-pulse o -...

o 6V DC

(BATTERY)

RI

TI

CI

QI

PHOTO -ELECTRIC CONTROLS

MARINE DIRECTION FINDERS

1957 WESTINGHOUSE TV

AUTO RADIO-OLDSMOBILE

III -FI KITS

COLOR DISPLAY GENERATOR

PLUG IN SPEAKERS

CRI

o -PULSE

o

o + PULSE

o

rememw

www.americanradiohistory.com

The Mighty Nine

TRIPLETT ELECTRICAL INSTRUMENT COMPANY Bluffton, Ohio

Over a half -century of experience

EDITORIAL STAFF

Sanford R. Cowan Publisher

Samuel L. Marshall Edlter

Oscar Fisch Assistant Editor

Robert T. Dargan Technical Editor

Charles W. Gardner, Jr. Production Manager

San D'Arcy Contributing Editor

Paul Goldberg _ Contributing Editor

Elbert Robberson Marine Communications Editor

Lawrence Fielding _ HI-FI & PA Editor

BUSINESS STAFF Advertising Sales

New York Richard A. Cowan and Jack N. Schneider East 300 West 43rd Street

New York 36, N. Y.

JUdson 2-4460

Chicago Jim Summers and Suite 55 C

Midwest Pure Oil Building 35 E. Wacker Drive Chicago 1, III

ANdover 3-1154

West Ted E. Schell Coast 2700 West 3rd Street

Los Angeles 57, Calif. DUnkirk 2-4889

Charles W. Hoefer 1664 Emerson Street Palo Alto, Calif. DAverport 42661

David Saltman Advertising Production Mgr.

Not once upon a time... Right now the mighty nine Triplett CIRCULATION VOMs stand out like giants. For every application and in every Harold Weisner Circulation Manager

price range there is a Triplett VOM Carol J. Binderman _ Ass't Circulation Mgr exactly suited to you. Madeleine Sturmer Circulation Processing

53 years reputation guarantees quality you can accept without question. No other manufacturer offers so many and so much.

BURTON BROWNE ADVERTISING

A For Best testing Around the tab, Prnduction Line

nt Bench

630 The Popular All -Purpose

V.0 -M

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The Smallest For Telephone Medium Sire The Fust V -0-M Medium Sire Complete V -O -M Service rot with 10,000 with

with Swrtr h Field Teslinq Ohms/Volt AC 570 bçatures

ELECTRONIC SERVICING (formerly Radio-TV Service Dealer) is published monthly by Cowan Publishing Corp., 300 West 43rd Street, New York 36, New York, JUdson 2-4460. Subscription Price: $3.00 one year, $5.00 two years in the United States, U. S. Possessions, Canada and Mexico. Elsewhere $1.00 per year additional. Single copies 50e. Sec- ond Class Mail privileges authorized at New York, N. Y.

POSTMASTER: SEND FORM 3579 TO ELECTRONIC SER- VICING, 300 WEST 43rd STREET, NEW YORK 36, N. Y.

Combination V O -M VIVM

A Good Lab and Production Line

V-0 Al


ELECTRONIC SERVICING

VOL. 18, NO. 5 'Member

B PA

FEATURE ARTICLES

MAY, 1957

Color Display Generator, by Walter J. Cerveny Use of this test instrument in adjusting and servicing color receivers.

Photo -Electric Industrial Controls, by Allan Lytel Circuits used in controlling industrial processes such as counting, fabric tension, etc.

1957 Westinghouse TV, by Sol Libes Power Tuning and Remote Control in Westinghouse receivers.

Radio Direction Finding in Marine Electronics, Part 1, by Elbert Robberson

Basic principles of direction finding antennas.

Auto Radios for 1957-Oldsmobile, by Andrew Dopple Removal, installation, and service problems.

Color Picture Tubes, Part 2, by S. L. Marshall Basic construction, and explanation of convergence procedures.

How One Man Got Started in Mobile Communications, by Oscar Fisch

Pointers for those interested in getting into this field.

Hi-Fi in Kit Form, by Peter Ruggiero There's a profit to be made by building and selling hi-fi from kits.

Plug in Speakers for P.A. Systems, by Leonard Feldman No more matching headaches with this system for multiple speakers.

Self Service Tube Testers Self service tube testers are here to stay. The serviceman can use them to increase both tube

sales and service business.

Servicing Emerson 1957 Receivers, Part 3, by Harold Bernstein

Concluding installment. Automatic noise inverter, "Bridged T" adjacent channel sound trap.

CIRCUIT AND SERVICE FORUM

Workbench The Answerman Complete Manufacturer's Schematics-TV

Admiral 14UY series chassis RCA 14-S-7052 chassis

Motorola TS 423 chassis Packard Bell 8852 chassis

Complete Manufacturer's Schematics-Radio 47, 48 Airline Model GTM 1108A Transistor Radio Philco Model T 7 Transistor Racio

Video Speed Servicing Systems General Electric ST line

4

8

10

12

16

18

20

22

24

50

63

S. R. Cowan Ad Libs

Trade Flashes

Philco Chassis TV -396

DEPARTMENTS

2 Association News 14 Advertisers' Index

THIS MONTH'S FRONT COVER

A complete blocking oscillator circuit is contained within this three-quarter inch molded cube. The circuit of the

encapsulated components is shown in the schematic. De-

signed by DuMont, it is called the "Pulse Cube."

Entire Contents, Copyright 1957, Cowan Publishing Corp.

54 42

25-40

43-46

56 Cover 1111

'COWAN PUBLISHING CORP., 300 West 43rd Street, New York 36, N.Y.

UNI -DIRECTIONAL

MODEL 737A

You have your choice of three

SHURE moderately priced general-purpose microphones

SEMI -DIRECTIONAL

MODEL 51

BI-DIRECTIONAL

MODEL 315

Where quality is essential, yet cost is a factor- you can rely on these SHURE Microphones FOR PUBLIC ADDRESS HOME RECORDING COMMUNICATIONS PAGING AND INTERCOM SYSTEMS

MODEL 737A "MONOPLEX": Uni -directional, moisture -proofed crystal microphone-reduces feedback by 67' ! Can be used under adverse conditions of background noise where conventional

microphones would be practically useless. "Humi-seal" Crystal for trouble -free operation even

in humid climates. High impedance unit with excellent response to 10,000 cps. Output -54.0 db. LIST PRICE $46.00

MODEL 51 "SONODYNE": Semi -directional, dynamic microphone. Switch for low, medium, or high impedance makes it three microphones in one! Ideal for recording and "close -talking" applications. Frequency response is 60-10,000 cps, Output -52.5 db. Unusually rugged microphone; can be used in any climate, indoors or outdoors. LIST PRICE $49.50

MODEL 315 "GRADIENT": Bi-directional high fidelity microphone with multi -impedance switch.

Picks up sound equally from front and rear; is "dead" at sides. Ideal for interview broadcasting or group recording. Frequency response 50-12,000 cps. Provides exceptional voice and music

reproduction. Particularly useful in installations where feedback is a problem. Output -57 db. LIST PRICE $85.00

All three units have rugged, die-cast metal cases and arc finished in a rich satin chrome.

SHURE BROTHERS, INC. ELECTRONIC SERVICING MAY, 1957 1

Microphones Electronic Components 206 HARTREY AVENUE EVANSTON, ILLINOIS

"In Electronics Since 1925"


aiCie0eiteafitedeedgeOar SELL AS WELL AS USEWENI TOOLS

1 SMALL COMPACT DISPLAY

4 BASIC

POWER

TOOLS

- ON COUNTER

-- IN WINDOW

-- FLOOR DISPLAY

- ON WALL

2'eÙu?#ue4w Xpaee»eàri»uimf,weilixe,it EVERYTHING THEY NEED FOR THE HOME WORKSHOP From this 1 compact display you can supply the proper tool for practically every requirement of the home handyman, hobbyist, or home repair man. With these tools he can solder, hot -cut plastic tile, heat -seal plastic containers, etc., remove old putty or dents from wood surfaces. He can saw almost any material any shape, swiftly and accurately. He can drill % " holes in metals or masonry; up to % " in

WEN

wood. He can sand and polish. Furthermore, you have the advantage of offering WEN products-recognized as the best designed, most complete line of power tools of professional quality at home workshop prices. They're U.L. listed; fully guaranteed. And they're PRE -SOLD for you by extensive national and local advertising, publicity in magazines, newspapers, trade papers, and by highway signs coast to coast.

A TREMENDOUS SUCCESS-ORDER FROM YOUR JOBBER TODAY!

PRODUCTS, INC 5808 NORTHWEST HIGHWAY, CHICAGO 31, ILL.

(Export sales, Scheel International, Inc., Chicago)

by S. R. COWAN

Jobbers' Views on Servicing Statistics, when reliable, can be in-

formative. However, it is a known fact that the means used to present data ac- quired can be, and often is, intended to mislead and confuse. Let us cite examples of statistics recently released by several sources which contradict each other.

RETMA'S 1956 "Fact Book" tells us there are 41 million TV sets, 142 million radios and 30 million auto radios now in use. A contemporary serviceman's magazine tells us there are 43.9 million TV sets, 107.2 million radios and 38.1 million auto radios in use. A parts jobbers' magazine tells us that jobbers claim that there are 36.3 million TV sets, and 33.7 million auto radios in use. (It says that 43.8 million homes are radio equipped, but it does not say how many radios are in use). RETMA tells us there are 25 thousand service firms and 17 thousand retailers that also do service work (total 42 thousand) now in business while the ,contemporary service magazine says there are now 62 thousand major service outlets. (We spent $87 thousand in 1952-3 to obtain the name of every legitimate service firm in business, getting 53 thousand names-and this figure subsequently diminished to 47 thousand by 1956).

In 1956, according to RETMA, jobbers sold over $1.3 billion worth of replacements of all types for civilian replacement use and $892 million worth for industrial replacement use, and this did not include military sales. Now the jobber magazine says that jobbers estimate that their 1957 civilian replacement volume will be $938 million and

2 ELECTRONIC SERVICING MAY, 1957


Ad 1/bg

that they estimate industrial plus government replacement sales volume will be $248 million. It's apparent that jobbers catering to industrials are trying to

discount the dollar volume to discour- age competition. There's entirely too

much spread between all these figures. Evidently someone either "goofed" or else these statistics are presented in such manner as to confuse intentionally. Actually the figures published would not be vital to the average businessman if he were satisfied with business conditions today.

Unhappily only a few servicemen, only a few jobbers, and only a few manufacturers are satisfied. Independ- ent service firms are facing extremely keen-and much unjustified-competition from any angles. Jobbers are catering more and more to industrials but less and less to servicemen. Manufac- turers are continually pressed to lower their prices despite ever-increasing costs and diminishing profits. We have reason to believe that the erratic action of the stock and bond markets indicate that comparable conditions prevail in industries other than electronics. We also believe that our government is cogni- zant of this fact and intends to do something about it during the fiscal year. Lowered taxes and more realistic taxing methods, with the realization that small, independent enterprises are the back- bone of American economy, are required. Our politicos know this and seem to be starting to make the moves to effect it. We hope so!

Industrial Electronics Potential

Last May, after two years of survey [Continued on page 6]

How Helps

Independent Service Dealers with their TV-Radio Service Business

(RAY 1 HtOf QUALITY

ECEIVING TUBES

RAYTHEON

NATIONAL

ADVERTISING W. U.

"OPERATOR 25" INDEPENDENT

SERVICE DEALER

Here are some of the many ways in which the makers of Raytheon TV and Radio Tubes help the Independent Service Dealer with his business.

1 For nearly 12 years Raytheon has offered the Raytheon Bonded Electronic Technician program to Independent Service Dealers. Dealers who qualify have their service and parts guarantee backed by a bond issued through Continental Casualty Company, one of the country's largest insurance companies. It gives them real prestige in the eyes of the customer.

2 Raytheon provides "Western Union Operator 25" service for Bonded Dealers in 23,000 cities and towns. In answer to phoned requests for fast, dependable, bonded TV-Radio service, "Operator 25" sends customers to Bonded Dealers.

tßaYet 4rr

iKt Lics>d- /wiv wiis,

U/!/ r 4 !LJ , 'hi/ NO ~_r ,G ~EVN ta+awr

RAYTHEON

BONDED

PROGRAM RAYTHEON

QUALITY

PICTURE

TUBES

3 Raytheon consistently runs national advertising, presenting Independent Service Dealers as the best in the business.

4 Raytheon has a network of independent distributors with well trained personnel who are eager to help independent dealers.

5 Raytheon makes a complete line of TV and Radio Tubes that are tops for replacement work - Raytheon All -Set Tubes - designed to help the versatile service dealer who repairs all makes and models.

For the whole Raytheon story, get in touch with your nearest Raytheon Tube Distributor.

TV-Radio service is your business ... serving you is ours

RAYTH EON MANUFACTURING COMPANY Receiving and Cathode Ray Tube Operations

Newton, Moss. Chicago, Ill. Atlanta, Ga. Los Angeles, Calif. Raytheon makes? Receiving and Picture Tubes, Reliable Subminiature and Miniature Tubes,

all these Semiconductor Diodes and Transistors, Nucleonic Tubes, Microwave Tubes.

ELECTRONIC SERVICING MAY, 1957 3


Fig. 1-Hickok color display generator also provides white dot and crosshatch output.

A color -display generator is lighter and more compact than an NTSC color -bar generator, and accordingly finds ready acceptance as a color -TV installation instrument. The unit illustrated in Fig. 1 provides white -dot and crosshatch outputs in addition to the chrominance display, which makes it a complete source of set-up signals in one compact package.

Crosshatch Facilitates Preliminary Convergence Adjustments

Set-up of the three -gun color picture tube is accomplished by the following steps:

1. Adjustment of the picture -tube accelerating voltage to the value

eoff or

Fig. 2-Beam-magnet and lateral - corrector construction.

How To Use A

COLOR DISPLAY GENERATOR by Walter J. Cerveny

Chief Engineer Television Equipment Hickok Electrical Instrument Co.

A discussion of the principal applications of the color bar generator as a source of set-up signal for

making preliminary adjustments, and checking a color television set.

eiIIIIIIIIIIIIIIIIIIIIIIIII IIIIIIIIIIIIIIIIIIIIIIIIIIiIIIIIIIIII IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII IIII IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIlIIIIIIIIIIIIIII IIIIII IIIIIIIIII IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII IIIIffi

specified by the receiver manufacturer.

2. Usual adjustments for black -and - white receiver installation, such as horizontal drive, horizontal and vertical linearity, height, width, focus, and centering.

3. Field purity adjustments. 4. Static convergence. 5. Dynamic convergence. 6. Tracking of the three color guns. 7. Adjustment of the color killer,

color -intensity control, and color - phasing control.

Horizontal and vertical linearity, height, and width adjustments are readily and accurately made using the crosshatch pattern as a reference. These are similar to the corresponding adjust -

Green Beam Motion

Blue Lateral Motion

Red Beam Motion

Blue Beam Motion

Fig. 3-Blue beam magnet produces only vertical motion of blue dot.

ments in black -and -white reception, and hence require no detailed explanation.

Static Convergence

Static convergence is concerned with the coincidence of the red, green, and blue beams in the central area of the

G

i

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99

picture -tube screen. Control of the color dot positions is accomplished by means of three beam magnets and a blue lateral corrector. Typical beam -magnet and lateral -corrector construction is illustrated in Fig. 2. A beam magnet is provided for each of the color guns, and the lateral corrector is an added

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Fig. 4-The color dots at the top and bottom of the screen, and on the left and the right side will usually be out of convergence.

R



control for the blue gun. The motions of the color dots re-

sulting from adjustment of these static convergence controls is shown in Fig. 3.

Note that the red and green dots are moved along opposite diagonals, so

that there is always a crossover point of the red and green dots, where these

two colors converge to yellow dots. Since the blue beam magnet produces only a vertical motion of the blue dot, as shown in Fig. 3, the blue lateral cor-

rector is provided to produce horizontal motion of the blue dots which is neces-

sary for coincidence of all three color dots; when the blue dots are moved into coincidence with the yellow dots, white dots result and convergence is

obtained. In general, these adjustments suffice to obtain convergence in the central area of the screen, only.

Vertical Dynamic Convergence

The color dots at the top and bottom of the screen, and at the left- and right- hand sides will usually be out of convergence, as depicted in Fig. 4. The next step is to adjust the vertical dynamic -convergence controls to make the columns of red and green dots parallel to the column of blue dots, as illustrated in Fig. 5.

[Continued on page 61]

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dots must be parallel to the blue

dots.

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GOytOR I I

GO_OR

how long would it take you to solve this service problem?

(Based on an actual case history taken from the Howard W. Sams book "TV Servicing Guide")

ro INTE-

GRATOR

2.5V

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047

450V

-r 25V F -P 1

VERT NUIT

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VERT. HOLD

CONTROL MEG

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VERT. 7 SIZE

5600 CONTROL

690 R

450V

o

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VERT. LINEARITY CONTROL

5

470n

BLUE 795n

GRN

RED

VERT

DEFLECTION 047 COILS

PHOTOFACThelps you lick problems like this

*20 in just minutes for only Let's take a look at this problem: This trouble symptom is present when there is no driving signal to the vertical deflection coils and when the horizontal scanning is normal. Look for the following possible causes:

1. Defective multivibrator or output tubes

2. Open coupling capacitors C71 or C69

3. Open linearity control R6 or cathode resistor R79

4. Open size control R5

5. Open output transformer T3

With the applicable PHOTOFACT Folder at your finger- tips, you trouble -shoot and solve this problem in just minutes. Here's how:

Using the Tube Placement chart (you'll find it in every PHOTOFACT TV Folder) you can quickly locate and check

per model! the multivibrator and output tubes.

Tubes okay?-then: Check waveform at grid of vertical output tube (W 10). Wave shapes and peak -to -peak values appear right on the PHOTOFACT Standard Notation schematic. Waveform correct?-then: Check for open R6, or R79 or for faulty components in the output plate circuit. The DC resistance of the vertical output transformer and the lead colors are also shown right on the schematic.

Waveform incorrect?-then: Check voltages at the pins of the multivibrator tube. They're right on the exclusive Standard Notation schematic.

Whatever the trouble, you'll locate it faster and easier with a PHOTOFACT Folder by your side. Be sure to use the complete Replacement Parts List to select the proper replacement for the repair.

Use the servicing method you prefer-checking of waveform, voltage or resistance- you'll find all the information you need at your finger-tips in PHOTOFACT.

For only *21/2¢ per model, PHOTOFACT helps you solve your service problems in just minutes-helps you service more sets and earn more daily!

Based on the average number of models covered in a single set of PHOTOFACT Folders.

MONEY BACK GUARANTEE!

Got a tough repair? Try this-at Howard W. Sams' own risk: see your Parts Distributor and buy the proper PHOTOFACT Folder Set covering the receiver. Then use it on the actual repair. If PHOTO - FACT doesn't save you time, doesn't make the job easier and more profitable for you, Howard W. Sams wants you to return the complete Folder Set direct to him and he'll refund your purchase price promptly. GET THE PROOF FOR YOURSELF- TRY PHOTOFACT NOW!

FOR SERVICE TECHNICIANS ONLY

Fill out and mail coupon today for Free subscription to the Sams Photofact Index -your up-to-date guide to virtually any receiver model ever to come into your shop. Send coupon now.

HOWARD W. SAMS & CO., INC. Howard W. Sams & Co., Inc. 2209 E. 46th St., Indianapolis 5, Ind.

Put me on your mailing list to receive the Sams Photo - fact Index and Supplements. My (letterhead) (business card) is attached.

E I'm a Service Technician: full time; part time

My Distributor is:

Shop Name

Attn:

Address:

City - _Zor,s- Siate L



AD LIDS [from page 3]

and research, we broadened our editorial scope so we could cover all phases of industrial electronic and commercial communications equipment servicing techniques along with radio and TV servicing. The transition is taking place slowly, methodically and in a pattern that will be most beneficial to all our readers, old and new alike.

Radio-TV servicing has been, is, and will continue for some- time to be the prime source of revenue to our subscribers. That industrial electronics and commercial communications servicing is providing an ever- increasing additional source of income for those service firms which have sought that type of business is extremely gratify- ing. Remember well this pre- diction: In due time the average service firm will make more money per annum from its industrial customers than it will from its regular home -set customers.

On what basis and what known facts justify the making of such a seemingly brash pre- diction? The answer is simple: Today, with 77% of our homes having a TV set (41 million in use) ; with 140 million home radios and 30 million auto radios in use; with upwards of 20 million radio phonographs and $200 million worth of Hi- Fi and PA equipment in use, the nation's annual maintenance fees to servicemen ap- proximate $2 billion of which $1.3 billion represents the amount spent by servicemen for the purchase of replacement tubes, parts, etc.

In contrast, the nation's use of industrial electronics and commercial communications devices has hardly begun and despite that fact Industry paid service fees and maintenance wages amounting to $400 mil -

6

JOIN THE 50,000 PROGRESSIVE

READY TO MODERNIZE WITH NEW

Over 50,000 TV -radio service dealers already have asked for the new General Electric shop plans (above) that were specially developed for the independent technician. Dealers in every part of the country know that today's growing market for service, calls for improved facilities ... and that proper planning saves space, costs, time, and labor.

You too can modernize for the in-

creased volume that lies ahead...by following the practice of other progressive technicians, and using General Electric's shop layout to equip your shop for top -efficiency service to more customers. Phone your local General Electric tube distributor for complete plans! They include dimension draw- ings and material lists, so a carpenter or builder can start work at once.

Progress /s Our Most /mporiant Product


GENERAL ELECTRIC

SERVICE DEALERS

GENERAL ELECTRIC SHOP PLANS!

ANONOdY ANOTHER G -E BUSINESS -BUILDING,

TIME -SAVING AID TO THE INDEPENDENT SERVICE TECHNICIAN..

Most complete tube guide ever published- the new edition of "Essential Character- istics"! Over 1500 types, with descriptions, ratings, and basing diagrams. Pocket size. See your General Electric tube distributor immediately!

tubes

essential characteristics

RECEIVING TUBES

TELEVISION PICTURE TUBES

SPECIAL-PURPOSE TUBES

GENERAI. ELECTRIC

lion last year-and in addition another $892 million for re-

placement parts, tubes, etc. Compare those figures for a

relatively new and still to be

greatly expanded service market with the civilian record. The dollar volume figures for industry service and parts sales

after 5 short years is almost level with civilian usage-and the latter, to say the least, is

mature, having had a 25 year head start.

It is opined by authorities on

the subject that less than 4% of this nation's manufacturing plants are now utilizing elec-

tronic devices, automation, etc.,

but that 40% will be within 5 years, 60% will be within 10

years, and that 90% will be in

15 years. Visualize that tremendous expansion and what it

represents in terms of potential dollars to be spent on servicing and purchasing of needed replacements. Fantastic is the word!

Aside from industrial use of

electronically controlled machinery-consider the expanded use of commercial communications equipment in years ahead. Today the 900,000 mobile, base and portable transmitters and receivers operated by 19,000

FCC licensees, and which pro-

vide 2 -way communications for

railroads, buses, etc., represent less than 14% of the present-

day potential. In other words, big as it is today, commercial communications usage is still

86% unsold. Try to visualize what a tremendous annual serv-

ice potential this market will

be 5, 10 or 15 years hence.

The foregoing factual pres-

entation should cause every

one now engaged in radio -TV servicing to reflect upon his

future opportunities. They are

bright indeed! And incidental- ly, have you noticed that one

of our competing magazines in the service field, being

shrewd enough to realize that [Continued on page 53]

7


F2ARW Photoelectric Control

L4 Dual Filament Light Source

To Loading Dock.

Fig. l a-A photo -electric case counting device. The pulse output of the photo -cell circuit feeds a counting circuit which stops the conveyor at the proper count.

L4 Warning

Light

Main Conveyor

F2ARW n

R W C1

Counter

Motor Starter

Line

Fig. 1 b-Block diagram of the counting device shown in Fig. la.

Fig. 2-Dual filament light source. (Courtesy Autotron Inc.)

Fig. 3-Medium speed, medium sen-

sitivity photo -electric relay. (G.E.)

MANY industrial operations use photocells for different types of

control. Safety devices are no longer the only use for these cells. The electronic portion of this industrial equipment is not difficult to service and repair once the operating principles are established.

Photo -Electric Counter

The operating principles are rather straight -forward. For example, shown in Fig. la is a case -counting device. Three units plus the motor control make up this system. A light beam from the light source is received by the photocell which, in this case, provides an output signal or pulse every time a case moves along the conveyer. These pulses are counted and the counter controls the conveyer motor.

In operation, the desired number of cases for an individual delivery is set on the counter dials. The "Start" button is pushed and, when the controls are warmed up, they automatically start the conveyer. As each case passes the light beam and interrupts it, the counter advances. At full count, which has been pre-set, the counter operates a relay which stops the belt.

There are a number of protective devices built -into the equipment. Relay RW is a warm-up protection which has a time delay long enough to permit the vacuum tubes to reach the proper operating condition before the relay starts the conveyer delivering cases. In the event of a tube failure the RW relay stops the conveyer. Filament current through the tubes must also pass through the relay. An open tube filament will stop the current through the relay and

Photo -Electric

INDUSTRIAL CONTROLS by Allan Lytel

Supervisor - Technical Information Unit General Electric Co.

The principles of operation of photo -electric control devices and their application to various industrial processes are treated in this article.

the spring -loaded contacts will open and stop the conveyer. The light source has a dual filament. If one burns out or opens, the other operates and there is no shut -down, but-as a warning device, a pilot light is lit to indicate that the lamp requires replacement.

Fabric Tension Control

A second example is shown in Fig. 4.

This is a tension control as used in fabric processing. The loop of fabric must be of the proper length to provide the necessary fabric tension. A photo -electric device is used to control the rate of feed. There are two controls, A and B. In normal operation B is interrupted but A is not.

If the loop becomes too short B is no longer interrupted and light reaches the B photocell. This speeds up the rate of fabric feed until B is again interrupted. Also-if the loop becomes too long control A is interrupted and this signal slows down the feed rate. A "fail-safe" arrangement is included to stop operation in case of a control failure.

Photo -Electric Control Building Blocks

Many commercial controls are similar to those above. There are generally four building blocks or basic components

used in these controls. They are: light sources, photo -cells, time -delays, and counter plus the motor controls. Each of these is discussed below.

Light Sources - These are simple light bulbs for use on 110/220 volts. Some have the dual filament and warning light as in the above examples. The light is focused in a narrow beam which falls upon the photocell. To increase the lamp life, the voltage is often reduced. This, of course, reduces the light output but in many cases reliable operation is still obtained, especially where the light only travels a short distance. Some light sources have a safety relay built-in. This is arranged to go into action when the lamp burns out, in which case it stops a motor, closes a

valve, or operates a trouble light. Fig. 5 shows a light source. D is the

input, P is the variable dropping resistance, and F is the filament. Relay R, the safety relay, is shown with the contacts A. Current through R pulls down the upper arm at A and provides a

complete circuit through the contacts. Lamp failure stops the current through R and the spring opens the contacts which stops the motor in series with these contacts.

Phototubes - There are three types of photo -electric cells. The photovoltaic cell produces a voltage difference upon exposure to light, the photoconductive



Control B

SIA Photoelectric

4), Control A LI AY Light Source

I C

moot I

L4 Dual Filament Light Source

Fl Photoelectric Control

Fig. 4-Photo-electric fabric tension

control. (Autotron Inc.)

changes resistance upon exposure, and the photoemissive or phototube emits electrons upon exposure to light. All three types have industrial applications but we are concerned here only with the last type.

A typical phototube is shown in Fig. 6. The large area negative cathode provides for the emission of electrons which are captured by the positive rod- like plate. Total current is small-usually less than 20 to 30 microamps. A phototube circuit is illustrated with a

relay in series with the triode (6J5) plate. Resistor R9 has a value of several

megohms and R1 (to limit the plate current in the triode) is 20K ohms.

This is a "light -energized" circuit. With no light on the phototube P, it is an open circuit. Bias (E2) prevents con-

duction through the triode and relay R is not energized. When light falls on the phototube a large number of elec-

trons are emitted from the cathode to

the plate. This current creates a large voltage drop across R2, large enough to overcome the initial bias and make the tube conduct. This energizes R for


o o TO MOTOR OR OTHER

DEVICE TO BE CONTROLLED

Fig. 5-Failure of the light source

de -energizes relay R.

ELECTRONIC SERVICING MAY, 1957

BUSS FUSES provide maximum protection against damage due to electrical faults

Protection against damage due to electrical faults can be no better than the device used to protect the equipment. The safest, most dependable protection you can get is with BUSS fuses.

To make sure BUSS fuses will clear the circuit should an electrical fault occur, BUSS fuses are electronically

tested. A sensitive testing device automatically rejects any fuse not cor- rectly calibrated, properly constructed and right in all physical dimensions.

This careful testing is also your as-

surance BUSS fuses won't give a false alarm by blowing needlessly. Shut- downs due to faulty fuses blowing without cause are eliminated.

By safeguarding users' equipment against damage-and by eliminating needless fuse blows-BUSS fuses give you double protection against loss of customer goodwill.

With a complete line of "trouble - free" BUSS fuses available in all sizes and types,-it is just good business to standardize on BUSS fuses.

For more information on BUSS and FUSETRON Small Dimension fuses and fuseholders .... Write for bulletin SFB. Bussmann Mfg. Co. (Div. of McGraw -Edison Co.) University at Jefferson, St. Louis 7, Mo.

BUSS fuses are made to protect-not to blow, needlessly rRVlrWOR1MY MAM4f M tIrCTRICA l IROttc'IOM

Makers of a complete line of fuses for home, farm, commercial, electronic, automotive and industrial ese.

9


Fig. 1-The Beverly low -boy television receiver having Power Tuning channel selection and adapter for remote control.

WESTINGHOUSE receivers for 1957 feature Power Tuning

channel selection, and push-button on - off control, plus remote control of fine tuning, channel selection, and volume control from anywhere in the room. The Beverly (Models 21KR19O and 21KR191) shown in Fig. I shows the location of the Power Tuning Bar.

Servicing these automatic and remote controls does not require an automation expert. To facilitate adjustments, this article will cover the complete operation of these units, a description of the adjustment procedures, and some helpful servicing hints.

Power Tuning

The Power Tuning feature is an electro -mechanical method of automatic, push -bar, channel selection of vhf channels. Automatic channel selection can be achieved for each position of the tuner. The unit can be pre-set to select only those stations available in the area and to skip channels where no signal is present. In areas having only one uhf station the unit can also be set to select this channel. In addition, the Model

H984 Chairside Remote Control unit (discussed below), is available as an optional accessory.

To operate the power tuning and select vhf channels the Power Tuning Bar is pressed until the desired channel number on the channel selector knob is at the arrow, and then released.

The schematic diagram for the unit is shown in Fig. 2. When the bar is depressed, 117 volts ac is applied to the motor. Solenoid action brings the eared disk (mounted on the rotor shaft) into engagement with the nylon pinion. As the gear assembly rotates, a cam causes a spring loaded arm to close lever switch 3 (see schematic diagram Fig. 2) which maintains the supply voltage and keeps the motor rotating for the remainder of the cycle.

At this stage of the cycle the roller on the cam engages and rotates the program disc which in turn rotates the tuner shaft. As the roller disengages, the cam lowers the spring loaded arm opening Switch 3, deenergizing the motor and bringing the mechanism to a stop with the program disc and tuner shaft in its correct position. 1f Switch 3

The operation, adjustment and circuit details of Automatic Power Tuning and Remote Control Unit for the new Westinghouse receivers are discussed in this article.

1951 WESTINGHOUSE TV Features Automatic Power Tuning

by Sol Libes

Technical Editor-Service Dept. TV-Radio Division Westinghouse Elec. Corp.-Metuchen, N. J.

is prevented from opening by a tubular clip inserted into the hole representing the unwanted channel on the programming disc, the motor will continue to i otate and cause the mechanism to continue to the next desired channel.

The receiver as shipped, is set to stop on every channel. To set for the auto-

matic skipping of channels not used in the area, follow the procedure described below.

The motor drive uni:, mounted on the rear of the tuner close to the left side of the cabinet, is shown in Fig. 3. The programming wheel can be seen extending from behind the motor as-

DIE-CAST

NYLON GROMMETS

RF TUNER

MIY-U9C IN64G

TUBE IN6OG

L 70V008M01 _5

I

C106 1.02

RED n

i1

SW 3- I GRAY

+ r-,aeocoeol

LL Ji BROWN

I) FINE TUNING

(2) CIIANN J- SELEGTOR

(3)'/OLUME

MOTOR ASS Y.

vi -1

- POWER TUNING PUSH BAR i

CHASSIS V2346-47..67

ORANGE/WHITE

2 PRONG PLUG

+++ TERMINAL BOARD

YELLO'M HITE

TO R 500 R 502

-r SW500

ON-OFF

4 WIRE CABLE GREEN

REMOTE UNIT H-984

WHITL-` BLACK '

RED.-._-._ -.1

117 VAC

AUDIO OUTPUT

8208 se

GREEN

REMOTE SOCKET

4 BUSS WIRE JUMPERS REOUIREC WITHOUT REMOTE CONTROL.

MALE PLUG

Fig. 2-Partial schematic showing the Power Tuning circuit and the intercon- nection between the remote control unit and the reciver.



Fig. 3-Programming clip being in-

serted into hole of channel

skipped.

to be

Fig. 4-A programming clip ready to

be inserted into a channel hole.

sembly near the left side of the cabinet. This wheel has twelve holes (thirteen holes on chassis having uhf tuners) and adjacent to each hole is a stamped channel number.

Programming clips (a bag containing the programming clips is attached to the back cover of the receiver) are inserted into the holes in the programming wheel corresponding to the channels to be skipped.

To insert a programming slip into a

hole, place a clip on an alignment tool, as shown in Fig. 4. Insert the clip into the side of the programming wheel on which the channel numbers are stamped, emerging from the non - stamped side. It is important to push the clips all the way into the holes so

that the lip of each clip is flush with the wheel.

When it is necessary to remove a

chassis containing power tuning it will be necessary, to first remove the two prong plug (seen in Fig. 5) from the terminal board on the tuner mounting bracket. This plug must be replaced when the chassis is installed in the cabinet.


AR -22

TR -4

,kll,(Ìlil

TR 11 and 12

AR 1 and 2

the best color TV picture the growth of color TV means an even greater demand for

CDR Rotors for pin -point accuracy of antenna direction.

2 a better picture on more stations CDR Rotors add to the pleasure of TV viewing because

they line up the antenna perfectly with the transmitted

TV signal giving a BETTER picture ... and making it

possible to bring in MORE stations.

Jr 3 tested and proven dependable

thousands and thousands of CDR Rotors have proven their dependability over years of unfailing performance in installations everywhere in the nation. Quality and engineering you know you can count on.

4 pre -sold to your customers the greatest coverage and concentration of full minute spot announcements on leading TV stations is

working for YOU ... pre -selling your customers.

the complete line a model for every need ...for every application. CDR Rotors

make it possible for you to give your customer exactly what is needed the right CDR Rotor for the right job.

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FOR SOUND

SATISFACTION

cove

RCA GOLD LABEL SPEAKERS!

Kass.,... .r.rr..s.. r+.-- POINOPPINPleb__ .. .-w,,b9954

. . .,.... for

Replace dead speakers with live RCA Gold Label Speakers. They're short on installation time ... long on customer satisfaction. All types built to RETMA size standards REC 148.. .

mounting hardware is included on most smaller sizes ... For all your speaker requirements ... play it smart and safe! Be sure you ask for RCA Gold Label Speakers ... at your local distributor.

RADIO CORPORATION of AMERICA

COMPONENTS DIVISION CAMDEN, N.J.

Photo of a typical direction finder using a loop antenna.

MOST of us are familiar with the MOST of a radio direction

finder. A loop antenna having a figure - of -eight response pattern is coupled to the front end of a receiver. Signals arriving in line with the loop are strong, while those coming in at right angles are in the "null" sector, and are very weak or not heard at all.

However, there is a little more to the matter than that, and a clear understanding of what actually takes place in marine Radio Direction Finders will help an installer newly entering the field to turn out good work.

Response Patterns First of all, you must abandon the

misconception that a loop antenna automatically has a figure -of -eight response pattern. This is not too generally un- derstood, probably because explanations of loop -antenna operation are immersed in somewhat complicated references to current phasing and the associated mathematics. Loop operation can be clarified a little by looking at it from a different angle-that of voltage and current amplitudes, with a simple wave analogy.

Fig. 1 represents a short vertical antenna connected by a shielded lead to a receiver. The signal input to the re -

Radio Direction Finding

In

Marine Electronics Part I

Directional characteristics of various antennas are discussed along with the factors which affect them. Emphasis is placed on the

loop antenna.

ceiver depends, of course, upon the transmitting station's field strength, but more important to our discussion, it also depends upon the radiation resistance of the antenna. Current excited in the antenna by the radiated field causes a signal voltage to appear across the radiation resistance of the antenna. Signal level is the same no matter from which direction the transmission comes.

Fig. 2 represents a pair of close - spaced short vertical antennas -connected to the balanced input of a receiver. With this arrangement receiver signal input depends upon the voltage difference existing between the two antennas at any given time. With a radio - wave front arriving in the direction of signal "A" in Fig. 2, at the same time the signal voltage peak is excited in antenna #1, antenna #2 will be at an excitation point down the front of the slope of the oncoming wave. Thus, a difference of potential exists between the two antennas and the receiver re- sponds to the signal. When the two antennas are one-half wave apart at the moment when the maximum positive voltage is induced in antenna #1, the maximum negative voltage would be induced in antenna e2. Thus, the greatest signal input is given to the receiver. With less spacing, the differ-

ence in potential possible between the antennas is, of course, reduced. In practical marine direction finders, the spacing between the equivalents of these two antennas must be very little; so it must be assumed to begin with, that signal voltages applied to the receiver will be very modest. Loop and associated receiver circuits should have highest possible Q to reduce any loss of this already small signal. Also, the receiver must be exceptionally sensitive and quiet.

Now, when a signal comes in from the direction of signal "B" at 45 -degrees, the effective distance along the line of wave travel between antenna

and #2 will be only .7 of that which

SHORT ERTICAL ANTENNA

--SHIELDED LEAD-IN

Fig. 1-A vertical antenna has a

non -directional response.



by Elbert Robberson

it was in the case of signal "A". There- fore, the voltage difference and receiver response will be somewhat less.

In a similar manner, a wave arriving from the direction shown as signal "C" will give a response of only .5 that obtained when the signal arrived in line with the two antennas. But the important feature is that a signal arriving in the direction of signal "D," at 90 -degrees to the axis of the two antennas, will present both antennas with the identical level of the incoming wave at the same time. Thus, no difference of potential will exist for this direction, nor will there be any receiver signal. Thus, a signal arriving from this angle is in the "null" sector of the antenna system.

It is important to note that between the zero -angle line and the 45 -degree angle line a signal reduction of only one-half power or 3 -decibels occurs. However, getting around to right angles from the axis of the antennas, the

SIGNAL C

60° SIGNAL B

45°

SIGNAL A 0°

ANT Noi

SIGNAL D 90°

Fig. 2-Directional variations with two vertical antennas.

A three band direction finder employing a ferrite loop.

rate of change is much more rapid. For example, a 3 -decibel difference exists in

the one degree between 88 and 89 -de-

grees. Between 89 and 90 the change is

much more pronounced-from the ex-

istence of signal to theoretically none at all.

This is the reason for the use of the null sector in direction finding, rather than the line of maximum signal, since the null is very much sharper than the broad area of maximum response.

The form of direction -finding antenna which has been discussed so far is the "Adcock," widely employed on shore for directional radiation and reception where the most efficient antenna height and spacing can be used. On a boat, the dimensions of the DF -antenna system are seriously limited. Therefore, vertical antennas are not used for boat direction finders. However, by making the antenna in the form of a coil which has several vertical members or windings (connected across in series at the top and bottom) the practical effect of a

much larger vertical antenna is obtained, giving much better signal sensitivity.

The loop antenna, while it affords greater signal strength from a given radio field, has the disadvantage of having equivalent horizontal sections at ton and bottom. These horizontal -antenna components are insensitive to ground - wave radiations which cancel because they arrive at the top and bottom sec-

tions at the same time. However, additional currents are induced in the circuit from any waves arriving from


... another

MALLORY service -engineered

product

Ziteagia prove MALLORY

"GEMS"

krdefelerne

To demonstrate how well Mallory "Gem" tubular capacitors resist moisture, we put some in plastic tubes filled with water. Months later, their internal resistance remains unchanged ... proving there has been no moisture absorption.

Sure, you don't expect to submerge the capacitors you install. But when you're looking for top performance, even under the toughest humidity- always ask for Mallory "Gems."

Get your stock today from your Mallory distributor. He carries them in all popular ratings for by-pass and coupling applications.

P R. MALLORY 8 CO. Inc.

MALLORY P. R. MALLORY 8 CO. Inc., INDIANAPOLIS 6, INDIANA

Cds Contra Vibrators Switch Resistors Power Supplies Mercury and Zinc

Batteries



FOR A

brighter

profit picture

Rely on the tube that has always been a favorite with leading independent service dealers.

(X 4/64 Wei*,

TUNG-SOL® RECEIVING TUBES

TUNG-SOL makes All -Glass Sealed Beam Lamps, Miniature Lamps,

Signal Flashers, Picture Tubes, Radio, TV and Special Purpose Electron Tubes and Semiconductor Products.

Window panes and lenses made of a solid, opaque metal have been developed by Raytheon Manufac- turing Company which allow invisible heat rays from sub -zero targets to reach a super -sensitive infrared detector. Other materials require targets to be 250 degrees or hotter for equal range. This advance, Raytheon scientists state, is a major breakthrough in the technology of infrared devices, opening a door to many new commercial and military applications. Use of this material, the scientists point out, may make it possible to detect enemy ships, planes and missiles from longer distances in total darkness without revealing the observer's position. It will also lead to more effective solutions of guidance, gunfire control and automatic tracking problems.

A testimonial dinner for Julius Finkel, president of JFD Electronics, Inc., Brooklyn, New York, celebrating his 70th birthday was held at the Commodore Hotel in New York City on March 30th. More than 200 friends, business associates and employees attended. Among the highlights of the ceremonies for Mr. Finkel, who first immigrated to this country in 1908 and became a pioneer in the electronics industry, was the presentation of a

plaque and bronze scroll signed by all JFD employees, a

silver plate from his seven sons who are all members of JFD, and tributes from members of the electronics industry.

The Heath Company, a subsidiary of Daystrom Incor- porated, broke ground for its new plant, it has been announced.

Robert Erickson, president of the firm, explains that the new plant will be located on Hilltop Road in South St. Joseph, Michigan, but will keep its Benton Harbor, Michigan mailing address.

Proclaiming the electronics industry "one of the most forceful, potent, and dynamic forces in our way of life," Mayor Richard J. Daley of Chicago offi- cially set May 15-23 as Electronics Week in Chicago.

During the week May 15-23 electronic industry leaders from all parts of the country will gather in Chicago for trade and industry meetings. These include the national conventions of the Radio - Electronic -Television Manufacturers Association (RETMA), and the National Electronic Distributors Association (NEDA), as well as the mammoth all - industry Electronic Parts Distributors Show, to be held at the Conrad Hilton, May 20-23. More than 12,000 are expected to attend the show alone.

tra d e An all -transistor radio for the Cadillac El Dorado

Brougham has been announced by the Delco Radio Division of General Motors. Thirteen transistors are used in the radio in addition to three germanium diodes. Use of two Delco high -power transistors to drive the speakers provide ample audio power re- serve and hence excellent tone quality at normal listening levels. Knife sharp selectivity is provided for adjacent channel rejection without sacrifice of broad "nose" selectivity for good tone quality.

Manual, push button and signal seeking tuning are provided in the receiver as well as a two speaker fader system and an electric antenna which automatically extends when the radio is turned on and retracts completely when the radio is turned off. This advanced design radio makes best use of the unique agc characteristics of transistors to provide reception almost completely free of fading problems.

A new line of Motorola medium power transistors has been announced by J. T. Hickey, Manager of the electronics company Semi -Conductor Division. The new transistors fill a gap in the power spectrum which formerly existed in the 100 milliwatt to 350 milliwatt range.

The transistors are now in use as audio amplifiers in portable radios, as driver units for power transistors, in dc converter units and numerous other applications.

A new replacement parts program for all Philco consumer products to insure prompt service throughout the United States was announced today by Ray Nugent, Gen- eral Manager of the Company's Accessory Division. Known as "Factory -Distributor 90 Day Service Parts Pro- gram," it calls for a balanced inventory of service parts in each Philco distributing territory. The new program calls for maintenance of a balanced 90 -day inventory of service parts in each Philco distributor territory, and pro- visions for an "emergency" service to Philco distributors for critically needed parts on a 24 -hour basis.

Browning Laboratories, Inc., Winchester, Massa- chusetts, announces a new line of Multiplex Modu- lator Transmitter equipment. Gardiner Greene, President, announced that "This new equipment now enables Browning to offer a complete Multi- plex system for the background music operator including transmitter, tuners, receivers, amplifiers, and accessories. We now undertake the complete respon- sibility in helping new stations get on the air -with this new service."



fla shes Erie Resistor Corporation, Erie, Pa., announces a

new company sponsored Educational Training Pro- gram for both technical and business employees. The program was initiated at the beginning of the 1956

Fall School Semester. It was originally developed to fill the needs of personnel in the Engineering and Research Departments. Response within the com-

pany has been so great that the program has been expanded to cover all employees.

Television marked another communications milestone

with what is believed to be the world's first transmission of a TV picture on a light beam. This technique was used

at Boston's WBZ-TV station. According to the faculty at

the University of New Hampshire, this represents a

major achievement in transmission of signals via a light beam. The television station's technical staff worked on

setting up this experiment for a period of nearly a month, in collaboration with engineers and scientists from Baird -

Atomic, Inc., Cambridge, Mass.

Television receiver production in February increased over the January output while retail sales of these items to consumers declined slightly but were reported to be

above the sales level of last year, RETMA announced. February TV output amounted to 464,697 receivers com-

pared with 450,180 sets made in January and 576,282 produced in February 1956. Cumulative production fig-

ures show 914,887 TVs made this year compared with 1,164,629 receivers produced during the corresponding months of 1956.

Retail sales to consumers of these receivers totaled 525,437 units in February compared with 623,359 sold in January and 530,554 TV sets sold in February 1956.

Cumulative TV set sales totaled 1,148,796 during Jan- uary and February of this year compared with 1,144,767 sold during the like 1956 period. TV sets manufactured with UHF tuning facilities totaled 68,219 in February'

compared with 67,079 produced in January.

Factory production and retail sales of radio receivers in February were reported by RETMA today to be above the corresponding month a year ago. Cumulative production and sales totals were reported to be substantially over the same two -month period of last year. February radio production totaled 1,264,765, including 522,859 automobile receivers, compared with 1,085,529 sets made in Janu- ary, including 521,624 auto receivers. February 1956

production had been reported at 1,093,506, includ-

ing 437,611 auto sets. Retail radio sales to consumers in February totaled 525,029, excluding auto re-

ceivers, compared with 563,363 sets sold in January and 454,867 radios sold in February 1956. Cumula- tive radio set sales this year total 1,088,392 com-

pared with 986,073 sets sold in the two -month period of last year.

Manufacturers' sales of receiving tubes increased substantially in February over the January level while TV picture tube sales declined. Cumulative sales compared with last year show the same trend. Cumulative sales of 82,031,000 receiving tubes during the first two months of this year show a sub-

tantial increase over the 77,895,000 sold in the corresponding 1956 period. The dollar value also increased to $67,801,000 thus far this year over the $62,070,000 worth of tubes sold during the first two months of last year.

TV picture tube sales in February totaled 728,-

363 units valued at $13,134,778 compared with 760,855 tubes sold in January with a dollar value of $13,594,525.

Preparations and promotional ideas to aid in the observance of "National Radio Week," May 5-11,

were contained in a promotion kit recently mailed to all radio set manufacturers, RETMA announced. RETMA's participation in the all -industry event is under the guidance of the Public Relations and Advertising Committee, headed by Julius Haber, of RCA. The slogan for this year's nationwide campaign again is "Give a Radio," the observance of which will be actively promoted by the nation's radio dealers, distributors, radio stations, national and regional radio networks, and community leaders, in addition to receiver manufacturers.

Executive Vice President James D. Secrest today again

appeared on Capitol Hill to ask Congress to restore the necessary funds to the FCC to enable its Bureau of Safety

and Special Radio Services to "do the essential job of fostering a maximum effective use of the radio spec-

trum." The appearance of RETMA before the Senate

Appropriation Subcommittee on Independent Offices

marks the second time this year the Association has ap-

peared in support of the FCC budget for the fiscal year

1958. Messrs. Secrest and Carroll White, RETMA Mo-

bile Radio Communications Manager, testified before the corresponding House group recently.

[Continued on page 49)

FOR a

ri hter

TV icture

Rely on the tube that has always been specified by leading independent set makers

-/75b9

TUNG-SOL® Magic Mirror Aluminized

PICTURE TUBES TUNG-SOL ELECTRIC INC., Newark 4, N. J. Sales Offices: Atlanta, Ga.; Columbus, Ohio; Culver City, Calif.; Dallas, Tex.; Denver, Colo.; Detroit, Mich.; Irvington, N. J.; Melrose Park, Ill.; Newark, N. J.; Seattle, Wash.



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ATTACHING SCREWS (2)

SPEAKER

SPEAKER LEADS

Fig. 1 -Location and details of speaker mounting.

W i\LI ( 1]

PL>t{ H1n7,,+..

SPEAKER FADER }. CONTROL

ï

¶'C4I!AL rliNINC k \U'4

Fig. 2-Location of radio controls showing the auxiliary rear speaker control (fader control). Rear seat speakers are optional on all models.

Auto Radios for 1951

"Oldsmobile" Circuit description, installation and removal hints, and servicing and adjustment procedures for the 1957 series of Olds-

mobile receivers are discussed.

THE introduction of printed circuits and transistors has brought about

a new concept in auto radios for 1957. These innovations allow for greater compactness and streamlining of the new sets.

Description

Two new sets using printed circuits are available for custom installation in the new 1957 Oldsmobiles, and are supplied by the Delco Radio Division of General Motors. These are the De Luxe model, part 1$989001 and the Super De Luxe Wonder Bar part $$98002. The De Luxe is a six tube plus rectifier set while the Super De Luxe contains seven tubes plus rectifier. The additional tube in the Super job is used to trigger the automatic tuner. Both sets have five mechanical push buttons for touch tuning.

by Andrew Dopple

Sets mount in the center of the instrument panel with a separate 6" x 9" elliptical speaker mounted directly in front of the tuner section (see Fig. 1). The receiver assembly consists of two separate units, the tuner section and a power amplifier section; however both units are bolted together which simplifies installation or removal. The auxiliary rear seat speaker control has been redesigned and relocated (see Fig. 2). It is now known as a fader control and is located directly behind the right hand control knob, (tuner). Counter- clockwise rotation increases the front speaker volume and decreases the rear speaker volume. Clockwise rotation decreases the volume of the front speaker and increases the volume of the rear speaker. After proper balance is obtained, the volume of both speakers is



MAST ASSEMBLY

CAP

UPPER SPACER

LOWER SPACER

NUT

,ASKET

SOCKET AND LEAD-IN ASSEMBLY

Fig. 3-Manual antenna assembly,

showing lead-in wire to radio.

controlled by the volume control. On the Super De Luxe set the selec-

tivity control has been re -located to just below the selector push -bar (see Fig. 2). A three position sliding switch regu- lates the sensitivity of the automatic tuner, maximum sensitivity being ob-

tained at the extreme right hand position. A foot selector switch is also included with the Super De Luxe model and is located on the left side of the front compartment floor, terminating at the rear of the receiver thru a three - prong plug. A tone control is located behind the left tuner volume control (see Fig. 2) on both models.

Manually adjusted antennas (see Fig. 3) or power antennas (see Fig. 4) are available, and mount on the left front fender. The control for the power antenna is installed directly above the tuner dial on the instrument panel. Auxiliary rear seat speakers are optional on all models.

Removal (All Models)

1. Remove front speaker a. The front speaker mounts on a

composition baffle directly in front of

the glove compartment. The baffle is

held in place by several clip fasteners and four self tapping screws (see Fig. 1). With a 5/16 socket wrench remove the self tapping screws and allow the speaker and baffle to hang from the clip end.

NUT

Fig. 4-Structural details of power

antenna located under fender.

b. With a phillips-head screw

driver remove the two screws holding the speaker to the baffle. Then dis-

connect the two speaker leads at the plastic push -in connectors and remove speaker.

2. Remove the seven phillips - head screws holding the glove box to in-

strument panel, push the box toward the front of car, and down and out.

FOOT SELECTOR LEAD (SUPER DELUXE ONLY)

FRONT SPEAKER LEADS

SUPPORT

REAR SEAT SPEAKER LEAD

Fig. 5-Location of key points

in removal procedure.

3. Disconnect the green battery "A" lead at the plastic push -in connector (see Fig. 5).

4. Disconnect antenna lead in. 5. On cars equipped with rear seat

speakers disconnect speaker wire from push -in connector located in clip, on

the lower right front corner of the power unit (see Fig 5).


s E WARE OF SUBSTITUTES

You know from long experience

the trouble -free operation

selenium rectifiers give!

Replace only with

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Xt.

APPROX. 1 °

1

MAGNETIC DEFLECTION

PLANE

, 11j0411 --' 1114111111111111111184.

= CENTERLINE

A, B and C = COLOR PHOSPHOR PHOTO- GRAPHIC LIGHT CENTERS

APERTURE MASI(

FACEPLATE

CENTER APERTURE

CENTER TRIO

Fig. 1-Construction of the typical three -gun tube. Note the convergence of the three beams at the central portion of the aperture mask.

.............s \ RADIAL CONVERGING

MAGNET ASSEMBLY

-

' I 5/8

LATERAL - CONVERGING

MAGNET

3 / n

i+

PURIFYING MAGNET fr1\

DEFLECTING YOKE

MAGNETIC -FIELD EQUALIZER ASSEMBLY 92CS-8488RI

Fig. 2-External details of the 21AXP22-A including accessories.

FRONT EDGE OF HOLDER TO BE IN LINE WITH t

FRONT EDGE OF BLUE POLE PIECE

LCFT EDGE or HOLDER PE ON CENTER LINE

Cr PLUE POLE PIECE

CONVERGENCE MAGNET POLE PIECES CENTERED

'OVER KINESCOPE POLE PIECES

LATERAL MAGNET ADJUSTMENT SLEEVE

Fig. 3-Relative positions of the beam controlling components.

Part 2

COLOR

PICTURE TUBES

by SAMUEL L. MARSHALL

A discussion of the construction, operating principles, and external components required for the three -gun color picture tube.

IN THE previous installment, color picture tubes were classified as being

either 1 -gun sequential or 3 -gun instan- taneous display devices. At the present writing the only tube used in commer- cially marketed color TV receivers is the 3 -gun tube. The most modern version of this tube shown in Fig. 2 is the 21AXP22-A.

Coating Faceplate With Phosphor Dots

A clear understanding of the operation of this tube and the manner in which the various external adjustments affect the movement of the various beams goes a long way in helping a serviceman set up the receiver quickly and efficiently. This understanding may be greatly facilitated by a knowledge of how the phosphor dot trios are de- posited on the inner surface of the faceplate.

To this end let us examine Fig. 1

which shows the manner in which the three color beams converge on the aperture mask and fall on the phosphor dots which cover the faceplate.

Without going too much into detail, the procedure by which the red, green, and blue phosphor dots are coated on the inner faceplate of the color tube makes use of an optical device called a "Lighthouse."* This device provides a

light source of high intensity at three distinct optical centers within the neck of the tube. These centers are shown in Fig. 1 as A, B, and C.

Every serviceman knows that the electron beam travels down the center line of the gun in a black and white tube until it enters the yoke. Here it travels a curved path, the point of emergence being dependent on the interplay of the horizontal and vertical magnetic effects. As these two magnetic fields go through their cyclical variations the beam emerging from the yoke traces out a solid angle much like the solid angle developed from the apex of a pyramid. Although the path in the yoke is curved, as stated previously, if we would visualize the point of this apex then we have defined the theoretical center of deflection.

With reference to the 3 -gun picture tube containing an aperture mask, we have the situation where a pinpoint source of light placed at this very same point will produce a light output array identical with the pyramidal electronic beam array just referred to.

*Recent Improvements in the 21AXP22 Color Kinescope, by R. B. James, L. B. Headrick, and r. Evans; RCA Rev. June, 1956. Developments of a 21 -Inch Metal -Envelope Color Kinescope, by H. R. Seelen, H. C. Moody, D. D. Van Ormer, and A. M. Morell; RCA Review, March, 1955.

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The light, on going through the apertures in the mask, falls on a chemical preparation, and excites a colored phosphor deposit on the faceplate. Orig- inally, a coating of a certain colored phosphor mixed with a photoresist material is applied to the faceplate. Follow- ing this, light from one of the optical centers is made to fall on the faceplate through the aperture mask. This "fixes" phosphor dots of a particular color at the points where the light strikes the faceplate. Successively applying phosphor preparations of the other two colors on the faceplate, and rotating the light sources in the Lighthouse around to each optical center in arcs of 120°, 357,- 000 phosphor trios are formed on the faceplate for a total of 1,071,000 phosphor dots.

External Assemblies Required for Beam Control

In view of the foregoing, it is entirely logical to assume that if, in a perfectly constructed tube, the electron beams from the three guns are made to pass through the photographic optical centers on their way to the mask -faceplate assembly, these beams will fall on the exact centers of their assigned phosphor dots.

Unfortunately, tubes manufactured in production are never perfect. In addition, distortion of the beam from its desired path occurs during deflection of the beam for a number of reasons. Some of these will shortly be discussed. As a result, it becomes necessary to resort to various external devices to make cor- rections for these deviations.

The appearance of the 21AXP22-A showing the relative placement of the various external control components is

shown in Fig. 2. Here we observe that in addition to the familiar deflection yoke, four more assemblies are used. These assemblies are labelled:

Lateral Converging Purifying Radial Converging Field Equalizer

No ion trap is needed in this tube because it is aluminized.

The location of the various assemblies relative to the lateral converging magnet (as we proceed from the base of the tube to the faceplate) is fairly well de -


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Al LiCalzi standing next to one of his mobile communication installations in a

crop dusting plane.

ASHORT time ago, I received what I

thought would be a routine and uneventful assignmel t. In line with our established policy of pointing out opportunities for expanding the field of operation of the serviceman beyond the limits set by home radio and TV servicing, our editor lined up a visit to a

Mr. Al LiCalzi in Bridgeton, New Jersey. Mr. LiCalzi, according to information supplied to us by the Com- munications Company (Comco) of Coral Gables, Florida, was just the man we were looking for. His story, we were told, would be helpful in paving the way for others to get into this field. So off I went to Bridgeton.

After a few detours I found the address and now came the first surprise. I had expected to find a service shop in the heart of the town's business section. Here, however, was a beautiful ranch home on the outskirts of the town. Could this be the right place? I rang the doorbell and the very gracious Mrs. LiCalzi answered. In answer to my inquiry, she said that if I followed the road right behind the house down to the airport, I'd probably find Al down there.

"Ah! That sounds better," I thought. "He must have a service shop at this airport, and probably specializes in aircraft radio." Down the road I went, but not very far. The airport was just about 300 yards away. This didn't look like

a commercial airport. It was a little too small. About five or six planes in all. I saw only one man on the field. "Must be the guy I'm looking for," I guessed. Sure enough, it was. A quick introduction and in no time at all we were talking turkey . and using first names.

"Look Al," I said, "I hope I'm in the right place. I came down here for a story on how you got into the Mobile Communication business and pass it on to our readers. What's the set up?" His answers to this and succeeding questions unfolded what was to me an absorbing account of his entry into this field. It was a story also, which should serve to point the way to servicemen who have intentions along these lines.

Al is a flyer. He holds a commercial pilot's license and in addition is a licensed aviation mechanic. One of his activities is that of a "crop -duster." This airport I spoke of was his own and the planes were those he used in crop dusting (except for his own "pleasure" plane). In connection with this work, Al soon found that ground to air communication would be extremely helpful. For one thing, a ground observer in a jeep could direct him to areas he might have missed. For another, he found that he could stay one jump ahead of tricky weather by getting re- ports from a strategically placed co- worker.

HOW ONE MAN GOT STARTED

IN

MOBILE

COMMUNICATIONS

So Al made contact with Communi- cations Company, Inc. and got himself some equipment. Up to this point, though he had a background in radio, his experience with communications equipment was rather limited. By carefully following the directions outlined in Comco's instruction manuals, he successfully installed t h e transmitter - receiver equipment in his "dusting" planes, and in a jeep. He followed this up with another installation in his home so that the little woman could contact him. (I couldn't help wondering if this wasn't a mistake). Another installation was made in the family car just to make sure she could keep tabs on him under any and all conditions. Finally, with the aid of a local F.C.C. licensed technician, the equipment was checked out and legalized.

Now crop dusting, as you can well imagine, is a seasonal occupation, so Al found time on his hands during the offseason periods. He was fascinated by this "mobile" business, and began to study it seriously. Along with this study, he gained experience by working and experimenting with his own equipment.

In talking to Al, you realize that he's a very realistic, and practical person. "Look" he said to me, "The way I see it, one of these days I'll go down for my annual physical check up and they may find that my blood pressure is a little

by Oscar Fisch

too high, or some other such thing. When that happens, I'lll have to stop flying. I might just as well be ready for that day. As long as I get a bang out of this communications stuff, why not go into it?"

As his first step he made arrange- ments with some local radio and TV servicemen, one of whom was the afore- mentioned F.C.C. licensee, to work with him. Next he contacted Comco, and after discussing the situation with them, was granted an agency for his area. Since that time, about a year and a half ago, working during the fall and winter months, Al has sold and installed about $30,000 worth of equipment. He has personally handled a large majority of all the service calls on the equipment. His average installation employs one fixed station and four or five mobile units.

It is of prime importance in an operation such as this to know who your

Fig. 1-Salem County Road Dept. installation. Note the antenna.



potential customers are and how to make your initial contact with them, so I asked Al how he handled this problem. As far as recognizing potential customers was concerned, the answer was emphatically given when Al went through a list of some of his accounts.

One of these for example, was the Salem County Road Department. A photograph showing the antenna of this installation may be seen in Fig. 1. In this case the equipment is used for the direct dispatching of crews and equipment to points where emergency road repairs are required, where snowbound conditions exist, etc. An- other case in point was the installation of equipment for the operator of one of the largest peach and apple orchards in the country. The system easily earns its keep by its use in co-ordinating the picking of the fruit with its delivery to the warehouses. Still another installation involved a road contractor, who used the equipment to insure the delivery of various road mixes at the proper time and at the proper tempera- ture. The list could go on and on. (Our issue of December 1956, lists many other potential users.)

On the matter establishing contact with these potential customers, Al's experience proves what most servicemen know, namely, that a satisfied customer is your best advertisement. He is con- vinced that word of mouth advertising ranks with the best. In addition he uses newspaper and radio advertising, but feels that the newspaper ads are more effective. Finally, direct calls are made where it is felt that a particular company can use the equipment to advantage.

The average serviceman going into mobile communications must reorient himself along financial lines. When he deals with the sale and installation of communications equipment, he will be dealing with much larger sums than those ordinarily involved in radio and TV sales and servicing. A $3,000 installation is commonplace. A $5,000 installation is not at all uncommon. An important implication of these figures is that you don't have to sell a system every day in the week to make a living. If you sold only one a month, your earn- ings would show a very healthy in -


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Fig. 1-Photograph of the Heathkit 25 watt, model W -5M.

KT66

Fig. 2-Partial schematic of the output circuit of the W -5M.

HI-FI IN KIT FORM by Peter Ruggiero

A discussion of how the average service dealer can compete with expensive Hi-Fi showrooms by utilizing kits for the

assembly of the various component units.

WITH the ever widening popular- ity of high fidelity sound systems

in the home, the service dealer throughout the country finds himself in a

unique, if somewhat baffling situation. He wants to sell high fidelity products, but a quick trip to any sound show- room in the area indicates that the set- up, furnishings, variety of stock carried (not to mention the elaborate electronic switching set-ups, number of speaker enclosures on display, etc.) make the prohibitive dollar signs loom before his eyes. He generally has neither the finances nor the space for such a display.

Selling Wired Kits

After much thought on this subject, we decided to launch a rather ambitious project. The Heath Company of Ben- ton Harbor, Michigan, is probably known to you. Did you know that Heathkits of great variety are available in the hi fi field? We found that with just five easily assembled and wired kits, a complete high-fidelity system can be made up and that the resulting system will stand on its own merits both in appearance, performance, and economy. It occurred to us, therefore, that here lies a practical approach to the

service dealer's hi fi problems. A sys-

tem such as the one described was completely wired and installed in barely more than 27 hours for all five components. It is felt that such a system installed in your shop, besides affording you with wonderful sound the whole day through, is bound to engender curi- osity in (and subsequent sales from) your customers. The nice thing about this type of service is the "custom built" approach, which is almost synonymous with hi fi. In such a service, you would not only be assembling components into an integrated system, you could actually sell the fact that each unit was individually built by you for your customer.

Details on The Kits

The first unit we built was the Heath - kit W -5M, a 25 watt basic power amplifier. It took approximately 7 hours of

labor. A photograph of the finished unit is shown in Fig. 1. It's a good idea in building any of these kits to check the parts list printed at the end of the instruction manual. Occasionally an error may take place. Then, too the packaging material is often elaborately inserted to protect the parts and a small part may be inadvertently thrown out with this waste material if you don't check first.

Always follow the assembly instructions in the order in which they are given. As a technical person you may find that the steps are overly detailed but don't rush ahead. These kit manuals are the result of many hours of engineering and trial and error. To put it another way if you follow the schematic or pictorial diagram in a random manner you may successfully complete the kit but if you follow the manual you just can't miss!

A partial schematic of the output cir-



cuit shown in Fig. 2 highlights some of the outstanding design features of this amplifier. Resistors R-1, R-2, R-3 and R-4 comprise the bias balancing system for the push-pull KT -66 output stage. In order for a push-pull circuit to be

fully effective in reducing distortion and providing full power output it is important that each tube of the pair be matched to its mate. While the KT -66

is a carefully engineered tube its trans - conductance may still vary within small limits. Such a condition might result in unequal currents in the output tubes which would in turn mean a small amount of unbalanced dc current flow-

ing through the primary of T-1, the output transformer. This would effec-

tively reduce the primary inductance and increase the distortion at low frequencies where large amounts of clean power are especially needed. By varying resistor R-1, the bias of one tube may be altered slightly with respect to the other, so that both draw equal current. This fact is easily established by connecting a

volt -meter from the cathode end of R-5 to the cathode end of R-6. Adjust R-1 until a zero reading is obtained. R-5 and R-6 must then have equal voltage drops across them (or equal current flowing through them since they are equal in value).

The completed unit should be placed where there is adequate ventila- tion, but need not necessarily be acces- sible to the customer because all necessary control functions are built into its companion piece, the Model WA -P2 Preamplifier.

Building The Preamp

The Model WA -P2 can be wired in about the same time as the amplifier. Here are incorporated all control features such as tone controls, phonograph equalization, volume, signal source selection, (from as many as five sources), as well as pleasing style. You will find, therefore, that the "parts density" may be a little greater than in the amplifier but again, if instructions are followed to the letter, you should encounter no great difficulty.

In our experience with this unit, we found it particularly important to place the parts exactly as shown in the pictorial diagrams and also to use sleeving


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Plug in Speakers for P. A. Systems

A COMPLETELY new approach to Pub- lic Address System installation is

fast becoming standard in this country. Besides the obvious advantages of having anything in the electronics business become more or less standardized, this particular innovation results in a much simpler job for the service dealer who is called upon to do Public Address installations as a regular part of his business.

The Old Approach

If you ever tackled a PA job in the old days, it was a pretty complicated affair. First of all, a determination as to the exact number of speakers and their location was required. Usually, in the interest of less arithmetic and more profits, the tendency was to have each speaker handle as much power as the next, because calculations involving equal impedances or resistances are fairly simple. Thus, if it was decided that four speakers would do the job and that a total of 10 watts of power was required, four speaker impedance matching transformers were selected whose

A description of a system which allows changing the number of speakers and the power delivered to each speaker, without resorting to complicated series parallel matching networks.

combined (parallel) primary impedance would match the 500 ohm output of the power amplifier. In other words, the primary impedance of each matching transformer was selected as 2000 ohms. The trouble came when it was realized that one of the speaker baffles was to be mounted in, say, the small executive office while another one was expected to cover a large, noisy production floor. The office personnel cried for mercy and were nearly deafened whereas the shop men couldn't hear the sys-

tem at all. An easy way out was to pump more power than necessary into each loudspeaker and then put resistive pads at each speaker and use them much as one would use a volume control on a radio. Although this system works it is both wasteful of amplifier

power (and thereby initial cost) and requires the purchase of rather expensive wirewound pads for as many speakers as there are in the system. Another al-

ternative was to get out the old slide rule and go through some arithmetic gymnastics and hope to come up with an answer. Fig. 1 illustrates what a gi- gantic task this would be. It can be seen that since each speaker is required to deliver a different percentage of the total 10 watts put out by the amplifier, each of the four impedances of the matching transformers would have to

be different. To make matters worse, the parallel impedance of all four would still have to be equivalent to 500 ohms. Try solving that by any means other than "trial and error." Actually, it can be done, using simultaneous equations

from your old algebra textbook. But then, assuming you'd gone to all that trouble and installed the system up to the last splice, what happens if your customer, upon hearing the system, likes it so much that he says "Say, could you add another speaker in the rest room? We overlooked that!"? Pull out all the matching transformers, unsolder all the connections, sit down with pen- cil and paper again and so on.

Plug In Speakers

The new method of PA system installation stems from a very common household phenomenon: the power re- ceptacles all over the house through which the utility company supplies 120 volts of ac. No one ever worries about plugging in lamp after appliance after electrical gadget-at least until the circuit fuse is overloaded. We know that the voltage available will always be around 120 volts and that each appliance will take only that amount of power in watts for which it was designed. The reason this is so is that the internal




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SERVICE DEALER 6 ELECTRONIC SERVICING COMPLETE MANUFACTURERS SCHEMATICS. An exclusive service of Cowan Publishing Corp. by special arrangement with John F. Rider, Publisher.

L RED

+235V.

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INTER = LOCK

115V. 60, SUPPLY


RCA CHASSIS KCS 1028 & KCS 102D

Tube No.

VI

FUM29W

Tube TYPO

-r-- E. Plme E. Screen E. Cathode E. Grid

_ ' Nome on `.

Fumioq Candnwn qg pe. Ns ß Memo rename.

N. Volta No. Vau No. Vds N°. Volt.

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14-S-7052 SERIES 14 -S -7052U

RI22' `CONTRAST I CONTROL

I01

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/ / 6DT6' SOUND DET

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OUTPUT

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VIDEO B Ist SYNC. AMP/

ELECTRONIC / MG,, ; 11

SERVICING ScIieinaIic

12 CONV. TRANS

6CB6 R.F AMP

V2 6U8 OSC 6 MIXER

VIOS 6CH8

2nd PIX I.F 8 SYNC OUT

T104 Ist PIO I F TRANS.

T105 2nd P I X

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SIOl / RIIO OFF -ON SWITCH S VOLUME CCMT

TIOI SOTAKEEUND

TRANS.

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t Aóá -, ös TRANS.

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V109 6006

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L108 HOR. FREO ADJ.

LUC/ WIDTH COIL

TIO8 POWER TRANS.

CHASSIS REAR VIEW

CHASSIS REMOVAL AND REPLACEMENT.-Remove the knobs from the side of the receiver.

Remove the three screws from under the front edge of the metal trim. This will allow the metal clip and bezel to be removed.

Take out the screws holding the rear panel and remove the panel. Remove the screw holding the top of the chassis to the handle brace located inside the cabinet at the top.

Unplug the speaker leads. Turn the receiver face downward on a protective cloth or

pad and remove the three screws from the bottom. Slide the case upward off the chassis and kinescope assembly.

Reverse the above procedure to reassemble the chassis and kinescope in the cabinet.


TO REMOVE FRONT WINDOW BEND TABS OUTWARD

báá

G\ .-. REMOVE REAR PANEL AND SCREW HOLDING

CHASSIS TOP

Gip

REMOVE KNOBS

REMOVE THREE BOTTOM CHASSIS SCREWS

REMOVE CLIP AND FRONT BEZEL

CHASSIS REMOVAL


HI FI IN KIT FORM [ from page 23]

in several places not called for in the instructions. This is one place where extra caution pays off in preventing shorts. We found, too, that the control lugs in some cases come very close to the bottom cover screws, and bent them away, accordingly. This unit contains no power supply Itut is connected, by

means of a power cable, to the amplifier discussed previously, from which it

derives necessary filament and B plus voltages. A "hum buck" control insures minimum hum regardless of filament unbalance from one set of tubes to the next. Two cathode follower circuits are employed, for low impedance outputs for tape recording purposes as well as

the main amplifier output. Tone con-

trol circuitry is the standard "losser" type, with continuously variable bass

and treble boost and attenuation. Sep-

arate high frequency "roll -off" and low frequency crossover controls for phono equalization offer a total of 16 combi- nations of equalization characteristics- more than enough to compensate for any recording made or yet to be made. Fig. 3 is a photo of the completed unit. While the basic model does not include a loudness control, provision is made for its inclusion should your customer require this refinement.

Fig. 3-Photograph of completed preamplifier built from a kit.

Tuner Kits The am Tuner, Model BC -1, and

the fm Tuner model FM -3A can be

wired in approximately 7 hours per kit. Since we were dealing with rf and if frequencies in this project, point to point wiring was the rule. The manual stresses keeping leads as short as pos-

sible, but it cannot be overemphasized. The finished units are identical in ap-

pearance. Figure 4 is a photograph of [Continued on page 51]

"99" TOOLS

cover the full range of electronic servicing -3 popular "99" roll kits - the 26 individual "99" tools shown - plus distributor backup stock kits.

New ! No. 99 S.M. Kit - 21 tools

o

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No. 99 -PR Roll Kit - 13 Tools

No. 99 -JR Roll Kit - 11 Tools

SERIES "99" TOOLS -1 No. 99-1 Handle (Regular)

) No. 99-2 Handle (Junior)

tee No. 99.3 Handle (Stubby) 1Z No. 99-6 3/16" Nut Driver

No. 99-7 7/32" Nut Driver N

No. 99-8 1/4' Nut Driver _._._ ..

8 No. 99-9 9/32" Nut Driver

No. 99-10 5/16" Nut Driver

No. 99-11 11/32" ut Driver




No. 99-81 3/16" & 9/32" Slotted, Reversible

No.99-82 #1 & #2 Phillips, Reversible

No. 99-83 3/16" & 9/32" Frearson, Reversible

No. 99-84 3/16" Clutch "G," Reversible

No.99-811 3/16" Slotted

1

No. 99-812 9/32 Slotted

No. 99-821 1 P tillips

No. 99-822 #2 P fillips

No. 99-38 Reamer (1/8"-3/8")

No. 99-39 Reamer

No. 99X10 Extension

Stubby Nut Drivers No. 99-58 No. 99-510 No. 99.512

XCELITE, INCORPORATED ORCHARD PARK, NEW YORK.

In Conad Charles W Pointon ltd., 6 Alcina Avenue, Toronto, Ontario



THE ANSWERMAN

Inquiries Sent To The Answerman Will Be Acknowledged Only

If Accompanied By Radio-TV Service Firm Letterheads.

by ELECTRONIC SERVICING Technical Staff

Dear Sir: I have a customer's TV receiver that

operates well except for one slight difficulty. With variations in the brightness control setting there are changes in the picture height. Is there anything I can do to prevent this condition? The receiver is a Du Mont chassis RA -343.

A. G. Great Neck, Long Island

Regulation of the high voltage can be increased by making the following al- terations which will help prevent vertical size changes with variations in brightness setting. Reduce R253 from 33K to 15K, 1 watt, and R248 from 68K to 18K. Increase R249 from 33K to 120K ohms. These changes in the cathode circuit of the picture tube, as

shown in Fig. 1, will improve the receiver in that better regulation will be obtained.

Mr. Answerman: I have run into several TV receivers

.1,14f - PIX TUBE

R24B 68 K

R249 33K

R253 33K

100K BRIGHTNESS Bt

Fig. 1-Picture tube cathode circuit of DuMont RA -103.

the type with metal cabinets, which result in a shock when the cabinet is touched. I have checked and can not seem to find anything wrong in the set. An example of this condition was found in an Admiral 14YP3 receiver.

H. P. Chicago, Ill.

There are a number of things that can be tried with receivers that exhibit complaints of this type. Perhaps the first is to try reversing the ac line plug in the wall outlet and determine if this helps. In the particular case of the Admiral receiver it is suggested that the parallel resistor -condenser combination (Fig. 2) of the 470K resistor (R601) and the .01 of condenser (C506) be checked to determine that they are properly connected. If resistor R601, connected between the control panel bracket and chassis should be disconnected or broken a static charge will build up on the cabinet. This charge is great enough to cause a shock to be felt when the cabinet is touched. It is likely that these components have become loosened, possibly during servicing of the receiver. In many other types of receivers, the resistor -condenser parallel combination connects between the picture tube mounting bracket and the chassis. If these components are not properly connected static charges can easily accum- ulated on the metal cabinet and produce shocks.

Dear Answerman: I have a GE "M" chassis in which

there is a considerable loss of contrast

//7 VA.C.

S50/ r---1

L__ J

R50/ 470K

C506 .O/ /if

TO CONTROL PANEL BRACKETS, CAB/NET, PICTURE TUBE DAG COATING AND PICTURE TUBE MOUNTING BRACKETS.

Fig. 2-Elements which may be re- sponsible for cabinet shock.

or picture drive. The sound is weak, also. I have checked the tuner, if strip and video detector circuit and have found nothing wrong. Voltages are about normal. Is it possible that the trouble is in an if coil?

S. R. Albany, N.Y.

Of course, it is possible that something is wrong in an if coil or stage. However, it is more likely that the trouble is occurring in the video amplifier section. It is probable that the video amplifier tube (6ÁU8) momentarily shorted in- ternally, as some of them occasionally do, and caused the contrast potentiom- eter to burn; thus increasing its resistance. A partial schematic is shown in Fig. 3. The contrast control, R163, should be checked to make sure it hasn't increased in value. As can be noted, the sound take-off is in the plate circuit of this tube; thus, trouble here will also affect the audio output level. Of course, there is another strong possibility that should be investigated, and that is incorrect negative bias furnished by the

Fig. 3-Partial schematic of video amplifier stage-GE "M" series.

horizontal output stage. Under certain conditions the negative voltage supplied by this stage for video amplifier bias has increased to such an extent that the gain of the video amplifier is reduced. There- fore, it is suggested that the horizontal output stage also be checked in problems related to video amplification. Measure the associated resistors and capacitors in this stage and try another horizontal output tube (12BQ6GA).

PHOTO -ELECTRIC CONTROLS [from page 9]

CATHODE

PHOTO- TUBE

- + + - E2 E1 -

20-25 V. 75-150 V.

D -C - D -C

Fig. 6-Light energized relay.

counting or control purposes. In a "dark energized" phototube cir-

cuit, as shown in Fig. 7, an interruption of the light beam actuates the relay. Initially, light falling on the phototube results in an effective "short" being placed across R3. This short results from the comparatively low resistance of the phototube when it is in a conducting state. Under these conditions the negative bias on the triode is the voltage drop across the portion of Rs between the cathode tap and the point marked -E. This tap is adjusted so that when light falls on the phototube, shorting Rs, the grid bias developed across the tapped portion of R2 is sufficient to cut


Fig. 7-Dark energized relay.



THE RIGHT

move IS TO

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Video grmecgS 5West's DATA SHEETS

Mfr: GE

Card No: GE ST -1

Section Affected: Picture

Symptons: Wiggles in pix, trailing whites.

Cause: Resistor reduced in value.

What To Do: Change: R162 (3.9K).

Chassis No. ST line

Mfr: GE

Card No: GE ST -2

Section Affected: Picture and/or Sound

Chassis No. ST line

Symptoms: Motorboat or flutter in pix and/or sound.

Cause: Open age filter capacitors.

What To Do: Change C150 (.05 µf) or C164 (.15 µf) .

Mfr: GE Chassis No. ST line

Card No: GE ST -3

Section Affected: Sync

Symptoms: Vertical hold range does not center properly.

Reason for Change: Altered circuit constants. (See Note Below) (Production change incorporated in some chassis).

What To Do: Add: 120K resistor in series with vertical

hold control.

G. E.

FROM VIDEO DET,

TO

SYNC CLIPPER

VIO6A 1/2 6ÁU8 VIDEO AMP.

/20,1.4 h 05,u f

390 ji h

R/62

01/

IMEG-

/00

6.2K -6V

2,2 MEG C

V103 6AU6 Isl. IF

1 C/64

PIN NO.6 OF V II4C 1/4 6 T8

A G.C. CLAMP

-,2 V

TUNER A.G.C.

43


G. E. Video Speed Se'ow Syueona DATA SHEETS

HEIGHT CONT.

VIO 8A //2 68L7 VERT osc.

/.8 MEG.

81- 800ST 5/0V

C209

TO P/N e5 OF DAMPER

TO P/N 5 V105

6C86 3rd IF/

TRANS F.

3rd. IF Y150 IO, h

. 22,u h

.0 2,u f

5

390,uh

3.9K TO VID.

AMP. OATH, 100 PIN 6

TO VID.

AMP.

GRID PIN 7

Mfr: GE Chassis No. ST line

Card No: GE ST -4

Section Affected: Raster

Symptoms: Bright vertical bars in raster, poor horizontal linearity, inadequate width.

Cause: Open capacitor

What To Do: Change C209 (40 mf).

1Ifr: GE

Card No: GE ST -5


Symptoms: Inadequate pix height.

Cause: Resistance increases in value.

Chassis No. ST line

What To Do: Change: R209 (1.8 megohm) or R210 (3 meg)

Mfr: GE

Card No: GE ST -6

Section Affected: Sound and pix

Symptoms: No pix; weak sound.

Cause: Defective video detector crystal.

What To Do: Replace: Y150, video detector crystal.

Chassis No. ST line

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Write today for complete information on Aermotor Steel Antenna Tow- ers and an Aermotor Franchise in your territory.

A?

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Dept. ES -5 44


Little Jack Horner Sat in a corner Listening to Hi-Fi

But his speaker was bad And he was quite mad For the music was naught

LOW nor HIGH

. .``? 7

// Now Little Jack Horner Sits in a corner His disposition's much

sweeter

For the music that swells Is as clear as a bell From his Twin -Cone

Norelco Speaker

re/co c i ! Speakers are available in 5", 8" or 12" sizes in standard impedances. Priced from $6.75 to $59.98. Blueprints are available for the do-it-yourself enclosure builder. Norelco Enclosures are available in three sizes, priced from $33.75 to $119.95.

ADD TO ... and improve any sound

system with /lore/co "'FULL RESPONSE SPEAKERS

Write today to Dept. E5 for brochures and prices of these unique speakers.

NORTH AMERICAN PHILIPS CO., INC.

230 Duffy Ave., Hicksville, L.I., N.Y.

Video S s2.4xioie s-ifsile014 DATA SHEETS

Mfr: Philco Chassis No. TV -396

Card No: PH396-I


Symptoms: Pix height adjustment inadequate

Reason for Change: Circuit improvement (Prod change-Run 3)

What To Do: Change: R17 from 470K to 820K.

Mfr: Philco

Card No: PH396-2


Chassis No. TV -396

Symptoms: Vertical sync and agc not performing at optimum.

Reason for Change: Circuit improvement (Prod change-Run 2 t

What To Do: Change: R52 from 220K to 390K. Note: See Cards PH396-3, 4, 5.

Mfr: Philco

Card No: PH396-3


Chassis No. TV -396

Symptoms: Vertical sync and agc not performing at optimum.


What To Do: Add: 10 megohm resistor between position 2

of range switch and the junction of R48 & R54.

Change: R54 from 6.8 meg. to 5.6 meg. Note: See Cards PH396-2, 4, 5.

P H I LCO

e

1/2 /2AU7 VERT. OSC.

470K HE/GH T CONTROL 2.5 MEG.

R/ 7

l/2 6AW8 NOISE

IN VER TER

© / /

§ 2.2 MEG.

TO SYNC SEP

R52

R48 2.2 MEG

//2 6AW8 NO/SE

IN VER TER

TO

A.G.C.

5.6K 47K

/0 MEG.

RADD R 54

220K

© TRONG

RANGE SW/

JTCH / WEAK

45


?/idea greed se u ciru1 Sesieof4 DATA SHEETS

.005,u f

0

//2 6AW8 NO/SE

INVERTER

R50

NORMAL

N_

O 2.2 MEG.

.005,u f 2.2 MEG. TUNER

l,2MEG. R66

//2 6A W8 NO/SE

INVERTER O%f

2

A.G.C.

WEAK

T

I

RANGE SWI TCH

WEAK

Intcd eireal

//2 6AM8 V/F

X-4

TO AUDIO TRA NSF.

T2

46

Mfr: Philco

Card No: PH396-4


Chassis No. TV -396

Symptoms: Vertical sync and age not performing at optimum.


What To Do: Change: R50 from 1 meg to 1.5 meg. Remove: R67 (15 meg). Note: See Cards PH396-2, 3, 5.

Mfr: Philco

Card No: PH396-5


Chassis No. TV -396

Symptoms: Vertical sync and age not performing at optimum.


What To Do: Change: R66 from 5.6 meg to 6.2 meg. Change: R38 from 2.2 meg to 4.7 meg. Note: See Cards PH396-2, 3, 4.

Mfr: Philco Chassis No. TV -396

Card No: PH396-6

Section Affected: Picture

Symptoms: Poor adjacent channel beat attenuation.

Reason for Change: Better circuit operation (Prod change-Run 3)

What To Do: Move: Choke X-4 from chassis onto the

printed circuit board.

MORE INCOME

IN 1957

FOR INDEPENDENT

TV: TECHNICIANS!

ea - oR.

Receiver ... precision -engineered

"for those who want the

finest"... is a non-

competitive line.

GENEROUS COMMISSIONS

THRU EXCLUSIVE

PROFITABLE TV

TECHNICIAN FRANCHISES

NOW AVAILABLE

You can recommend ATR with the pride and assurance of your own know-how and the reputation and craftsmanship Of AMERICAN TELEVISION & RADIO

..**"... as original sets /... as replacement sets /... as the No. 1 set in two -set homes %/. . and for special chassis installations

(without cabinet)

UNEQUALLED IN

PERFORMANCE

UNMATCHED IN QUALITY

CONSTRUCTION

UNSURPASSED IN

BEAUTY

FOR FULL INFORMATION - WRITE TODAY FOR COLORFUL

BROCHURE SHOWING THE NEW LINE OF ATR TV SETS

ALSO MANUFACTURERS OF DC.AC INVERTERS. "A"BATTERY ELIMINA"ORS, AUTO RADIO VIBRATORS

AMERICAN TELEVISION & RADIO Co. Quatcry PToduerl St.rce f93í

SAINT PALL I, MINNESOTA-U. S A


ELECTRONIC / Mß'1 SERVICING sciena is

TRANSISTOR RADIO MODEL GTM 1108A AIRLINE

-ro c C

L 201

6b00O6b6Öó86Öa 6bO00O00006Ö0006bO0O0000006ÖÎîóbO00p0O066ÖüÒ 74 &.fjN

00 C201

1 1

Si- zªY cºi6

R211 1

31

T 202ÿy t¡T¡)rt{ 1 c2O4

2 ST¡i s v"~AJ

T Tr 7 B 4 2N253 R.E221

4i e f -ARC ' OL 7 tt B. ,..,_r -r C t07T It 206

2N¿54 j A Gi `206

RL 2 lj T203 1 L C

llTr

TtO 8210

Pm `tZ4; Ct09

la It tai - IN[ DET.

TZ

'E1t VOLUME CONTROL

T201

I L2O2 i

(ta

Rv+I"C206 Ì E Al.+__i I

,2N252 sv-..

R201 ' 201% 76V 1-

4>,IIttO

C214 lY

'216

C21!

7116

8WI

7R2pIr-ONOFF let 1 C1

EV 2N291

Bottom View of Printed 3oard Showing Top Components Symbolically

OSCILLATOR TRIMMER

SPEAKER BRACKET

7203 ADJUSTMENT \\

VOLUME CONTROL

R212

FILTER - CAPACITOR

ELECTRICAL SPECIFICATIONS Frequency range ........ ............ ...... .....-......... ....540 to 1600 KC Power Output Intermediate Frequency 455 KC Undistorted 035 watts

Maximum 060 watts Transistor Complement

1 2N252 Converter 1 2N253 1st 1F Amp. 1 2N254 2nd IF Amp. 1 1N87G or 1N295 ................ . .... . . -Diode Detector 1 2N238... ............. ........ ... .Audio Driver 1 2N291 Audio Output

L 201 ANT

A

Sn+ c 0 .0047

C 2DI

CONVERTER 2 N252

JUNCTION TRANSISTORS NO. TYPE FUNCTION

2.252 PMP CONVERTER

MSS OM I.F. AMPLIPIFR

TNT. N I.F. AMPLIFIER

ZOOM PMP AUDIO DRIVER

2N2M POP AUOIO OUTPUT

1,31: MTA. MOE DETECTOR

E 66v

R 203 wTR

ORO 00T

T 201 1st 1E TRANS.

OSCILLATOR COIL

Loudspeaker 23/4" PM

Power Supply:

Wards -62-96 -Eveready - 226

RCA -VS -300 Burgess P6

Average current Drain 17 ma.

Ist I AMP. dII 3

2N253 2d

3 ,I G. OPT

T 202 2nd I TRANS.

v 3 V

750

CHASSIS NO. V2278-2

2nd I.E AMP.

2N254

NOTE L DURING SERVICING TOTAL BATTERY CURRENT SHOULD BE METERED. WITH NO SIGNAL AND VOLUME

CONTROL AT MINIMUM TOTAL BATTERY DRAIN APPROX. 18 MA.

2. VOLTAGE MEASUREMENTS MADE WITH A V.T.V.M. FROM POINTS INDICATED TO CND. WITH TUNING CAPACITOR AT MAKIMUM, VOLUME CONTROL AT MINIMUM, BATTERY SOURCE AT 9 VOLTS.

DETECTOR IN295

IN87G

TRANSISTOR

DRIVER 214238

SPEAKER -- DETECTOR

IN295 OR NATO

- EARPHONE JACK.11

wM4

2 AUDIO /

/OUTPUT 214249 OR 257 I

1

POSITIVE

TERMINAL

POSITIVE

BATTERY CONTACT

- AUDIO OUTPUT TRANSFORMER

7204

- CONVERTER -2N2S2

.t- - -- PRINTED BOARD

OSCILLATOR COIL

1,11.1111..

1701 ADJUSTMENT

T252 ADJUSTMENT III I AMP -214251

BATTERY END OF CHASSIS - SPEAKER BRACKET

ASSEMHI+- ---

AUDIO OUTPUT

214291

C 213 5

R 220 470

Top View Parts Layout

I111., w

1.202

-

LOOP ANTENNA 1.201

Battery Installation

- IItLAuvE umler

POSITIVE CONTACT

POSIT VE TERMINAL

NEGArIVE rtkMIV.IL


PHILCO TRANSISTOR RADIO MODEL T7

ELECTRONIC / /%ia.,uei eh'1

SERVICING Sc/ieerta4cd.

L5021L Transistor, 1st audio 34-6001-9

L5028 Transistor, audio output, 2 used, matched pair 34-6005

L5114L Transistor, 1st and 2nd IF amp.

2 used. 34-6000-4

LAI Antenna coil 32-4668

LS1 Speaker 36-1664-2

R23 Volume Control, 15K ohms with on -off switch. 33-5583

T1 Transformer, osc. 32-4669

T2 Transformer, audio input 32-8742

T3 Transformer, audio interstage 32-8741

T4 Transformer. audio output 32-8743

X1 Choke, antenna isola- tion, wound on R1 32-4685

Xtal Crystal diode, type IN527 34-8038

Z1 Transformer, 1st IF 32-4667-2

Z2 Transformer , 2nd IF 32-4667-1

Z3 Transformer, 3rd IF 32-4667

Printed Panel 54-6255

RI 680

.99V

02

CONVERTER L -5113L

ov TI

R4 Y

M IN527 XTAL

.96v

C3

02TM 1

2 R2 820

R3 1000

NW

ZI E----- IF=455KC I I?MMF

l° i61 TCI

47MMF -I( C7

1---1 GI

I

-1 I

3

Í S,ae I- öI F , .j1..o1111, IT. I

/ CIB ( TC2 TC3 46V

j

Is LO. - -_TC4 RIO. L-

005 / MF

R6 / - 4700 /

/ C5 -- OI

/ MF

/ -

/

R7 4700

IST IF AMP

L- 5114 L

R8 18K

04 MF

12MMF

--1( C8

2ND IF AMP

L -5114L

o

© 01 MF

C9 RII I OO K

2 35

Z3 r-_-

RI2 4700

á

2 ND DET L -5113L

1.42V

2.31 V

ÌR13 ¿R14 70 ¿ 82

RIS 82

2

J NOTE IN LATER PRODUCTION, C3 IS .OIMFD,

PART NUMBER 30-1238-6. VOLTAGES MEASURED WITH A V.T.VM., MODEL 6100. A STATION SIGNAL WAS BEING RECEIVED.

/

/

TRANSISTOR SVMBOLr BASING

COLLECTCn _MARKING DOT,

LINE OR KEY

WAS

PRI ST

C7 2NDI.F TRANS.

22

C7

TC 4

C5

RII 2ND IF AMP.

TC 5

CB

3RD I.F..TRANS

2 3

RI4

MIT TER BOTTOM VIEW

Cl2 100 MF

L6

X X

W IIÍÍiIii

® ©OD SEC. ST. P I SEC. FIN.

FIN.

o o N

CII

02 MF

RI6 330

XL8

T2 GREEN

IST I.F TC3 TRANS. OSC.TRANS

IST I.F. TC2 TOI AMP.

C6 R9. 21 R8 RIO C4 TI R6CONY R5 R4 C2 LI

2ND CII DET.

'CRITICAL LEAD DRESS OF GANG GROUND LEAD.

1ST AUDIO

L- 502 IL

L3

r CIO RI6 C9 RI3 LB R15 RI2

C B OSC.

C A

RI7 120

6Vx

L4

AUDIO OUTPUT L-5026 MATCHED PAIR

BLUE

Co ma

2.85V

T3 03

RIB

ém 47

XI ON L6 RI L2 CI4 RI8 R22 RI9 R21 C15 L3

«0 5%

0 2b6Y

óñ R20 o. 1000 om 5%

2.85V

R19 22

P21 150

2A9Y AA^, 3.0V

V

OV

L-5028

AUDIO OUTPUT

PRIVATE LISTENING

JACK

SPEAKER (LSI). OR

PRIVATE LISTENING UNIT HAS A 15 OHM IMPEDANCE

o

///\TO REMOVE SPEAKER REMOVE LEADS FROM LUGS, STRAIGHTEN LUGS,

AND PUSH SPEAKER FREE.

R7 L5 R2 C3 R24 R3 L9 Cl2 T3 R20 XTAL

®) Ln IST AUDIO

L4

2 IJ

RI7

L7

AUDIO OUTPUT

T4

ANT Composite Panel View, Showing Parts Replacement and Tuning Adjustments


TRADE RASHES

[from page 15]

TELERAMA, sponsored by the Council of Radio and

Television Service Associations of Delaware Valley was

held recently at the Ritz -Carlton Hotel in Atlantic City,

New Jersey. Exhibits and demonstrations were shown by

RCA, GE, Raytheon, and many other large firms.

Perma Power is building a new factory at 3100 N.

Elston Avenue, Chicago, Illinois. They anticipate mov-

ing in the immediate future.

The Philco Service Division is seeking local non - retail service shops to handle service calls for Philco merchants who do not have their own service facilities. These shops would make standard charges for service labor and parts. They will cover an area of approximately twenty miles in radius. Those interested may contact Philco Service Headquarters at 2nd and Westmoreland Sts., Philadelphia 40, Pa.

Blonder -Tongue Laboratories has consolidated its engineering, manufacturing and administrative operations in a three level building in Newark, New Jersey. The move enables the company to accelerate research and development work, increase production capacity, and offer more extensive display and dem- onstrator areas for distributors, dealers and industrial accounts.

WORKMAN TV INC., announced a new line of model #GM Miniature Globar Resistors. These resistors

will be available at all electronic parts jobbers in the U.S.,

and Canada. The resistors (1/4" long by 1/16" diameter) are specially designed for modern circuitry where severe

space limitations demand the tiniest of components.

Capable of dissipating one -fifth wait of power continu-

ously, the resistors are very stable in value even at

temperatures as high as 125°C.

Mr. David Wald, president of Dewald Radio Mfg. Corp., manufacturers of radio, television and electronic products announces the appointment of Mr. George H.

Fass as National Domestic Marketing Director. Mr. Fass

was previously connected with Dean Electronics and has

also been a manufacturers' representative. Mr. Seymour

Wald will act as assistant sales manager to Mr. Fass.

Estimated Department of Defense military electronics expenditures in major categories of military functions in-

creased substantially during the second quarter of fiscal

year 1957 over the first quarter, according to a compila-

tion issued. Total expenditures in the first half of the fiscal year 1957 are expected to exceed $1.53 billion.

Comdr. Edmund B. Redington, recently retired Coast Guard electronics expert, has joined RETMA as a staff engineer and liaison member of the

RETMA Engineering Department assigned to the Military Products Division at RETMA headquarters, Executive Vice President James D. Secrest an-

nounced.

Favorable consideration of a proposal that RETMA change its name in recognition of industry trends and that several divisions broaden their product scopes and membership services highlighted the Association's first quarterly meetings. The Board of

Directors referred to the Organization Committee a proposal that RETMA's name be changed by sub-

stituting "Electronics" for the present "Radio Elec-

tronics -Television" in the interest of simplicity and in keeping with the growing diversity of the indus-

try's products.

The electronics industry established a new record during 1956, RETMA revealed in issuing its third annual "Electronics Industry Fact Book." Factory

sales of radios, television, phonographs, military and industrial equipment and components were $5.9 bil-

lion, it was said. When distribution, servicing, and broadcasting revenues are added, the "Fact Book" states, the industry value totals $11.6 billion-twice the value of the billings in 1950 but only half that anticipated by 1965. Consumers enthusisastically en-

dorsed another one of the industry's new products, the transistor radio, by purchasing 986,000 units from manufacturers. Copies of the "Fact Book" are available to non-RETMA members and the general public for 50 cents a copy from RETMA headquarters, 1721 DeSales St., N.W., Washington 6, D. C.

Transistor sales in January and February more than

doubled the number sold in the corresponding period last

year. This upward trend in sales of the semiconductor

device emphasizes the steady growth in both production

and application.

A new 25,000 square foot plant for Rek-O-Kut is

scheduled to go into operation in July, it was an-

nounced by George Silber, President of the com-

pany. The company's new plant will cover an entire city block in Queens, N. Y. The new plant is an

outgrowth of the greatly increased sales volume in

the high fidelity components industry in recent years, according to Silber. It will be one of the most modern in the industry and will enable Rek-O-Kut to substantially increase its production over present facilities in the Long Island City plant.

*BURGESS P57PoktabWe/W.0 BATTERY PROGRAM

STA{, çgLO

BURGESS BATTERIES FOR QUICK SALES-EXTRA PROFITS

¡Noll

e III i

POINT OF SALE

MERCHANDISING AIDS THAT SELL BATTERIES

! BURGESS BATTERIES

8(N EA' NERF

WILL INCREASE

YOUR SALES!

Here's a four -barrelled portable

battery promotion that's bound

to boost your battery profits in

1957. Built around proved sales -

getters, the Burgess program

has everything ... Be sure to

see your Burgess distributor

soon for complete details about

this big new 1957 promotion.

NEW SALES STIMULATING PROMOTION IDEAS!

IT'S ANIMATED! New action display merchandiser at left has colorful animated action. Use in window or on counter. Will display assort ment of most popular Burgess portable types or both batteries and a radio.

Window card In full BA"E J4R1ES `..

enter at right Is Just 1,5 like the one described NER.E ,heve except it Is not all mated.

Full line wire rack at left accommodates complete inventory of

radio batteries. Dur- able, full-time sales- man. Best merchandiser of all!

. BATTERY TESTERS OTHER MOTION DISPLAYS

,.a11116ESS e.TlGla

A new dual-purpose wall chart or

counter easel contains Portable

Radio Picture Chart, Replacement

Guide Index end Cross Reference

Chart. Ask your jobber. It is FREE!

WINDOW STREAMER

A big, bright full -color window

banner that's double -designed ta

stop the customer and tie in with the other Burgess sales aids for maximum impact in the store.

FREE!

RETAIL PRICE CARD l --s

Furnishes Burgess portable "I

battery numbers, voltages 14.

and up-to-date retail prices

in "easy to select" form. I,

FREE!

REPLACEMENT BATTERY STICKER

Provides ample space for replacement battery number and dealer im- print - a sure repeat business

getter! FREE!

1 : . .

BURGESS BATTERIES BURGESS BATTERY COMPANY FREEPORT ILLINOIS



PHOTO -ELECTRIC CONTROLS [from page 42]

off the triode, and under these conditions no current flows through the relay.

Interruption of the light beam re- moves the short across R3. Now R3 in series with R1 is connected across the B plus supply with the junction of R1

and Rs positive with respect to -E. Thus, we have two opposing voltages being applied between the triode grid and its cathode; the positive voltage drop between the grid end of R3 and

-E, and the positive voltage drop between the cathode end of the tapped portion of Rs and -E. The net result is a reduction in bias between grid and cathode. This causes plate current to flow; thereby actuating the relay and closing the contacts across "A."

A dc power source is not required, ac serving as well. The amplifier tube acts as a rectifier to the tube conducting when the place is positive. 1

How to increase your income

e Two-way radio e Microwave relay e Home electronics e Industrial electronics e Radar Find out how you can increase your monthly income by in-

stalling and maintaining the types of electronic devices listed

above.

Anyone now in the radio -television servicing field can qualify.

A Commercial FCC license will open the door to new profit

areas ... and the work is interesting.

Don't limit yourself to receiver servicing. Prepare yourself to

handle the more profitable jobs in electronics. Fill out the

coupon below and mail it TODAY. The information is free!

CLEVELAND INSTITUTE OF RADIO ELECTRONICS Desk SD -S, 4900 Euclid Bldg., Cleveland 3, Ohio Please rush the Free booklets to

Norne

Address

City

Member National Home Study Council

MIO

SELF SERVICE

TUBE TESTERS

DURING the last year, there has been an intense interest on the part of

service dealers in the operation of self service tube testers. The questions below are a composite of the many inquiries received from service technicians and dealers by Calex Mfg. Inc., major manufacturer of these testers.

Can money be made with self service testers?

Yes. The average drug store or other such location sells about $40 worth of tubes per week at list price (some sell over $100). After the store takes its commission of 25% to 30% and after you figure the cost of the tubes, that still leaves about $12 per week profit on each machine.

What about all the sets that cannot be fixed by buying a tube?

Those customers who fail to repair their set at the self service checker, are prepared for a major shop job. But, let's face it, 80% of the TV troubles can be repaired by tube replacement. And that doesn't count the battery operated radios, car radios, etc. When a

customer fixes his own set he brags about it and introduces his neighbors to the self service tester.

How can the service dealer get into this business?

Many dealers have already started. There is terrific interest on the part of many more. For example, more than 1,000 service dealers wrote in for a manual on "How To Run A Tubetest- ing Route" in reply to a recent ad by the Calex Manufacturing Inc. of Sea- ford, N. Y. The best way for a service dealer to start, is to stop mulling it over and place a tester in his own shop, and in as many local drugstores as he feels he can cover. A little experience in his own shop, with the self service trade, is worth more than all the discussion that has been made on the subject.

Can 1 get financial assistance if I want to expand rapidly?

The tester manufacturer can help you somewhat in extending terms, and you should see your tube jobber who is just as anxious as you are to have you expand your tube business.

How do I handle the details of this new business?

The tester manufacturer gives you all the dope, including catalogue sheets, consignment forms, window banners, inventory forms, etc.

How often are the stores visited for refilling stock?

Stores that sell over $75 per week are visited once per week. Stores that sell around $40 per week, once every two weeks, and stores below $30 per week, once every three weeks. On the average, once every two weeks.

Will it hurt my service business?

No, it will help. You will sell many times more tubes than you now do; and after all, that is the profit making part of your business. Also some service dealers have placed signs on their drug- store testers advising the customer that the service dealer backs up the tubes sold. Some offer credit on the tube toward a service call, if it does not repair the set.

Is it too late to start now?

If your area does not have a tester in the large volume drug stores and supermarkets, you are fortunate since you can get in on the ground floor. If the better spots are already covered in your area, you can still get in the picture; new shopping areas, normal turnover, some stores want better testers, and, believe it or not some drug stores have refused testers because they did not want to infringe on their local service shop's business.



HI FI IN KIT FORM

[from page 41]

the FM tuner. What's more, the cabinet size is equal to that of the preamplifier just discussed. Thus, all the units can be stacked or mounted side by side on a book -shelf, etc. The if transformers and the discriminator transformer (in the case of the FM tuner) are pre - aligned at Heath, but it is usually pos-

sible, by realignment, to improve performance and calibration considerably. Since, unlike the home builder, you are

in the fortunate position of having the necessary generators and meters to per-

form this alignment in the shop, you may reasonably expect superior results.

Fig. 4 - Photograph of the com-

pleted FM tuner built from a kit.

A circuit usually not encountered in table model radios is shown in Fig. 5.

It is a part of the schematic of the am tuner and is known as a "whistle filter." In AM reception, if two adjacent channels are separated by only 10kc, their difference frequency will beat, through the normal heterodyning process and produce a sharp, annoying whistle. The reason this is not apparent in smaller receivers of the non -hi-fi variety is that the audio response of such receivers sel-

dom extends to 10,000 cycles in the first place, so that this effect is not apparent. In hi fi equipment, where amplifiers are

Ba -

47K

(TUNED FOR MIN. /OKC OUTPUT)

LI

TO OUTPUT

CATHODE CI C2 FOLLOWER (t l

.002 I .002

RI 82K

Fig. 5-Schematic showing whistle

Alter used in AM tuner.

flat to at least 20,000 cycles, the whistle

is quite pronounced, particularly at the

high end of the dial, where stations are

usually crowded close to one another.

The circuit, consisting of L-1, C-1, C-2

and R-1 is called a bridged T filter and is set to provide a sharp notch in the

frequency response at 10,000 cycles. Be-

cause the filter action is so sharp, slight

misadjustment of L-1 will render it in-

effective. If the circuit were tuned to

11 kc, the response at 10 kc would be

practically flat, and no attenuation of the

whistle would take place. It is suggested,

therefore, that in tuning the whistle

filter, an audio oscillator be used, care-

fully set at 10 kc. This method is de-

scribed in the manual along with several

other alternatives which we found to be

not as effective. The FM tuner, while somewhat more

"open" from the wiring aspect, requires even more care than the AM tuner. Here we are dealing with a band of

frequencies between 88 and 108 mc (and an if of 10.7 mc, which is quite "hot"

all by itself). Skill in soldering will

really make a difference, for a cold

solder joint in a by-pass disc capacitor

can cause oscillation and regeneration which is very difficult to track down once the set is completed. Follow the

component and lead dress recommended in the instruction booklet and align the

completed receiver with instruments rather than by ear. You will find that the sensitivity is at least as good as that specified by Heath and generally much

better.

System Assembly

Having completed the electronic as-

sembly of the units outlined, intercon-

nections are made by means of shielded

phono -cable equipped with standard RETMA phono plugs at each end. That is, the am tuner, the fm tuner and a

record changer are hooked into the ap-

propiate inputs of the WA -P2 preampli-

fier, which serves as the control center

of the system. The amplifier output of

the preamp is connected to the basic

amplifier (W -5M) input by means of a

similar cable. Connection from the am-

plifier to the speaker system can be

made using virtually any twin lead

cable-even TV 300 ohm twin -lead

works fine.

Loudspeaker Systems

Speaker enclosure and system kits,

available as models SS -1 and SS -1B, re-

quire neither the artistry of a cabinet maker nor the skill of a carpenter. All

the parts are prefabricated and what's more, the necessary crossover capacitors

and inductors are included, for a true

4 -way speaker system. You may be

able to work with a qualified cabinet finisher to obtain professional results.

Far be it from us to set your labor rates, but you can readily see that with a modest investment for the electronic elements of the system and 27/ hours of labor, plenty of room is left for sub- stantial profits, while at the same time providing your customer with an excel-

lent hi fi system at far less than he would have to pay for finished units available today. Ea

Sell More Antenna Replacements with the new

CHANNEL MASTER® TV Antenna Check -Up Kit Who says antenna sales must slow down during the Spring and Summer months? Channel Master offers you a brand new concept in antenna merchandising that's sure to perk up your antenna business. It's the nationally advertised "TV Antenna Check -Up Kit" - designed to build store traffic for you by making present TV owners aware of their faulty antenna installations.

CALL YOUR CHANNEL MASTER DISTRIBU- TOR NOW ! He also has Posters, Streamers, and Newspaper Mats to help you merchandise the "TV Antenna Check -Up Kit."

NEIAW4f7fi'YA ESE A moo. nil tM-d Om.. C. . Rag. U.S. Pa.. Wilco and Canado

R

This 3 -piece consumer literature kit includes:

16 -page illustrated booklet "Better Pictures On Your TV Set" 10 -point check-up folder "Spotting Antenna Trouble" Literature about the TW Antenna

Use these kits as free giveaways or

mailing pieces to build store traffic.

Tie -In with Channel Master's

High -Powered

National Advertising in

America's Leading Magazines

-1P()Sir

lE o ELLENVILLE, NEW YORK



FREEby subscribing to ELECTRONIC SERVICING

FREE now on this special order form you will get FREE!

96 PAGE TV SCHEMATIC PACKET wpm

,¿._- ..- P S O' Vv ?3f11 l . -.

EMMA,.

You get 16 more pages of new schematics in every issue

Every issue of ELECTRONIC SERVICING now carries 16 pages of new TV schematics. Many of these will not be available from any other source for months. Each schematic is crystal clear and accurate - (prepared by John F. Rider) - ready for immediate use and easy filing for future reference. The schematics include Alignment Data, Wave- forms, Operating Voltages, Tube Location Guide, Essential Parts Numbers, etc.

In addition you'll get 4 more new pages of VIDEO SPEED SERVICING SYSTEMS Data Sheets in each issue

HURRY ... HURRY ... This Special Offer Good Only While The Present Supply of Schematic Pockets Lost

--TEAR OFF - MAIL TODAY - GET YOUR FREE 96 -PAGE TV SCHEMATIC PACKET FREE --- ELECTRONIC SERVICING, 300 W. 43rd St., New York 36, N. Y.

I accept your FREE OFFER . . . a complete 96 PAGE TV SCHEMATIC PACKET together with a 2 -year subscription to Electronic Servicing. Here is my $5.00

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Radio-TV Service Organization D Employee

Retail Store having Service Department D Service Mgr.

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Firm having electronic equipment which I service and maintain

If some other type of company describe

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(Please Print)

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Address

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Name of firm

Firm's business address

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MAGNETIC FLUX

92C5-6490

COLOR PICTURE TUBE [from page 19]

EXTERNAL MAGNET

NTERNAL POLE PIECE

i -DIRECTION OF BEAM MOVEMENT

Fig. 4-Radial control of beam by radial converging magnets.

fined from the figure. To establish the location of the lateral converging magnet relative to the tube itself we refer to Fig. 3 which shows the left edge of the magnet holder as being positioned directly above the center line of the blue pole pieces. In this figure a fixed magnet is used; however later designs are making use of an electromagnet so that the adjustment may be made from the front of the receiver.

Radial and Lateral Static Convergence Magnets

One of the items for which the tube must be corrected is mechanical mis- alignment of the three electron guns. It will be observed from Fig. 1 that these guns are slightly tilted (approximately 1°) toward the tube's axis. This tilt aids in converging the three beams at the center aperture of the mask. If any gun is originally misaligned its corresponding beam will strike the mask or enter a different aperture, thereby lighting up a phosphor of an adjacent trio.

The geometric phosphor design is

such that as the beam goes through successive apertures it strikes successive trios, and lands on phosphors of the same color only. In this case the beam may be converged again on its correct phosphor trio by adjustment of the static radial and lateral converging magnets shown in Fig. 2.

A more detailed view of the operation of these magnets is shown in Figs. 4

and 5. Here we show electromagnetic control of the static convergence functions; although pm components may be used as well. Radial converging magnets as shown in Fig. 4 provide

DIRECTION OF BEAM MOVEMENT

POLLEE PIECEeCE S 75" APPROX.

EXTERNAL MAGNET

DIRECTION OF BEAM MOVEMENT

Fig. 5-Lateral magnet controls horizontal motion of the blue beam.

radial control of the beams in the manner shown by the arrows in the figure; radial, in this case, referring to a direction along a radius through the tube's axis. A lateral magnet provides horizontal control (see Fig. 5) of the blue beam with respect to the red and green beams, the latter two being made to move in a direction opposite to the blue beam, as shown by the arrows in this figure.**

POINT I POINT I . .o . AO , Pow TI ©

l.t. P/.(3

LATERAL

DISPLACEMENT

RADIAL DISPLACEMENT

Fig. 6-Effect of static convergence adjustments on beam motion.

It is common practice, as shown in Fig. 1, to mount the 21AXP22-A so that the blue gun is above the red and green guns. Thus, viewed from the front, the blue beam appears below the red and green beams as in Fig. 6.

Static convergence adjustments are illustrated in this figure. In 6A we show radial adjustment of the three beams to produce convergence at point 1. In Fig. 6B however, we find that straight radial adjustment will not

**Earlier blue lateral controls provide motion of only the blue beam relative to fixed red and green beams.



produce convergence, the blue beam being somewhat to the right of point 1.

Here it becomes necessary to apply additional lateral motion of the blue beam bringing it over to the left with respect to the red and green beams. This involves simultaneous motion of the red and green beams in one direction and the blue beams in the opposite direction, and is effected by means of a lateral convergence magnet. The ob- jective is to position the blue beam laterally between the red and green beams, as in Fig. 6C; following this the beams may be converged by radial adjustments.

To provide better control of the beams, and to minimize interaction of the static convergence fields on each other, polepieces are mounted directly on the tube guns as shown in Figs. 4

and S. These polepieces are also used to identify the different color guns and to establish the correct locations of the convergence electromagnets on the neck of the tube. Thus, in Fig. 5, we observe that the lateral electromagnet is

mounted so that its center line is 75°

displaced from the center line of the lateral pole piece. Note the opposing fields produced by the lateral electromagnets as shown by arrows for the blue gun and for the red and green guns.

[To be continued]

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pp xis article concerns itself with odd I problems originating in the damping circuit of the horizontal amplifier. To solve problems of this nature a thorough knowledge of the receiver circuitry is extremely helpful.

RCA KCS 68C

The receiver was turned on and it vas observed that the picture was hook-

ing at the top and bending intermit- tently. It seemed to be an agc problem as the contrast could not be lowered

to a point we could consider normal. The agc control was adjusted, but did not lower the contrast sufficiently to eliminate the hooking. The tubes re-

ceiving agc voltage were then replaced individually, but had no effect. (rf amp. 6BQ7, 1st and 2nd video if 6AU6 and 6CB6, the first audio 6AV6, agc amplifier 6CB6.) Voltage checks were then made at the screen, cathode and grid of

the agc amplifier, V 111, 6CB6. All were found to be approximately correct. The voltage (agc voltage) at the plate measured approximately one volt negative

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instead of about 5 or 6 volts negative. The schematic of this portion of the receiver, Fig. 1, was next studied. This receiver uses a variation of the keyed agc system. A composite video signal is fed from the 6AG7 plate circuit to the grid of V 113, 6SN7, sync separator. This tube conducts only on sync pulse tips because of the high bias on its cathode. On conduction the positive sync pulses are fed from the cathode of the sync separator V 113 to the grid of the agc amplifier. Simultaneously a pulse is fed from the horizontal output circuit through capacitor C177 to the plate of V 111. The agc tube is cut off and will only conduct on the simultaneous positive voltages arriving at its grid and plate. The plate current produces a voltage drop across R144, 56 k. This drop provides the agc voltage. The sync pulse varies in size in accordance with the video signal. The greater the signal strength the greater the sync pulse voltage, and therefore the greater the negative agc voltage. Knowing these facts, the agc circuitry was examined. Capacitors C177 and C176, the agc pulse transfer condensers were checked for leakage but were found to have none. At this point we noticed

RF 6807

/sT. VIDEO IF 6AU6

AGC

WORK Unusual Service Problems

And Their Solutions

by PAUL GOLDBERG

Service Manager

that the width of the picture just man- aged to fill the screen. We tried to increase the width by adjusting the width and horizontal linearity controls, but could not increase the width at all. L107, the horizontal linearity coil was examined for burned turns, but was found to be perfect.

On occasion, L107 develops shorted turns which cause an insufficient width condition. We were obviously working on the assumption that the insufficient width and insufficient agc voltage had a

common cause. The yoke was next un- plugged and a new yoke was tried. (This yoke is of the plug-in variety). Immediately the width spread out and the hooking disappeared. As there was no trapezoidal effect, the yoke was ex -

2ND. VIDEO I F 6C8 6

ls r. AUDIO 6AV6

Z Z 0 §R144

56K

AGC CONI.

VIII 6C86 AG

AMP.

#135V t2/8 V

ÌÌ

V/DEO AMP. 6AG7

0J-

0

HOR.LIN.

f /55 V

y'373 V

TO HOR. SYNC. AMP.

C/77 C176 39 Z /00l uuF .u.uF jC/99 , _ I - I

I

IC 20 I (1)

I = I

I - IW I

1 J I

I O

'' IC 193 L/07 1270,

IL/uF DEFECTIVE -+-

V/13 6SN7

SYNC. SER

Fig. 1-Partial schematic of the RCA KCS -68C, showing

VERT. DEFL.

CO /L S

the keyed agc circuit.



BENCH This Month's Problem:

Analysis of troubles

arising in the damper

circuit.

amined for a defective component. Ca- pacitors C193, C205, and C199 were checked. C193, 270 mmf, was found to be leaking. Its resistance measured one meg. Therefore, instead of replacing the entire yoke, just this condenser was replaced. The original yoke was again installed and the receiver functioned properly.

The shunt resistance created by the defective C193 lowered the agc pulse voltage to such a point that a slight over- load occurred. This caused insufficient width and the hooking and bending of the picture.

DUMONT RA - 130A

The receiver was turned on and it was noted that the raster's width was short about three inches on each side. There

HOR. OUTPUT 6866'S I--_

6SN7 HOR. OSC.

DAMPERS 6W4'9

8 "'-

Fig. 2-Partial schematic of horizontal output and damper in DuMont chassis RA 130A

DEFECTIVE

was also some blooming when the brightness was increased. The horizontal linearity of the raster was satisfactory, however. Fig. 2 illustrates the portion of the schematic involved. The two 6W4's were replaced, then the two 6BG6's, but they had no effect. The 6SN7 horizontal oscillator was also replaced, but had no effect. Adjusting the drive and width controls didn't increase the width either. The schematic revealed that the secondary winding of the flyback transformer T206 was es- sentially in series with the primary, thus forming an auto -transformer circuit. It was also observed that a series shunt type size control was used across the secondary of T206. The portion of the size control's inductance between termi- nals 1 and 3 was in series with the deflection yoke, whereas that portion between 2 and 3 was in parallel with the yoke. This horizontal size control pre- sents a constant load to the secondary and permits a variation of size without affecting linearity. R373 is the damping resistor across the series portion of the size control to prevent ringing. Resis- tors R360, R361, R362, R363, R364 (each 10 k) provide damping for the yoke. The extra 6BG6 and 6W4 are needed because of the high current involved.

/X2

R343 470K EACH-'

760 _LIE Fill

HOR. SIZE CONT.

IX R3 42

R344 )4 R345

- TO

373 VERT OUT

1

3 C285 .519 lO K

EACH

R360

R36/

1

T R362

R363 R364

Keeping these facts in mind, and also that the horizontal linearity was satisfactory, we eliminated the possibility of defective condensers in the 6BG6 circuitry. The condensers across the hori- ontal linearity coil would also cause a

horizontal linearity problem. C303, 160

mmf, was checked for leakage and found to be functioning properly. The high voltage resistors R342, R343, R344,

R345 were resistance checked and found to be O.K. Occasionally these resistors will decrease in value to such an extent that the width will be affected severely

As there were no white vertical lines nor a trapezoidal effect, the yoke was eliminated as a possible cause of our trouble. The yoke damping resistors R360, R361,

R362, R363 and R364 were resistance checked and found to measure a total of

6.5 K instead of 50 K. Here was our trouble. Capacitor C285, .5mf, was next measured for possible leakage, but it checked good. Instead of installing five

10 K resistors at two watts each, which was called for, we installed two 25 K at 10 watts each. Thus, we have a 20

watt damping resistance.

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ASSOCIATION NEWS by Samuel L. Marshall

National Alliance of Television and Electronic Service Associations (NATESA)

The annual Radio -TV -Electronic Service Industry Convention and Institutes will take place at the Chi- cago Sheraton Hotel, 505 N. Michigan Ave., August 16th, 17th, 18th, 1957. This affair has been sponsored over the last seven years by NATESA. This year, three separate local affiliates, Will County Television & Radio Service of Joliet, Milwaukee Association of Radio & Television Service (MARTS) of Milwaukee, Television Electronic Service Association (TESA) Chicagoland will be co -hosts.

Directors and Alternates representing affiliated lo- cals, from points as far separated as Fairbanks, Alaska; Seattle, Washington; Miami, Florida; Boston, Massa- chusetts; San Francisco, California; Canada; Vene- zuela; Panama Canal Zone, will conduct official business and plan the future of the independent service industry. Non-members are invited to participate.

Three very special Institutes, one each on business, technical and association activities will be conducted by top level experts from various phases of the over-all industry. Breakfasts, luncheons, cocktail parties, ban- quets, floor shows and other special activities will glamorize the three day affair.

Empire State Federation of Electronic Technicians Associations (ESFETA)

Gordon Vrooman, of Syracuse, and Syracuse TV Technicians Association, was reelected President of the Empire State Federation of Electronic Technicians As- sociations at the 8th annual meeting held in the Hotel Syracuse. Robert Larsen, of Valley Stream, and the Radio Television Guild of L. I., was elected Vice Presi- dent. George Carlson of Jamestown, and Electronic Technicians Association of Jamestown, was elected Secretary, P. P. "Pat" Pratt, of Buffalo, and Television Electronic Service Association of Western N. Y., received a unanimous vote for reelection as Treasurer. The Sergeant at Arms position went to Thomas Salis- bury of Rome, and the Mohawk Valley TV Techni- cians Guild.

California State Electronics Association (CSEA)

A campaign intended to familiarize state senators with the significance of the state licensing bill, and plans for the Second Annual Convention and installa-

tion highlighted CSEA's Board of Directors meeting in Fresno.

H. Lawrence Schmitt, President of CSEA, said that a report by legal counsel Anthony J. Anastasi to directors advised the bill still is in committee, normal channel en route to the Senate floor. Directors and Board of Delegates were enlisted to work with their local associations in setting up the local level among their senators.

Schmitt said Jim Wakefield, Convention Committee chairman, reported manufacturers' regional representa- tives were giving the convention solid support. He reported a series of discussions and panels would be offered on such topics as business operations, servicing, cost accounting, customer relations and accounts re- ceivable.

TESA, S.W. Mo.

TESA, S.W. Mo. met at Davison's TV in Buffalo. An interesting discussion of tube replacements in

warranty with nearly everyone getting into the act provided some real down to earth assistance and information on the subject. A new application form was atuhorized to be printed after being approved in committee.

All the names of shops in attendance were placed in a hat for purpose of choosing the next meeting place. A-1 TV in Buffalo was the place designated by the drawing. All technicians and shop owners are invited to attend. We hope to have a discussion on "How to price TV Service," led by Carrol King.

Long Island Guild

Chris Stratigos, long active in Guild affairs, has been elected to the presidency of the Long Island Radio and Television Guild. At a regular scheduled meeting, the Guild, while endorsing the principle of licensing, with- held full support pending three considerations which TV repairmen consider as essential for effective licensing. These are: 1) That the television service industry be assured of

full representation in the preparation of any licensing bill within the state of New York.

2) That an active member of the television service industry be a part of any permanent commission that might be established to supervise licensing.

3) That before any local licensing bill is passed an attempt be made to obtain state or at least county wide licensing.



above. These horizontal antenna signals add to or subtract from the vertical - antenna signal voltages, depending upon their phase, or time of arrival. This results in bearing errors or, in many instances, the absolute obliteration of the null. Since signals arriving from above are usually experienced only at high frequencies, or at night at relatively great distances on the low radio - beacon frequencies, this defect inherent to the loop antenna over the Adcock or vertical antenna is accepted as a

necessary evil. It is important however, that the defect be recognized and ex-

plained to the customer in order to avoid subsequent dissatisfaction on his part.

In directive antennas it is important to note that anything which might arti- ficially or extraneously induce a higher or lower voltage in one antenna over that of the other would give the effect of shifting the null position. Hence, it is very important that such systems be

accurately balanced. In loop antennas,

ANT.

LESS THAN 180°

(a)

_NULL _ LINE

\ i

SIGNAL LOBES

MOBILE COMMUNICATIONS [from

crease. It may take a little time to close a deal. Time may be lost in following blind leads. But the large dollar value of the one you do sell provides an ample margin of profit.

Closely tied to this financial reorienta- tion, there must be a positive and dy-

namic approach to the selling aspect of the operation. Too many servicemen, unfortunately, sell service only (plus a

few replacement parts). Mr. LiCalzi has emphasized selling and has found

page 21]

it to be a rewarding and satisfying ex-

perience. He enjoys the selling aspect

every bit as much, and perhaps even more than the installation and servicing.

Statistics released by the F.C.C. show a fantastic rise in the use of mobile

communication equipment each year. We've done our best to show how one man is taking advantage of the oppor-

tunities which exist. The important question, however, is-"What are YOU going to do about it?" al II

MARINE RADIO DIRECTION FINDERS [from page 13]

only the inductive component of incoming waves must induce the signal voltage. Signal induced capacitively on one side of the loop or the other from the electro -static component of the incoming wave would unbalance the volt-

age difference, giving rise to a shifting of the null.

The practical result of this antenna effect is illustrated by Fig. 3.. In this case, an outside antenna is connected to

the receiver input. The effective time of arrival of the electro -statically induced signal current is such that it tends to

add to the voltage on one side of the circuit and subtract from that on the other. This distorts the figure -of -eight response pattern of the system, and one lobe is, therefore, larger than the other. With only a small amount of this pick- up, the nulls are shifted toward one another, as shown in Fig. 3a. A greater amount of signal input from the antenna effect results in the even more distorted null positions of Fig. 3b.

signal input from the external When

MUCH LESS THAN 180°

(b)

SINGLE IMPERFECT

NULL \ ONE

BROAD LOBE

(C)

Fig. 3-Different lobe patterns produced by connecting an external antenna to

the receiver, in addition to the loop: (a) slight distortion with weak additional

signal; (b) greater distortion with stronger signal; (c) pattern loop and external

antenna signals are equal.

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antenna equals loop signal, the smaller of the two lobes is completely removed, resulting in the cardioid response pattern of Fig. k. When this antenna effect occurs accidentally from the pres- ence of undesired conductive elements capacitively coupled to the receiver input, severe bearing inaccuracies result.

In some radio direction finders, the antenna effect is put to practical use through deliberate connection of an external antenna to obtain the uni -directional cardioid pattern. In the case of confusion as to which of the two pos-

sible reciprocal bearings is the correct one, switching in this external antenna will give the loop a broad uni -directional response pattern by which the correct direction may be "sensed." Since, in boat navigation, the pilot is seldom in a position where he does not know which of the two reciprocal bearings is correct, this sense feature has small value, and for this reason, many modern direction finders have no such provision.

A number of different input circuits are used in marine direction finders.

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Fig. 4a shows the balanced input scheme which was at one time most common, and is still found in larger equipments. This circuit is capable of the greatest accuracy and the balance control can be manipulated to compensate for unwanted antenna effect due to capacitance.

Simple one -band direction finders designed for reception of marine beacons are built with a high -impedance loop, the inductance of which is designed to tune directly across the beacon band. However, it is desirable today that a radio direction finder be capable of receiving signals not only on the low - frequency band, but also on the broadcast and the marine radiotelephone frequencies. This is too great a frequency spread for the loop to cover directly, so circuits such as that shown in Fig. 4b are used. For low -frequency reception, an extra capacitor is shunted across the loop to lower its resonant frequency. Inductance of the loop is such that it will resonate directly across the broadcast band. On the high -frequency, or marine radiotelephone band, an inductance added in parallel with the loop lowers the effective inductance of the circuit, permitting it to tune across the high -frequency channel. An- other system that permits covering a wide band of frequencies is the use of a low -impedance loop which is small enough to tune directly across the high -

LOOP

(b)

LOADING COIL

TO

BALANCED RECEIVER

INPUT

wá

g2 W mW tiOW tr

LOOP

TO BALANCED RECEIVER INPUT

(c) (d)

Fig. 4-Types of input circuits used

with direction finders.

frequency band. For the lower frequencies, loop circuit resonance is

brought about by the addition, inside the set, of a loading inductance (Fig. 4c. Having only a small proportion of turns in the loop antenna, this sys-

tem is least sensitive for general use. Not all radio direction -finder loop

circuits, by any means, are balanced. Many direction finders have the circuit shown in Fig. 4d. This circuit has the advantage of simplicity and sensitivity. However, it must be noted that for accurate bearings, circuit resonance is essential, so that inductive and capacitive reactances cancel. When the loop is off -resonance on the low -frequency side, there will be a large lag- ging current, and off -resonance on the high -frequency side, a leading current. Naturally, the reactive voltages, having different phasing from those developed across the desired resistive element of the circuit, add to and subtract from normal loop signal response. An off - tune unbalanced loop will thus act as if an outside antenna were connected.

[To be continued]

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1951 WESTINGHOUSE TV

Chairside Remote Control

The Model H984 Chairside Remote Control Unit, shown in Fig. 6, provides full control over channel selection, fine tuning and volume from any place in the room. This unit is an optional ac-

cessory and is installed merely by removing the two jumpers from the fe-

male socket on the rear apron of the receiver and inserting the male plug from the remote unit cable into the socket.

Remote channel selection is accomplished with the Remote unit as with the Power Tuning Bar, simply by

pressing the button and releasing it. With the button depressed, switch 1

(Fig. 2) is closed and current is al-

lowed to flow through the motor from the ac line, thus activating the Power Tuning. The operation from then on is as described previously.

Remote Fine Tuning is performed by a germanium crystal diode acting as a

variable capacitive reactance across the local oscillator tank circuit in the rf tuner.

Servicing The Remote Control Unit

And Power Tuning

The troubles listed here would most

MOTOR DRIVE ASS'Y

LEVER SPRING

NYLON GROMMET

RE TUNER 470V008M03

[From page 11 ]

likely have their causes external to the system. The system, however, can be

quickly and easily serviced. 1. Dirty relay contacts.

All switch and control contacts may be cleaned with a contact cleaner. If spring contacts should become carbonized or burned, re-

surface the contact with crocus cloth. Defective cable. The cable should be positioned away from areas of heavy traffic and under normal operating conditions should require no main- tainance. If the cable becomes damaged check each individual wire for continuity and for any possible short between wires.

3. Defective Motor. To check the motor, turn the set off and check for continuity with an ohmmeter or, with power applied, check the motor leads for proper supply voltage. To restore normal operation in case of increased torque due to accumulation of household dust, heat and low line voltage, the mechanism should be cleaned and the tuner detent lubricated.

4. Improper programming. Check to see that all the program -

POWER TUNING BAR--_

TENSION SPRING ""--ir -

(2)

SW 50i

POWER TUNING BRACKET

CLUTCH J SPRING

2 PRONG MALE PLU

Fig. 5-View of interior of set showing the power tuning assembly.

ming clips are pressed flush against the programming wheel and that they are inserted from the rear of

the receiver. Check to see if the leaf springs are making contact. If not, reform the springs. Check the phosphor bronze spring which rests on the programming clips. If the spring fails to rest properly on the programming slips it may be reformed. Care must be taken to insure that the programming clips will pass under this spring during manual tuning. Fig. 6-Plug-in remote control unit.

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AXIAL -LEAD RESISTORS

Vitreous -enameled, power -type units de signed to withstand high temperatures...-;,:.

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TYPE AB POTENTIOMETERS

Resistance material is

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Worn page 24]

impedance of the supply (or, the "looking backwards into the line" resistance) is extremely low. That's the same as saying that we have a "constant voltage" source, which, in fact, is exactly the case. It's true that the total amount of power we can extract from the system is limited by fuses, wiring, etc., but so long as we stay within those limits, the voltage will remain constant regardless of the wattage drawn from the system. This idea was translated, in its en- tirety, to public address amplifier design. In other words, the amplifier voltage decided upon is 70.7 volts (just like the 120 volts at the baseboard receptacle). Of course, it should be remembered that since we are dealing with audio signals, this voltage appears only when full signal is applied to the amplifier input, but this is not important to the method of figuring out speaker transformers and sound distribution which follows. Now, in order for an amplifier to behave this way, regardless of wattage being "drawn" from it by the load, the amplifier must have a low internal impedance. Such impedances are obtained by means of large amounts of negative feedback. An amplifier whose nominal source impedance without feedback is 10 ohms will have an internal source impedance of only 1 ohm if 20 db of inverse feedback is applied.

Designing PA Installations

1. The first step in designing a PA installation is to decide on the total power which will be required in the system to adequately cover the volume of space acoustically. Anyone who has done PA work, even using older methods, will have an easier time here, because of previous experience. One watt of electrical power fed to an average efficiency loudspeaker will generally cover about 3000 cubic feet in which light -machinery factory work is taking place, for example. In selecting an amplifier, always allow for future addition of speakers in locations not originally planned for.

2. Decide where you are going to place each speaker to get best coverage

and determine whether two speakers in a large open area will do a better job if fed with one watt each and properly spaced than a single speaker at one end of the area fed with two watts, etc.

3. Determine how much power each speaker is to handle. Base your considerations purely on acoustic requirements, not on "even numbers," etc.

4. Here's the trick of the whole problem. Simply divide the watts required from a given speaker into the number 5000 and presto! Out comes the required primary impedance of the speaker matching transformer. For example, if a given speaker should produce a maximum of two watts, use a 2500 ohm primary -to -voice -coil -secondary transformer. If another speaker, mounted to cover a larger area, is sup- posed to handle five watts, use a 1000 - ohm - primary - to - voic - ooil - secondary matching transformer, etc. No pads! No mathematics! No complete revamp- ing of the entire system every time a

new speaker is to be added to the existing installation!

How the System Works The reason for the magic number 5000 becomes fairly obvious if you recall the

formula for power, W = Z

By trans - z

posing, we get Z= W, where Z is the

unknown primary impedance of the required matching transformer, W is the power required from a given speaker, and E is the output voltage. Since E, the voltage, is always constant regardless of load and since its value is 70.7 volts, per the new PA system standard, E2 is always 5000 (70.7 x 70.7). It doesn't matter how many speakers you hang on to the system, nor is it important how great the difference between the power desired from one speaker to the next. The formula still works, providing you purchase a PA amplifier equipped with an output marked "70.7 volts."

Figure 2 illustrates how simply the problem of Fig. 1 can be solved using this new approach. Did you get the answers doing it thet hard way?

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COLOR BAR GENERATOR

[ from page 5]

Although this portion of the con-

vergence procedure can be accomplished using either dot output, or crosshatch output from the generator, it will be

found that use of crosshatch (or vertical bars) facilitates the adjustments con-

siderably. The reason for this is that indication of vertical line-up is more

apparent to the observer when a con-

tinuous line pattern is used, rather than a succession of dots.

It is very helpful to note that the vertical column of blue dots (or the

blue vertical bar) is a reference line for vertical convergence-that is, the

red and green columns must finally come into line with the blue column. To understand why this is so, observe the color -dot motion produced by ad-

justment of the three vertical -tilt controls, as shown in Fig. 6. While a

horizontal component of motion is produced by the red and green tilt controls, the blue tilt control produces only

vertical motion of the blue dots.

The same observation applies to the dot motion resulting from adjustment of the vertical -amplitude controls, as

illustrated in Fig. 7. Hence, it must be concluded that since the blue dynamic controls can change only the vertical spacing of the blue dots, final vertical convergence can be obtained only along the line defined by the vertical blue -dot column.

This is an important guidepost to observe in vertical dynamic convergence, which will assist the beginner

o , ._

v i!,fr. P. CIN.

a P" `A..

o b d 'v o o o o

a I If b,

b e

ó i .cd'

a' \ \o.

e", \o.

Blue Red Green Fig. 6-Motion of dots from ad-

justing vertical -tilt controls.

o

Blue Red Green Fig. 7-Motion resulting from ad-

justing vertical amplitude controls.

immensely. More experienced set-up

men can dispense with the guidance of

the blue -dot reference line, but the ap-

prentice is strongly advised to take advantage of this built-in reference pro-

vided by the color picture tube. The beginner will also find it useful to al-

ways keep the center -screen area con-

verged by retouching the beam -magnet adjustments as required, while gradually working in the top and bottom convergence with the dynamic controls.

Remember these important general principles:

1. The static controls (beam magnets and lateral corrector) produce uniform motions of the color dots over the entire screen area.

2. The dynamic controls (tilt and amplitude) produce non -uniform motions of the color dots at various screen areas.

Horizontal Dynamic Convergence

In essential respects, horizontal dy-

namic convergence follows the same general principles as vertical dynamic convergence. Keep the center of the screen converged to white dots by re-

adjustment of the static controls, as

required-meanwhile, gradually work the left and right-hand edges of the screen into convergence by adjustments of the horizontal dynamic controls.

The blue dots will form a reference line for final convergence, when the

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The tremendous demand for portable TV sets opens another BIG market for good set -to -antenna plug-in outlets. MOSLEY Flush Sockets meet this need-supplying attractive, convenient, customer -approved wall outlets for every installation requirement.

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R G R G R G R

B

s a e

Fig. 8A-The blue dots are curved to a peak in center -screen, 8B-Rows of red and green dots are then straightened out.

following, adjustments are made: First advance the blue horizontal amplitude control to maximum (so that appreci- able blue -dot displacement is obtained). Then, adjust the blue horizontal phase control for "resonance"-i.e., so that the blue dots are curved to a peak in center -screen, falling off equally to either side, as shown in Fig. 8A. Finally, adjust the blue amplitude control to make the row of blue dots perfectly straight-it is advisable to use a yard- stick or other straight -edge to insure that the row of blue dots is really straight.

The rows of red and green dots can then be straightened and brought into convergence with the blue dots (or horizontal bars, if used) by adjustment of the red and green phase and amplitude controls, as depicted in Fig. 8B. It will be found that the procedure is

complicated somewhat by the interaction of the various convergence controls, so that touch-up of previous adjustments will be required from time to time.

Convergence is by far the most tedi- ous and time-consuming portion of the set-up procedure, and the beginner must be prepared to undergo an extended training period before facility is ac-

quired.

Adjustment of Color Phasing Control

The color display provided by the generator is a spectrum of hues which permits the receiver color -phasing control to be accurately adjusted at the end of the set-up procedure. The correct sequence of hues is depicted in Fig. 9. When the color -phasing control is properly adjusted, the spectrum appears with reddish -orange at the extreme left side of the screen followed by a gradual transition to red, blue,

R

and green at the right side of the screen.

Red

Fig. 9-Proper phasing produces correct color sequence and hues.

Other Applications

These are the principal applications of the dot, bar, crosshatch, and color - display outputs of the generator in set- up procedure. In addition, the color - display signal finds numerous useful applications in servicing the chrominance circuits of the color -TV receiver. These cannot be discussed in detail within the limits of this article, but may be listed in part as follows:

1. Alignment of the quadrature transformer.

2. Checking color -detector outputs for correct relative levels.

3. Check of burst -gate timing. 4. Check of matrix gain. 5. Adjustment of afc balance con-

trol. 6. Test of color -killer threshold. 7. Localization of circuit faults in

the three color channels. It is apparent that a color -display

generator, in spite of its relative simplicity as compared with an NTSC color - bar generator, is a highly useful instrument in both set-up and servicing applications. In addition to its use in the shop its light weight and portability make the color -display generator particularly valuable for field use.

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SERVICING 1951

EMERSON RECEIVERS by HAROLD BERNSTEIN

Service Manage-, Emerson Radio & Phonograph Corp.

Concluding installment on important features of the

1957 Emerson TV Receivers.

Important Note-In the March installment of this article an important paragraph was erroneously omitted. This paragraph reads as follows:

"All of the models in the DeLuxe series are 21" receivers incorporating a

full power transformer chassis (5U4GB rectifier tube and parallel filaments), and the new Standard Coil Neutrode type tuner for superior signal to noise

ratio and trouble free operation." The section describing the video de-

tector and agc action, on page 42 of the March issue, applies only to the DeLuxe Series.

Automatic Noise Inverter

Figure 7 is a simplified diagram of the automatic noise inverter used in the Eldorado sets. The detected composite video signal is amplified by the sync

amplifier, V-1, and fed to the sync

separator, V-3. A portion of this signal, taken from the junction of R-1 and R-2, is fed to the grid of the noise

VI SYNC AMP

R3

_ILi

NOISE

inverter, V-2. The cathode and grid bias voltages of V-2 are such that the tube will not conduct for any signal equal to or less in amplitude than the sync pulses tips, since these tips are kept just below the cut off point of the noise inverter tube. Any noise pulses, however, which are of greater amplitude and of the same polarity as the sync pulses will cause the tube to conduct and amplify these noise pulses. The amplified noise pulses (which are now of greater amplitude and of opposite polarity from the original noise pulses contained in the video signal) are also fed to the input of the sync separator tube where they are effectively cancelled before they have a chance to upset the operation of the sync separator tube. Those noise pulses which were lower in amplitude than the sync pulses are not affected, but they are not of sufficient amplitude to cause poor sync. The resistor R-7 couples the grid leak bias of the sync separator to the grid of the noise inverter. Slight

V2 V3 NOISE INVERTER SYNC SEP

= RB C4

R9 R7

2.2MEG R6

NO/SE1

*140V

1L. JL,

Fig. 7-Simpl fled diagram of the noise

circuit inverter

YOU CAN STOP A

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AUTOMATIC VOLTAGE STABILIZER

If you're harassed with a television or other electronic equipment installation that just won't operate right, chances are that a fluctuating voltage condition exists and prevents tubes and other components from functioning properly. One sure way of making voltage behave is with the Acme Electric automatic voltage stabilizer. Re- gardless whether the input voltage ranges from 95 to 130 volts, the output voltage will automatically be corrected to 115 volts ± 3%.

Another feature to remember, this unit uses no current unless the TV set is in operation. An automatic relay disconnects primary circuit under "no load" conditions and automatically connects circuit when load is applied to the secondary dr - cuit. Secondary voltage is indicated on voltmeter while unit is in operation. Furnished complete, ready to plug-in. See this Acme Electric Automatic Voltage Stabilizer at your dealer.

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variations in signal amplitude will affect the sync separator's grid leak bias. This will automatically change the grid bias to the noise inverter so that the tips of the sync pulses will remain clamped just under the cut off point of the noise inverter. This tube therefore can only conduct on high amplitude noise pulses which are the ones we desire cancelled.

Adjacent Channel Sound Trap

These receivers use an extremely high efficient "Bridged T Trap" for the adjacent channel sound trap. When adjusted properly, an attenuation ratio well in excess of 1000 to 1 may be obtained. The circuit using this trap is shown in Fig. 8. In the design of the

Bridged T the impedance of AB is made equal to the impedance of BD at the desired trap frequency. The impedance of BC is such, that at the desired frequency a phase reversal takes place, whereby the voltage across BD is equal in amplitude but opposite in phase to the voltage across BC.

/ST VIDEO /F

B C

2ND VIDEO /F

Fig. 8 -Bridged T sound trap.

OLDSMOBILE FOR 1957 [from page 17]

6. If set is a Super De Luxe -disconnect foot selector button plug from rear of set.

7. With a small screw driver remove the front panel control knobs, and washers.

8. With a %" deep socket, remove the two front panel mounting nuts from the controls.

9. With a 7/16" wrench remove the two bolts holding the receiver to the two mounting brackets (hold set while removing these bolts to prevent falling).

10. Bring set forward to clear controls from panel and remove set. To replace receiver reverse above procedure.

Push Button Adjustment

1. Pull button to left and pull out to maximum.

2. Tune to the desired station. 3. Push button all the way in; station

is now locked in. 4. Proceed with remaining buttons

in the same manner.

Trimmer Adjustment

1. Fully extend antenna. 2. Tune to weak station between 600-

1000 kc with volume full on. 3. Adjust trimmer (located at right

lower rear of tuner section) for maximum volume.

Note. Trimmer adjustment can be made thru the glove box after installation.

Service Hints

Complaints of speaker rattle have been traced to vibration of the clips etc., which hold the composition speaker baffle. Be sure all clips, bolts, etc., are tight and that the baffle does not vi- brate against wires or some other ob- ject. Many speaker complaints have been eliminated by replacing the baffle clips with self tapping screws. In fact, this was done at the factory in all recent Oldsmobile cars.

VOLUME TUNER TUNING CONTROL SECTION CONTROL

t

,

DIAL

REAR

' SPEAKER

TRANS- FORMER

FRONT SPEAKER

a THIS TYPE OF LINK

USED WITHOUT REAR SPEAKER

FADER CONTROL KNOB

USED WITH REAR SEAT SPEAKER

Fig. 6 -Output link details.

Bench Testing

Radios removed from cars which do not have rear seat speakers, have a jumper wire which connects the transformer output to the speaker lead (see Fig. 6). If car is equipped with a rear seat speaker the fader completes this connection and also connects to the rear speaker lead.

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Advertisers' Index

Acme Electric Corporation Aermotor Company American Television & Radio Anchor Products Company Astron Corporation

63 44

Co. 46 60 43

B & K Manufacturing Co.

Barry Electronics Corp. Burgess Battery Company Bussmann Manufacturing Co.

55 64 49

9

Calex Manufacturing Co. 53 Channel Master Corp. 51

Cleveland Institute of Radio Electronics 50

Communications Company, Inc. 58 Cornell-Dubilier Elec. Corp. 64

Electronic Chemical Corp. 58 Electro Products Labs, Inc. 16

General Cement Mfg. Co. 59 General Electric Company 6-7

Heath Company 57

International Crystal Mfg. Co. 56

JFD Manufacturing Co. Inc 63

Jensen Industries 63

Mallory, P. R. & Co. Inc. 13

Merit Coil & Transformer Corp. 62 Mosley Electronics, Inc. 62

North American Philips Co., Inc. 45

Ohmite Manufacturing Company 60

Planet Sales Corp. 54

RCA Batteries Cover 4 RCA Service Parts 21

RCA Speakers 12

Radiait Corporation 11

Radio Receptor Company 17

Raytheon Manufacturing Co. 3

Recoton Corporation 61, 64 Roney Plaza Hotel 61

Sams, Howard W. & Co. Inc. 5

Service Instruments Company 62 Shure Brothers, Inc. 1

South River Metal Products Co. 64 Sprague Products Company 19

Standard Coil Products Co. Cover 3

Tele Scopic Products 62 Triplett Elec. Instrument Co. Cover 2

Tung -Sol Electric, Inc. 14, 15

Vaco Products Company 56

Walker Martin, Inc. 60 Walsco Electronics Corp. 23 Wen Products, Inc. 2

Xcelite, Inc. 41

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