reference Designators852 8807 001 . . . . . SCHEM, RFI BOARD . . . . . . . . . . . . . . . . . 0 DWG839 5202 001 . . . . . PRINTED PC BD. . . . . . . . . . . . . . . . . . . . . . . 1 EA516 0074 001 . . . . . *CAP, DISC 5000PF 1KV 20% Z5U . . . . . . . 77 EA C001,C002,C003,C005,C006,C007,C008,C009,C010,C011,C012,C013,C01

4,C015,C016,C020,C021,C022,C023,C026,C027,C028,C029,C030,C031,C032,C033,C038,C039,C040,C041,C042,C043,C044,C045,C046,C047,C048,C049,C050,C051,C052,C053,C054,C055,C056,C057,C058,C059,C060,C061,C062,C063,C064,C065,C066,C067,C068,C069,C070,C071,C072,C073,C074,C075,C076,C077,C078,C079,C081,C082,C083,C084,C085,C086,C088,C089

610 0740 000 . . . . . HEADER, PIN 36CKT . . . . . . . . . . . . . . . . . . . 1 EA610 0768 000 . . . . . PC HEADER, 24 PIN. . . . . . . . . . . . . . . . . . . . 2 EA610 0769 000 . . . . . HDR 50 PIN STRAIGHT . . . . . . . . . . . . . . . . . 2 EA494 0218 000 . . . . . CHOKE, WIDE BAND 2.5 TURN. . . . . . . . . . . 1 EA548 2400 201 . . . . . RES 100 OHM 1/2W 1% . . . . . . . . . . . . . . . . 56 EA R14,R15,R16,R21,R22,R23,R26,R27,R28,R29,R30,R31,R32,R33,R38,R39,

R41,R42,R43,R44,R45,R46,R47,R48,R49,R50,R51,R52,R53,R54,R55,R56,R58,R59,R60,R61,R62,R63,R65,R66,R67,R68,R69,R70,R71,R73,R74,R76,R77,R78,R81

548 2400 101 . . . . . RES 10 OHM 1/2W 1% . . . . . . . . . . . . . . . . . . 2 EA R82,R83548 2400 301 . . . . . RES 1K OHM 1/2W 1%. . . . . . . . . . . . . . . . . 11 EA R10,R11,R12,R13,R20,R40,R57,R64,R79,R84,R87548 2400 351 . . . . . RES 3.32K OHM 1/2W 1% . . . . . . . . . . . . . . . 2 EA R85,R86614 0687 000 . . . . . TERM BD 12 TERM . . . . . . . . . . . . . . . . . . . . 2 EA TB1,TB2548 2400 301 . . . . . RES 1K OHM 1/2W 1%. . . . . . . . . . . . . . . . . . 2 EA R10,R11,R12,R13,R20,R40,R57,R64,R79,R84,R87548 2400 066 . . . . . RES 4.75 OHM 1/2W 1% . . . . . . . . . . . . . . . . 3 EA R72,R75


Table 7-22. STATUS PC BD ASSY - 992 5437 001 (H)Harris PN Description QTY UM Reference Designators839 7440 001. . . . . . SCHEM, XMTR CTRL BOARDS . . . . . . . . . 0 DWG843 3256 001. . . . . . PRINTED BD . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA384 0611 000. . . . . . *LED, RED T1-3/4 ESD . . . . . . . . . . . . 12 EA DS1,DS2,DS3,DS4,DS5,DS6,DS7,DS8,DS9,DS10,DS11,DS12384 0610 000. . . . . . * LED, GREEN T-1 3/4 ESD. . . . . . . . . . . . 3 EA DS013,DS015,DS016610 0770 000. . . . . . HDR 34 PIN STRAIGHT. . . . . . . . . . . . . . . . . . 1 EA548 2400 277. . . . . . RES 619 OHM 1/2W 1% . . . . . . . . . . . . . . . . 12 EA R10,R11,R12548 2400 451. . . . . . RES 33.2K OHM 1/2W 1%. . . . . . . . . . . . . . . . 3 EA R13,R17,R19548 2400 234. . . . . . RES 221 OHM 1/2W 1% . . . . . . . . . . . . . . . . . 2 EA R14,R15548 2400 321. . . . . . RES 1.62K OHM 1/2W 1%. . . . . . . . . . . . . . . . 2 EA R16,R18548 2400 309. . . . . . RES 1.21K OHM 1/2W 1%. . . . . . . . . . . . . . . . 2 EA R20,R22548 2400 393. . . . . . RES 9.09K OHM 1/2W 1%. . . . . . . . . . . . . . . . 2 EA R21,R23550 0955 000. . . . . . TRIMPOT 5K OHM 1/2W 10%. . . . . . . . . . . . . 4 EA R24,R25,R26,R27604 0905 000. . . . . . SW, PB MOMENTARY . . . . . . . . . . . . . . . . . . 1 EA604 0903 000. . . . . . SWITCH, TGL SPDT MOM OFF . . . . . . . . . . . 1 EA604 0904 000. . . . . . SW, TGL SPDT . . . . . . . . . . . . . . . . . . . . . . . . 1 EA358 2177 000. . . . . . SPACER, LED MOUNT .380 LG . . . . . . . . . . 16 EA384 0806 000. . . . . . LED, BI-COLOR RED/GREEN ESD . . . . . . . . 1 EA DS014

Table 7-23. PWB, MOTOR POT INTERFACE - 992 6576 001 (D)Harris PN Description QTY UM Reference Designators939 6853 001. . . . . . PWB, ASSY, MOT POT . . . . . . . . . . . . . . . . . . 1 EA404 0161 000. . . . . . SOCKET RELAY 9KH2 . . . . . . . . . . . . . . . . . . 2 EA #K001,#K002574 0431 000. . . . . . RELAY 4PDT 24VAC . . . . . . . . . . . . . . . . . . . . 2 EA K001,K002550 0923 000. . . . . . POT 1K OHM 1/2W . . . . . . . . . . . . . . . . . . . . . 1 EA R001358 1726 000. . . . . . SPRING, HOLD DOWN . . . . . . . . . . . . . . . . . . 2 EA #K001,#K002254 0002 000. . . . . . WIRE, BUS CU 20AWG. . . . . . . . . . . . . . 0.100 FT

Table 7-24. PA CAVITY, - 992 9864 001 (B)Harris PN Description QTY UM Reference Designators007 4030 002. . . . . . FINGER STOCK 0097-0542-02 . . . . . . . . 7.350 EA031 1710 017. . . . . . GSKT, RF. . . . . . . . . . . . . . . . . . . . . . . . 18.585 FT358 1036 000. . . . . . CLAMP, HOSE RANGE 9.125 TO 10_ . . . . . . 1 EA358 1165 000. . . . . . COLLAR 1/4 HOLE . . . . . . . . . . . . . . . . . . . . . 1 EA358 3123 000. . . . . . STUD, BRS 10-32 X 1-1/2 . . . . . . . . . . . . . . . . 1 EA #C029358 3126 000. . . . . . STUD, BRS 10-32 X 2-1/4 . . . . . . . . . . . . . . . . 1 EA #E003402 0001 000. . . . . . CLIP, FUSE 1.062 60A 600V . . . . . . . . . . . . . . 2 EA #R004410 0062 000. . . . . . INSULATOR SQ NS5W 1216 . . . . . . . . . . . . . 2 EA #R004410 0152 000. . . . . . INSULATOR BSHG NS5W-4103 . . . . . . . . . . . 1 EA #E003410 0156 000. . . . . . INSULATOR BSHG NS5W-4203 . . . . . . . . . . . 1 EA #E003410 0163 000. . . . . . INSULATOR FEED THRU . . . . . . . . . . . . . . . . 0 EA E001424 0011 000. . . . . . GROMMET 1-1/4 MTG DI . . . . . . . . . . . . . . . . 1 EA448 0224 000. . . . . . HANDLE ALUM . . . . . . . . . . . . . . . . . . . . . . . . 1 EA452 0125 000. . . . . . CLAMP, GEAR. . . . . . . . . . . . . . . . . . . . . . . . . 1 EA452 0126 000. . . . . . GEAR, SPUR SPLIT HUB . . . . . . . . . . . . . . . . 1 EA452 0128 000. . . . . . GEAR, SEGMENT . . . . . . . . . . . . . . . . . . . . . . 1 EA494 0004 000. . . . . . CHOKE RF 7UH. . . . . . . . . . . . . . . . . . . . . . . . 1 EA L010514 0194 000. . . . . . CAP 10-100PF 15KV TEST . . . . . . . . . . . . . . . 1 EA C016516 0402 000. . . . . . CAP 4800 PF 20KV . . . . . . . . . . . . . . . . . . . . . 3 EA C013,C014,C030540 1217 000. . . . . . RES 22.0 OHM 50W 10% . . . . . . . . . . . . . . . . 1 EA R004620 0208 000. . . . . . ADAPTER, N, STRAIGHT, UG-30/U . . . . . . . . 1 EA


620 0498 000 . . . . . ADAPTOR 3-1/8 . . . . . . . . . . . . . . . . . . . . . . . 1 EA810 2264 001 . . . . . LOCKING PLATE . . . . . . . . . . . . . . . . . . . . . . 2 EA #R004817 0839 001 . . . . . BRKT STOP . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA817 1335 235 . . . . . POST, GEAR MTG.. . . . . . . . . . . . . . . . . . . . . 2 EA817 1895 017 . . . . . SHAFT, GRID INPUT TUNE . . . . . . . . . . . . . . 1 EA822 0362 001 . . . . . STOP, FAIL SAFE. . . . . . . . . . . . . . . . . . . . . . 1 EA822 0456 001 . . . . . BLOCK, SHIPPING . . . . . . . . . . . . . . . . . . . . . 1 EA822 0460 001 . . . . . ANGLE,TUBE SOC BASE PLATE . . . . . . . . . 1 EA822 0506 001 . . . . . PLATE, FILAMENT FEED THRU . . . . . . . . . . 2 EA829 3899 001 . . . . . INDUCTOR, OUTPUT LOADING . . . . . . . . . . 1 EA L10829 4253 001 . . . . . EXTENSION . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA829 7490 001 . . . . . PLATE SIDE . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA #C013829 7574 001 . . . . . PLATE SIDE . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA #C015829 9745 007 . . . . . BLOCKER . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA C029839 4165 001 . . . . . PLATE SHORT . . . . . . . . . . . . . . . . . . . . . . . . 1 EA839 5902 001 . . . . . PLATE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA839 7546 001 . . . . . SHIELD, CAVITY RF TOP . . . . . . . . . . . . . . . 1 EA914 7670 002 . . . . . RF CHOKE, (2UH). . . . . . . . . . . . . . . . . . . . . . 1 EA L002916 9985 001 . . . . . SUPPORT ASSY. . . . . . . . . . . . . . . . . . . . . . . 1 EA917 0432 001 . . . . . CAP ASS ANODE CONN . . . . . . . . . . . . . . . . 1 EA917 0559 002 . . . . . BEARING BLOCK ASSY. . . . . . . . . . . . . . . . . 2 EA917 1895 010 . . . . . STRAP, E1-C13 . . . . . . . . . . . . . . . . . . . . . . . 1 EA917 2501 004 . . . . . BLOCK, BEARING CENTER. . . . . . . . . . . . . . 1 EA922 0446 013 . . . . . COVER, TUBE ACCESS . . . . . . . . . . . . . . . . 1 EA922 0446 022 . . . . . STRAP, R4 CONNECTION. . . . . . . . . . . . . . . 2 EA #R004922 0446 033 . . . . . CABLE, PA PATCH. . . . . . . . . . . . . . . . . . . . . 1 EA922 0446 091 . . . . . BAR, CONTACT . . . . . . . . . . . . . . . . . . . . . . . 1 EA922 0459 001 . . . . . ANGLE, SHIPPING BLOCK . . . . . . . . . . . . . . 1 EA922 1067 001 . . . . . BLOCK, BEARING . . . . . . . . . . . . . . . . . . . . . 1 EA922 1067 002 . . . . . PLATE, BEARING . . . . . . . . . . . . . . . . . . . . . . 1 EA922 1067 005 . . . . . SHAFT, PA TUNING . . . . . . . . . . . . . . . . . . . . 1 EA922 1295 005 . . . . . PLATE, CAP . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA929 3989 001 . . . . . SHORT RING ASS . . . . . . . . . . . . . . . . . . . . . 1 EA929 4129 001 . . . . . ASSY, BLOCKER, PLATE . . . . . . . . . . . . . . . 1 EA929 4322 001 . . . . . CONDUCTOR ASSY. . . . . . . . . . . . . . . . . . . . 1 EA929 7884 001 . . . . . LEAD ANODE ASSY. . . . . . . . . . . . . . . . . . . . 1 EA929 7885 001 . . . . . CABLE ASSY . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA929 7885 002 . . . . . CABLE ASSY-FILAMENT LEADS . . . . . . . . . 1 EA929 7916 001 . . . . . COUPLING FLEX . . . . . . . . . . . . . . . . . . . . . . 1 EA929 7946 001 . . . . . CLAMP, TUBE MOD. . . . . . . . . . . . . . . . . . . . 1 EA939 5926 001 . . . . . PLATE BOTTOM WELD . . . . . . . . . . . . . . . . . 1 EA939 8208 017 . . . . . ASSY, FILAMENT ENCLOSURE . . . . . . . . . . 1 EA943 4754 025 . . . . . PANEL, CAVITY FRONT . . . . . . . . . . . . . . . . 1 EA943 4754 026 . . . . . PANEL, CAVITY REAR. . . . . . . . . . . . . . . . . . 1 EA943 4760 001 . . . . . SIDE CAVITY . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA943 4782 001 . . . . . SHELF, CAVITY RF TOP . . . . . . . . . . . . . . . . 1 EA943 4972 003 . . . . . PNL, CAVITY SIDE . . . . . . . . . . . . . . . . . . . . . 1 EA992 5567 002 . . . . . SOCKET & INPUT CKT ASSY . . . . . . . . . . . . 1 EA


Table 7-25. SOCKET & INPUT CKT ASSY - 992 5567 002 (W)Harris PN Description QTY UM Reference Designators300 1535 000. . . . . . SCR, 6-32 X 3/16 . . . . . . . . . . . . . . . . . . . . . . . 2 EA300 2104 000. . . . . . SCR, 6-32 X 1/2 . . . . . . . . . . . . . . . . . . . . . . . 10 EA304 0034 000. . . . . . NUT CAP 6-32 BRASS . . . . . . . . . . . . . . . . . . 4 EA335 0041 000. . . . . . WASHER, NYLON 0.75 ID. . . . . . . . . . . . . . . . 2 EA335 0104 000. . . . . . WASHER PLAIN .156 ID . . . . . . . . . . . . . . . . . 8 EA354 0145 000. . . . . . LUG SHAKE .150 MTG . . . . . . . . . . . . . . . . . . 3 EA354 0146 000. . . . . . LUG SHAKE .176 MTG . . . . . . . . . . . . . . . . . . 1 EA354 0147 000. . . . . . LUG, SHAKE #6 45 DEG . . . . . . . . . . . . . . . . . 1 EA354 0386 000. . . . . . TERM, LOCKING #10 RING . . . . . . . . . . . . . . 9 EA410 0001 000. . . . . . INSULATOR ROUND NS5W 0104 . . . . . . . . . 4 EA410 0004 000. . . . . . INSULATOR ROUND NS5W 0108 . . . . . . . . . 4 EA410 0153 000. . . . . . INSULATOR BSHG NS5W-4104 . . . . . . . . . . . 1 EA410 0157 000. . . . . . INSULATOR BSHG NS5W-4204 . . . . . . . . . . . 1 EA494 0004 000. . . . . . CHOKE RF 7UH. . . . . . . . . . . . . . . . . . . . . . . . 2 EA L001,L003516 0205 000. . . . . . *CAP, RF, 500PF 5KV 20% X5T . . . . . . . . . . . 1 EA C002516 0206 000. . . . . . CAP, RF, 1000PF 5KV 20% X5V. . . . . . . . . . . 4 EA C011,C012,C017,C018516 0436 000. . . . . . CAP, RF, 5PF 7.5KV 10% NPO. . . . . . . . . . . . 1 EA C001520 0071 000. . . . . . CAP VAR 11 TO 53UUF . . . . . . . . . . . . . . . . . 1 EA C009542 0169 000. . . . . . * RES 25 OHM 5% 25W. . . . . . . . . . . . . . . . . . 2 EA R002,R003810 2753 015. . . . . . COUPLING. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA813 5604 002. . . . . . STUD BRS 6-32 X 7/16 . . . . . . . . . . . . . . . . . . 4 EA817 0002 001. . . . . . WASHER BLOCKER PLATE . . . . . . . . . . . . . . 7 EA817 0003 001. . . . . . INSULATOR BLOCKER PLATE . . . . . . . . . . . 7 EA817 0077 001. . . . . . SPACER. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 EA817 0253 001. . . . . . STRAP CATHODE INDUCTOR. . . . . . . . . . . . 1 EA #L008817 0484 001. . . . . . TUBE INS. . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 EA817 0577 001. . . . . . STRAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA #L009817 0686 001. . . . . . STRAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA #C001817 0718 001. . . . . . BUSHING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA817 1864 001. . . . . . STUD, CAP . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 EA817 2167 001. . . . . . ANGLE MTG. . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA829 4006 001. . . . . . STANDOFF . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 EA829 4043 001. . . . . . PLATE BLOCKER . . . . . . . . . . . . . . . . . . . . . . 1 EA829 4104 001. . . . . . SCREW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA829 4296 001. . . . . . MOUNT CAPACITOR . . . . . . . . . . . . . . . . . . . 1 EA829 7609 001. . . . . . STRAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA #L006829 7610 001. . . . . . STRAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA #L005829 7612 001. . . . . . STRAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 EA829 7614 001. . . . . . FLAG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA829 7615 001. . . . . . STUD 7.5 LONG. . . . . . . . . . . . . . . . . . . . . . . . 1 EA829 8862 001. . . . . . PLATE, CONTACT. . . . . . . . . . . . . . . . . . . . . . 2 EA839 4647 002. . . . . . INDUCTOR. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA #L004839 4648 002. . . . . . INDUCTOR. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA #L007839 4649 001. . . . . . DIELECTRIC FIL/CATH . . . . . . . . . . . . . . . . . . 2 EA839 5133 001. . . . . . PLATE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA839 5741 004. . . . . . SCREEN BLOCKER . . . . . . . . . . . . . . . . . . . . 1 EA839 5742 001. . . . . . GRID BLOCKER . . . . . . . . . . . . . . . . . . . . . . . 1 EA843 4758 001. . . . . . BASE PLATE-TUBE SOCKET. . . . . . . . . . . . . 1 EA917 0033 001. . . . . . BLOCK ASSY. . . . . . . . . . . . . . . . . . . . . . . . . . 1 EA917 0035 001. . . . . . BLOCK, ADJUSTMENT . . . . . . . . . . . . . . . . . . 1 EA917 1864 002. . . . . . STUD, 8-32UNC X 2.96 LG . . . . . . . . . . . . . . . 1 EA917 2166 001. . . . . . CARBON GRAPHITE ROD . . . . . . . . . . . . . . . 2 EA917 2428 002. . . . . . TILE ABSORBING . . . . . . . . . . . . . . . . . . . . . . 1 EA


922 0446 035 . . . . . CABLE, CAVITY INPUT . . . . . . . . . . . . . . . . . 1 EA929 4018 001 . . . . . BASE PLATE ASSY . . . . . . . . . . . . . . . . . . . . 1 EA929 4028 001 . . . . . TUBE SOCKET ASSY. . . . . . . . . . . . . . . . . . . 1 EA929 4683 001 . . . . . CATHODE RING ASSY. . . . . . . . . . . . . . . . . . 1 EA929 4684 001 . . . . . FILAMENT RING ASSY . . . . . . . . . . . . . . . . . 1 EA929 9135 488 . . . . . ASSY, CONTACT RING . . . . . . . . . . . . . . . . . 1 EA929 9135 489 . . . . . ASSY, CONTACT RING . . . . . . . . . . . . . . . . . 1 EA939 4218 002 . . . . . CONTACT ASSY, GRID . . . . . . . . . . . . . . . . . 1 EA939 5890 001 . . . . . CONTACT, SCREEN . . . . . . . . . . . . . . . . . . . 1 EA


SECTION VIIIDIAGRAMS

8.1 INTRODUCTIONThis section provides PA Efficiency curves and a list of

the diagrams that are contained in the separately sup-ply Drawing Package.

* See separate drawing package provided with manual

** Contained in this section

8396337304 COVERSHEET HT-20/25

8397822015 FAMILY TREE, HT-25FM

8397495063 CABINET OUTLINE DRAWING

8529163008 SCHEMATIC, OVERALL HT20/25

8221295055 SCHEMATIC, AMP RF D SERIES

8395303001 SCHEM, LOW PASS FILTER

8397227002 SCHEM, REMOTE SCREEN CTRL

8397440001 SCHEM, XMTR CTRL BOARDS

8397617001 SCHEM, SIMPLIFIED VSWR

8397618001 SCHEM, SIMPLIFIED AUTO PW

8397624003 SCHEM, IPA MULTIMETER

8397822007 PWR DISTRIBUTION

8397822008 PWR DISTRIBUTION

8435400791 SCH, AC CONTROL BOARD

8528807001 SCHEM, RFI BOARD

8528808002 SCHEM, DIGITAL & STATUS

8170548001 RUNNING SHEETS

8172067018 RUNNING SHEET, MAIN CAB


Figure 8-1A. PA Efficiency Curve for HT 25CD

Figure 8-1B. PA Efficiency Curve for HT 20CD


APPENDIX AMANUFACTURERS DATA

A.1 INTRODUCTIONThis appendix consists of the following technical datawhich identifies operating characteristics and parame-ters for various replaceable items used throughout theHARRIS HT 20/25FM FM BROADCAST TRANSMIT-TER circuitry.

a. Technical Data Sheet, Eimac 8990 Tetrodeb. Engineering Newsletter, Eimac WHM65D69c. Semiconductor Base Diagrams 1859-41d. Engineering Report, Susceptibility of the Open-

Delta Connection to Third Harmonic and Tran-sient Disturbances

e. HARRIS Engineering Power Distribution Recom-mendation

f. Extending Transmitter Tube Life

888-2609-001 A-1WARNING: Disconnect primary power prior to servicing.

A-2 888-2609-001WARNING: Disconnect primary power prior to servicing.

technical manual ht 25cd - 994 9569 002 ht 20cd -...

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