Manuals / Fluke / Home Audio / Stereo Amplifier

Fluke 5725A instruction manual High Voltage Amplifier A3, Input Amplifier

Models: 5725A

1 208

Download 208 pages 33.86 Kb

Page 94

5725A

Instruction Manual

4-40. High Voltage Amplifier (A3)

The High Voltage Amplifier assembly, operating with the step-up signal transformers, constitutes an amplifier with an inverting gain of 100. It amplifies 2.2V to 11V signals from the 5700A Oscillator and returns 220V to 1100V to the 5700A where they go to the 5700A OUTPUT HI/OUTPUT LO binding posts. The signals to and from the 5700A come through the High Voltage Sense assembly (A6) where they are switched.

The High Voltage Amplifier assembly consists of an input amplifier, integrator, window comparator, input clamp, transconductance and cascode stage, midstage, midstage -400V filter, high voltage heat sink assemblies, autobias current source, autobias sense circuit, high voltage amplifier feedback, and temperature monitoring circuits.

The High Voltage Amplifier drives the primary winding of the appropriate signal transformer depending on the frequency of operation. Signal transformers are interfaced to the High Voltage Amplifier via connector J604. Relays that select signal transformers are mentioned under the heading "Signal Transformers" further on.

The High Voltage Amplifier assembly uses the ±400V supplies from the Power Supply assembly. Lethal voltage appears on the heat sink assemblies. Do not open the 5725A cover without referring to the access procedures and warnings in Section 6.

Figure 4-4 is a block diagram of the High Voltage Amplifier assembly. Refer to the block diagram or the schematic to better understand theory of operation.

4-41. Input Amplifier

The input amplifier, U602, is an op amp whose input comes from HV IN on J653 through R623 and R621. HV IN is the 2.2V to 11V ac signal generated by the 5700A and routed through the High Voltage Sense assembly. The input amplifier has a high- frequency gain of 5.5, but because feedback resistor R622 is ac-coupled through C615, the gain is much higher at low frequencies. The inverting input of U602 is buffered with Q601. The nominal output of the input amplifier, LVAMP TP602, is about 6V dc.

4-24

Image 94

Fluke 5725A instruction manual High Voltage Amplifier A3, Input Amplifier

Contents

Instruction Manual 5725AAmplifier LIMITED WARRANTY AND LIMITATION OF LIABILITY Table of Contents 5725A Theory of OperationTroubleshooting MaintenanceCalibration and Verification Service Centers Schematic DiagramsHow to Obtain Parts Parts ListsTable List of TablesTitle 5725A 8-15Figure List of FiguresTitle viii 5725AInstruction Manual Declaration of the Manufacturer or Importer Interference InformationBescheinigung des Herstellers/Importeurs Page LETHAL VOLTAGE OPERATOR SAFETY SUMMARYHIGH VOLTAGE Terms in this ManualUse the Proper Power Cord Symbols Marked on EquipmentPower Source Use the Proper FuseDo Not Service Alone SERVICING SAFETY SUMMARYFOR QUALIFIED SERVICE PERSONNEL ONLY Use Care When Servicing With Power OnGet Help FIRST AID FOR ELECTRIC SHOCKFree the Victim From the Live Conductor Never Accept Ordinary and General Tests for DeathIntroduction and Specifications Chapter5725A Instruction Manual1-1.Introduction 1-2.Where to Go From Here 1-5.5725A Instruction Manual 1-3.How to Use the Manuals1-4.5725A Getting Started Manual 1-6.5700A/5720A Series II Manual Set1-11.Specifications 1-10.5700A/5720A Series II Service ManualDC Voltage Specifications 1-12.DC Voltage SpecificationsIntroduction and Specifications 5720A5700A 5725A5700A Instruction ManualNotes Introduction and SpecificationsDC Voltage Specifications Overshoot 5 %5720A 1-13.AC Voltage Specifications5725A Instruction Manual5720A Introduction and SpecificationsAC Voltage Specifications 95 % Confidence LevelInstruction Manual 5725A5700A 99 % Confidence Level5700A Introduction and SpecificationsAC Voltage Specifications 95% Confidence LevelInstruction Manual 5725ARange 5725A Amplifier Introduction and SpecificationsAC Voltage Specifications Figure 1-1. Volt-HertzCapability5720A 1-14.Resistance Specifications5725A 5720A5700A Introduction and SpecificationsResistance Specifications 5700A5725A Instruction ManualTable 1-12.Current Derating Factors Introduction and SpecificationsResistance Specifications I < IL5720A 99% 1-15.DC Current Specifications5725A 5720A 95%5700A Introduction and SpecificationsDC Current Specifications 5700ANotes 5725AInstruction Manual Overshoot: <5 %AC Current Specifications 1-16.AC Current SpecificationsIntroduction and Specifications 5720A 99%Instruction Manual 5725A5720A 95% 95 % Confidence Level5700A Introduction and SpecificationsAC Current Specifications 99 % Confidence LevelInstruction Manual 5725A5700A 95 % Confidence LevelAC Current Specifications Introduction and SpecificationsStability ±1 C Note 1-28 5725AInstruction Manual General Specifications 1-18.General SpecificationsIntroduction and Specifications Guard isolation: 20Temperature Coefficient for 0-18C and 28-50C 1-19.Auxiliary Amplifier Specifications5220A AC Current, 180-dayspecifications 5725ATitle InstallationChapter Page5725A Instruction Manual2-2.Unpacking and Inspection 2-1.IntroductionInstallation TYPE 5725AInstruction Manual VOLTAGE/CURRENT2-5.Cooling Considerations 2-3.Service Information2-4.Placement and Rack Mounting Service Information2-6.Connecting to the 5700A Calibrator Figure 2-2.Correct Way to Dress Interface Cable2-7.Selecting Line Voltage Selecting Line Voltage2-8.Accessing the Fuse 2-9.Connecting to Line Power Connecting to Line Power5725A Instruction ManualOperating Notes Chapter5725A Instruction Manual3-1.Introduction Operating NotesPOWER 3-2.Front Panel FeaturesFigure 3-1.Front Panel Features 5725ATable 3-1.Front Panel Features A B C D E F G HRear Panel Features 5725A STANDBY Indicator5725A 3-3.Rear Panel FeaturesFigure 3-2.Rear Panel Features Instruction ManualCALIBRATION Switch A B C D E F G HTable 3-2.Rear Panel Features 5700A CALIBRATOR Connector3-4.Turning on the 5725A Amplifier 3-5.Warm Up3-6.5725A Operating Functions and Modes 3-7.StandbyVoltage Standby Operating Notes Current Standby5725A Operating Functions and Modes 3-10 Voltage OperateOperating Notes 3-11Current Operate Conditions That Activate the 5725A3-12.Conditions That Activate the 5725A Theory of Operation ChapterHigh Voltage Heat Sink Assemblies High Voltage Sense Assembly A6High Voltage Amplifier A3 High Voltage Amplifier Feedback4-1.Introduction 4-2.Overall Functional Description5725A Figure 4-1.5725A Overall Block DiagramInstruction Manual 4-3.1100V AC Range Functional Description 4-4.11A Range Functional Description 4-7.Voltage and Current Standby Modes 4-5.Operation in the 11A DC Range4-6.Operation in the 11A AC Range 4-8.Voltage Standby4-10.How the 5700A and 5725A Communicate 4-11.Description of the Out-GuardLines 5725A Side4-12.Description of the In-GuardLines 4-13.Functional Summaries by Assembly 4-15.Interconnect Assembly A1 4-14.Detailed Circuit Description4-16.Power Supply Assembly A4 REF DES 4-17.High Voltage Supply SectionASSEMBLY Table 4-1.Internal Fuse Data4-18.Switching Section 4-19. Current-LimitSection 4-20.System Supply Section4-23.Microcomputer 4-22.Digital Assembly A54-21.Fan Supply Section 4-24.External RAMDetailed Circuit Description Figure 4-2.Digital Assembly Block DiagramTheory of Operation aq19f.eps4-28.Strobe Lines 4-26.EEROM4-27.Data Latch 4-29.Led Driver4-34.Current Amplifier Assembly A2 4-32.Power Up and Reset Circuitry4-33.Watchdog Timer 4-31. Break-DetectCircuitryInstruction Manual 5725Aaq20f.eps 4-35.Error Amplifier Section 4-36.Output Stage Section 4-37.Monitor Section4-38.Control and Switching Section 4-39.Power Supply Section4-40.High Voltage Amplifier A3 4-41.Input AmplifierDetailed Circuit Description Theory of Operationaq22f.eps 4-43.Window Comparator 4-42.Integrator4-44.Input Clamp 4-47.Midstage -400VFilter 4-45.Transconductance and Cascode Stage4-46.Midstage 4-48.High Voltage Heat Sink Assemblies4-49.Autobias Current Source 4-50.Autobias Sense Circuit4-51.High Voltage Amplifier Feedback 4-52.Signal Transformers4-53.Temperature Monitoring Table 4-2.Signal Transformer Usage4-54.High Voltage Sense Assembly A6 Detailed Circuit Description Theory of Operationaq21f.eps 4-55.Sense Amplifier Section ±3.2V during calibration STANDBY VOLTAGE LIMITS1 4-56.Analog Monitor SectionSIGNAL PHYSICAL4-58.Analog Input Switching Section 4-57.Serial Interface/Guard Crossing Section4-59.Control Section 4-60.AC Line Voltage Selection Section 5725A Instruction ManualCalibration and Verification Chapter5725A Instruction Manual5-1.Introduction 5-2.Where to Find Further InformationCalibration and Verification 5725A Instruction ManualFluke Corporation static awarenessA Message From 6.DO NOT SLIDE S.S. DEVICES OVER ANY SURFACE Maintenance Chapter5725A Instruction Manual6-1.Introduction 6-2.Replacing the Fuse6-3.Cleaning the Air Filter 6-5.Cleaning PCA’s 6-4.General CleaningGeneral Cleaning A. TOP VIEW 6-6.Access ProceduresFigure 6-3.Assembly Location Diagram B. BOTTOM VIEW6-7.Initial Access Procedure HIGH VOLTAGE 6-8.Accessing the Power Supply Assembly A4 6-9.Accessing the Digital Assembly A55725A WHEN REINSTALLING DIGITAL ASSEMBLYFigure 6-5.Accessing the Digital Assembly Instruction Manual6-10.Accessing the Current Amplifier Assembly A2 6-11.Accessing the High Voltage Amplifier A3 Figure 6-6.Correct Way to Dress Cables6-12.Accessing the High Voltage Sense Assembly A6 6-14.Accessing the Interconnect Assembly A1 6-15.Enabling Front or Rear Binding Posts 9.Reinstall the top cover Troubleshooting Chapter5725A 7-3.Self Diagnostics 7-2.5725A Fault Codes7-1.Introduction 5725A Instruction Manual Table 7-1.5725A Fault CodesFAULT MESSAGEFAULT Self DiagnosticsTable 7-1.5725A Fault Codes cont MESSAGE7-4.Manual Tests for Fault Isolation FAULT NO Manual Tests for Fault IsolationTable 7-2.Analog Monitor Faults MESSAGE7-9. Reduced-VoltageTroubleshooting Mode 7-10.Testing the Power Supply By Itself Testing the Power Supply By Itself5725A Instruction ManualList of Replaceable Parts Chapter5725A Instruction Manual8-1.Introduction 8-2.How to Obtain Parts8-5.Service Centers 8-3.Manual Status InformationTable 8-2.Final Assembly 8-6.Parts ListsAssembly Name 5725ATable 8-2.Final Assembly cont Parts ListsList of Replaceable Parts Instruction Manual Table 8-2.Final Assembly cont5725A TM1 W1 W13 W14 W15 W16 W44 XF501List of Replaceable Parts Parts ListsFigure 8-1.Final Assembly aq24f.tifInstruction Manual Figure 8-1.Final Assembly cont5725A aq25f.tifList of Replaceable Parts Parts ListsFigure 8-1.Final Assembly cont aq26f.tifInstruction Manual Figure 8-1.Final Assembly cont5725A aq27f.tifList of Replaceable Parts Parts ListsFigure 8-1.Final Assembly cont aq28f.tifInstruction Manual Figure 8-1.Final Assembly cont5725A aq29f.tifList of Replaceable Parts Parts ListsFigure 8-1.Final Assembly cont aq30f.tifInstruction Manual Figure 8-1.Final Assembly cont5725A aq31f.tifList of Replaceable Parts Parts ListsTable 8-3.A1 Interconnect PCA 5725A-1611 5725AInstruction Manual Figure 8-2.A1 Interconnect PCAList of Replaceable Parts Parts ListsTable 8-4.A2 Current Amplifier PCA Table 8-4.A2 Current Amplifier PCA cont 5725AInstruction Manual Reference Description DesignatorTable 8-4.A2 Current Amplifier PCA cont Parts ListsList of Replaceable Parts R233,R237,R238 R273 R243,R244 R247,R248Figure 8-3.A2 Current Amplifier PCA 5725A5725A-1650 aq37f.epsList of Replaceable Parts Parts ListsTable 8-5.A3 High Voltage Amplifier PCA 5725A Table 8-5.A3 High Voltage Amplifier PCA contTable 8-5.A3 High Voltage Amplifier PCA cont Parts ListsList of Replaceable Parts R640,R642 R641,R648 R643 R647 R651 R654,R661,R6845725A-1661 5725AInstruction Manual Figure 8-4.A3 High Voltage Amplifier PCAList of Replaceable Parts Parts ListsTable 8-6.A4 Power Supply PCA Reference DesignatorInstruction Manual Table 8-6.A4 Power Supply PCA cont5725A ReferenceList of Replaceable Parts Parts ListsTable 8-6.A4 Power Supply PCA cont R351 R355 R361,R362Instruction Manual Figure 8-5.A4 Power Supply PCA5725A 5725A-1631Table 8-7.A5 Digital PCA Parts ListsList of Replaceable Parts Reference5725A-1650 5725AInstruction Manual Figure 8-6.A5 Digital PCAList of Replaceable Parts Parts ListsTable 8-8.A6 High Voltage Sense PCA Instruction Manual 5725ATable 8-8.A6 High Voltage Sense PCA cont Table 8-8.A6 High Voltage Sense PCA cont Parts ListsList of Replaceable Parts R154 R155 R156,R158,R168 R173 R162 R171 R172,R1755725A-1601 5725AInstruction Manual Figure 8-7.A6 High Voltage Sense PCATable 8-9.A12 Transformer Enclosure Assembly Parts ListsList of Replaceable Parts 5725A Figure 8-8.A12 Transformer Enclosure Assemblyaq32f.tif List of Replaceable Parts Parts Listsaq33f.tif Instruction Manual 5725Aaq34f.tif List of Replaceable Parts Parts Listsaq35f.tif Table 8-10.A30 Inductor PCA 5725AInstruction Manual Figure 8-9.A30 Inductor PCASchematic Diagrams Chapter5725A Figure 9-1.A1 Interconnect PCA Schematic Diagrams5725A-1611 aq48f.epsInstruction Manual 5725AFigure 9-1.A1 Interconnect PCA cont Schematic Diagrams Figure 9-1.A1 Interconnect PCA contFigure 9-2.A2 Current Amplifier PCA 5725AInstruction Manual 5725A-1650Schematic Diagrams Figure 9-2.A2 Current Amplifier PCA contInstruction Manual 5725AFigure 9-2.A2 Current Amplifier PCA cont Schematic Diagrams Figure 9-2.A2 Current Amplifier PCA contFigure 9-3.A3 High Voltage Amplifier PCA 5725AInstruction Manual 5725A-1661Schematic Diagrams Figure 9-3.A3 High Voltage Amplifier PCA contInstruction Manual 5725AFigure 9-3.A3 High Voltage Amplifier PCA cont Figure 9-4.A4 Power Supply PCA Schematic Diagramsaq59f.eps 5725A Figure 9-4.A4 Power Supply PCA contInstruction Manual Schematic Diagrams Figure 9-4.A4 Power Supply PCA contInstruction Manual AT PINS 12 AND 13 OF U5075725A TYPICAL COMMUNICATIONS ACTIVITYSchematic Diagrams Figure 9-5.A5 Digital PCA contSTANDBY 5725AInstruction Manual VOLTAGE STANDBYSchematic Diagrams Figure 9-6.A6 High Voltage Sense PCA contInstruction Manual 5725AFigure 9-6.A6 High Voltage Sense PCA cont Schematic Diagrams Figure 9-6.A6 High Voltage Sense PCA contInstruction Manual 5725AFigure 9-6.A6 High Voltage Sense PCA cont Figure 9-7.A12 Transformer Enclosure Assembly Schematic Diagramsaq45f.eps 5725A Instruction ManualIndex 5725A Page 5725A