ultra lamp

Accessory part number 00 100569 00

Safety Class 1 (IEC 1010-1)Installation Category II

Publication Number: 85 101294 00Date: August 1995

UltrAA Lamp Accessory

Service Manual

UltrAA Lamp Accessory Service Manual

___ ({ PAGE }) October 1994

Varian Australia Pty Ltd is the is the owner of copyright on this document andany associated software. Under law, the written permission of Varian AustraliaPty Ltd must be obtained before either the documentation or software is copied,reproduced, translated or converted to electronic or other machine-readableform, in whole, or in part.

1994 Varian Australia Pty Ltd (A.C.N. 004 559 540)

All rights reserved

UltrAA Lamp Service manual

Contents

Safety practices and hazards

Electrical hazards

UV radiation

Heat hazards

Other

‘Warning’ and ‘Caution’ messa ges

Warning symbols

Field service policy

Spare parts policyOperational spare parts

WarrantyContract maintenanceUltrAA lamp warranty

General Information

Overview

Theory of Operation

Standard hollow cathode lamps

UltrAA hollow cathode lamps

UltrAA lamp control module

Specifications

Features and options

Electrical supply

Electrical output

Performance

Environmental conditions

Weights and dimensions

Pre-installation

Photron Superlamp de-installation

Installation

Retro-fit kit installation

Typical installation time

Installation procedure

Testing

Single lamp instruments

Control module installation

Performance testing

Spares and test equipment

Diagnostics

Diagnostic LEDs

Test points

Electronics

Input power section

Circuit description

±15 VDC supply circuit

Output power section

Exlploded diagram

UltrAA Lamp wiring details

Interwiring diagram

Assembly diagram

UltrAA lamp PWB schematic


October 1994 ({ PAGE }) ___

Safety practices and hazards

Operation of an UltrAA Lamp Accessory involves the use of high voltages andradiant energy. Careless, improper or unskilled use of this accessory can causedeath or serious injury to personnel, or severe damage to equipment andproperty.

All users of an AA (Atomic Absorption) instrument and its accessories must befamiliar with the correct operating procedures.

The cover on the accessory must not be removed by the operator.

Service is to be performed only by Varian trained, Varian qualified or Varianauthorized Customer Service Representatives (CSRs).

The safety practices described below are provided to help the CSR operate theaccessory safely. Read these safety practices thoroughly before attempting tooperate the accessory, and always operate the accessory in accordance withthese safety practices.

Electrical hazards

The UltrAA Lamp Accessory contains electrical circuits, devices andcomponents operating at dangerous voltages. Contact with these circuits,devices and components can cause death, serious injury, or painful electricshock. Panels or covers which are retained by screws on the accessory may beopened only by Varian trained, Varian qualified or Varian approved CSRs.Appropriate warning labels are attached to the instrument in easily visiblelocations to warn of the dangers in that immediate area.

Replace blown fuses with ones of the size and rating stipulated in the textadjacent to the fuse holder or in the service manual where listed. Always ensurethe accessory is turned off and disconnected from the mains supply beforeattempting any replacement.

All electrical components float above chassis ground with some potentialdifferences > 500V DC. To avoid death, serious injury, or painful electric shock;never touch electrical components or connectors until at least 18 seconds afterpower supply is switched off.

The internal power supply common operates above chassis ground potential.To avoid damage to the power supply or the associated AA instrument; neverconnect the common to chassis ground.

UV radiation

The UltrAA hollow cathode lamp emits UV radiation. Always wear UV absorbingsafety glasses when directly viewing an energized UltrAA hollow cathode lamp.

Heat hazards

Hot surfaces can present heat hazards that can result in burns.

The glass envelope of an UltrAA lamp can become much hotter than that of astandard hollow cathode lamp. Before touching an UltrAA hollow cathode lamp,turn off the lamp and allow it to cool.



Other

Care should be taken when working with glass parts to prevent breakage andcuts. This is especially important when handling hollow cathode lamps.

The UltrAA Lamp Accessory weighs approximately 7.5 kg (16.5 lb). Take carewhen lifting or moving the accessory.

'Warning' and 'Caution' messages

A 'Warning' message is used in the text when failure to observe instructions orprecautions could result in death or injury.

A 'Caution' message is used when failure to observe instructions could result indamage to equipment (Varian supplied and/or other associated equipment).

A 'Note' message is used to give advice or information.

Warning symbols

The following is a list of symbols that appear in conjunction with warnings in themanual. The hazard they describe is also shown.

Electrical shock Eye hazard Hot surfaces

Broken glass Drop hazard Fire hazard

The following is a US Federal Communications Commission advisorystatement:


October 1994 ({ PAGE }) ___

Field service policy

Varian accessories are designed to be serviced in the field by Varian trainedand authorized CSRs. In the normal course of field service, it is policy tocomplete troubleshooting and repairs at the accessory location. Board ormodule replacement techniques are the recommended method of repair for thisaccessory. Most faulty boards and modules can be repaired in a workshop orreturned to the factory for repair. When time permits, repairs may be attemptedto component level on site.

Spare parts policyProprietary items and parts that are unique to the Varian equipment should besourced from service kits or from a Varian Service Center. Common items maybe sourced locally and equivalent parts may be used unless otherwisespecified.

Operational spare parts for all Varian instruments and major accessories areavailable for a period of seven years after manufacture of the final productionunit. Operational spare parts may not be provided after this period unlessavailable. Varian will effect functional repair to any of their products during theseven years following manufacture of the final production unit.

Operational spare parts

Operational spare parts are defined as individual electrical or mechanical partssusceptible to failure through wear and tear during their normal operation.

General hardware (for example, sheet metal parts, structural members,assemblies and castings) will normally outlast the useful life of an instrument oraccessory, and therefore will only be supplied if available after the finalproduction unit is manufactured.

WarrantyVarian OSI warranty covers any defect in materials and workmanship, but notagainst consequential damages. Full details relating to the terms of warrantyare expressed in the Contracts/Policies section of the Instrument Log Book,publication number 85 101092 00, and are also available from any Varian Salesand Service Office or Agency. No other warranty is expressed or implied.

Consumable items such as (but not limited to) nebulizers, light sources andother glassware items, temperature probes and graphite components aresubject to a limited or pro-rated warranty.

The Varian warranty provides for specific legal rights. There may also be otherrights that vary from country to country or region to region. The warrantyapplies only to the correctly installed Varian equipment and cannot be extendedto cover the associated miscellaneous installations. The warranty does notcover defects that may be caused by users of the equipment, inappropriateapplications, unauthorized service, etc.



Contract maintenance

Quotations for contract maintenance may be obtained from any Varian Sales orService Office.

UltrAA lamp warranty

Warranty cover extends to 5000 milliampere-hours, pro rata, at or below therecommended lamp operating current (not the boost current).


October 1994 1-{ PAGE } ___

1 General information

1.1 OverviewThe Varian UltrAA Lamp Accessory is a high intensity hollow cathode spectralline source for the provision of lower detection limits, increased sensitivity andimproved calibration linearity.

It is designed to complement the new generation spectrometers (SpectrAA600/800), however, it may be retro-fitted to existing SpectrAA 5, 10/20, 30/400and 250 Plus series instruments.

This product replaces the OEM product, the Photron Superlamp, providing ourcustomers with improved performance, reliability, flexibility and lamp lifetimes.Varian will no longer supply the Photron Superlamp power supply module,however, Varian will continue to supply Photron lamps.

The intensity of the UltrAA lamp is increased by a factor of 3 to 5 (giving abouta 10 % reduction in photomultiplier volts) with an increase in sensitivity of about10 to 15% compared with a standard hollow cathode lamp.

The UltrAA Lamp Accessory features the ability to power two UltrAA lamps,hence, is able to utilize the Smart Lamp Management feature of the SpectrAA600/800 series instruments (automatic 20 minute pre-warming of the standbylamp).

✒ Note Only the unboosted section of the UltrAA lamp will be automatically powered bythe instrument. An operator is required to manually strike the boost circuit whensetting up for an automated run or immediately prior to use.

Later model Zeeman spectrometers will be factory pre-fitted with the UltrAALamp Accessory's unique loom terminating in a connector on the instrument’srear panel, thus, providing the customer with the option to later purchase andself install the accessory.

A special retro-fit kit must be ordered with the UltrAA Lamp Accessory for olderspectrometers already in the field. In this case, the UltrAA Lamp Accessory willrequire installation by a Varian Customer Support Representative (CSR).

Varian UltrAA hollow cathode lamps cannot be used with the PhotronSuperlamp supply. They may be used in standard SpectrAA hollow cathodelamp sockets without the boost facility. Photron Superlamps will fit into socketswired for UltrAA lamp operation, however, they will only function as a standardhollow cathode lamp without the boost current applied.

Standard hollow cathode lamps are also functional in both lamp turret positionswhich are fitted with the UltrAA lamp wiring, and automatic lamp recognition willremain operational.

UltrAA lamp automatic lamp recognition capability is only available to the newgeneration spectrometers. It is included in version 1.4 and greater of theSpectrAA OS/2 system software (85 101055 00).

1.2 Theory of operationTo gain a clearer understanding of the way in which an UltrAA lamp operates,this section draws on a comparison between the standard hollow cathode lampand the UltrAA hollow cathode lamp.


___ 1-{ PAGE } October 1994

Standard hollow cathode lamp

In the standard unboosted hollow cathode lamp, the spectral line of interest iscreated by the following process:

Positively charged ions of a rare gas (usually Neon or Argon) are accelerated tothe wall of the cathode by the applied high voltage electric field. On collision, anatom of the cathode material is ejected from the cathode surface. This processis termed sputtering. After the atom (or ion) has been ejected, it can then beexcited by collision with rare gas atoms, rare gas ions and electrons. The raregas serves two purposes; 1. sputtering and 2. excitation.

These collisions result in a transfer of energy causing the metal atoms tobecome excited. Atoms in the excited state are unstable, therefore, they returnto the ground state, emitting radiation at the characteristic wavelength for thatelement. A metallic vapor of ground state atoms is formed. This metallic vaporcan extend several millimetres from the mouth of the hollow cathode.

Atoms in this region are not excited by the discharge. These atoms canreabsorb the emission from the cathode and cause the line width of the lamp tobe increased and distorted. This phenomenon is known as ‘self-absorptionbroadening’ and is a limitation of the standard hollow cathode lamp. Self-absorption broadening results in degradation of absorption sensitivity andincreased calibration curvature. This is minimized by using the recommendedlamp operating currents, which offers a compromise required to obtain the bestsensitivity, high signal-to-noise ratio and long lamp life.

Varian standard hollow cathode lamp

UltrAA hollow cathode lamp

In the boosted UltrAA hollow cathode lamp there are two discharges:

1. The hollow cathode discharge.It supplies the atoms of interest via the sputtering process and excitation ofthe atoms within the cathode (as described above).

2. The boost discharge.Its purpose is to excite the atoms at the mouth of the cathode that thenormal hollow cathode lamp cannot excite.

The boost discharge is supplied by a filament that is coated with a material thatejects electrons when heated. The electrons are directed across the mouth ofthe cathode with suitable shielding and a second anode. The electrons collidewith the unexcited metal atoms and excite them.



The intensity of the lamp will therefore increase by eliminating self-absorptionbroadening and exciting more atoms, thus, providing an increase in theemission output of the lamp. This provides a reduction in baseline noise,improving signal-to-noise ratios and detection limits. The reduction in linebroadening also improves analytical sensitivity and provides improved linearcalibration.

The increased diameter of the lamp’s envelope serves two purposes:

1. Increased rare gas volume which results in increased lamp life.

2. Increased distance between the cathode, anodes and filament to the outerenvelope surface which results in a lower surface (touch) temperature,however, they are still much hotter than standard hollow cathode lamps.

Varian UltrAA hollow cathode lamp

UltrAA lamp control module

The hollow cathode current is supplied by the spectrometer in the normalmanner. The 5 to 15 mA current is pulsed at mains frequency and there isapproximately a 250 V drop across the lamp.

With boost current applied to the lamp, the current is fixed at 150 mA DC andthere is about a 40 V potential difference across the boost circuit.

The difference between Varian boosted UltrAA hollow cathode lamps andcompetitive designs is that the two current supplies are isolated. There are twoanodes as opposed to a shared anode and the boost discharge is directedacross the mouth of the cathode rather than through the cathode. The majordrawback with competitive designs is that the sputtering and excitation processare not totally independent. Changing one will effect the other. Thus, inpractice, the operator is required to optimize the excitation current using apeaking meter. This restricts lamp operation to from full automation.

If there is no boost current then 12 volts is applied to the boost filament to makestriking easier. In many cases the boost voltage will strike the lampspontaneously, however, for reliable striking, a capacitor that is charged to500V can be discharged through the lamp by selecting the ‘strike’ position ofthe lamp control switch. Once a boost current has been established, thefilament voltage is reduced to extend filament life and reduce heat generationwithin the lamp.



1.3 Specifications

Features and options

Capability to power two UltrAA lamps simultaneously.

Automatic lamp recognition with the new generation SpectrAA 600/800 seriesinstruments. Requires SpectrAA OS/2 software version 1.4 or greater (p/n85 101055 00).

Truly independent lamp and boost supply circuits.

Fixed (non adjustable) boost current supply.

All new generation SpectrAA 600/800 series Zeeman systems, with serialnumbers greater than 9411XXXX, include UltrAA lamp capability as standard.

Optional retro-fit kit available for instruments not containing the factory fittedUltrAA lamp loom. This includes flame series instruments not ordered with theUltrAA lamp accessory and earlier SpectrAA series instruments such asSpectrAA 5/10/20/30/40/250 Plus/300/400 and 30/40/300/400 Zeemansystems.

Improved lamp lifetimes compared with Photron Superlamps.

Analytical performance at least equal to or better than Photron Superlamps.

Electrical supply

Voltage 100, 120, 220 or 240 VAC ±10%230 +14% / -6% (using 240V tapping)230 +6% / -14% (using 220V tapping)

Frequency 50 or 60 Hz ±1 Hz

Power Rating 150 VA maximum

Electrical output (typical)

Boost run current 150 mA +10% / -5%

Boost run voltage 40 VDC ±10 VDC

Boost strike voltage 400 VDC ±60 VDC

Filament voltage 1.2 VDC ±10% (lamp off)12 VDC ±10% (prior lamp strike)5 VDC ±10% (lamp run)

Performance

Drift Less than 8% change in intensity per hour (after 25 minutes warm up)

Characteristic concentration (furnace)As < 0.5 µg/LPb < 0.5 µg/LSe < 1.0 µg/L

Noise At least 30% less than that for a standard Varian hollow cathode lamp when tested on the same instrument.



Signal intensity (EHT)Not less than a 10% reduction in the photomultiplier voltage (EHT)when compared to a standard Varian hollow cathode lamp tested onthe same instrument. The following EHT voltages are desirable targetvalues:As < 380 VPb < 335 VSe < 360 V

Lamp lifetime > 5000 mA-hours (based on operating, not boost, current)

Environmental conditions

Operating

Altitude 0 to 853 m (0 to 2800 ft)Temperature 10 to 35°C (50 to 95°F)Humidity 8 to 80% (non-condensing)


Storage


Weights and dimensions

Net weight 7.5 kg (16.5 lb)

Shipping weight 11 kg (24 lb)

Height 145 mm (5.7 in)

Depth 355 mm (14 in)

Width 240 mm (9.5 in)



2 Pre-installation

This section of the manual is only applicable if the customer has a PhotronSuperlamp installed on their SpectrAA system and it is to be replaced by theUltrAA lamp accessory.

2.1 Photron Superlamp de-installationTools required:Posi-drive screwdrivers 1 & 2 point Flat blade screwdriverPermanent marker Side cutting pliers3mm hex balldriver [250/600] 72 100208 00

1. Disconnect the SpectrAA instrument from the mains power and remove anyhollow cathode lamps from the instrument’s lamp turret.

2. Remove the required instrument covers to gain access to the instrument’slamp turret area.

3. Remove the cover plate [30/40/300/400/800] from below the optics chassis(adjacent to the burner shield).

4. Loosen and move the circuit breaker/switch [Zeeman], if required, to allowlater removal of the lamp turret disk.

5. Remove the four screws (socket cap head on 250/600) securing the lampturret disk to the turret drum and gently separate. Release existing turretlooming from any clamps if required.

6. Remove the position 1 lamp octal socket from the lamp turret disk byremoving the lamp alignment adjuster screws and the pivot screw. Takecare not to lose the three small springs under each socket.

7. Remove the lamp extractor and spring to gain access to the socket wiring.

8. Take note of and/or mark the two wires that are joined between theinstrument’s original standard lamp wiring and the Superlamp loom. Referto figure 2.1.

9. Cut the two wires of step 8 (usually blue and black) allowing sufficientlength for later transfer to the UltrAA lamp retro-fit loom socket.

10. The two lamp recognition wires that were not used, hence, insulated oninstallation of the Superlamp loom, will also be required for later transfer tothe UltrAA lamp retro-fit loom socket. The table below indicates the usualwire color and pin position for transfer. Wire color may vary betweendifferent instruments, therefore, a continuity check back to the instrument’spower board may be required for correct wire identification.



Fig. 2-1 Superlamp wiring

Pin Number UltrAA HCL octal lamp socket Color

1 Standard HCL cathode Black

3 Standard HCL anode Blue

4 Lamp recognition common Red

8 Lamp recognition White

11. Remove the Superlamp loom and socket from the instrument and discard.

12. Continue with the UltrAA lamp retro-fit loom installation from step 8 insection 3.1 of this manual. Replace steps 12 and 13 of section 3.1 inreference to lamp socket 1 with:Solder the wires identified in steps 8 to 10 of section 2.1 to the pinsindicated in the above table.



3 Installation

All SpectrAA 600/800 Zeeman series instruments, with serial numbers9411XXXX or greater, will have the UltrAA lamp looming factory pre-installed.The looming will be terminated at the instrument’s rear panel with a femaleconnector. The UItrAA lamp control module is then simply connected to theinstrument through this plug and then to mains power. On such a system, theUItrAA lamp control module is considered to be customer installable.

For all other SpectrAA systems, a retro-fit loom must be fitted by a Variantrained and authorized Customer Service Representative (CSR).

3.1 Retro-fit kit installation

Typical installation time

The approximate time required for installation of an UltrAA lamp retro-fit kit is 2hours.

Installation procedure

The installation technique for this kit is similar for all SpectrAA models, with theexception of single lamp units. Refer also to the UltrAA lamp wiring diagram atthe end of this chapter. When correctly installed, lamp positions 1 and 2 of thelamp turret will support UltrAA lamp operation in addition to standard hollowcathode lamps.

If a Photron Superlamp is already installed, its removal is covered in section 2 -Pre-installation.

Retention of Superlamp capability in position 1 is possible by installation of theUltrAA lamp wiring into turret positions other than position 1. This option canmake UltrAA lamp installation extremely difficult due to the requirement foradditional wiring through the centre of the turret.

Tools required:Soldering iron SolderPosi-drive screwdrivers 1 & 2 point Flat blade screwdriverPermanent marker Long nose pliersSide cutting pliers Masking tapeCoded HC lamp (any element)3mm hex balldriver [250/600] 72 100208 00Pin removal tool * 72 100261 00

* Only required if pin removal is necessary after incorrect positioning of pins intoconnector.

1. Disconnect the SpectrAA instrument from the mains power and remove anyhollow cathode lamps from the instrument’s lamp turret.

2. Remove the required instrument covers to gain access to the instrument’slamp turret area.

3. Remove the cover plate [30/40/300/400/800] from the below the opticschassis (adjacent to the burner shield).

4. Loosen and move the circuit breaker/switch [Zeeman], if required, to allowlater removal of the lamp turret disk.



5. Remove the four screws (socket cap head on 250/600) securing the lampturret disk to the turret drum and gently separate. Release existing turretlooming from any clamps if required.

6. Remove the position 1 and 2 lamp octal sockets from the lamp turret diskby removing the lamp alignment adjuster screws and the pivot screw. Takecare not to lose the three small springs under each socket.

7. Remove the lamp extractors and springs to gain access to the socketwiring.

8. Feed the pilot wire (included in kit) through the centre of the turret until it isaccessible from the other end.

9. Use masking tape, or similar, to secure the pinned end of the retro-fit loomto the pilot wire exiting from the lamp socket end of the turret. Ensure thatthe pilot wire is taped to the heat shrunk section of the loom to avoid stresson the contact pins.

10. Guide the retro-fit loom through the centre of the turret while gently pullingon the pilot wire.

11. Carefully remove the tape and pilot wire from the retro-fit loom.

12. Take note of and/or mark wires in existing lamp socket for lateridentification, prior to de-soldering.

The table below shows wire color and pin positions for SpectrAA30/40/300/400/800 lamp octal sockets. Please take note of the wire colors andpositions of your customer’s particular instrument, as wire colors have variedbetween instruments and throughout product life.

Lamp socket 1 Lamp socket 2

Pin number Wire color Pin number Wire color

1 Brown 1 Red

3 White 3 Black

4 Black/White 4 Black/Black

8 Brown 8 Red

13. De-solder wires from the existing lamp socket pins for transfer to thesame pin positions in the retro-fit loom sockets. Feed the existing lampsocket wires through the 50 mm sleeving on the retro-fit loom and solderthe wires into the new lamp socket.

14. Slide the sleeving of the retro-fit loom over all lamp wires and position it intothe socket exit groove. This will ensure that the sleeving will bear againstthe extractor spring on re-assembly of the socket and not on the individualwires.

15. Replace the lamp extractors and springs.

16. Refit the lamp sockets to the lamp turret disk.

17. Cable tie the retro-fit loom to the existing looming to secure it into position.

18. Replace the lamp turret disk onto the turret drum taking note of the locatingpin position [30/40/300/400/800] or by aligning the lamp socket 1 with theopto flag on the turret drum [250/600]. Refit the turret drive chain prior tosecuring disk, if applicable.

19. Reposition the circuit breaker/switch, if applicable.



20. All SpectrAA 600/800 flame systems, with serial numbers 9411XXXX orgreater, have a hole in the instrument rear panel to allow mounting of theUltrAA lamp loom connector. Other SpectrAA systems do not have thismodification.

If no hole for mounting the connector on the rear panel is provided, thenfeed the retro-fit loom through the exit hole on the left hand edge of theinstrument base (and through the lower left skirt panel on 250/600/800).

If a hole is provide on the rear panel, then remove the bung and mount theconnector as shown below. The housing (see step 22) will not be required,however, insertion of the connector pins into the connector housing should beperformed prior to mounting (see step 23).

21. Place a self-adhesive cable clamp on the instrument base to route the loomclear of the rotating turret, if required.

22. Slide the connector components over the loom as shown below.

23. Insert connector pins into the connector housing ensuring that theypositively ‘click’ into place.

UltrAA lampconnector

HCL lampsocket 1

HCL lampsocket 2

Color Pin Pin Pin

Red 1 5 -

Orange 2 6 -

Yellow 3 7 -

Green 4 - 5

Blue 5 - 6

Violet 6 - 7

25. Screw the housing over the connector. Remove the two screws to invert theclamping piece, then secure the loom into the housing. Refer to step 22.



26. Test the correct operation of the newly installed loom (refer Testing below).

27. Replace all previously removed covers.

Testing

Prior to connecting the UltrAA lamp control module to the instrument, thefollowing checks should be conducted.

1. Insert a coded standard hollow cathode lamp into the lamp socket positionsinstalled with UltrAA lamp wiring. Power the instrument and run theSpectrAA software to ensure that the coded lamp is automaticallyrecognised.

2. Turn on the lamps and confirm that they are operating correctly. Forexample, enter the Optimization page and note the EHT value.

3. If operation is correct then proceed to the control module installation section.Rectify any problems before proceeding.

Pin Number HCL octal lamp socket

1 Standard HCL cathode

2 No connection

3 Standard HCL anode

4 Lamp recognition common

5 Boost anode

6 Boost filament

7 Boost filament return/boost cathode

8 Lamp recognition

Single lamp instruments

As lamp socket position 2 is not used on single lamp instruments, the retro-fitloom requires a simple modification.

1. Cut the wires from lamp socket 2 of the retro-fit loom (green, blue and violet)at the end of the heatshrunk section where the wires exit from the sleeving.Discard lamp socket 2 and its associated wiring.

2. At the other end of the loom, trim back the pinned green, blue and violetwires to the heatshrunk section where the wires exit from the sleeving.

3.2 Control module installation

Warning The UltrAA lamp control module weighs 7.5 kg (16.5 lb). It can cause injury ordamage if allowed to drop.

Remove all protective packaging from the accessory.

Set the voltage selector switches on the rear panel of the UltrAA lamp controlmodule to the local supply voltage. If in doubt, check the mains voltage with amultimeter.

Check the rear panel silkscreening for the correct value of fuses to be used forFS1 and FS2.



Nominal Voltage SW2 SW3 Fuse Rating240 ±10% A D

230 +14% -6% T 2A230 +6% -14% B D

220 ±10%120 ±10% A C T 4A100 ±10% B C

Warning Application of an incorrect supply voltage can create a fire hazard.Never connect the accessory to the mains power supply until voltage selectorswitches and fuses have been correctly selected.

Place the control module on top of the GTA accessory or bench and connect allcables as shown below.

✒ Note Connection to the SpectrAA instrument may be either through a connector onthe rear panel or through a flying lead (retro-fit loom) exiting the left hand sideof the instrument base.

Interconnection diagram

Performance testing

1. Power on the instrument and load the SpectrAA software.

2. Remove any obstructions in the light path such as the furnace workheadfrom the sample compartment.

3. Insert an UltrAA lamp into an UltrAA lamp turret position. Call up thatelement and check that the lamp is automatically recognised (SpectrAA600/800 software version 1.4 or greater).

4. After setting the recommended lamp current (if required), enter theOptimize page and align the lamp, pressing ‘rescale’ as required. Note theEHT value displayed.

5. Power on the UltrAA lamp control module and strike the boost of the UltrAAlamp (the LED will illuminate in the lamp control switch). Press ‘rescale’ andensure the lamp is still optimally aligned. Note the EHT value displayed.



Warning The glass envelope of an UltrAA lamp becomes very hot during operation.Before touching an UltrAA hollow cathode lamp, turn off the lamp and allow itto cool.

6. The EHT value with the boost on should be at least 10% less than that withthe boost off.

7. Repeat the procedure for the other UltrAA lamp turret position.



6 Spares and test equipment

This section lists spare parts, tools and service kits that are available to support the UltrAA lamp accessoryin the field. Information in this section is listed as follows:❑ Parts grouped into common categories❑ Kits available and their contents❑ All available parts in part number order and reference number order❑ Loom interconnection

A comprehensive list of spare parts has been made available for ordering. Multiple quantities have beenprovided in specific kits where individual components are not available separately. These kits arestrategically priced so that kit replacement will not be expensive if needed.

Parts are referenced to the exploded diagram at the back of this section (eg 12, is item number 12 onexploded diagram), a section page (eg 9-1, is page 1 of chapter 9) or the circuit board layout in theElectronics section (eg IC3/4, is integrated circuit 3 and 4 on the layout).

Covers/Panels

Part Number Description Qty Ref0910091700 COVER CABINET 1 -0910092500 PLATE SCREENPRINT 1 190910096200 PLATE SOCKET MOUNT 1 3-34210103500 STANDOFFXM4X70 POLYPROPYLENE 1 102110016400 INSULATOR PWB 1 21

Electrical

Part Number Description Qty Ref0210142790 ASSY PWB ULTRAA LAMP SUPPLY 1 200510024500 CAPACITOR 560UF 250V/ELECTRO 1 80510029500 CAPACITOR EL 33UK 25V C4321 1 111410106100 DIODE BR254 BRIDGE RECTIFIER 1 74810022500 SWITCH ROCKER DPDT 1 64810025400 SWITCH SLIDE 240VAC/5AMP/DPDT 1 145310015700 TRANSFORMER ULTRAA-LAMP SUPPLY 300VA 1 25610025200 LAMP 110V 0.3W-RED C/W PUSHFIX 1 5

Fuses/Fuseholders

Part Number Description Qty Ref1910006400 FUSE 1 AMP/FAST ACTING/5x20MM/GLASS 1 9-11910006500 FUSE 2 AMP/FAST ACTING/5x20MM/GLASS 1 9-11910007000 FUSE 2 AMP /SLO-BLO/5x20MM/GLASS 1 9-11910008590 FUSEHOLDER PANEL MOUNT/5X20MM - QTY 2 2 131910008600 FUSE 4 AMP/SLO-BLO/5X20MM/GLASS 1 9-19910077500 KIT ULTRAA LAMP FUSES 1 -



Kits

Part Number Description Qty Ref7910019700 KIT ESD FIELD SERVICE 1 -9910076900 KIT ULTRAA LAMP RETROFIT 1 -9910077000 KIT ULTRAA LAMP SERVICE 1 -9910077100 KIT ULTRAA LAMP ELECTRONIC 1 -9910077200 KIT ULTRAA LAMP FASTENERS 1 -9910077500 KIT ULTRAA LAMP FUSES 1 -

Looms/Connectors

Part Number Description Qty Ref0110499490 ASSY LOOM ULTRAA LAMP LAMPS SUPPLY 1 6-50110499590 ASSY LOOM ULTRAA LAMP MAINS DISTRIB’N 1 6-50110499690 ASSY LOOM ULTRAA LAMP INTERMEDIATE 1 6-50110499790 ASSY LOOM ULTRAA LAMP CONTROL 1 40110500090 ASSY LOOM MAINS INPUT FILTERED 1 150110532990 ASSY LOOM ULTRAA LAMP RETROFIT 1 -0110535590 ASSY LOOM 4 LAMP Z ULTRAA 600 1 -0110582390 ASSY LOOM 4 LAMP Z ULTRAA 800 1 -0110582490 ASSY LOOM 8 LAMP Z ULTRAA 800 1 -1210103800 COVER BURNDY/CABLE GLAND/CLAMP/SHELL 18 1 161210108500 HOUSING BURNDY 7WAY/PLUG/SOCKET CONTACTS 1 171210108600 HOUSING BURNDY 7WAY/PANEL/RECEPT/PIN CNCTS 1 3-3

Miscellaneous

Part Number Description Qty Ref0810121700 GLAND CABLE 5-10MM , HOLE DIAM 16MM 1 184610003300 SPRING ADJUSTING SCREW 1 3-74910008600 TIE CABLE LARGE RELEASABLE 1 9

Tools

Part Number Description Qty Ref7210020200 DRIVER HEX 2MM (COMPONENT REMOVAL FROM HEATSINK) 1 -7210020800 DRIVER HEX 3MM (250/600 TURRET DISK REMOVAL) 1 -7210026100 TOOL PIN REMOVAL AMP 305183-R 1 -

UltrAA Lamps

Part Number Description Qty Ref5610108100 LAMP ULTRAA ARSENIC 1 -5610108200 LAMP ULTRAA LEAD 1 -5610108300 LAMP ULTRAA SELENIUM 1 -



9910076900 Kit UltrAA Lamp Retrofit

Description Qty RefASSY LOOM ULTRAA LAMP RETROFIT 1 -CLAMP CABLE SELF ADHESIVE 2 -PLATE SOCKET MOUNT 1 3-3COVER BURNDY CONNECTOR 1 3-3HOUSING BURNDY RECEPTACLE 1 3-3SCREW M3 4 -WASHER SPRING 4 -TIE CABLE 2 -WIRE TINNED COPPER (PILOT WIRE) 0.8m -S/W SPECTRAA 600/800 1 -INSTRUCTION ULTRAA LAMP RETROFIT 1 -

9910077000 Kit UltrAA Lamp Service

Part Number Description Qty Ref0110499790 ASSY LOOM ULTRAALAMP CONTROL 1 40210142790 ASSY PWB ULTRAA LAMP SUPPLY 1 201910008590 FUSEHOLDER PANEL MOUNT/5X20MM - QTY 2 1 134810022500 SWITCH ROCKER DPDT 1 64810025400 SWITCH SLIDE 240VAC/5AMP/DPDT 1 145610025200 LAMP 110V 0.3W-RED C/W PUSHFIX 1 57210020200 DRIVER HEX 2MM (COMPONENT REMOVAL FROM HEATSINK) 1 -7210020800 DRIVER HEX 3MM (250/600 TURRET DISK REMOVAL) 1 -7210026100 TOOL PIN REMOVAL AMP 305183-R 1 -9910077100 KIT ULTRAA LAMP ELECTRONIC 1 -9910077200 KIT ULTRAA LAMP FASTENERS 1 -9910077500 KIT ULTRAA LAMP FUSES 1 -

9910077100 Kit UltrAA Lamp Electronic

Part Description Qty RefDIODE BR254 BRIDGE RECTIFIER 1 1DB 1/2/3DIODE RC205 BRIDGE RECTIFIER 2 7IC 339N COMPARATOR 2 IC 9IC 340T-15 REGULATOR VOLTAGE +15 V 2 IC 6IC 79L15AC REGULATOR VOLTAGE -15V 2 IC 5IC LM317 VREG 3-TERM ADJ 2 IC 7/8IC OPAMP TL071CP LIN 8DA 2 IC 3/4IC OPCPL M0C3021 BP 6DA 2 IC 1/2INSULATOR MICA T0218 2 TR 1/3INSULATOR SPACER MICA TO220 2 IC 7/8RELAY DIL COIL/12V/1K CONTACTS/1A/250VAC 2 RL A/BRELAY PWB/SPDT/12V COIL/1A 125VAC CONTACTS 2 RL C/DRESISTOR 10E 5%/5.6W/100PPM/WIRE WOUND 2 R 13/29RESISTOR 180K 5%/0.4W/100PPM/METAL FILM 2 1R 1RESISTOR 18K 5%/0.5W/100PPM/METAL FILM 2 1R 2/3RESISTOR 82K 5%/5W/200PPM/METAL FILM 2 R 4/5TRANSISTOR MTH6N85 MOSFET/N-CHAN/POWER 2 TR 1/3TRANSISTOR PN200 PNP MED. POWER 2 TR 2/4



9910077200 Kit UltrAA Lamp Fasteners

Part Description Qty RefADHESIVE BACKED CABLE LATCHING CLIP 1 1BUSH (COVER LOCATING) 2 3CLIP 'CANOE' (PLASTIC FEET) 4 -LUG SOLDERLESS UTILUX H1999/150 5 12NUT M 3 HEX 10 -NUT M 4 HEX 10 -SCREW M 4 X 12 PAN XYLAN 20 -SCREW M 4 X 16 PAN XYLAN 4 -SCREW M 4 X 20 PAN XYLAN 5 -SPRING ADJUSTING SCREW 5 3-7TIE CABLE PANDUIT PLT1M-DTP 40 -TIE CABLE LARGE RELEASABLE 4 9WASHER FLAT 4,3 ID X 8,6 OD XYLAN 20 -WASHER FLAT 3,2 ID X 6,6 OD S/S 10 -WASHER SPRING 3.1 ID SS 10 -WASHER SPRING 4.1 ID STN ST 20 -

9910077500 Kit UltrAA Lamp Fuses

Part Number Description Qty Ref1910006400 FUSE 1 AMP/FAST ACTING/5x20MM/GLASS 10 9-11910006500 FUSE 2 AMP/FAST ACTING/5x20MM/GLASS 10 9-11910007000 FUSE 2 AMP /SLO-BLO/5x20MM/GLASS 10 9-11910008600 FUSE 4 AMP/SLO-BLO/5X20MM/GLASS 10 9-1

Parts available

This table lists all parts available for the UltrAA lamp accessory in part number order.

Part Number Description Qty Ref0010056900 ULTRAA LAMP CONTROL MODULE 1 -0110499490 ASSY LOOM ULTRAALAMP LAMPS SUPPLY 1 6-50110499590 ASSY LOOM ULTRAALAMP MAINS DISTRIB’N 1 6-50110499690 ASSY LOOM ULTRAALAMP INTERMEDIATE 1 6-50110499790 ASSY LOOM ULTRAALAMP CONTROL 1 40110500090 ASSY LOOM MAINS INPUT FILTERED 1 150110532990 ASSY LOOM ULTRAALAMP RETROFIT 1 -0110535590 ASSY LOOM 4 LAMP Z ULTRAA 600 1 -0110582390 ASSY LOOM 4 LAMP Z ULTRAA 800 1 -0110582490 ASSY LOOM 8 LAMP Z ULTRAA 800 1 -0210142790 ASSY PWB ULTRAA LAMP SUPPLY 1 200510024500 CAPACITOR 560UF 250V/ELECTRO CDDG 1 80510029500 CAPC EL 33UK 25V C4321 1 110810121700 GLAND CABLE 5-10MM , HOLE DIAM 16MM 1 180910091700 COVER CABINET 1 -0910092500 PLATE SCREENPRINT 1 190910096200 PLATE SOCKET MOUNT 1 3-31210103800 COVER BURNDY/CABLE GLAND/CLAMP/SHELL 18 1 161210108500 HOUSING BURNDY 7WAY/PLUG/SOCKET CONTACTS 1 171210108600 HOUSING BURNDY 7WAY/PANEL/RECEPT/PIN CNCTS 1 3-31410106100 DIODE BR254 BRIDGE RECTIFIER 1 71910006400 FUSE 1 AMP/FAST ACTING/5x20MM/GLASS 1 9-11910006500 FUSE 2 AMP/FAST ACTING/5x20MM/GLASS 1 9-11910007000 FUSE 2 AMP/SLO-BLO/5x20MM/GLASS 1 9-11910008590 FUSEHOLDER PANEL MOUNT/5X20MM - QTY 2 2 131910008600 FUSE 4 AMP/SLO-BLO/5X20MM/GLASS 1 9-1



2110016400 INSULATOR PWB 1 214210103500 STANDOFFXM4X70 POLYPROPYLENE 1 104810022500 SWITCH ROCKER DPDT 1 64810025400 SWITCH SLIDE 240VAC/5AMP/DPDT 1 144910008600 TIE CABLE LARGE RELEASABLE 1 95310015700 TRANSFORMER ULTRAA-LAMP SUPPLY 300VA 1 25610025200 LAMP 110V 0.3W-RED C/W PUSHFIX 1 55610108100 LAMP ULTRAA ARSENIC 1 -5610108200 LAMP ULTRAA LEAD 1 -5610108300 LAMP ULTRAA SELENIUM 1 -7210020200 DRIVER HEX 2MM (COMPONENT REMOVAL FROM HEATSINK) 1 -7210020800 DRIVER HEX 3MM (250/600 TURRET DISK REMOVAL) 1 -7210026100 TOOL PIN REMOVAL AMP 305183-R 1 -7910019700 KIT ESD FIELD SERVICE 1 -9910076900 KIT ULTRAA LAMP RETROFIT 1 -9910077000 KIT ULTRAA LAMP SERVICE 1 -9910077100 KIT ULTRAA LAMP ELECTRONIC 1 -9910077200 KIT ULTRAA LAMP FASTENERS 1 -9910077500 KIT ULTRAA LAMP FUSES 1 -

Control module parts

This table lists the parts referenced in the exploded diagram of figure 6-1 in reference number order.

Ref Part Number Description Qty2 5310015700 TRANSFORMER ULTRAA-LAMP SUPPLY 300VA 14 0110499790 ASSY LOOM ULTRAALAMP CONTROL 15 5610025200 LAMP 110V 0.3W-RED C/W PUSHFIX 16 4810022500 SWITCH ROCKER DPDT 17 1410106100 DIODE BR254 BRIDGE RECTIFIER 18 0510024500 CAPACITOR 560UF 250V/ELECTRO CDDG 19 4910008600 TIE CABLE LARGE RELEASABLE 1

10 4210103500 STANDOFFXM4X70 POLYPROPYLENE 111 0510029500 CAPC EL 33UK 25V C4321 113 1910008590 FUSEHOLDER PANEL MOUNT/5X20MM - QTY 2 214 4810025400 SWITCH SLIDE 240VAC/5AMP/DPDT 115 0110500090 ASSY LOOM MAINS INPUT FILTERED 116 1210103800 COVER BURNDY/CABLE GLAND/CLAMP/SHELL 18 117 1210108500 HOUSING BURNDY 7WAY/PLUG/SOCKET CONTACTS 118 0810121700 GLAND CABLE 5-10MM , HOLE DIAM 16MM 119 0910092500 PLATE SCREENPRINT 120 0210142790 ASSY PWB ULTRAA LAMP SUPPLY 121 2110016400 INSULATOR PWB 1

✒ Note: Items 1, 3 and 12 are not available separately. If required, they can be obtainedby ordering the kit of UltrAA lamp fasteners, part number 99 100772 00.

Loom interconnection

This table should be referred to in conjunction with the interwiring diagram of the Electronics section for loomidentification.

Part Number Description From To0110499490 ASSY LOOM ULTRAA LAMP LAMPS SUPPLY PL4/7 1SK20110499590 ASSY LOOM ULTRAA LAMP MAINS DISTR’N 1T1 (prim) 1SW1/2/30110499690 ASSY LOOM ULTRAA LAMP INTERMEDIATE 1T1 (sec) PL1/2/50110499790 ASSY LOOM ULTRAA LAMP CONTROL 1SW4/5 PL3/60110500090 ASSY LOOM MAINS INPUT FILTERED 1SK1 1FS1/2



7 Diagnostics

This section of the manual provides diagnostic and trouble-shooting informationfor the UltrAA lamp accessory, and may be used in conjunction with theElectronics section.

7.1 Diagnostic LEDsDue to the simplicity of this design, the only diagnostic aids provided for theUltrAA lamp control module are on-board light emitting diode (LED) voltagestatus indicators.

An LED that is illuminated (on), indicates the presence of the monitored voltageto be within the range specified below.

LED and test point locations

CircuitReference

IndicatedVoltage Status

LED "On"Voltage

D25 Lamp run > 70 VDC

D26 Lamp strike > 350 VDC

D27 +15 VDC -

D28 -15 VDC -

* 1 Boost current 1 > 80 mA

* 2 Boost current 2 > 80 mA

* There are two LED indicators located on the front panel lamp control switchesof the UltrAA lamp control module labelled 1 and 2. When illuminated, theyindicate that lamp 1 and/or 2 has been struck and is running with boost currenton.



Warning The LED voltage status indicators are provided as a quick visual referenceonly. A non illuminated LED does not guarantee the absence of a voltage. Toavoid death, serious injury, or painful electric shock, never touch electricalcomponents or connectors until at least 18 seconds after power supply isswitched off.

7.2 Test pointsThe following test points are provided so that safe and secure "hands-free"connections can be made to test equipment without the need to place handsnear high voltages.

Warning All electrical components float above chassis ground with some potentialdifferences > 500V DC. To avoid death, serious injury, or painful electricshock,never touch electrical components or connectors until at least 18 seconds afterpower supply is switched off.

Caution When connecting test equipment to the UltrAA lamp accessory, ensure thatthe test equipment is not grounded and that leads are fully insulated. To avoiddamage to test equipment, the accessory or the AA instrument connected,never earth any part of the circuit through test equipment or otherwise.

Prior to making any measurements, ensure that test equipment probes are ofsufficient voltage rating.

TP1 +15 VDC

Measure with reference to TP2.Tolerance is ±5% (+14.25 V to +15.75 V).

TP2 Common (not chassis ground)

TP3 -15 VDC

Measure with reference to TP2.Tolerance is ±5% (-15.75 V to -14.25 V).

TP4 Lamp 1 filament voltage

Measure with reference to TP5 with an UltrAA lamp connected. Withthe lamp control switch 1 set as follows:‘Off’ 1.2 VDC ±10%‘On’ before striking 12 VDC ±10%‘On’ after striking 5 VDC ±10%

TP5 Lamp 1 cathode/filament return



TP6 Lamp 2 filament voltage

Measure with reference to TP7 with an UltrAA lamp connected. Withthe lamp control switch 2 set as follows:‘Off’ 1.2 VDC ±10%‘On’ before striking 12 VDC ±10%‘On’ after striking 5 VDC ±10%

TP7 Lamp 2 cathode/filament return

R13 Lamp 1 boost current sense resistor

Measure the voltage across R13 with an UltrAA lamp connected andrunning.The voltage should be 1.50 VDC +10% / -5% (1.65 V to 1.42 V).

This directly relates to a boost current of 150 mA +10% / -5%

R29 Lamp 2 boost current sense resistor

Measure the voltage across R29 with an UltrAA lamp connected andrunning.The voltage should be 1.50 VDC +10% / -5% (1.65 V to 1.42 V).

This directly relates to a boost current of 150 mA +10% / -5%

C2 Strike voltage capacitor

The strike voltage can be measured between the positive (+)terminal of C2 and TP5 [TP7].This voltage should be 400 ±60 VDC (340 V to 460 V).

The run voltage can be measured between the negative (-) terminalof C2 and TP5 [TP7].This voltage should be 40 ±10 VDC (30 V to 50 V) with the boostoperating and approximately 80 VDC when the boost is off.



9 Electronics

This section provides detailed descriptive information on the electrical operationof the UltrAA lamp accessory. It may be referred to in conjunction with theDiagnostic section of this manual.

To access the UltrAA lamp accessory’s circuit board, remove the two screwssecuring the cover at the top of the rear panel and slide it forward to lift it off thebase.

Access to the rear of the fuse holders, bridge rectifiers and large filtercapacitors will require the removal of the UltrAA lamp supply circuit board andthe underlying transparent insulator.

Warning All electrical components float above chassis ground with some potentialdifferences > 500V DC. To avoid death, serious injury, or painful electricshock,never touch electrical components or connectors until at least 18 seconds afterpower supply is switched off.

Caution The internal power power supply common operates above chassis groundpotential. To avoid damaging the power supply or the associated AAinstrument, never connect the common to chassis ground.

9.1 Input power sectionThe mains power inlet connector on the rear panel is an integral line filter withvaristor attached.

Control module rear panel

Mains input line voltage to the UltrAA lamp accessory is selected using SW2and SW3, located on the rear panel of the control module.

Fuses FS1 and FS2 are delay acting and located in M205 (20 mm x 5 mm) fuseholders on the rear panel. Refer to the table below for fuse ratings and voltageselector switch settings.



Nominal Voltage SW2 SW3 Fuse Rating240 ±10% A D

230 +14% -6% T 2A230 +6% -14% B D

220 ±10%120 ±10% A C T 4A100 ±10% B C

The transformer, 1T1, is mounted onto a base plate, along with three filtercapacitors and diode bridge rectifiers. No components are mounted directlyonto the accessory's base.

The secondary windings of the transformer are allocated to provide thefollowing functions:

120 VAC 500 VDC lamp anode strike voltage.

66 VAC 90 VDC lamp anode running voltage (referenced to ±15 VDCsupply).

18/0/18 VAC ±15 VDC power supply.

14 VAC 12/5 VDC lamp 1 filament voltage.

14 VAC 12/5 VDC lamp 2 filament voltage.

✒ Note The above secondary windings carry floating voltages. That is, these voltagesare not referenced to chassis or mains ground.

9.2 Circuit descriptionUltrAA hollow cathode lamp boost current is supplied by the UltrAA lamp controlmodule, independently of SpectrAA instrument circuitry.

The boost discharge is supplied by a filament which acts as a cathode for theboost circuit. There are two anodes; one used by the SpectrAA instrument as ina standard hollow cathode lamp and the other for the boost discharge. That is,the boost discharge is directed across the mouth of the hollow cathode and notthrough it. This is achieved by allowing the boost supply to float above chassisground.



9.2.1 Run/strike voltage circuit

The 120 VAC transformer tapping voltage is doubled and stored asapproximately 400 VDC across the capacitor, C2, to be used for striking theUltrAA hollow cathode lamp.

With the lamp control switch in the ‘on’ position, relay RLA [RLB] will beenergised, resulting in placement of the run voltage onto the boost anode of theUltrAA hollow cathode lamp. The run voltage (approx. 90 VDC) is supplied bydiode bridge rectification of the 66 VAC tapping of the transformer. It isreferenced to the common of the ±15 VDC supply.

On activation of the lamp control switch’s momentary ‘strike’ position, theoptical AC switch (IC1/IC2) will conduct and discharge the strike voltage storedin C2 through the boost anode of the lamp, causing it to strike. The return pathfor the strike/run current is through the filament/cathode (not shown).

{ EMBED Word.Picture.6 }

By the nature of the optical AC switch (IC1/IC2), it will continue to conduct evenafter the UltrAA hollow cathode lamp has struck and its control voltage hasbeen removed. Diode D5 [D6] will start to conduct once the anode voltage hasdropped below the run voltage. When the lamp control switch is returned to the‘off’ position, relay RLA [RLB] is de-energised, hence the current falls to zeroand the optical AC switch will cease to conduct.

The comparators of IC9 monitor the above circuitry for the presence of the runand strike voltages. Their presence is indicated by illumination of diodes D25and D26 respectively. For further detail, refer to the Diagnostics section of thismanual.



9.2.2 Filament voltage circuit

14 VAC from the transformer is diode bridge rectified (approx. 18 VDC) and isthen supplied to an LM317T adjustable voltage regulator (IC7 [IC8]).

While the lamp control switch is in the ‘off’ position, relay RLA [RLB] will be de-energised, thus the resistor network (R21/22/23) [(R37/38/39)] on the voltageadjustment pin of the voltage regulator is shorted out. This results in theregulator reference voltage of 1.2 VDC being supplied across the UltrAA hollowcathode lamp boost filament.

In the ‘on’ position and prior to striking, relay RLA [RLB] will be energised andRLC [RLD] de-energised, thus the resistor R21 [R37] will be switched out of theresistor network. This results in the supply of 12 VDC across the filament to aidstriking.

In the ‘on’ position and with the lamp’s boost current struck, both relay RLA[RLB] and RLC [RLD] will be energised, thus the resistor R21 [R37] will beswitched into the resistor network. This results in a reduced supply of 5 VDCacross the filament to extend filament life and reduce the heat generated withinthe UltrAA hollow cathode lamp.

A recommended period of about three seconds should be allowed between the‘on’ and ‘strike’ positions of the lamp control switch to allow boost filamentwarming.

9.2.3 Constant current circuit

Constant boost current regulation, fixed at approximately 150 mA, is providedby a return-line current sensing circuit.

The current through R13 [R29] (the boost current) is monitored and comparedby the op-amp IC3 [IC4] with the reference voltage produced by the voltagedivider of R8 and R9 [R24 and R25]. The resultant error signal is used to drivethe gate of the MOSFET TR1 [TR3] to provide the required current.

Overvoltage protection for the operational amplifier is provided by the zenerdiode D9 [D17] and for the MOSFET by D12 [D20].




9.2.4 Boost current sense circuit

The comparators of IC9 also monitor the boost current. If the boost current ispresent, the comparator will energise relay RLC [RLD] resulting in the reductionof the filament voltage from 12 V to 5 V (refer to 5.2.2). It will also illuminate theLED located on the front panel lamp control switch/s to indicate that the UltrAAhollow cathode lamp has struck and is operating with normal boost current.


9.2.5 ±15 VDC supply circuit

The ±15 volts required for the powering of the operational amplifiers andcomparators is derived from an LM79L15 (-15 V) and an LM340T-15 (+15V)voltage regulator (IC5 and IC6 respectively). These are supplied from an on-board bridge rectifier (DB1) connected to the 18/0/18 V tapping of thetransformer. This power supply is designed to provide approximately 100 mA ofcurrent.

9.3 Output power sectionThe table below is a quick reference to the pin positioning of the output stage ofthe boost supply.

Pin Number PCB PL4 PCB PL7 UltrAA connector

1 Boost anode 1 Boost anode 2 Boost anode 1

2 Boost filament 1 Boost filament 2 Boost filament 1

3 Boost filamentreturn/boostcathode 1

Boost filamentreturn/boostcathode 2

Boost filamentreturn/boost cathode 1

4 Boost anode 2

5 Boost filament 2

6 Boost filamentreturn/boost cathode 2



2

3

4

5

6

78

9

10

12

13

12021

11

14

15

16

17

18

19

Fig. 6-1 UltrAA lamp control module exploded diagram

ultra lamp

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