VR1, VR2 | Agilent Technologies AGILENT MODELS 6023A and 6028A

Table 5-5. A3 Front-Panel Board Parts List

Ref. Desig.	Agilent Model	Agilent Part Number	Description
R68	All	0698-6362	Resistor, fixed film 1KΩ 0.1% 1/8W
R69	All	0698-6343	Resistor, fixed film 9KΩ 0.1% 1/8W
R71	6023A	0698-6363	Resistor, fixed film 40KΩ 0.1% 1/8W
R71	6028A	0698-8861	Resistor, fixed film 6.66KΩ 0.1% 1/8W
R72	6023A	0698-7353	Resistor, fixed film 19KΩ 1% 1/8W
R72	6028A	0698-4493	Resistor, fixed film 34KΩ 1% 1/8W
R73	6023A	0757-0280	Resistor, fixed film 1KΩ 1% 1/8W
R73	6028A	0698-3476	Resistor, fixed film 6.00KΩ 1% 1/8W
R74	All	0683-1025	Resistor, fixed film 1KΩ 5% 1/4W
R75	All	0683-3025	Resistor, fixed composition 3KΩ 5% 1/4W
R77	All	0757-0458	Resistor, fixed film 51.1KΩ 1% 1/8W
R78	All	0698-3159	Resistor, fixed film 26.1KΩ 1% 1/8W
R79	All	0757-0441	Resistor, fixed film 8.25KΩ 1% 1/8W
R80	All	0757-0438	Resistor, fixed film 5.11KΩ +1% 1/8W
R81	All	0683-5135	Resistor, fixed composition 51KΩ ± % 1/4W
R82	All	0683-1025	Resistor, fixed composition 1KΩ 5% 1/4W
R83	All	0683-5125	Resistor, fixed composition 5.1KΩ ~5% 1/4W
R84	All	0683-1025	Resistor, fixed composition 1KΩ 5% 1/4W
R85	All	0757-0280	Resistor, fixed film 1KΩ 1% 1/8W
R86	All	0698-5808	Resistor, fixed film 4KΩ 1% 1/8W
R87	6023A	0698-3201	Resistor, fixed film 80KΩ 1% 1/8W
R87	6028A	0757-0449	Resistor, fixed film 20KΩ 1% 1/8W
R88	6023A	0757-0449	Resistor, fixed film 20KΩ 1% 1/8W
R88	6028A	0757-0453	Resistor, fixed film 30.1KΩ 1% 1/8W
R89	All	0683-5135	Resistor, fixed composition 51KΩ 5% 1/4W
R90	All	0757-0199	Resistor, fixed film 21.5KΩ + 1% 1/4W
R91	All	0683-5235	Resistor, fixed composition 51KΩ 5% 1/4W
R92,93	All	0757-0452	Resistor, fixed film 27.4KΩ 1% 1/8W
S1,2	All	5060-9436	Switch lighted pusbutton
U1	All	1826-0502	IC switch analog quad
U2	All	1826-0493	IC op amp lo-bias hi-impedance
U3	All	1826-0346	IC op amp dual general purpose
U4,5	All	1826-0876	IC A/D CMOS 3-1/2 DGT
U6	All	1820-1144	IC gate TTL LS NOR quad
U7	All	1826-0502	IC switch analog quad
U9	All	1826-0138	IC comparator GP quad
VR1	All	1902-3092	Diode zener 4.99V 2%
VR2	All	1902-0064	Diode zener 7.5V 5%
W4	All	7175-0057	Wire 22 AWG
W7	6028A	7175-0057	Wire 22 AWG
W8	6023A	7175-0057	Wire 22 AWG
W11	All	7175-0057	Wire 22 AWG

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Agilent Technologies AGILENT MODELS 6023A and 6028A service manual IC A/D Cmos 3-1/2 DGT, VR1, VR2

Contents

Autoranging Certification Safety Summary Safety Symbol Definitions Printing History Table of Contents Replaceable Parts Troubleshooting Circuit DiagramsSafety Considerations Scope Manual Revisions Item Description Calibration Procedure IntroductionTest Equipment Required Operation Verification Tests Type Required Characteristics USE Recommended Model Test Equipment Required Initial Setup 1KVA Calibration Procedure MON Vout Iout Measurement Techniques Performance TestsCR7 Current-Monitoring Resistor Setup Constant Voltage CV Tests Basic Test Setup RMS Measurement Test Setup, CV Pard Test Peak-To-Peak Measurement Test Setup, CV Pard Test 6023A 6028A KHz Noise, CV Peak-to-Peak Pard Load Transient Recovery Waveform Constant Current CC Tests CC Pard Test Setup Troubleshooting Initial Troubleshooting Procedures Control Board Test Connector, A2J7 PIN no Signal NameVdc WAVEFORM/CONDITIONS Source Repair and Replacement Electrostatic Protection A2 Control Board Removal A4 Power Mesh Board Removal Overall Troubleshooting ProcedureA3 Front-Panel Board Removal A1 Main Board Removal Using the Tables SetupNode Measurement Main Troubleshooting Setup Main Troubleshooting Setup Modified Mains Cord Set For Troubleshooting Troubleshooting No-Output Failures Front-Panel Troubleshooting A2J7-26 A2J7-25 PWM-ON PWM-OFF Defective Check Functional CircuitsBoard Troubleshooting Bias Supplies Symptoms Defective Circuit Check ComponentsSymptoms Defective Check Functional Circuits Board Node + Measurement Source Measurement Source Node +Node + N0DE Power Section Blocks Troubleshooting AC-Turn-on CircuitsSetup Measurement Source Setup Measurement Relay Enable Troubleshooting PWM & ClockPower Limit Troubleshooting DC-To-DC Converter + OUTPWM-ON PWM-OFF Troubleshooting CV Circuit Troubleshooting CC Circuit Troubleshooting OVP Circuit Troubleshooting Down ProgrammerA4U4OUT Waveforms SET Voltage Vdc Node + Page Autoranging Power Block Diagram Overview Block Diagram Simplified Schematic Simplified Schematic DC-to-DC Converter Down Programmer Pfet Control Signals Timing Diagram Constant-Voltage CV Circuit Power-Limit Comparator Constant-Current CC CircuitOvervoltage Protection OVP Circuit Control-Voltage Comparator Initial-Ramp Circuit Pulse-Width Modulator PWMBias Voltage Detector AC-Surge Dropout Detector Second-Delay Circuit Display CircuitsPage Replaceable Parts Reference Designators Ordering Information Description Abbreviations Electrical Parts CR1CR2 CR3 XA2P2 XA2P1Mechanical Parts Control Board Assembly CR3 Page Page Page VR4 VR3VR5 DS1 CR5DS5 VR1 IC A/D Cmos 3-1/2 DGTVR2 NPN SI Pfet TS1 Chassis Electrical A1TB1 A2 Board Mechanical PartsA3 Board Mechanical Parts A4 Board Mechanical Parts Option 220 220V Operation Option 240 240V Operation Component Location and Circuit Diagrams Schematic Diagram Notes Pin locations for other semi-conductors are shown below Top View, Top Covers Removed Main Board A1 Component Location Control Board A2 Component Location Front-Panel Board A3 Component Location Power Mesh Board A4 Component Location Page Page General Information SpecificationsOption 002 Hardware Table A-1. Specifications, Option Remote Programming Input Compliance Voltage ± Current Programming EnableOutput Impedance 10.2 k ohm ± 5% Temperature Coefficient Status Indicators Remote Trip and Remote Reset Timing Power-on PresetMaximum Output Voltage logic high + On State logic low Table A-1. Specifications, Option Pulse Timing Bias Supplies DC Output Ratings 25C ±Short Circuit Output Current Pard Typical Installation Connector Assembly Procedure Figure A-1. Mating Connector Assembly Operation Local/Remote Programming Resistance Voltage or Current Remote Resistance Programming Figure A-4. Calculating Value of Series Dropping Resistor Figure A-5. Remote Resistance Programming Remote Monitoring Status Indicators Remote Control Remote Reset Overvoltage Power-On Preset Figure A-8. Remote Control AC Dropout Buffer Circuit Multiple Supply System Shutdown Maintenance Bias Supplies Troubleshooting Resistance and Voltage Programming Troubleshooting Current Programming Figure A-11. Troubleshooting Current Programming of CV Mode Figure A-13. Troubleshooting Status Indicators Page Table A-3. Replacement Parts REF. Desig Model no Description 100 VR9 101 Indicator and Qualifier Symbols OLD Symbol NEW SymbolLogic Symbols and Definitions 102 Definitions Schematic Notes Schematic Diagram Notes 103 Schematic Notes Figure A-15. Option 002 Board, Component Location 104 Figure A-16. Option 002 Board, Schematic Diagram 105 Page Model 6028A Model 6023A107 From 108