Agilent Technologies AGILENT MODELS 6023A and 6028A Measurement Source, Node + N0DE

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Table 3 5. Performance Failure Symptoms (continued)

SYMPTOMS	DEFECTIVE	CHECK FUNCTIONAL CIRCUITS
	BOARD
CV overshoots	A2	A2U10A, A2CR20, A2R94

Output noise ( < 1KHz)	A2, A1	CV Circuit

Output noise ( > 1KHz)	A1, A4	Transformer A1T1, Output Filter, snubbers A4R7
		/R8 /C5 / CR5, A4R13/ 14 / C6 /CR6, A4R33 /C13
CV regulation, transient response,	A2, A1	Wrong sensing (paragraph 3-40), low ac mains
programming time		voltage, CV Circuit
CC regulation	A2	Low ac mains voltage, CC circuit

CV oscillates with capacitive loads	A2	A2U10, A2C51, A2R95, A2R96, A2R86, A2C47,
		A2R71, A2C36
CC oscillates with inductive loads	A2	A2U10, A2R86, A2C47, A2C43, A2R77, A2U3D,
		A2R30, A2C44, A2R76, A2R75, A2C42, A2C41,
		A2R16

+15V on A2 Control Board. Voltage regulator A2U12 regulates the voltage across resistor A2R29 to be 1.25Vdc. That sets the current through zener diode A2VR1 at 7.5mAdc. The output voltage is 1.25Vdc plus 11.7Vdc across A2VR1 plus the voltage across A2R34.

Circuit Included. + 15Vdc bias supply circuitry from connector pin A2P1-27 through test point A2J3-2 on A2 control board.

Setup. The Main Troubleshooting Setup, page 29. Apply the ac mains voltage to the bias transformer, and set the external supply to 0Vdc.

Input:

NODE (+ )	MEASUREMENT	SOURCE
A2U12(IN), A2C17(+)	≈ 24Vdc	A1U1, AlC1 (+)
Outputs:
NODE ( + )	N0DE ( - )	MEASUREMENT
A2U12 (OUT)	A2U12 (ADJ)	1.25Vdc
A2U12 (cath.)
A2U12 (anode.)	11.7Vdc
A2VR1 (anode.)
A2R34, A2R33	2.05Vdc
A2LR3 (cath.)
A2VR3 (anode.)	6.2Vdc

To check if load on + 15V is shorted, remove jumper A2W1 .

-15V on A2 Control Board. Voltage regulator A2U4 regulates the voltage across resistor A2R32 to be 1.25Vdc.

Circuit Included. -15Vdc bias supply circuitry from connector pin A2P1-30 through test point A2J3-21 on A2 control board.

Setup. The Main Troubleshooting Setup, page 29. Apply the ac mains voltage to the bias transformer, and set the external supply to 0Vdc.

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Contents Autoranging Certification Safety Summary Safety Symbol Definitions Printing HistoryTable of Contents Replaceable Parts Safety Considerations TroubleshootingCircuit Diagrams ScopeManual Revisions Item DescriptionTest Equipment Required Calibration ProcedureIntroduction Operation Verification TestsType Required Characteristics USE Recommended Model Test Equipment RequiredInitial Setup 1KVACalibration Procedure MONVout IoutMeasurement Techniques Performance TestsCR7 Current-Monitoring Resistor Setup Constant Voltage CV TestsBasic 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 PardLoad Transient Recovery Waveform Constant Current CC Tests CC Pard Test Setup Troubleshooting Initial Troubleshooting ProceduresVdc Control Board Test Connector, A2J7PIN no Signal Name WAVEFORM/CONDITIONS SourceRepair and Replacement Electrostatic ProtectionA2 Control Board Removal A3 Front-Panel Board Removal A4 Power Mesh Board RemovalOverall Troubleshooting Procedure A1 Main Board RemovalNode Using the TablesSetup MeasurementMain Troubleshooting Setup Main Troubleshooting SetupModified Mains Cord Set For Troubleshooting Troubleshooting No-Output Failures Front-Panel TroubleshootingA2J7-26 A2J7-25 PWM-ON PWM-OFF Defective Check Functional CircuitsBoard Symptoms Defective Check Functional Circuits Board Troubleshooting Bias SuppliesSymptoms Defective Circuit Check Components Node + Measurement SourceMeasurement Source Node +Node + N0DE Setup Measurement Source Power Section BlocksTroubleshooting AC-Turn-on Circuits Setup MeasurementRelay Enable Troubleshooting PWM & ClockPower Limit PWM-ON Troubleshooting DC-To-DC Converter+ OUT PWM-OFFTroubleshooting CV Circuit Troubleshooting CC CircuitTroubleshooting OVP Circuit Troubleshooting Down ProgrammerA4U4OUT Waveforms SET Voltage Vdc Node + Page Autoranging Power Block Diagram OverviewBlock Diagram Simplified Schematic Simplified Schematic DC-to-DC Converter Down ProgrammerPfet Control Signals Timing Diagram Constant-Voltage CV CircuitOvervoltage Protection OVP Circuit Power-Limit ComparatorConstant-Current CC Circuit Control-Voltage ComparatorBias Voltage Detector Initial-Ramp CircuitPulse-Width Modulator PWM AC-Surge Dropout DetectorSecond-Delay Circuit Display CircuitsPage Replaceable Parts Reference DesignatorsOrdering Information Description AbbreviationsCR2 Electrical PartsCR1 CR3XA2P2 XA2P1Mechanical Parts Control Board Assembly CR3 Page Page Page VR4 VR3VR5 DS1 CR5DS5 VR1 IC A/D Cmos 3-1/2 DGTVR2 NPN SI PfetTS1 Chassis ElectricalA3 Board Mechanical Parts A1TB1A2 Board Mechanical Parts A4 Board Mechanical PartsOption 220 220V Operation Option 240 240V OperationComponent 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 Output Impedance 10.2 k ohm ± 5% Temperature Coefficient Table A-1. Specifications, Option Remote ProgrammingInput Compliance Voltage ± Current Programming Enable Status IndicatorsMaximum Output Voltage logic high + Remote Trip and Remote Reset TimingPower-on Preset On State logic lowShort Circuit Output Current Table A-1. Specifications, Option Pulse TimingBias Supplies DC Output Ratings 25C ± Pard TypicalInstallation Connector Assembly ProcedureFigure A-1. Mating Connector Assembly OperationLocal/Remote Programming Resistance Voltage or Current Remote Resistance Programming Figure A-4. Calculating Value of Series Dropping ResistorFigure A-5. Remote Resistance Programming Remote Monitoring Status Indicators Remote ControlRemote Reset OvervoltagePower-On Preset Figure A-8. Remote ControlAC Dropout Buffer Circuit Multiple Supply System ShutdownMaintenance Bias SuppliesTroubleshooting Resistance and Voltage Programming Troubleshooting Current ProgrammingFigure A-11. Troubleshooting Current Programming of CV Mode Figure A-13. Troubleshooting Status Indicators Page Table A-3. Replacement Parts REF. Desig Model no Description100 VR9 101Logic Symbols and Definitions 102 Indicator and Qualifier SymbolsOLD Symbol NEW Symbol DefinitionsSchematic Notes Schematic Diagram Notes 103Schematic Notes Figure A-15. Option 002 Board, Component Location 104Figure A-16. Option 002 Board, Schematic Diagram 105 Page Model 6028A Model 6023A107 From 108