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Fluke 5725A instruction manual Accessing the Current Amplifier Assembly A2, 6-10

Models: 5725A

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Maintenance 6

Access Procedures

4.If you want to completely remove the Digital assembly, remove the ribbon cable by releasing the catches on the board-mounted connector.

Caution

When replacing the Digital assembly, make sure the ribbon cable is pulled fully into the 5725A chassis. Be sure to leave no fold trapped between the back of the pca and the metal panel or else shorting to the component leads can occur.

Accessing the Current Amplifier Assembly (A2)

6-10.

Warning

To avoid electrical shock, do not proceed with the following access procedure until you have completed the initial access procedure, which removes line power and checks for high voltage on the power supply. This assembly drops into an area of live line voltage.

The Current Amplifier assembly lays flat on the top of the instrument, toward the front. Proceed as follows to access the Current Amplifier assembly:

1.Perform the Initial Access Procedure.

2.Turn over the 5725A so that the bottom is facing up.

3.Remove the bottom cover by removing the six screws on the bottom surface.

4.Remove the two screws labeled _A and _B and turn the 5725A over again.

5.Remove the five retaining screws on the Current Amplifier assembly. Lift the Current Amplifier assembly by pulling on the plastic wire-tie loops, and place the assembly in the service position.

Caution

When reinstalling the assembly, refer to Figure 6-6 and make sure cable harnesses are dressed as shown, to avoid shorting wires to the bridge rectifier heat sink or chassis.

Note

When reinstalling the assembly, lower it into place squarely to make sure its connector seats correctly in the Interconnect assembly connector.

6-11

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Fluke 5725A instruction manual Accessing the Current Amplifier Assembly A2, 6-10

Contents

5725A Instruction ManualAmplifier Page Table of Contents Theory of Operation 5725ACalibration and Verification Instruction Manual 5725AList of Tables TableTitle Instruction Manual 5725AList of Figures FigureTitle 5725A viiiInstruction Manual Interference Information Declaration of the Manufacturer or ImporterBescheinigung des Herstellers/Importeurs Page Terms in this Manual OPERATOR SAFETY SUMMARYHIGH VOLTAGE LETHAL VOLTAGEUse the Proper Fuse Symbols Marked on EquipmentPower Source Use the Proper Power CordUse Care When Servicing With Power On SERVICING SAFETY SUMMANYFOR QUALIFIED SERVICE PERSONNEL ONLY Do Not Service AloneNever Accept Ordinary and General Tests for Death FIRST AID FOR ELECTRIC SHOCKFree the Victim From the Live Conductor Get HelpChapter Introduction and SpecificationsInstruction Manual 5725AIntroduction Where to Go From Here 5700A Operator Reference Guide How to Use the Manuals5725A Instruction Manual 5700A Operator Manual5700A Service Manual Specifications±5C from calibration temperature Introduction and SpecificationsSpecifications DC Voltage Range Resolution5725A Instruction ManualAC Voltage Introduction and Specifications SpecificationsAC Voltage continued Voltage Range 5725AInstruction Manual AC Voltage continuedTemperature Introduction and SpecificationsSpecifications ±5C from calibration temperatureNote5725A Instruction Manual Two-WireCompFour-Wire Four-WireIntroduction and Specifications SpecificationsDC Current 5725A Instruction ManualAC Current Introduction and Specifications SpecificationsAC Current continued Instruction Manual ResolutionResolution 5725ATemperature performance: Operating: 0C to 50C Introduction and SpecificationsSpecifications General SpecificationsInstruction Manual 5725AConnecting to the 5700A Calibrator InstallationService Information Placement and Rack MountingInstruction Manual 5725AUnpacking and Inspection InstallationIntroduction VOLTAGE/CURRENT 5725AInstruction Manual TYPEService Information Service InformationPlacement and Rack Mounting Cooling ConsiderationsFigure 2-2.Correct Way to Dress Interface Cable Connecting to the 5700A CalibratorSelecting Line Voltage Selecting Line VoltagewCaution Accessing the FuseConnecting to Line Power Connecting to Line PowerInstruction Manual 5725AChapter Operating NotesInstruction Manual 5725AOperating Notes Introduction5725A Front Panel FeaturesFigure 3-1.Front Panel Features POWER5725A STANDBY Indicator A B C D E F G HRear Panel Features Table 3-1.Front Panel FeaturesInstruction Manual Rear Panel FeaturesFigure 3-2.Rear Panel Features 5725A5700A CALIBRATOR Connector A B C D E F G H ITable 3-2.Rear Panel Features CALIBRATION SwitchWarm Up Turning on the 5725A AmplifierStandby 5725A Operating Functions and ModesVoltage Standby 5725A Operating Functions and Modes Current Standby3-10 Voltage OperateCurrent Operate 3-11Conditions That Activate the 5725A 3-12 Conditions That Activate the 5725AChapter Theory of OperationHigh Voltage Amplifier Feedback High Voltage Sense Assembly A6High Voltage Amplifier A3 High Voltage Heat Sink AssembliesIntroduction Overall Functional DescriptionFigure 4-1.5725A Overall Block Diagram 5725AInstruction Manual 1100V AC Range Functional Description 11A Range Functional Description Voltage Standby Operation in the 11A DC RangeOperation in the 11A AC Range Voltage and Current Standby Modes4-11 How the 5700A and 5725A Communicate4-10 Description of the Out-GuardLines 5725A Side4-12 Description of the In-GuardLines4-13 Functional Summaries by Assembly4-15 Interconnect Assembly A1Detailed Circuit Description 4-144-16 Power Supply Assembly A4REF DES High Voltage Supply Section4-17 ASSEMBLY4-18 Switching Section4-20 Current-LimitSection4-19 System Supply Section4-22 Digital Assembly A5Fan Supply Section 4-21aq19f.eps Figure 4-2.Digital Assembly Block DiagramTheory of Operation Detailed Circuit Description4-27 EEROM4-26 Data LatchBreak-DetectCircuitry Power Up and Reset CircuitryWatchdog Timer Current Amplifier Assembly A25725A Instruction Manualaq20f.eps 4-35 Error Amplifier Section4-37 Output Stage Section4-36 Monitor Section4-39 Control and Switching SectionPower Supply Section 4-384-41 High Voltage Amplifier A34-40 Input AmplifierTheory of Operation Detailed Circuit Descriptionaq22f.eps 4-43 Integrator4-42 Window Comparator4-46 Transconductance and Cascode Stage4-45 Midstage4-50 Autobias Current Source4-49 Autobias Sense Circuit4-51 Signal TransformersTemperature Monitoring High Voltage Amplifier Feedback4-54 High Voltage Sense Assembly A6Theory of Operation Detailed Circuit Descriptionaq21f.eps 4-55 Sense Amplifier Section±3.2V during calibration STANDBY VOLTAGE LIMITS1 Analog Monitor Section4-56 SIGNAL4-58 Analog Input Switching SectionSerial Interface/Guard Crossing Section 4-574-59 Control Section4-60 AC Line Voltage Selection SectionInstruction Manual 5725AChapter Calibration and VerificationInstruction Manual 5725AWhere to Find Further Information IntroductionCalibration and Verification Instruction Manual 5725AChapter MaintenanceInstruction Manual 5725AIntroduction Replacing the FuseCleaning the Air Filter General Cleaning Cleaning PCA’sGeneral Cleaning B. BOTTOM VIEW Access ProceduresFigure 6-3.Assembly Location Diagram A. TOP VIEWwWarning Initial Access ProcedureHIGH VOLTAGE Accessing the Digital Assembly A5 Accessing the Power Supply Assembly A4Instruction Manual WHEN REINSTALLING DIGITAL ASSEMBLYFigure 6-5.Accessing the Digital Assembly 5725A6-10 Accessing the Current Amplifier Assembly A2Accessing the High Voltage Amplifier A3 6-11Figure 6-6.Correct Way to Dress Cables 6-12 Accessing the High Voltage Sense Assembly A66-14 Accessing the High Voltage Output TransistorsAccessing the Interconnect Assembly A1 6-136-15 Enabling Front or Rear Binding Posts9.Reinstall the top cover Chapter TroubleshootingInstruction Manual 5725A5725A Fault Codes Self DiagnosticsIntroduction MESSAGE Table 7-1.5725A Fault CodesFAULT 5725A Instruction ManualMESSAGE Self DiagnosticsTable 7-1.5725A Fault Codes cont FAULTManual Tests for Fault Isolation MESSAGE Manual Tests for Fault IsolationTable 7-2.Analog Monitor Faults FAULT NOProblem 5 Fault When Entering Current Operate Reduced-VoltageTroubleshooting ModeProblem 3: Fault When Entering Voltage Operate Problem 4: Fault When Entering Current StandbyTesting the Power Supply By Itself 7-10Testing the Power Supply By Itself Instruction Manual 5725AChapter List of Replaceable PartsInstruction Manual 5725AIntroduction How to Obtain PartsManual Status Information Newer Instruments5725A Service CentersAssembly Name Table 8-1.Final AssemblyList of Replaceable Parts Table 8-1.Final Assembly contFigure 8-1.Final Assembly 5725Aaq24f.tif Figure 8-1.Final Assembly cont List of Replaceable Partsaq25f.tif aq26f.tif Figure 8-1.Final Assembly cont5725A Instruction ManualFigure 8-1.Final Assembly cont List of Replaceable Partsaq27f.tif aq28f.tif Figure 8-1.Final Assembly cont5725A Instruction ManualFigure 8-1.Final Assembly cont List of Replaceable Partsaq29f.tif aq30f.tif Figure 8-1.Final Assembly cont5725A Instruction ManualFigure 8-1.Final Assembly cont List of Replaceable Partsaq31f.tif Table 8-2.A1 Interconnect PCA 5725Aaq36f.eps List of Replaceable Parts5725A-1611 Figure 8-2.A1 Interconnect PCA5725A Instruction ManualTable 8-3.A2 Current Amplifier PCA Table 8-3.A2 Current Amplifier PCA cont List of Replaceable PartsReference Description Designator 5725AInstruction Manual Table 8-3.A2 Current Amplifier PCA contaq37f.eps List of Replaceable Parts5725A-1650 Figure 8-3.A2 Current Amplifier PCA5725A Instruction ManualTable 8-4.A3 High Voltage Amplifier PCA List of Replaceable Parts Table 8-4.A3 High Voltage Amplifier PCA contDesignator R640,R642 5725AInstruction Manual Table 8-4.A3 High Voltage Amplifier PCA contaq38f.eps List of Replaceable Parts5725A-1661 Figure 8-4.A3 High Voltage Amplifier PCATable 8-5.A4 Power Supply PCA 5725AInstruction Manual List of Replaceable Parts Table 8-5.A4 Power Supply PCA contR351 R355 R361,R362 Table 8-5.A4 Power Supply PCA cont5725A Instruction Manualaq39f.eps Figure 8-5.A4 Power Supply PCAList of Replaceable Parts 5725A-16315725A Instruction ManualTable 8-6.A5 Digital PCA aq40f.eps List of Replaceable Parts5725A-1650 Figure 8-6.A5 Digital PCATable 8-7.A6 High Voltage Sense PCA 5725ATable 8-7.A6 High Voltage Sense PCA cont List of Replaceable PartsR154 R155 R156,R158,R168 R173 R162 R171 R172,R175 5725AInstruction Manual Table 8-7.A6 High Voltage Sense PCA contaq41f.eps List of Replaceable Parts5725A-1601 Figure 8-7.A6 High Voltage Sense PCATable 8-8.A12 Transformer Enclosure Assembly 5725AInstruction Manual Figure 8-8.A12 Transformer Enclosure Assembly List of Replaceable Partsaq32f.tif aq33f.tif 5725Aaq34f.tif List of Replaceable Parts5725A Instruction Manualaq35f.tif Figure 8-9.A30 Inductor PCA List of Replaceable PartsTable 8-9.A30 Inductor PCA 5725A-16035725A Chapter Schematic DiagramsInstruction Manual 5725Aaq48f.eps Schematic Diagrams5725A-1611 Figure 9-1.A1 Interconnect PCA5725A Instruction ManualFigure 9-1.A1 Interconnect PCA cont Figure 9-1.A1 Interconnect PCA cont Schematic Diagrams5725A-1650 5725AInstruction Manual Figure 9-2.A2 Current Amplifier PCAFigure 9-2.A2 Current Amplifier PCA cont Schematic Diagrams5725A Instruction ManualFigure 9-2.A2 Current Amplifier PCA cont Figure 9-2.A2 Current Amplifier PCA cont Schematic Diagrams5725A-1661 5725AInstruction Manual Figure 9-3.A3 High Voltage Amplifier PCAFigure 9-3.A3 High Voltage Amplifier PCA cont Schematic Diagrams5725A Instruction ManualFigure 9-3.A3 High Voltage Amplifier PCA cont Schematic Diagrams Figure 9-4.A4 Power Supply PCAaq59f.eps 5725A Figure 9-4.A4 Power Supply PCA contFigure 9-4.A4 Power Supply PCA cont Schematic DiagramsTYPICAL COMMUNICATIONS ACTIVITY AT PINS 12 AND 13 OF U5075725A Instruction ManualFigure 9-5.A5 Digital PCA cont Schematic DiagramsVOLTAGE STANDBY 5725AInstruction Manual STANDBYFigure 9-6.A6 High Voltage Sense PCA cont Schematic Diagrams5725A Instruction ManualFigure 9-6.A6 High Voltage Sense PCA cont Figure 9-6.A6 High Voltage Sense PCA cont Schematic Diagrams5725A Instruction ManualFigure 9-6.A6 High Voltage Sense PCA cont Schematic Diagrams Figure 9-7.A12 Transformer Enclosure Assemblyaq45f.eps Instruction Manual 5725AIndex 5725A Page Instruction Manual 5725AManual Supplement rear Change #1