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Agilent Technologies 2712A HOW to Replace the Memory Backup Battery, Tools and Supplies, Parts

Models: 2712A 2948

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Model 890412

Service

HOW TO REPLACE THE MEMORY BACKUP BATTERY

Description

The battery that backs up non-volatile memory has a limited lifetime. It should be replaced every five years or whenever it shows signs of deterioration. Replacing the battery must be done carefully so as to not interrupt the contents of the RAM. If the RAM looses its contents, the entire A2 Digital Assembly will have to be replaced because its serial number and option information will be lost.

Replacing the backup battery consists of unplugging and freeing the A2 Digital Assembly, wiring a power supply and resistor to RAM power supply pin, removing the old battery and soldering in the new one, removing the power supply backup, and re-assembling the instrument.

The normal precautions against electrostatic discharge must be followed but

do not place the A2 Digital Control Assembly on a conductive metal

surface, which could short the battery or the RAM power supply pin.

The substitute power supply must be floating if the solder iron has a grounded tip. (All soldering is done with the HP8904A completely disconnected from the power line.)

Do not apply too much heat to printed circuit connections when soldering. The traces on the multilayer board are easily damaged.

Do not overstress the interconnecting cables.

Tools and Supplies

Desoldering Tool	Resistor, 10 kR
Needle Nose Pliers	Solder Iron
Power Supply (Floating) or 3V Battery	Torx Driver

Parts

If the instrument has serial prefix 2942A and below order a 2.8V battery (HP 1420-0281)and three insulators (HP 3050-0990). If the instrument has serial prefix 2942A and above order a 2.8V battery (HP 1420-0338).

Procedure

1.Switch LINE to OFF and disconnect the power cord.

2.Remove the instrument’s top cover. The cover may be tightly secured in the groove of the bottom cover. If the top cover does not pull off easily after backing out the screw on the rear edge, back out the screw on the rear edge of the bottom cover also.

rev.15DEC89

Troubleshooting (Memory Backup Battery)

8-48.1

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Agilent Technologies 2712A, 2948 manual HOW to Replace the Memory Backup Battery, Tools and Supplies, Parts

Contents

Agilent Technologies Innovating the HPWayMultifunction Synthesizer Copyright@ HEWLETT-PACKARD CompanyRegulatory Information Safety Considerations Safety Considerationsfor this Instrument Product Markings Contents Service cont’d Section Reu.200CT88Introductionto this Section Replaceable Parts ListReference Designationsand Abbreviations Used in this Manual Replaceable Parts List Updating Manual Updates How to OrderAbbreviations 1 AccessNable 6-1.Reference Designations ALCAbbreviations 2 Description Replaceable PartsRev.01JUL91 Number CodeHPPart Description Number Mfr- Mfr. Part Number Code Fible 6-3.Replaceable PartsCAPACITOR-FXD22PF +-5% Poovdc CER 0+-30 Not Assigned Reference HP Part Description Designation NumberReference HP Part Description Designation Number MfrRev.1 7MAY88 Me 6-3. Replaceable PartsReference HP Part Designation Number CONNECTOR-RFSMC M PC 5 W H M DIODE-SWITCHING 80V 200MA 2NS DO45Not Assigned Connector Spin M Post Type CONNECTOR-RF SMC M PC W H MReference Mfr RESISTOR-TRMR 1K 10% C TOP-ADJ 17-TRN Cable 6-3.Replaceable PartsHP Part Description RESISTOR-TRMR20K 10% C TOP-ADJ 17-TRNMfr. Part Number 0698-3430Rev.17MAY88 Description MfrIC Instm Ampl CUR 10-DIP-P PKG Transistor Array 16-PIN Plstc DIPIC OP AMP Prcn 8-DIP-C PKG IC OP AMP LOW-BIAS-H-IMPD 8-DIP4 PKGNble 6-3. Replaceable Parts HPPart DescriptionA10 L e 6-3. Replaceable PartsBle 6-3.Replaceable Parts Miscellaneous PartsHPPart Reference HPPart Description Mfr Designation Number CodeRIVET-BUND PL-STEM DOME-HD .125DIA Deck AssyRnftsund Plstem DOME-HD .125DIA RIVET-BUND Plstem Domehd .125DIAKeypad Punched PANEL, Front AYNot Separaretlyreplaceable Shield DisplayReference HPPart Designation Number QW. DescriptionQty.Description Designation Code Mfrm Mfr. Part Number Code Lbble 6-3. Replaceable PartsOrder by Description IZZ-9 Main Deck Assembly Top, 2923A and above Model 8904A Main Deck Assembly Bottom Main Deck Assembly Bottom, Option 006 2948A and above Reu.30NOV89 Front Panel Assembly, 2923A and above Rent Panel Assembly, Option 006 2948A and above Reu.30NOV89 Rear Panel Assembly Rear Panel Assembly, Option 005 2948A and above Rev.30N0 Covers, Labels, and ROMs Rev.ZSSEP88Output Cables 1 Output Cables, Option 005 29484 and above 2 Rev.30N0V89 Table of Contents Rev.15DEC89 Option ConversionsNumber 2942A and below Titled Hardware Modifications Instrument ModificationsRevision 22987A with HP 08904-8701 0 as A2U12 Parts Required Modification ProcedureFRONT-TO-REAR-PANELOUTPUT Conversion Description Tools RequiredFl Channel Config Operation VerificationDescription REAR-TO-FRONT-PANELOUTPUT ConversionRev.15DEC89 Rear-to-Front-Panel Output Conversion Fl Channel Config Ront Panel Output Hardware Output Cable Routing ALL Options Rev.01JUL91 Firmware UpdatesBardware Modifications Firmware Updates A2U12 and A2U13Different function Modification for Possible Ground Wire Shock Hazard Serial Prefix 2737A and belowParts Location Shown with Power Supply Removed Firmware Updates/Hardware ModificationsGround Wire Wrapping Firmware Updates/Hardware ModificationsHPPartNumber ~~ Qty Description Parts ListModification for Output Overvoltage Protection Improvement Fixed Resistor, 261 orModification for Potential Power Supply Short Cabinet Parts Color Change1. Modificationfor Front Panel Assembly Reu.15DEC89 Firmware UpdatesIHardwareModificationsRemoving the Front Panel Installingthe Front Panel Dont-Panel Assembly, 2923A and above A3 or A10 Output Assembly Phase Synchronization Option Section ServiceBefore Applying Power Safety ConsiderationsHOW the Section is Organized Iwarning Service TOOLS, HELPS, and Information Schematic Symbology and Schematic Diagram NotesSchematic Diagram Notes 1 Pin of socketSchematic Diagram Notes 2 Schematic Diagram Notes 3 Llzble 8-1.Schematic Diagram Notes 4 Digital Symbology Reference InformationSchematic Diagram Notes 5 Combinational Logic Symbols and FunctionsDigital Symbology Reference Information Schematic Diagram Notes 6Schematic Diagram Notes 7 Only with D-type flip-flops Gate and Dependency-BinaryLlable 8-1.Schematic Diagram Notes 8of MiscellaneousService Schematic Diagram Notes 9Schematic Diagram Notes 10 Active LevelsSchematic Diagram Notes 11 EnableWhat the Multifunction Synthesizer Can Do Principles of Operation OverallHow Waveforms Are Generated Channel a Generating Staircases in the Phase Accumulator Output of the Phase Adder for P=O, 1, Further Digital Waveform Processing with Options Pulse Phase @PHASE FreouencyFreouency SUM Pulse Level Interrelationshipof the Circuit Assemblies Analog Waveform ProcessingReu.15DEC89 Principles of Operation Overall Synthesizer PASSY- t A2 Digital Assembly GeneralDigital-to-Analog Converter Service Sheet A3 Output Assembly Service Sheets 1 through GeneralTrack-and-Hold Circuit Service Sheet Simplified Diagram of the Sampler Drive 10.Simplified Diagram of the Sampler Amplifier Sine X/X CompensationService Sheet Low-Pass Filters Service SheetAudio Amplifier Service Sheet 12, and 24 dB Attenuators Service SheetFloating Output Amplifier Service Sheet Floating Amplifier Driver and On/Off Switch Service SheetOvervoltage Protectionand Output Circuits Service Sheet Troubleshooting General Rev.15DEC89 Troubleshooting GeneralProcedure A2 Digital Assembly to A3 or A10 Output Assembly InterfaceEquipment 1. How to Access A3 in Instruments Equipped with Option Troubleshooting Digital/Output Interface Serial PrefixFl Channel Config PeriodFl Channel Config Pin Frequency HzA3/A10 Connection Function A3 Key Sequence A10 Key SequenceIC Pin Level F3 Memory Map Access J1 and J5 Clocks A10Pin Miscellaneous ControlA2 Digital Assembly to A1 Keyboard Assembly Interface Fl Keyboard CheckAMPTD, Wave Form Pin Key Pressed Response lTLF3 Memory Map Access Key Sequence Annunciator Status IC on A2 Pin Level lTLA2 Digital Assembly to A5 Display Assembly Interface DescriptionA3 or A10 Output Assembly Phase Synchronizationoption Troubleshooting Phase SynchronizationHP 8904A Opts After keying in 8 7, the display should be IFirmware Revision 18387A Serial No IFirmware Revision 18387A Serial No HP 8904A Opts 02/01After keying in 4 8, the display should be Begin again at step Tools and Supplies HOW to Replace the Memory Backup BatteryTroubleshooting Memory Backup Battery 48.1 PartsTroubleshooting Memory Backup Battery Rev.15DEC89 Troubleshooting Memory Backup Battery 48.3Page N a 12.4. Line Voltage Wiring Harness A3 Component Coordinates 1 R300Ipower Supply Conditioners L0nA Current SourceA3 Component Coordinates 2 CompSs2 On the A3 schematicRev.28MAR89 I813IldIll3 JJOlfl3 dWHS 31901 N3AILlO ONV15.Service Sheet Information Component Locator Changes Rev.28MAR89 54.1Coup OUT Aooitions I T I a L Instrument SettingsAmpto Instrument Settings Measure K2A+ a Component Coordinates 1Ss4 56.1Ss4 A6 Schematic and Component locator Ss5 Output Assembly 0 A3/A10