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Fluke 45

1. 7 a 9eu rzu 42 924624 ju op 241 91 42718 qb30f eps Figure 9 1 A1 Main PCA 9 2 Schematic Diagrams AC BUFFER ARL RELAY BOTTOM VIEW LESS Q 7 PLACES 1615 13 11 4 2 COMMON 9 a 6 EE 3 68 66 64 63 62 ACTIVE 190 V888CR ACR ACRA ACRE ACR4 AGND2 ACSO 000 RMSI SIASI USSF BIAS2 RMSD ARTN 6 FILTER R59 10K GUARD 12 GRD DOV LOW amp 5 hai a ENUETY REF RESISTOR SENSE 5 COMPARAT DCU DIVIDER amp OHMS REFERENCE Qi 8 DC HIGH MPS6S60 8 A D HISH 8 5 DIODE TEST 13 Sog 7 R F RESISTOR SENSE DHMS kDHMS MOHHS mUDC 3UDC DIODE TEST 9 A D BUFFER Wi 0 5 oy o 8 INTEGRATOR 5 5 24 m FS T gt O 500 2500 440 1000V EAST 26 R2 10 54 5 WH VDDRELAY 5 108 3 L 11 jigoov a 6 gt gt gt L
2. qb36f eps Figure 7 5 Cycle Float Charge Rate Switch Test 45 7 18 Calibration 7 12 The Battery Pack Option is adjusted at the factory for optimum performance and should not require adjustment when installed However if either of the two adjustment pots on the top of the Battery Pack Option circuit assembly have been turned inadvertently or if the unit has been repaired the following procedure can be used to reset the controls for optimum battery life and proper power supply system performance The following equipment is needed to perform these adjustments An 18000 1 2 watt 5 resistor e voltmeter The following steps describe how to adjust the Battery Pack Option 1 With the Battery Pack Option installed in the meter and with the meter disconnected from line power unplug the battery connectors from the battery and terminals Figure 7 6 2 Install the 1800 Q resistor across the battery pack connectors Connect the meter to line power and turn the meter ON Connect the test leads from another voltmeter across test points TP1 and TP2 on the Battery Pack Option circuit assembly as shown in Figure 7 7 Adjust the front potentiometer R39 top of the Battery Pack Option circuit assembly until the voltmeter across the test points reads 9 25 V Turn the meter OFF Connect the test leads from another voltmeter across TP1 and TP2
3. er 8191 241 qb21c eps Figure 5 1 Test Point Locator cont 5 8 Diagnostic Testing and Troubleshooting Error Codes A2TP3 GROUND TEST POINT LOCATIONS DISPLAY PCA qb22c eps Figure 5 1 Test Point Locator cont 5 9 45 5 4 General Troubleshooting Procedures The Fluke 45 allows for some fault isolation using self diagn
4. XR 1817 Y BITS 1 BIT 4 BIT 3 X BIT2 X BIT 1 BIT 7 X BIT 6 X BIT 5 X BIT 4 X BIT 3 X BIT 2 1 1 T Clear to receive T Clear to receive 35 ps 35 ps qb09 eps Figure 5 4 Display Controller to Microprocessor Signals 5 17 45 Table 5 5 Display Initialization A2TP4 Dtest A2TP5 LTE Power Up Display Initialization All Segments OFF All Segments ON default 1 1 0 Display Test Pattern 1 0 Display Test Pattern 2 NEM LL NEL NE REMOTE SMF MAX dB AUTO ANODE 1 if 13 12 d i 11 11 11 bi 11 jEXL RG cA HOLD gt p my if Hz qb26f eps qb27f eps Figure 5 6 Secondary Display When a Fluke 45 display is initially powered up all display segments should come on automatically If this display does not appear proceed with the following steps Note If the display is operational but has problems with front panel button presses proceed directly to step 9 1 Check the three power supplies with respect to GND A2TP3 or A2U1 42 on the Display Assembly Diagnostic Testing and Troubleshooting Calibration Failures e VCC A2UI 6 4 85 to 5 35 dc e VEE A2UI 19 5 0 to 6 0 V dc e VLOAD A2UI 18 28 5 to 32 0 V dc 2 Check the filament drive signals FIL1 and FIL2 these c
5. 2 2 2 2 6 List of Replaceable Parts Parts er 841 B e 16 E 462 9 228 9eu rzu 2 2 2 241 yal qb30c eps Figure 6 2 A1 Main PCA 6 11 45 Table 6 4 A1A1 True Rms Reference Description 5 1 Total Note Designator No Qty CAP TA 2 2UF 10 35V 697433 1 CAP TA 68UF 20 6 3V 821785 2 HEADER 2 ROW 100CTR RT ANG 8 PIN 845326 1 RES CF 3 3K 5 0 25W 854554 1 IC BPLR TRUE RMS TO DC CONVERTER 687019 1 45 4006 qb31c
6. 9 3 A2 Display 9 4 Tr e Rims 9 5 AA Battery rera Ce Fre a Oo Er UP 9 6 5 IEEE 488 Interface Chapter 1 Introduction and Specifications AUCH OD aes Operating Options and ACCeSSOFI6S ien era sien rete eei dotada osea Organization of the Service Manual CONVENTIONS covers EY e eed seniors Specifications 45 1 2 Introduction and Specifications 1 Introduction 1 1 Introduction The Fluke 45 Dual Display Multimeter also referred to as the meter is a 4 1 2 digit 30 000 count meter with a 5 digit 100 000 count high resolution mode designed for bench top field service and system applications The meter uses a dual vacuum fluorescent display allowing for two types of readings from a single input Primary and secondary displays show the user defined readings side by side Even though the readings are made sequentially the displays show both readings at all times for ease of comparison Some features provided by the meter are e Computer interface operation via the RS 232 interface included or
7. 2 27 2 28 2 29 Diode Contimuity eire nter 2 30 lucia ii 2 31 Active uli EE 2 32 As Di iie ere De SEC Ro 2 33 Serial Communication Guard 2 34 Digital Kernel eerte t e RE 2 35 5 232 rtetfaCe eere psa dese 2 36 hilo reco 2 37 a e Geht rye buy e rr 2 38 aie riesco ede dete ep etude aes teens eU PIE ER e PE 2 30 E ees mi nici eal 2 40 TEEE 488 Option 2 41 Display Assembly rtt ban 2 42 Main Assembly Connector essere 2 43 Front Panel Switches dieit ede tenir ee 2 44 2 45 Drive Carcuit eic 2 46 Watchdog Timer and Reset Circuit eee 2 47 Display Controller with General 3 1 3 2 Warranty Repairs and Shipping Information
8. Introduction i a Servicing Surface Mount Error General Troubleshooting 6 Digital Troubleshooting 4 Power Supply Troubleshooting eee Raw DC Supply iet FH get berba ede 5 Volt Switching Supply eene IDVOFGE a i te KE Ue E Analog Troubleshooting eese enne Uart n DC Volts Troubleshooting eene AC Volts Troubleshooting eene Ohms Troubleshooting sssrinin ainni enne iii 45 Service Manual 5 15 Display Assembly Troubleshooting 9 16 Calibration Failures e eer ete PIU rite 5 17 5 18 Calibration Related Components 5 19 Calibration Interrelationships eene 5 20 Retrieving Calibration Constants 5 21 Replacing the 05 00 6 List of Replaceable 3 6 1 tei bane 6 2 How t Obtain 6 3 How to Contact Fluke cecinere pae eie a e daten 6 4 Manual Status Information nennen rennen 6 5 Newer Instr mehts ro 6 6 rig
9. 3 26 Install Miscellaneous Chassis Components eese 3 27 Install the Battery Option 3 28 Install the Rims dre t tte EpL ede ER bales 3 29 Install the Analog Measurement Processor Shields 3 30 Install the Main PCA Contents continued 3 31 Install the TEEE 488 402 2 3 32 Assemble the Front Panel 3 33 Install the Front Panel Assembly eee 3 34 Install the Handle and Mounting Brackets 3 35 Install the Meter resine ornan the Performance Testing and Calibration eee 4 1 ntrod ctiOTi et nre teret ena e I eee ERR e ro CREARE eed 4 2 Required Equipment eee ettet ted tien anni i 4 35 Performance Tests ioc 4 4 Front Panel Calibration enne eene nnne 4 5 Hisl 4 6 Entering Calibration Mode sse 4 7 Exiting Calibration 4 8 DC Volts Calibration Front 4 9 AC Volts Calibration Front 4 10 DC and AC Milliamp Calibration Front Panel 4 11 DC and AC Amps Calibration Front 4 12 Ohms Calibration Front Panel 4 13 A
10. Pa A D CONVEO Serial Communication Guard Crossing Digital Kernel ui Ere te ERE ate tei i RS 232 Interfaces 2 1 45 2 2 2 36 2 37 2 38 2 39 2 40 2 41 2 42 2 43 2 44 2 45 2 46 2 47 IEEE 488 Option Connections eee Display Assembly Main Assembly Connector Front Panel Switches Display Beeper Drive Circuit Watchdog Timer and Reset Circuit Display Controller with FIP Theory of Operation 2 Introduction 2 1 Introduction This chapter presents a layered description of Fluke 45 circuitry First the multimeter is described in general terms with a Functional Block Description Then each block is detailed further often to the component level with Detailed Circuit Descriptions Refer to Chapter 9 of this manual for full schematic diagrams Signal names followed by a are active asserted low Signal names not so marked are active high 2 2 Functional Block Description Refer to Figure 2 1 Overall Functional Block Diagram during the following functional block descriptions 2 3 Power Supply The Power Supply functional block provides voltages required by both the vacuum fluorescent display 30 V dc 5 2 V dc and 5 V ac and the in guard circuitry 5 25 V d
11. 30V 30 5 ps 5V Grid X 1 30V qb11f eps Figure 2 11 Grid Anode Timing Relationships 2 24 static awareness A Message From Fluke Corporation Some semiconductors and custom IC s can be damaged by electrostatic discharge during handling This notice explains how you can o minimize the chances of destroying such devices 5012 1 Knowing that there is a problem 2 Leaning the guidelines for handling them 3 Using the procedures packaging and bench techniques that are recommended The following practices should be followed to minimize damage to S S static sensitive devices LL 3 DISCHARGE PERSONAL STATIC BEFORE HANDLING DEVICES USE A HIGH RESIS 1 MINIMIZE HANDLING TANCE GROUNDING WRIST STRAP 2 KEEP PARTS IN ORIGINAL CONTAINERS UNTIL READY FOR USE 4 HANDLE S S DEVICES BY THE BODY 5 USE STATIC SHIELDING CONTAINERS FOR 8 WHEN REMOVING PLUG IN ASSEMBLIES HANDLING AND TRANSPORT HANDLE ONLY BY NON CONDUCTIVE EDGES AND NEVER TOUCH OPEN EDGE CONNECTOR EXCEPT AT STATIC FREE WORK STATION PLACING SHORTING STRIPS ON EDGE CONNECTOR HELPS PROTECT INSTALLED S S DEVICES 6 DO NOT SLIDE S S DEVICES OVER ANY SURFACE C 9 HANDLE S S DEVICES ONLY AT A STATIC FREE WORK STATION 10 ONLY ANTI STATIC TYPE SOLDER SUCKERS SHOULD BE USED 11 ONLY GROUNDED TIP SOLDERING IRONS SHOULD BE USED 7 AVOID PLASTIC VINYL AND STYROFOAM
12. general maintenance 7 6 8 8 general maintenance information 3 3 general operability 7 9 general troubleshooting procedures 5 10 H how to contact fluke 6 4 how to obtain parts 6 3 ieee 488 controller 488 interface 4 15 1eee 488 option 05 2 5 ieee 488 option connections ieee 488 transceivers connector input protection 2 10 input protection circuit input signal conditioning 2 3 install miscellaneous chassis components 3 10 analog measurement processor shields 3 11 install the battery option 3 11 install the front panel assembly 3 15 install the handle and mounting brackets install the ieee 488 option install the main pca install the meter case install the rms pca installation 7 7 installing the 1 488 option 8 9 inverter isolation circuits L line fuse 3 4 list of replaceable parts low battery disconnect low battery indicator detector 7 5 low battery indicator detector and low battery disconnect test 7 10 main assembly connector 2 20 main assembly connectors manual status information 6 4 microprocessor 2 19 N newer instruments 6 4 0 2 12 ohms calibration computer interface 4 18 ohms calibration front panel 4 11 ohms troubleshooting 5 14 operating instructions options and accessories organization of the service man
13. 55420 NIVN 9 1 33S SNOILV907 LNIOd 1531 OLd LILV si C8LdLiv Y 622 2 yu 901 j 229 3z rz8 ala 012 j 66 LNLW ASN HOS 96 1 ASN 64119 HOS SION Old LIV 8055 LNANSYNSVAN 33S qb20c eps Figure 5 1 Test Point Locator cont 5 7 45 5 1 4
14. 24 5 ADD 0 GDD 10 21 DIGITAL 45 1001 Sheet 2 of 3 qb46sc tif Figure 9 1 A1 Main PCA cont 9 5 Service Manual 45 Series 1 059 62 0rd 829 169 Ur gt 923 uallo Bu va 5 as cu 685 812 199 149 859 849 098 19 45 4001 1 A1 PCA cont Figure 9 9 6 Schematic Diagrams TO BATTERY OPTION X L0H BATTERY R44 07 15 d MM M 5 62K 1x UDDRELAY ive i 21 UBDRELAY 36 45 20 ALL C42 4 144002 BSSDURCE C26 942 V JAL upp 5 20
15. 8 23 Failure to Generate a Service Request 8 24 Schematic Diagram e Reuter 8 25 List of Replaceable Parts 2 Schematic 45 Service Manual List of Tables Table Title 1512 ACCESSORIES E 2 1 Analog Measurement Processor Pin Name 20 224042 001 2 2 Relay Operation tee era e Pee Eee eee ES 2 3 Reference Resistance ee Ute erret ip rte eaii 2 4 Volts Input Signal Dividers eese nennen 2 5 Front Panel Switch Scanning eese enne 2 6 Display Initialization Modes eese nennen 3 1 FUSES 4 1 Recommended Test Equipment 0 02222100 0 00000000000000000 4 2 Performance Tests for Volts Diode Test Ohms and Frequency Functions 4 3 Performance Tests for mA Current Functions 4 4 Performance Tests for Current Functions 4 5 Front Panel Calibration neo canta e ene Sn 4 6 Specifications Increase with Different Calibration Points esses 4 7 Calibration Using the Computer Interface
16. 12 _ D10 GRI 0 lt 9 gt 1171 09 GRID 8 10 08 07 GRI 0 lt 6 gt __8 06 05 5 GRI D4 GRI D3 GRI D lt 10 gt ANODEO GRI 010 ANODE1 ANODE2 REMOTE ANODE3 13 ANODE4 EXT TRG 5 i n ANODEG T ANODE7 ANODE8 ANODE9 19 45 1002 ANODE10 ANODE1 1 ANODE1 2 ANODE1 3 PRI MARY DI SECONDARY DI SPLAY 2388 ANODE TI ONS ANCDE DEFI NI TI CNS qb48sc tif Figure 9 2 A2 Display PCA cont 9 9 45 Series Service Manual 45 4006 Figure 9 3 A1A1 True rms PCA Schematic Diagrams NOTES UNLESS OTHERWISE SPECIFIED 1 ALL RESISTANCES ARE OHMS 1 8 WATT 5 2 ALL CAPACITANCES ARE IN MICROFARADS U1 Cz BUF IN 6876 3U NC COM OFFSET CHIP SEL DEN IN dB AD637 LAST USED NOT USED 223 oo NEN o pur c a 45 1006 qb49sc tif Figure 9 3 A1A1 True rms PCA cont 9 11 45 Series Service Manual 54 D Figure 9 4 A4 Battery PCA UNLLSS OTHERWISE SPECIFIED A L RESISTANCES BRE IN OHn5 178WRTT 5 MICKOFARADS 125485786891 CYCLEZFLOAT CHARGE RATE SWITCH CRS MBR140 CRS MBRL40 S IRFR120 R3 47K CERM LOW BATTERY INDICATOR DETECTOR TRICKLE
17. 4 25 DC and AC Amps Calibration Computer Interface 4 26 Ohms Calibration Computer 2 4 27 Continuity Hysteresis Threshold Calibration Computer Interface 4 28 Frequency Calibration Computer Interface esses 4 29 Concluding Calibration Using the Computer Interface 4 30 Alternate Ohms Calibration Computer Interface 4 1 45 4 2 Performance Testing and Calibration 4 Introduction 4 1 Introduction This chapter of the Service Manual provides performance tests that can be used at any time to verify Fluke 45 operation within published specifications A complete calibration procedure is also included The performance test and if necessary the calibration procedure can be performed periodically and after service or repair 4 2 Required Equipment Equipment required for performance testing and calibration is listed in Table 4 1 Table 4 1 Recommended Test Equipment Instrument T Recommended Minimum Specifications Type Model Multifunction DC Voltage Fluke 5700A Calibrator Range 90 mV to 1000 V dc with wideband Accuracy 005 option AC Voltage Frequency Voltage Accuracy 1 kHz 29 mV to 750 V 0 05 100 kHz __ 15 mV to 300 mV 1 25 AC Milliamps Frequency Current Accuracy 1 kHz 29 mA to 100 mA 0 125 DC Milliamps Frequenc
18. 1088902024 suuo 1ueujeJnseelwv 5 LA 01 07 SHH OW OGA zg SLO AVL LHA 15 ez 98 95 19 490 09 sayy annoy SHH SHH OL 01 615 Jejunoo KouenbejJ Service Manual SWH 043002 Jeygng OV 9U sjunys 159 Aw jndu qb02f eps Figure 2 2 Analog Simplified Schematic Diagram 2 8 Theory of Operation 2 Detailed Circuit Description Table 2 1 Analog Measurement Processor Pin Name Description Pin Name O 1 VDD 5 V supply 2 ACBO AC buffer output 3 AIN Amps input 4 AGND2 Analog ground 2 5 ACR4 AC buffer range 4 6 ACR3 AC buffer range 3 7 ACR2 AC buffer range 2 8 1 AC buffer range 1 9 VSSACR 5 V supply for AC ranging 10 not used 11 LO A D converter low input 12 GRD Guard 13 RRS Reference resistor sense for ohms 14 V4 Tap 4 on the DCV input divider ohms reference network 15 V3 Tap 3 on the DCV input divider ohms reference network 16 V1 Tap 1 on the DCV i
19. caes IBBE 488 Controllers tects eene tito tire e ee rere aene IEEE 488 Transceivers Connector eene General 4 eene enhn Removing the IEEE 488 Interface Option esee Installing the IEEE 488 Interface Option eene Performance Testing e eee err re etre aee Troubleshootin iuste etie ieiuno ee tne ropas Power up Problems Communication Failure to Select IEEE 488 Interface Option Failure to Handshake on 488 22 2 2221 Failure to Enter Failure to Receive Multiple Character Commands Failure to Transmit Query Responses Failure to Generate an End or Identify EOL Failure to Generate a Service Request SRQ Schematic tee eoe De tickers denies ua xev teat Last of Replaceable tive eee 45 8 2 Option 05 IEEE 488 Interface 8 Introduction 8 1 Introduction The IEEE 488 Interface turns the Fluke 45 into a fully programmable instrument for use with the IEEE Standard 488 1 1987 interface bus IEEE 488 bus With the IEEE 488 Interface the Fluke 45 can
20. 21 514 19 S17 16 S11 pin 15 or 58 14 Reference resistances are identified in Table 2 3 OHMS VOLTAGE SOURCE LOW 171 RREF REFERENCE RESISTOR A D INTEGRATE REFERENCE HIGH A1RT1 amp A1R5 ACTIVE FILTER A D INTEGRATE UNKNOWN R UNKNOWN RESISTOR LOW VRX IXRX RX VRREF IX RREF M RREF qb04f eps Figure 2 4 Ohms Simplified Schematic Table 2 3 Reference Resistance Voltage Source A1Z1 Reference Resistor 100 300 Q 1 1000 2 3 1 3V 10 01 10 kQ 30 1 3V 100 5 100 kQ 300 1 3V 1 MQ 1000 1 3V 10 MQ 30 MQ 3V 10 100 MQ 300 MQ 10 Diode Test 3V 1 2 13 45 185 4 A1RT1 A1C1 5 COVERTER A1Z2 FEEDBACK RESISTOR qbO5f eps Figure 2 5 AC Buffer Simplified Schematic Table 2 4 AC Volts Input Signal Dividers Range Drive Signal 122 Feedback Resistor Overall Gain 100 300 mV ACR1 111 1 1000 mV 3 V ACR2 12 25 111 1 10 30 V ACR3 1 013 111 1 025 100 300 750 V ACR4 2 776 0025 2 24 100 and 300 Ranges The 100 MQ and 300 ranges perform a conductance reading the mathematical reciprocal of this reading is used as a display in ohms The reference resistor A1Z1 10 MQ is integrated first then the unknown resistance is used for DE
21. 2 3 3 General Maintenance Information 3 4 Required Equipment e erret acest detta ree 3 5 Power Requiremients 4 2 3 6 Static Safe Handling edite 3 7 aia 3 8 Fuse Test and 3 9 Line 3 10 Current Input FUSES tertie tete 3 11 Testing Current Input 3 12 Replacing the 500 mA and 440 mA Input Fuses F1 and F5 3 13 Replacing the 10 A Input Jack Fuse 2 2 4 22 2 1 3 14 Disassembly Procedures 3 15 Remove the Meter 200440440400 3 16 Remove Handle and Mounting 0 212 3 17 Remove the Front Panel 3 18 Remove the Display uci ciere 3 19 Remove the 488 3 20 Remove the 3 21 Remove the Analog Measurement Processor Shields 3 22 Remove the RMS PC A ee rte te tlt ri Re tr ERE epa 3 23 Remove the Battery 404202404 3 24 Disconnect Miscellaneous Chassis Components 3 25 Assembly Procedures oio
22. 7 1 45 7 2 Option 01 Battery Pack Introduction 7 1 Introduction The Fluke 45 01K Battery Kit is a field installable option that may be installed in the meter The installation of the Battery Kit facilitates portable operation of the meter for typically eight hours 7 2 Specifications Specifications for the Battery Kit Option are as follows of Cell Sealed Lead Acid Rechargeable e Battery Voltage 8 Volts Nominal e Charge Time 16 Hours Typical w meter off 7 3 Theory of Operation 7 4 Functional Block Description The Battery Pack Option PCA consists of the five functional blocks illustrated in Figure 7 1 Each block is described below e Switching Power Supply The Switching Power Supply regulates the 7 5 V to 35 V raw dc input provided by the main circuit board J1 7 The supply output 9 3 V to 9 8 V temperature compensated is used to charge the 8 V lead acid battery e Cycle Float Charge Rate Switch The Cycle Float Charge Rate Switch monitors the charging current required by the battery pack and sets the output voltage accordingly 9 35 V for trickle charging or 9 8 V for cyclic charging e Low Battery Indicator Detector The Low Battery Indicator Detector monitors the battery pack voltage outputting a logic low to turn on the meter low voltage indicator when the battery pack voltage is below approximately 7 7 V Low Battery Disconnect The Low Battery
23. 4 2 Required Equipment 4 5 Performance Tests 4 4 Front Panel enne enne enn 4 5 Higiene 4 6 Entering Calibration 4 7 Exiting Calibration Mode sese 4 8 DC Volts Calibration Front 4 9 AC Volts Calibration Front 4 10 DC and Milliamp Calibration Front Panel 4 11 DC and AC Amps Calibration Front 4 12 Ohms Calibration Front Panel 2 0 40 1 00 4 13 Alternate Ohms Calibration Front 4 14 Continuity Hysteresis Threshold Calibration Front Panel 4 15 Frequency Calibration Front Panel eene 4 16 Editing the Prompt for Different Calibration Points 4 17 Calibration Using the Computer Interface 2201 1 4 18 4 19 5 232 dicU 4 20 IEBE 488 IntetfaGe deo 4 21 The Calibration Procedure essere 4 22 DC Volts Calibration Computer Interface 22 4 23 AC Volts Calibration Computer Interface esses 4 24 DC and AC Milliamps Calibration Computer Interface
24. 7 Option 01 Battery tinae pL ibam ns 7 Introduction 4 2 Specifications esce iet eclesie Lei e de 7 3 Theory of Operation eee etit eter et Rr Oa ete eu ce 7 4 Functional Block esses 7 5 Switching Power Supply eene 7 6 Cycle Float Charge Rate Switch esses 7 7 Low Battery Indicator 7 8 Low Battery Disconnect sescca sinisiipien 7 9 Constant Voltage Trickle Charger eee 7 10 Other 7 11 7 12 7 13 7 14 Performance Testing eion iriso 7 15 General Operability ois 7 16 Low Battery Indicator Detector and Low Battery Disconnect Test 7 17 Cycle Float Charge Rate Switch 222212 7 18 15192 Troubleshoounmg 1520 Additional Tests Eon ore E Er cna Er aerias 7 21 Schematic Diagram secu neree de 7 22 Last of Replaceable Parts eee eet ree ettet eraat ien nea 8 Option 05 488 Interface
25. e The Battery Pack Option is physically installed in the meter e The red and black battery pack wires have been disconnected Refer to Table 7 1 for description of any equipment that is required during the performance tests 1 Disconnect the meter from line power Now turn meter power on 1 on then off 0 off Note Do not connect the battery pack until after the option assembly is turned on later in this procedure 2 Connect the 1 8 kQ resistor across the battery pack wires Connect the voltmeter Low to TP1 and High to TP2 Connect the meter to line voltage but do not turn the meter on Check for a voltmeter reading of 9 35 V 0 01V Now turn power on Check for a voltmeter reading of 9 25 V 0 01 V Qv qe w Remove the voltmeter and the 1 8 resistor 7 9 45 Service Manual 7 10 7 Observing the polarity markings on the battery pack connect the red wire to the positive terminal Then connect the black or brown wire to the negative terminal Reversal of these connections causes fuse 1 to open 7 16 Low Battery Indicator Detector and Low Battery Disconnect Test The following test is necessary only after repairs have been made to either the Low Battery Indicator Detector or the Low Battery Disconnect circuit 1 2 Turn the meter OFF Unplug the two battery pack connectors from the battery pack terminals Observing the correct polarity connect the variable power supply to
26. Diagnostic Testing and Troubleshooting Calibration Failures Table 5 7 Components Unique to Calibration Steps Related Component Main PCA 1 A1AR1 A1R2 A1R3 A1U1 A1VR1 A1Y1 s gt ON mA x x x x x x x Frequency 32 x 5 23 45 Service Manual Table 5 8 Calibration Hierarchy Calibration Type Prior Calibration Required DC Volts none AC Volts DC Volts DC Amps DC Volts AC Amps DC Volts Ohms DC Volts Continuity Hysteresis Threshold none Frequency Continuity Hysteresis Threshold Table 5 9 Calibration Constants 5 24 1 0 97025 to 1 03775 VDC range 1 2 0 97025 to 1 03775 VDC range 2 3 0 97267 to 1 04554 VDC range 3 4 0 96782 to 1 04035 VDC range 4 5 0 96792 to 1 04045 VDC range 5 6 0 9975 to 1 0025 100 mV gain 7 0 9975 to 1 0025 320 mV gain 8 0 9975 to 1 0025 3 2 V gain 9 100 to 100 VAC offset range 1 10 0 9725 to 1 0275 VAC range 1 11 100 to 100 VAC offset ranges 2 through 4 12 0 9725 to 1 0275 VAC range 2 13 0 9725 to 1 0275 VAC range 3 14 0 9725 to 1 0275 VAC range 4 15 0 9725 to 1 0275 VAC range 5 16 0 9500 to 1 0500 ADC range 1 17 0 9500 to 1 0500 ADC range 2 18 0 9500 to 1 0500 ADC range 3 19 0 9225 to 1 0775 AAC range 1 20 0 9225 to 1 0775 range 2
27. IN WORK AREA PORTIONS REPRINTED WITH PERMISSION FROM TEKTRONIX INC AND GERNER DYNAMICS POMONA DIV Dow Chemical 0 000000000000 02 O2 GB WW WW O9 O9 WW GB O2 O9 O9 WW WB O9 O9 55 55 O9 O9 WW WB WH O9 O9 O9 O9 O9 W W Chapter 3 General Maintenance E Warranty Repairs and Shipping Information General Maintenance Information 1 Required Power Static Safe Handling Fuse Test and Replacement esee Current Input FUses rue e tree pee bn deett Testing Current Input Fuses eese Replacing the 500 mA and 440 mA Input Fuses and F5 Replacing the 10 A Input Jack Fuse F2 esses Disassembly Remove Meter Case secet ed Remove Handle and Mounting Brackets sees Remove the Front Panel Assembly eee Remove the Display eate Remove the IEEE 488 Option esee Remove the Main eiii Eph ta Rev eee Remove the Analog Measurement Processor Shields Remove
28. When the Microprocessor drives OPTS W to VEE to enable the VCC2 power supply the CLR input to the D flip flop A5U9 13 goes high to enable the flip flop The Q output A5U9 9 remains low until the Microprocessor does an initial dummy memory cycle to the IEEE 488 Controller approximately 1 ms later The rising edge at the end of the chip select signal A5U9 11 clocks the flip flop and causes output to go high This action removes the hardware reset to the IEEE 488 Controller This delay is followed by another dummy read cycle and a series of six memory write cycles that program the IEEE 488 Controller For each character that it receives or transmits the IEEE 488 Controller generates an interrupt to the Microprocessor These interrupts are generated by driving the open drain interrupt output A5U6 10 low This signal is buffered by a tri state buffer whose output at A5U4 3 drives the IRQ2 input to the Microprocessor low When the Microprocessor responds to the interrupt and takes the necessary actions by reading and writing registers the IEEE 488 Controller both ASU6 10 and subsequently A5U4 3 go high again Resistor A5R3 provides a pull up termination on open drain interrupt output A5U6 10 Tri state buffer output A5U4 3 is pulled up by resistor A5R2 to terminate the IRQ2 signal when the buffer is tri stated off When the Microprocessor performs a memory cycle to the IEEE 488 Controller the lower three bits of the address b
29. 1 Allow the Fluke 45 to stabilize in an environment with ambient temperature of 18 to 28 C and relative humidity of less than 70 Then turn the Fluke 45 on and allow it to warm up for at least 1 hour 2 The Cal Enable button is located on the right side of the display and is recessed beneath a calibration seal Enable the calibration mode by pressing the Cal Enable button for about three seconds CAL appears in secondary display Use a small screwdriver or equivalent blunt tipped object Avoid using sharper tipped objects such as pencils When the calibration mode is enabled the unit first beeps then displays VDC CAL From this point the calibration menu can be scrolled to a specific function using the and 52 editor buttons To display the first prompt for the selected calibration function press the button In the calibration mode most buttons are disabled only the AUTO A and edit buttons and the Cal Enable button remain active These buttons described more fully as follows 1 Cal Enable button Enables the calibration mode when pressed for 3 seconds Exits the calibration mode when pressed momentarily 2 Editor buttons Used to scroll to the desired calibration function in the calibration menu or to edit the displayed calibration prompt e Once calibration mode has been entered the calibration menu appears in the following sequence VDC VAC mADC mA AC ADC AAC V gt Hz The menu does not wrap going
30. 10 50V C0G 1206 CAP CER 10PF 10 50V COG 1206 DIODE S1I BV 70 0V IO 50MA DUAL SOT23 DIODE SI 100 PIV 1 0 DIODE SI BV 75V O 250MA SOT23 DIODE SI SCHOTTKY BARRIER 40V 1A DIODE SI DUAL BV 50V IO 100MA SOT23 DIODE SI BV 100 I0 100MA DUAL SOT23 HEADER 1 ROW 050CTR 20 PIN HEADER 1 ROW 050CTR 14 PIN HEADER 1 ROW 100CTR 4 HEADER 1 ROW 050CTR 10 PIN HEADER 1 ROW 100CTR 3 PIN RELAY ARMATURE 2 FORM C 5VDC LATCH CONTACT FUSE 15AMP SPRING COIL COMP SS 750 240 SOCKET IC 28 PIN DUAL WIPE BEAM TYPE CONTACT FUSE CONTACT FUSE 848200 837237 837518 644978 747287 844738 822387 697409 697433 851738 721050 697433 837393 782615 821553 769240 769786 844733 816843 831867 822403 769687 740571 747311 742320 698555 830489 837732 851659 821116 831529 831511 631184 831503 845334 603001 844287 836411 756353 659524 844287 7 gt S 10 Wasa pony op Aa Aaa a List of Replaceable Parts 6 Parts Table 6 3 A1 Main PCA cont Destinator Description SE Total Note No Qty Q 1 TRANSISTOR SI NPN SELECT IEBO SOT 23 821637 1 Q 2 8 TRANSISTOR SI N JFET SOT 23 820860 7 Q 9 TRANSISTOR SI NPN SMALL SIGNAL SOT 23 742676 1 Q 10 12 TRANSISTOR SI PNP T092 698290 2 Q 11 13 TRANSISTOR SI NPN SELECTED IEBO TO 92 685404 2 R 2 RES WW 10 5 5W 30PPM 822064 1 R 3 RES WW 010 5 1W 100PPM 820845 1 R 4 19 22 5 200
31. 5 125 200 1206 746743 3 R 5 3 RES WW 3 5k 5 5W 20 PPM 107695 1 R 6 7 i RES CERM 100K 5 3W 820811 2 R 8 16 17 RES CERM 22 4 596 125W 200PPM 1206 746230 3 R 9 37 38 59 5 RES CERM 10K 5 125W 200PPM 1206 746610 4 R 10 5 100 5 125 200 1206 740548 1 11 15 5 RES CERM 47K 5 125W 200PPM 1206 746685 10 31 39 45 55 56 R 18 5 RES CERM 1M 5 125W 200PPM 1206 746826 1 R 20 27 29 3 200 5 125 200 1206 746339 3 R 21 RES CERM 215K 1 125W 100PPM 1206 836643 1 R 23 RES CERM 61 9K 1 125W 100PPM 1206 821330 1 R 24 RES CERM 16 9K 1 125W 100PPM 1206 836635 1 R 25 i RES CERM 13 3K 4 196 125W 100PPM 1206 836619 1 R 26 RES CERM 845 1 125W 100PPM 1206 821322 1 R 28 32 RES CHI CERMET 1K 5 1 8W 745992 2 R 30 RES CF 20K 5 0 25W 441477 1 R 33 RES CERM 180 5 125W 200PPM 1206 746321 1 R 35 RES CF 220K 5 0 25W 851837 1 R 36 i RES CF 1M 5 0 25W 649970 1 R 40 2 5 470 5 125 200 1206 746792 1 41 RES CERM 10 5K 1 125W 100PPM 1206 851852 1 R 42 RES CERM 68 1K 1 125W 100PPM 1206 851845 1 R 43 RES CF 10K 5 0 25W 697102 1 R 44 RES CERM 5 62K 1 125W 100PPM 1206 837047 1 R 46 49 A RES CF 0 50 5 0 25W 830646 4 R 50 53 RES CERM 432 4 196 125W 100PPM 1206 811885 2 R 51 52 RES CERM 47 5 125W 200PPM 1206 746263 2 R 54 60 RES MOX 22M 5 1W 200 PPM 688887 2 R
32. 8 24 Schematic Diagram The schematic diagram for the IEEE 488 Interface Option is included in Chapter 9 of this manual 8 25 List of Replaceable Parts Figures 8 4 and 8 5 provide illustration for the parts lists in Tables 8 3 and 8 4 respectively Refer to Chapter 6 for parts ordering information Option 05 IEEE 488 Interface 8 List of Replaceable Parts Table 8 2 Option 05 IEEE 488 Interface Final Assembly Total Qty Reference Designator Description Note A IEEE 488 INTERFACE PCA 814152 1 H SCREW PH P LOCK STL 6 32 250 152140 1 H CONN ACC MICRO RIBBON SCREW LOCK KIT 836585 1 MP SPACER SNAP PWB NYL 1 375 845347 1 PRINT MATL INST SHT FLUKE 45 IEEE 488 856005 1 1 1 gt CABLE ASSY IEEE 834978 CABLE ASSY FLAT 14 COND MICROMOD 3 IN 831560 CABLE ASSY FLAT 20 831578 1 45 5 T amp B qb43c eps Figure 8 5 Option 05 IEEE 488 Interface Final Assembly 8 13 45 Service Manual cCcccccccuoummocecccooo 2 Reference Designator 6 11 HK Table 8 3 5 488 Interface Fluke Total Description es Qty Note CAP CER 0 1UF 10 25V X7R 1206 nos CAP CER 0 022UF 10 50V X7R 1206 747279 DIODE SI BV 75V O 250MA SOT23 830489 HEADER 2 ROW 100CTR 24 831834 HEADER 1 ROW 050CTR 20 PIN 831529 HEADER 1 ROW 050CTR 14 P
33. J SERIAL COMMUNICATION CURRENT e SHUNTS 45 1001 RELAYS amp DRIUERS Sheet 1 of 3 qb45sc tif Figure 9 1 A1 Main cont 9 3 45 Series Service Manual TP17 TP18 PRO 831 01277 R21 R22 59 21 45 4001 Figure 9 1 1 PCA cont 9 4 Schematic Diagrams CS 6 NC SK 66 65 NC DI 64 GND DO 25 paraco 22 po 52 DATA O DATAC1 _ 12 at p 51 DATAC1 DATAC2 15 60 parate DATAC3 15 04159 paracz DATACO 7 DATAC4 16 04 4 58 DATAC4 pATACS _ 22105 05 22 ___ 5 _ 18 ne 56 gt DATAC7 19 55 20 _ 5966 07 ae 19 SWRS 0 00 1 59 A 18 SWR4 AD AL 17 SUR ai 52 ADD 1 51 RDD C2 ADDI 3 gt 16 __5 50 ADDC3 fapp 4 6 15 SHRI AB A4
34. eese 45 8 3 5 488 Interface PCA Figure CA CA CA P9 gt 7 2 IUe List of Figures Title Overall Functional Block Diagram eene nennen Analog Simplified Schematic Diagram sese DC Volts 300 V Range Simplified Schematic see Ohms Simplified Schematic eese eene AC Buffer Simplified DC mA Amps Simplified Schematic eene Active Filter Simplified Schematic esee A D Converter Simplified Schematic essen Command Byte Transfer Waveforms esses nennen nennen Grid Control Signal Timing eie torte ttt reiten eur reae Pines 12 24 Grid Anode Timing 1 1 Replacing the Line Fuse 2002 001 0 1 debate Replacing the External 100 mA Input Fuse 2 Removinis the C Removing the Handle and Handle Mounting Brackets 5 Eour Wire Configuration choros etaim eer Test Volt Swa
35. 21 100 to 100 AAC offset range 3 22 0 9225 to 1 0775 AAC range 3 23 0 9990 to 1 0090 OHMS range 1 24 1 0000 to 1 0100 OHMS range 2 25 1 0040 to 1 0140 OHMS range 3 26 0 9990 to 1 0090 OHMS range 4 27 0 9990 to 1 0090 OHMS range 5 28 0 9990 to 1 0090 OHMS range 6 29 0 9886 to 1 0035 Slow Siemens 30 0 9910 to 1 0010 Medium and Fast Siemens 31 0 9999 to 1 0001 Frequency calibration 32 10 0 to 10 0 Slow offset 33 1 0000 to 1 0006 Slow negative gain Chapter 6 List of Replaceable Parts How to Obtain Parts eco How to Contact Manual Status Information Newer Instr nents 45 6 2 List of Replaceable Parts 6 Introduction 6 1 Introduction This chapter contains an illustrated list of replaceable parts for the Fluke 45 Dual Display Multimeter Parts are listed by assembly alphabetized by reference designator Each assembly is accompanied by an illustration showing the location of each part and its reference designator The parts lists give the following information e Reference designator An indication if the part is subject to damage by static discharge e Description e Fluke stock number e Total quantity e Any special notes 1 factory selected part Caution A symbol indicates a device that may be damaged by st
36. 746529 603693 746214 740548 845458 830646 810440 746297 745992 746305 769257 837567 746024 746479 Option 01 Battery Pack List of Replaceable Parts Table 7 2 A4 Battery Pack PCA cont Reference Fluke Total Designator Description Stock Qty Note No T li INDUCTOR FXD DUAL EE24 25 0 4MH 1 2A 817379 1 1 IC VOLT REG ADu 1 2 TO 37 V 1 5 AMPS 460410 1 2 C COMPARATOR DUAL LOW PWR SOIC 837211 1 u 3 C CMOS HEX BUFFERS SOIC 837229 1 4 C VOLT REG ADJ SWITCHING REGULATOR 821215 1 VR 2 C 1 23V 150 PPM T C BANDGAP V REF 634451 1 ZENER UNCOMP 15V 596 8 5MA 0 2W SOT 23 83787 1 4 ZENER UNCOMP 6 8V 5 20MA 0 2W SOT 23 83795 1 1 WIRE ASSY BATTERY BLACK 834960 1 2 WIRE ASSY BATTERY RED 844332 1 45 Service Manual m oc roe RI4 816 wi BLACK qb40c eps Figure 7 9 A4 Battery Pack PCA 7 18 OO OO OO CO CO OO OO CO Chapter 8 Option 05 488 Interface LR Theory Of Operation cec ceteri re Functional Block Detailed Circuit Assembly Connectors esses Address Decoding Circuit eee TsOlation Er
37. A1R7 and A1K1 The signal is routed directly through 101 to the active filter and the a d converter without attenuation Higher voltages are attenuated by the dc input divider 171 For the 300 V range switches 53 and S9 in AIUI connect the 121 10 resistor to the 171 10 01 kQ resistor forming 1000 1 divider See Figure 2 3 The 510 switch in routes the signal to the active filter Pin 3 of A1Z1 serves as divider common which is also the a d converter low signal sensed through 1 9 2 23 Ohms Resistance measurements are made using the ratio ohms technique See Figure 2 4 A voltage source is connected in series with the reference resistor A1Z1 and the unknown resistor Since the same current then flows through both resistors the unknown resistance is determined from the ratio of the voltage drops across the reference and unknown resistors Theory of Operation 2 Detailed Circuit Description Depending on the range 53 56 59 513 or S15 connects the Analog Measurement Processor ohms voltage source to a reference resistor The resulting current passes through the reference resistor 1 2 the protection resistors AIRS and unknown resistance The a d converter integrates with the voltage across the unknown through the OVS input pin 23 For DE integrate reference the a d converter uses the voltage across the reference resistor through RRS pin 13 and Ohms Reference High through 55
38. Continuous tone for continuity Brief tone for normal forward biased diode or semiconductor junction Open Circuit Voltage 3 2 volts maximum Continuity Capture Time 50 us maximum 10 us typical Maximum Rated Input Input Protection 1000 volts dc or rms Introduction and Specifications 1 Specifications Frequency 5 Hz to gt 1 MHz Applicable Functions Volts AC and Current AC Range Slow amp Medium Accuracy 1000 Hz 01 Hz Hz 05 2 10 kHz Hz 1 Hz 05 1 100 kHz 1 Hz 10 Hz 05 1 1000 kHz 10 Hz 100 Hz 05 1 1 MHz 100 Hz 1 kHz For measurement of 1 MHz and lower accuracy is 05 1 For measurement above 1 MHz accuracy is not specified Sensitivity of AC Voltage 5 Hz 100 kHz 30 mV rms 100 kHz 300 kHz 100 mV rms 300 kHz 1 MHz 1V rms Above 1 MHz Not Specified Sensitivity Level of AC Current 5 Hz 20 kHz gt 3 mA rms 45 Hz 2 kHz gt 3 Arms Note When the meter is set to measure frequency and there is no input signal i e the input terminals are open the meter may read approximately 25 kHz rather than zero This is due to internal capacitive pickup of the inverter power supply into the high impedance input circuitry With source impedance of lt 2 this pickup will not affect the accuracy or stability of the frequency reading 45 Service Manual Environmental Warmup Time 1 hour to rated s
39. Perform the following procedure to test these fuses 1 Plug a test lead into input terminal and power up the meter 2 Press to select the ohms function General Maintenance Fuse Test and Replacement 3 Insert the test lead probe into the 100 mA input terminal If the fuse is good the meter will read between 11 and 15 Q If the fuse is blown the meter will read gt 10 MQ to OL 4 Remove the test lead probe from the 100 mA input terminal and insert it into the 10 A input terminal If the fuse is good the meter will read between 04 and 1 00 If the fuse is blown the meter will read gt 10 MQ to OL 3 12 Replacing the 500 mA and 440 mA Input Fuses 1 and F5 The 100 mA jack is protected by 2 fuses F1 and F5 F1 is mounted in the front panel 100 input jack Figure 3 2 and F5 is located inside the meter To replace first unplug the line cord Then press in on the input jack and turn it 90 degrees counterclockwise Slide out the fuse holder and fuse Replace a blown fuse with one of identical rating see Table 3 1 and reinsert the fuse and holder into the input terminal socket Secure the fuse holder by pressing in and turning the holder 90 degrees clockwise To change the internal F5 fuse see Replacing the 10 A Input Fuse later in this section Rear Panel Power Line Cord Connector To remove Squeeze and slide out F3 Line Fuse T 125 mA 250 V Slow Blow Fuse Holder Spare fuse provide
40. Revision levels are printed on the component side of each PCA Table 6 1 Manual Status Information Ref or Option Assembly Name Fluke Part No PCA Revision Levels No 05 IEEE 488 Interface PCA 814152 00 6 5 Newer Instruments Changes and improvements made to the instrument are identified by incrementing the revision letter marked on the affected pca These changes are documented on a manual supplement which when applicable is included with the manual 6 6 Parts The following pages give detailed listings of Fluke 45 parts Note This instrument may contain a Nickel Cadmium battery Do not mix with the solid waste stream Spent batteries should be disposed of by a qualified recycler or hazardous materials handler Contact your authorized Fluke service center for recycling information List of Replaceable Parts 6 Parts Table 6 2 Final Assembly Reference Description Note Designator A 1 MAIN PCA 814137 1 A 2 5 DISPLAY PCA 609179 1 F 1 FUSE 5X20MM 500A 250V FAST 838151 1 F 2 FUSE 406X1 5 FAST 11A 1000V FAST 943118 1 F 3 4 FUSE 5X20MM 0 125A 250V SLOW 822254 2 F 5 FUSE 0 44 A 1000V FAST 943121 1 H 1 2 CONN ACC D SUB FEMALE SCREWLOCK 250 844704 2 H 3 NUT EXT LOCK STL 6 32 3440D 152819 1 H 4 7 14 SCREW FHU P LOCK SS 6 32 250 320093 5 H 8 SCREW PH P LOCK STL 6 32 250 152140 1 H 9 SCREW PH P THD CUT STL 4 14 500 853668 1 H 10 11 SCREW TH P SS 4 40 187 721118 2 H 12 13 SCREW PH P LO
41. SOT23 DIODE SI 100 PIV 1 0 AMP DIODE SI 100 PIV 3 3 AMP SCHOTTKY FUSE 095X 28 5A 125V FAST AXIAL HEADER 1 ROW 050CTR 10 PIN TRANSISTOR SI NMOS 1W D PAK TRANSISTOR SI PNP SMALL SIGNAL SOT 23 TRANSISTOR SI NPN SMALL SIGNAL SOT 23 RES MOX 1 5K 5 1W RES CERM 47K 5 125W 200PPM 1206 RES CERM 130K 5 125W 200PPM 1206 RES CERM 523K 1 125W 100PPM 1206 RES CERM 100K 1 125W 100PPM 1206 RES CERM 10 5K 1 125W 100PPM 1206 RES CERM 10M 5 125W 300PPM 1206 RES CERM 470K 5 125W 200PPM 1206 RES CERM 330K 5 125W 200PPM 1206 RES CERM 51K 5 125W 200PPM 1206 RES VAR CERM 10K 20 0 3W RES CERM 59K 1 125W 100PPM 1206 RES CERM 301K 1 125W 100PPM 1206 RES CERM 470 5 125W 200PPM 1206 RES CERM 3 3K 5 125W 200PPM 1206 RES METAL FILM 2 26k 1 0 5W RES CERM 10 5 125W 200PPM 1206 RES CERM 100K 5 125W 200PPM 1206 RES CERM 12 5 125W 200PPM 1206 RES CF 0 50 5 0 25W RES CF 560 5 0 25W RES CERM 100 5 125W 200PPM 1206 RES CERM 1K 5 125W 200PPM 1206 RES CERM 120 5 125W 200PPM 1206 RES CERM 910 5 125W 200PPM 1206 RES VAR CERM 200 20 0 3W RES CERM 6 8K 5 125W 200PPM 1206 RES CERM 2 2K 5 125W 200PPM 1206 No 769786 769240 822403 816843 837492 837468 740597 769687 837732 830489 698555 837740 696427 831503 822106 742684 742676 603685 746685 851761 844956 769802 851852 783274 746792 746776 746693 837559 851803 821652 740506
42. The controller receives commands over a three wire communication channel from the Microprocessor on the Main Assembly Each command is transferred serially to the Display Controller on the display transmit DISTX signal with bits being clocked into the Display Controller on the rising edges of the display clock signal DSCLK Responses from the Display Controller are sent to the Microprocessor on the display receive signal DISRX and are clocked out of the Display Controller on the falling edge of DSCLK Figure 2 9 shows the waveforms during a single command byte transfer Note that a high DISRX signal is used to hold off further transfers until the Display Controller has processed the previously received byte of the command Once reset the Display Controller performs a series of self tests initializing display memory and holding the DISRX signal high After DISRX goes low the Display Controller is ready for communication on the first command byte from the Microprocessor the Display Controller responds with a self test results response If all self tests pass a response of 00000001 binary is returned If any self test fails a response of 01010101 binary is returned The Display Controller initializes its display memory to one of four display patterns depending on the states of the DTEST A2UI 41 and LTE A2U1 13 inputs The DTEST input is pulled up by A2ZI but may be pulled down by jumpering A2TP4 to A2TP3 GND The LTE input is
43. Using decades of 1 0 300 Q short 0 00 0 04 100 Q 99 93 100 09 3 kQ short 0 0000 0 0002 1 0 9993 1 0007 30 10 9 993 10 007 300 100 99 93 100 07 3 MQ 1 MQ 0 9992 1 0008 30 MQ 10 MQ 9 972 10 028 300 100 MQ 98 0 102 0 Performance Testing and Calibration 4 Table 4 3 Performance Tests for mA Current Functions Function Range Rate Input Level Frequency Display 30 30 29 982 30 018 100 100 99 93 100 07 Table 4 4 Performance Tests for Current Functions Range Rate Input Level Frequency Display 4 4 Front Panel Calibration The Fluke 45 features closed case calibration using known reference sources The multimeter automatically prompts you for the required reference sources measures them calculates correction factors and stores the correction factors in the nonvolatile calibration memory Closed case calibration has many advantages There are no parts to disassemble no mechanical adjustments to make and the Fluke 45 can be calibrated by an automated instrumentation system The Fluke 45 should normally be calibrated on a regular cycle typically every 180 days or 1 year The chosen calibration cycle depends on the accuracy specification you wish to maintain The Fluke 45 should also be calibrated if it fails the performance test or has undergone repair To meet the specifications in Chapter 1 the Fluke 45 should be calibrated wi
44. essen 8 1 Introduction souder te n ipeo 8 2 Dheoty oL Operation tenore 8 3 Functional Block 8 4 Detailed Circuit 8 5 Main Assembly Connectors 8 6 Address Decoding Circuit ettet 8 7 Isolation tenen e nee 8 8 IBBB 488 Controller iiit coiere ert t e eene 8 9 IEEE 488 8 10 General Maintenance ede 8 11 Removing the IEEE 488 Interface Option eese 8 12 Installing the IEEE 488 Interface Option eese iv Contents continued 8 13 Performance Testing eresie 8 14 Troubleshooting 8 15 e etui he e eerta 8 16 Communication Problems sess 8 17 Failure to Select IEEE 488 Interface Option 8 18 Failure to Handshake on IEEE 488 Bus esses 8 19 Failure to Enter 8 20 Failure to Receive Multiple Character Commands 8 21 Failure to Transmit Query Responses 1 8 22 Failure to Generate an End or Identify EOL
45. the buffer applies the opposite polarity reference voltage and the integrator integrates back down until the comparator toggles A counter measures the integrate reference time If the a d converter is overloaded and the integrator does not return to its starting point by the end of the integrate reference phase S77 discharges integrator capacitor 1 16 The reference voltage for volts current and diode test modes is provided by a 6 3 V zener diode AIVRI The reference amplifier in the Analog Measurement Processor 2 17 45 Service Manual provides 2 mA of current through 1 Resistor network 173 divides the 6 3 V down to 1 1 V REFERENCE INPUT REFERENCE COUNTER A D COMPARATOR INTREGRATE REFERENCE REFERENCE INPUT INTEGRATOR INTEGRATE INPUT Figure 2 8 A D Converter Simplified Schematic qb08f eps 2 33 Serial Communication Guard Crossing The Microprocessor communicates with the Analog Measurement Processor using this isolated two wire full duplex asynchronous interface circuit When the Microprocessor is transmitting to the Analog Measurement Processor the transmit data bits appear at A1U6 11 which drives the combination of AQ19 A1R33 and A1U3 1 The optocoupler A1U3 then optically transfers this information to its output circuit comprised of 103 7 1 30 A1R28 and A1R27 The transmitted data is then presented to and A1U1 40
46. 1 900 1s CALREF xxxx x CALSTEP 27 3 19 00 2s CALREF xxxxx CALSTEP 28 4 190 0 kQ 3 5 CALREF CALSTEP 29 5 1 900 MQ 3 5 CALREF CALSTEP Performance Testing and Calibration 4 Calibration Using the Computer Interface Table 4 7 Calibration Using the Computer Interface cont ao Threshold Calibration Step Apply input Wait for meter settling time Send 30 0 000 mV dc 1s CALSTEP 31 20 00 mV 1s CALSTEP Frequency Calibration 32 10 kHz 2 000 V p p 2s CALSTEP represents the known exact ohms value of the source 190 source calibrates the 300 range on the Fluke 45 to 0 06 2 digits 0 02 For calibration of this range to 0 05 2 digits 0 02 use 290 source and the procedure detailed under Alternate Ohms Calibration Computer Interface This procedure can also be used with appropriate discrete resistor values such as a decade box on all ranges Note that the 290 kQ and 2 9 MQ ranges are quite sensitive to noise Any movement of the input leads or movement of the hands or body in the vicinity of the leads can cause noisy readings Use shielded leads during this calibration These two cal points should be verified for accuracy at the conclusion of calibration 4 21 The Calibration Procedure Now select calibration mode on the Fluke 45 Using a thin blunt tipped object press the recessed Cal Enable button for three seconds Avoid
47. 18 operational Table 5 1 describes the error codes Note Each error code is displayed for 2 seconds Any button press during this period aborts the error display Diagnostic Testing and Troubleshooting Error Codes Table 5 1 Error Codes ROM test failed External RAM test failed Internal RAM test failed Display self test failed Display dead EEROM meter configuration corrupted EEROM calibration data corrupted UNCAL annunciator also lights A D chip dead Measurement self test failed Refer to Troubleshooting information later in this chapter Error 1 ROM A1U8 checksum match failed All do bytes in the ROM including a checksum byte are summed Error 2 External RAM A1U10 check failed Error 3 Internal RAM A1U6 check failed Complementary patterns are alternately written and read from each RAM location for both external RAM and the 256 bytes internal to the 6303Y Main Processor A1U6 If the pattern read from any RAM location is not the same as the pattern written the test fails Error 4 Display self check failed Error 5 Display dead The display processor automatically performs a self check on power up and the Main Processor attempts to read the result of this test EEROM A1U5 meter configuration corrupted or EEROM not initialized At power up A1U6 reads CRC from EEROM A1U5 location then reads configuration data from another location in EEROM calculates an algorithm to compa
48. 2 No 1010 1 92 EN61010 1 1993 to 1000 V Overvoltage Cat I 600 V Overvoltage Cat II UL3111 1 See the following for an explanation of CATI and CATII categories CATI OVERVOLTAGE Installation CATAGORY I Pollution Degree 2 per IEC1010 1 refers to the level of Impulse Withstand Voltage protection provided Equipment of OVERVOLTAGE CATEGORY I is equipment for connection to circuits in which measures are taken to limit the transient over voltages to an appropriate low level Examples include protect electronic circuits CAT II OVERVOLTAGE Installation CATAGORY II Pollution Degree 2 per IEC1010 1 refers to the level of Impulse Withstand Voltage protection provided Equipment of OVERVOLTAGE CATEGORY Il is energy consuming equipment to be supplied from the fixed installation Examples include household office and laboratory appliances Electromagnetic Compatibility Meets FCC Part 15 Subpart J EN61326 1 1998 RS 232 C Baud rates 300 600 1200 2400 4800 and 9600 Odd even or no parity One stop bit Options Battery Option 01K Type 8 V Lead Acid Operating Time 8 hours typical lights when less than 1 2 hour of battery operation remains Meter still meets specifications 1 45 Recharge Time 16 hours typical with meter turned off and plugged into line power Battery will not charge when meter is turned on 488 Option 05 Capability Codes SH1 T5 L4
49. 30 seconds maximum protected with a 11 A 1000 V 17 000 A interrupt rating fast blow fuse Note Resistance between the COM binding post and the meter s internal measuring circuits is approximately 003 Q AC Current Resolution Medium Burden Voltage Typical at full range Accuracy Accuracy Frequency mA To 100 mA 20 50 Hz 2 100 2 10 7 2 100 50 Hz 10 kHz 0 5 100 0 5 10 0 8 2 mA 100 mA 10 20 kHz 2 200 2 20 2 1 10 20 50 Hz 2 100 2 10 7 2 A 1 10 50 Hz 2 kHz 1 100 1 10 1 3 2 0 5 to 1 A 20 50 Hz 2 300 2 30 796 4 0 5 to 1 50 Hz 2 kHz 1 300 1 30 1 3 4 mA accuracy specifications apply within the following limits based on reading rate Slow Reading Rate Between 15 000 and 99 999 counts full range Medium Reading Rate Between 1 500 and 30 000 counts full range Fast Reading Rate Between 150 and 3 000 counts full range Introduction and Specifications Specifications Maximum Crest Factor 3 0 Maximum Input mA 300 mA dc ac rms Protected with a 500 mA 250 V 127 sheet I fast blow fuse and a 440 mA 1000 V fast blow fuse A 10 A dc or ac rms continuous or 20 A dc or ac rms for 30 seconds maximum Protected with a 11 A 1000 V 17 000 A interrupt rating fast blow fuse Note Resistance between the COM binding post and the meter s internal measuring circuits is appr
50. 52 VREF 51 VREF GUARD 12 GUARD 17 GUARD 20 GUARD 22 GUARD 24 1 25 26 A1U1 ANALOG MEASUREMENT PROCESSOR LEd 0d tld Zd 22 124 04 3 ON ON O 55 P37 07 51 P12A2 1 DIGR P20 10 DIGS P21 DSCLK P22 12 RX P23 13 TX P24 14 DISRX P25 15 DISTX P26 16 EESK P27 17 SWA1 P52 21 SWR2 P53 22 SWRS3 P54 23 SWR4 P55 24 SWR5 P56 25 SWR6 P57 26 qb19f eps 6Y OLY ZLY ELV Std 9 VIV vY SIN 99A ON 494 933 99d 994 1033 94 0033 294 40 194 MSLdO 09d Llvd MOT A1U6 MAIN PROCESSOR Figure 5 1 Test Point Locator 5 6 5 Error Codes Diagnostic Testing and Troubleshooting
51. C34 cas 42 50 427504 1788 2509 SLOW FUSE C FrLe CJ 309 59 EARTH GND POWER SUPPLY 45 1001 Sheet 3 of 3 qb47sc tif Figure 9 1 A1 Main PCA cont 9 7 45 Series Service Manual 45 4002 Figure 9 2 A2 Display PCA 9 8 Schematic Diagrams 05 74 423 8 16 NOTES UNLESS OTHERW SE SPECI FI ED 74HC132 1 ALL RESI STANCE 15 OWS 2 ALL CAPACI TANCE 15 CRO FARADS REFERENCE DESI GNATON NOT USED 2 051 Ji 0 0 0 0 R12 R6 9 11 1 TP6 U6 14 21 UPD75212AGF ANODE lt 13 gt 13 ANODE14 lt 12 gt 4 ANODE13 RESET2 1 ANODE12 1 ANODE lt 10 gt 11 ANODE lt 9 gt 17 ANODE10 m ANODE lt 8 gt 20 ANODES ANODE8 ANODE lt 6 gt 22 ANODE7 ANODE6 ANCOES ANODE4 ANODE3 lt 1 gt 28 ANODE2 ANODE lt 0 gt 29 ANODE 1 30
52. CHARGER LAST 5 NOT USED 04 ____ ______ 545 ____ 4 10 12 215 ____ 1 5 10 101 2 6 015 ____ 01 8 11 4 JYRI _____ R45 E 11 13528 R14 100K 1 CERM V R11 130K CERM YR2 V CRO MBR140 Q6 R28 S 12 lt N7 J CERM 4N4002 52 5904 R31 100 CERM SWITCHING POWER SUPPLY 22 504 CERM 30HQ10F IRFR120 S 100K CERM Schematic Diagrams 9 45 1004 Figure 9 4 A4 Battery PCA cont qb53sc tif 9 13 45 Series Service Manual Figure 9 5 A5 IEEE 488 Interface PCA Schematic Diagrams NOTES UNLESS OTHERWISE SPECIFIED 1 1 ALL RESISTANCES ARE IN OHMS 1 8WATT S 8 800615 ALL CAPACITANCES ARE IN MICROFARADS g 2004 5 800011 8 10 MAIN PWB F 1 1 2 2 5 DATACE 06017 4 5 5 16 DATAC 4 6 2818 lt 3 DATACOI 4 t u je DATAL 017 i DIN o SHIELD 12 5 2105 13 RESET _ 14 55 prog 16 17 18 19 20 21 24 m NO Po ol jun 0 1010 REFERENCE DESIGNATIO
53. COM connectors on the Fluke 45 Select the function and range on the Fluke 45 and the input level from the 5700A using the values listed in Table 4 2 The display should read between the minimum and maximum values listed in the table 3 Connect a cable from the Output VA HI and LO connectors of the 5700A to the 100 mA and COM connectors on the Fluke 45 Select the function and range on the Fluke 45 and the input level from the 5700A using the values contained in Table 4 3 The display should read between the minimum and maximum readings listed in the table 4 The following tests require a Fluke 5725A Amplifier or equivalent to be used with the 5700A The input level for the performance test will be set on the 5700A but will be output from the 5725A Amplifier Connect a cable from the Output VA HI and LO connectors of the 5725A to the 10 A and COM connectors on the Fluke 45 Select the function and range on the Fluke 45 and the input level from the 5700 using the values contained in Table 4 4 The display should read between the minimum and maximum readings listed in the table Performance Testing and Calibration 4 Performance Tests Table 4 2 Performance Tests for Volts Diode Test Ohms and Frequency Functions Function Range Rate Input Level Frequency Display 100 mV slow short 0 006 0 006 90 mV 89 971 90 029 1000 mV slow 900 mV 899 71 900 29 300 mV short 0 02 0 02 300 mV 299 90 300 10 3V 3 V 3 001
54. D Converter Figure 2 8 shows the dual slope a d converter used in the Fluke 45 A voltage level proportional to the unknown input signal charges integrates a capacitor for an exact amount of time This capacitor is then discharged by a reference voltage of opposite polarity The capacitor discharge time which is proportional to the level of the unknown input signal is measured by the digital circuits in the Analog Measurement Processor and sent to the microprocessor In the medium and fast measurement rates the a d converter uses the 300 mV or 3 V range These ranges typically uprange at a display of 32 000 in the medium rate In the slow rate the a d converter uses one of two additional ranges 100 mV and 1000 mV The uprange point for these additional ranges is a display of 99 999 In the ohms function only a typical uprange point is a display of about 98 000 During the integrate phase the a d buffer in Analog Measurement Processor A1U1 applies the signal to be measured to one of the four integrate resistors in resistor network A1Z3 The choice of resistor depends on the measurement range Switch S69 connects output B 1 pin 47 for the 100 mV range S71 uses output B 3 pin 48 for the 300 mV range S73 uses output B1 pin 49 for the 1000 mV range and S75 uses output B3 pin 50 for the 3 V range Refer to Figure 8 1 The current through the selected integrator resistor charges integrator capacitor A1C16 After the integrate phase
55. Operation The Microprocessor communicates to the Analog Measurement Processor via the Serial Communication circuit using an asynchronous communication protocol Communication to the Analog Measurement Processor originates at 106 11 which is normally low when no communication is being done Communication from the Analog Measurement Processor to the Microprocessor appears at A1U6 10 and is normally low unless communication is in progress 2 37 EEROM The EEROM contains 64 registers each of which is 16 bits long These registers are used to provide non volatile storage of meter configuration and calibration information When the Microprocessor is communicating to the EEROM Chip Select A1U5 2 goes high to enable the EEROM interface When the Microprocessor is reading data from the EEROM the data bits are serially shifted out on the Data Out signal A1U5 6 with each one to zero transition of the Serial Clock A1U5 3 When the Microprocessor is writing commands and data to the EEROM the bits are serially shifted into the EEROM on the Data In signal A1U5 5 with each zero to one transition of the Serial Clock A1U5 3 The EEROM drives the Data Out signal A1U5 2 19 45 6 low to indicate that it is busy writing the register thereby controlling the timing of the write cycle The microprocessor waits for this signal to go high before performing other EEROM operations If the EEROM fails to drive this
56. SRI RL1 DT1 E1 LEO and CO External Trigger Input VIH 1 35 V minimum VIL 1 25 V maximum Input Threshold Hysteresis 0 6 V minimum NO ON CA PO Ne SMe eS NYY YY YY YY b2 PPYPPP Y 2 22 2 23 2 24 2 25 2 26 2 27 2 28 2 29 2 30 2 31 2 32 2 33 2 34 2 35 16 E Chapter 2 Theory of Operation e ER Functional Block Power Supply Analog Measurement Input 2 2 Input Signal Conditioning eee Analog to Digital A D Converter eene Serial Communication Guard Crossing Digital Kernel 2 tette egeo ee dene ep aereas Display Assembly cieca em reri tert eb Rete tue IEEE 488 Interface Option 05 Battery Pack Option 01 Detailed Circuit Description eene enne Power Supply Circuit Raw DC Supply eei need etie 5 Volt Switching Supply eese Invertet eite eee AC NOMS 22522 ier
57. When the Analog Measurement Processor is transmitting data back to the Microprocessor the data bits appear at A1U1 39 which drives the input of a Darlington driver A1U2 1 The Darlington driver output then drives 1 29 and A1U4 1 to transfer the information to the output of the optocoupler at 104 7 Resistors A1R32 and 1 34 complete the optocoupler output circuit Data is then routed to AITP7 and A1U6 10 on the Microprocessor 2 34 Digital Kernel The Digital Kernel is composed of six functional circuit blocks the RS 232 interface the Microprocessor the EEROM Electrically Erasable Read Only Memory the RAM Random Access Memory the ROM Read Only Memory and the IEEE 488 Option Connections These blocks are described in the following paragraphs 2 18 Theory of Operation 2 Detailed Circuit Description 2 35 RS 232 Interface The RS 232 interface is composed of connector 115 RS 232 level shifter A1U7 and the hardware serial communication interface SCI in Microprocessor A1U6 The transmit signal from the SCI A1U6 14 goes to the RS 232 driver A1U7 12 where it is inverted and shifted to transition between approximately 5 0 and 5 0 V dc When nothing is being transmitted by the meter the driver output A1U7 5 is 5 0 V dc The receive signal from 1 5 goes to the RS 232 receiver 107 4 where it is inverted and shifted to transition between 5 0 and 0 V dc When nothing is being transmitted to the meter the receiv
58. after OPTSW goes to 5 0V dc the initial read access clocks 509 11 causing A5U9 9 to go high to remove the reset from A5U6 22 This action is followed by another dummy read cycle for delay The Main Assembly then sends six write cycles to initialize ASU6 The IRQ2 interrupt is then enabled and the serial poll status byte is initialized At this point the IEEE 488 Interface Option is ready to respond to transactions on the IEEE 488 bus Note Each time that the IEEE Interface Option is selected in the BAUD menu by pressing AUTO the IEEE 488 Interface Option initialization is repeated as described above with the exception that no hardware reset is performed via the OPTSW signal 8 19 Failure to Enter Remote If the IEEE 488 Interface Option does not enter remote check that the remote local control circuit is operating properly When the IEEE 488 Interface Option is the active instrument interface the remote local control state is polled by the Main PCA approximately every 1 0 ms Normally 505 8 goes low for approximately 1 0 us during the read cycle that checks the state of 506 If A5U3 11 is low during the read cycle 506 is in the local state If A5U3 11 is high during the read cycle 506 is in the remote state When A5U6 indicates that it is in remote the REMOTE indicator on the display is turned on 45 8 20 Failure to Receive Multiple Character Commands Monitor the interrupt signal fr
59. begun to execute If the E clock remains a 1 628 us rectangular wave the SWR2 A1U6 22 keyboard scan line may be shorted to ground This condition would cause the Main Processor to HALT after reset Check whether the 6303Y Main Processor is attempting to access ROM LIR 64 should transition for a short period of time after reset If it does the 6303 Y Main Processor is probably operational and the problem is external to the processor The processor can execute an instruction that stops both itself and the E clock Therefore the absence of any activity on pin 68 does not necessarily mean that A1U6 or A1Y2 is bad If some other failure prevents proper ROM access the processor may have just gone to sleep This can be verified by checking for a rectangular wave occurring at pin 68 for a short time after RESET transitions high on pin 7 106 and A1Y2 are probably operational if this rectangular wave is present 5 15 45 MCU Write Do D7 MCU Read Do D7 qb24f eps Figure 5 3 Main Processor Timing To check the ROM decode circuitry verify that A1U9 6 is transitioning low and that these transitions correspond roughly to the low going transitions of LIR Pin 6 must be low when LIR is low see Figure 5 3 Verify that this signal also appears at the ROM Chip Enable A1U8 20 If the ROM Chip Enable is present the problem is with the ROM itself or there is a fault in the add
60. driver 45 4 Ensure that the nylon standoff support front center of the Main is in place Then slide the Main PCA onto the chassis slider taps Fasten the Main PCA to the chassis with a 6 32 1 4 inch panhead screw Connect the transformer cable F and RS 232 cable at the Main PCA 3 31 Install the IEEE 488 Option Both the instruction sheet provided with the IEEE 488 Option and Chapter 8 of this manual fully describe installation The following instructions provide installation procedure essentials If necessary refer to Chapter 8 paying particular attention to Figures 8 2 and 8 3 1 Check that the plastic standoff remains the appropriate hole in the Main narrow end of the standoff down If necessary install the two ribbon cables on the IEEE 488 circuit board Each cable fits in only one socket and in only one direction Make sure the cables lock firmly in place Attach opposite ends of the ribbon cables onto the Fluke 45 Main PCA Install the IEEE 488 PCA into the small slot in the side of the Fluke 45 two ribbon cables facing forward The end of the plastic standoff fits into the hole in the IEEE 488 PCA Make sure the IEEE 488 is firmly gripped against the retainer on the standoff and that the rear of the pca rests upon the support just forward of the transformer Secure the rear of the IEEE 488 PCA with the panhead Phillips screw Connect t
61. eene 4 8 Calibration Mode Computer Interface Commands eene 4 9 EEROM Calibration Constants sees nen nennen nennen 5 1 Error CodeS 9 2 5 3 DC Volts Troubleshoot rtr mea eere cred d ehe oru 9 4 Volts Troubleshooting rrr re e ee pe E 9 22 Display eie nr rente te et ta egt SEE de et endet seeds 5 6 Calibration Steps and Related Components eee 5 7 Components Unique to Calibration Steps sese 956 Calibration Hierarchy hee e ai Hber epa Pay esas 5 9 Calibration Constants ioter ii ei ENSE a eoa VR 6 1 Manual Status nennen nennen enne 6 2 Final Assembly 6 3 6 4 True Rms une e UE ETUR EE Mee VEM 6 5 A2 Display PCA inset titer Tiere ret eee eet aere te ore tea eX R dee teo do 7 1 Option 01 Battery Pack Final Assembly eee 7 2 A4 Battery isse ce eee tire det 8 1 488 Transceiver Control 8 2 Option 05 IEEE 488 Interface Final Assembly
62. eps Figure 6 3 A1A1 True Rms PCA Q R R R R U U U U Z Reference Designator oca 1 e A N Table 6 5 A2 Display PCA Description CAP CER 0 1UF 10 25V X7R 1206 CAP TA 4 7UF 10 20V DIODE SI BV 75V O0 250MA SOT23 TUBE DISPLAY VAC FLUOR 7 amp 8 SEG 10CHAR HEADER 1 ROW 050CTR 20 PIN AF TRANSD PIEZO 22 MM FLUKE 45 3021 PWB DISPLAY TRANSISTOR SI PNP 40V 300 mW SOT 23 RES CERM 10K 5 125W 200PPM 1206 RES CERM 2 2M 5 125W 200PPM 1206 RES CERM 1 2M 5 125W 200PPM 1206 RES CERM 47K 5 125W 220 PPM 1206 IC CMOS 4 BIT MPU D75212GF SMR RESONATOR SMR CERM 4 19 MHz IC CMOS DUAL MONOSTB MULTIVBRTR SOIC IC CMOS QUAD 2 IN NAND W SCHMT SOIC RES CERM SOIC 16 PIN 15 RES 10K 5 List of Replaceable Parts 747287 605433 830489 783530 831529 602490 609161 742684 746610 811778 806240 746685 688879 688317 806620 837245 836296 LI Ll lt lt alan aa anni Gg Parts 6 6 13 45 6 14 TP4 Figure 6 4 2 Display 05
63. from Hz back to V DC can only be accomplished by successively pressing the 25 button e Once has been pressed to initiate calibration prompting press either 25 once initially to enter the editor mode Then use these buttons to edit the calibration prompt value The calibration prompt value can be edited by digit Use to select the digit to edit Use to increment the selected digit To select a lower digit value continue incrementing with 2 the meter wraps from 9 back to 0 Press when the edited value is correct 3 button Used to select a calibration function calibrate store constants derived from input source into memory or exit editor mode Each time the Fluke 45 prompts you for a reference source apply the requested source to the appropriate input and COM terminals allow for both calibrator and meter settling time and press the button When is pressed the numeric display field blanks while the Fluke 45 performs the necessary calculations Do Not change the reference source while the display is blank If the calibration step is successful the Fluke 45 displays an intensified reading equal to the calibration prompt value before changing to the next prompt Note The meter emits a and displays Error if a calibration step fails Usually this happens if the reference is not within an anticipated range 5 to 15 depending on the step At this point the intensified reading equals the raw uncalibrate
64. if the signal is detected high Since ACON is high when the meter is operating on battery power the IEEE 488 Interface Option cannot be selected as the active interface during battery operation The displayed IEEE message is dim and the battery indicator blinks if the Fluke 45 software detects ACON to be high when the option editor is entered The ACON signal A1U6 33 is low when the meter is operating from line power 8 18 Failure to Handshake on IEEE 488 Bus Check VCC2 with a voltmeter When the Fluke 45 is operating on line power VCC2 should be about 0 1V lower than VCC VCC2 is controlled by the Microprocessor which sets A1U6 28 high when operating on line power and causes OPTSW to be driven to a 5 0V dc level The OPTSW signal controls the gate of FET switch 5 1 on the IEEE 488 Interface Option to turn VCC2 on The Reset circuit consists of ASCRI ASR1 502 509 When the meter is operating on batteries the Reset circuit converts the OPTSW signal to a digital signal that disables access to 506 When operating from batteries OPTSW is at about 5 0V dc A5U2 9 is high A5U2 10 is low and A5U9 9 is low to reset 506 via pin 22 When the meter is connected to ac line voltage again this circuit resets 506 OPTSW transitions to 5 0V dc 502 9 is low near GND A5U2 10 is high and A5U9 9 stays low until the Address Decoder detects a memory access to the IEEE 488 Interface Option About 1 0 ms
65. integrate reference 2 25 AC Volts AC voltage and ac current inputs are scaled by the ac buffer then converted to a representative dc voltage by the true rms ac to dc converter Refer to Figure 2 5 JFETs A1Q2 to A1Q8 switch the ranges of the buffer amplifier ATARI The JFET drive signals ACRI to pins 5 to 8 turn the JFETs either on at 0 V or off at VAC The ratio of the feedback resistor to the 1 111 input resistor divides the input signal by 10 100 or 1000 These arrangements are summarized in Table 2 4 This signal is then amplified by 25 using the 2 776 and 115 7 buffer output divider resistors The A1Z2 111 1 kQ feedback resistor is left in parallel with the higher range feedback resistors For the 300 750 V range the 2 776 kQresistor becomes the feedback element A1R15 and A1C2 compensate the 300 mV range of the ac buffer The ac signal is then routed to the rms converter by Analog Measurement Processor switch 38 Capacitors AIC1 1 7 1 2 and A1A1C3 function as dc blocking capacitors 1 1 provides input bias current for the rms converter buffer and is the converter s averaging capacitor The rms converter output is divided down 2 5 by 174 1 19 and A1C10 form the passive filter for ac volts Analog Measurement Processor switch S80 shorts AIR19 both during ranging and in the fast measurement rate Components AIR16 1 17 A1C3 2 14 Theory of Operation 2 Detaile
66. measurements dc volts dc current ohms and diode test are then filtered by the active filter AC measurements ac volts and ac current are passively filtered after being converted to a dc voltage In the medium and fast measurement rates the a d converter uses one of two ranges 300 mV and 3 V full scale In the slow rate the a d converter uses one of two additional ranges 100 mV and 1000 mV full scale for a total of four ranges Theory of Operation 2 Detailed Circuit Description 2 21 Relays Latching relays A1K1 A1K2 and A1K3 route and connect the input signal to the functional blocks required by the selected function The Analog Measurement Processor 101 function control outputs which are 8 ms positive pulses 0 V to VDD at FCO to 5 pins 28 to 33 control the relay driver 102 The 102 drivers are NPN Darlington pairs Relay functions are defined in Table 2 2 Table 2 2 Relay Operation DC mV 3 V Reset Set Set DC 10 V 30 V 100 V 300 V 1000 V Set Set Set ACV Set Set Reset Ohms amp ohms Reset Reset Set M ohms Reset Set Set Diode Test Reset Reset Set mA DC and ADC Set Set Reset mA AC and AAC Set Set Set Frequency Set Set Reset 45 FILTER qb03f eps Figure 2 3 DC Volts 300 V Range Simplified Schematic 2 22 DC Volts For the mV and 3 V ranges the input signal is applied to through A1R6
67. pulled down by A2R12 but may be pulled up by jumpering A2TP5 to A2TP6 VCC The default conditions of DTEST and LTE cause the Display Controller to turn all segments on bright at power up Table 2 6 defines the logic and the selection process for the four display initialization modes The two display test patterns are a mixture of on and off segments forming a recognizable pattern that allows for simple testing of display operation The Display Controller provides 10 grid control outputs and 14 anode control outputs Each of these 24 high voltage outputs provides an active driver to the 5 V dc supply and a passive 70 Theory of Operation 2 Detailed Circuit Description nominal pull down to the 30 V dc supply These pull downs are internal to the Display Controller The output port P63 of the Display Controller is used as a grid control output for GRID 10 of the vacuum fluorescent display A high voltage output from P63 is provided with a 10 resistor A2R1 and PNP transistor A2Q1 provide an active driver to the 5 V dc supply and a passive 47 KQ pull down A2R4 to 30 V The Display Controller drives the vacuum fluorescent display in a multiplexed manner by strobing each grid individually while the segment data for that display area is presented on the anode outputs Each grid is strobed for approximately 427 microseconds every 5 368 milliseconds resulting in each grid on the display being strobed about 170
68. the required 1 V reference switching oscillator regulator comparator current limit comparators and output switch The controller chip is supported by several external components C7 sets the oscillator frequency R17 C6 and C8 are required for stability R15 R21 and R20 set the output voltage level The variable width pulse from U4 5 is first level shifted and clamped by R23 R24 and CR7 and then coupled to the FET switch circuit through inverter U3 2 Hex inverters U3 4 U3 6 and U3 10 are connected in parallel to provide sufficient drive to the FET gate FET switch Q5 is turned on at the beginning of each square wave drive cycle and turned off at the point necessary to set the desired output voltage The current limit is set by the voltage drop across the 0 1 ohm resistance provided by the parallel configuration of five 0 5 ohm resistors R29 R34 R35 R36 and R37 Current limiting occurs when the voltage drop across the ohm resistance is greater than approximately 100 mV Current limiting is effected by reducing the duty cycle of the switching transistor Q5 which in turn reduces the output voltage of the supply A bootstrap supply for the driver and coupling clamp circuits is provided by CR8 R25 C9 C11 VR3 The output level has a negative temperature coefficient to provide the proper charging voltage level for the battery pack over a broad temperature range This negative coefficient is provided by the Temperature Compensation circu
69. the upper side of the Main PCA The component side of the Rms PCA faces forward 3 29 Install the Analog Measurement Processor Shields The Analog Measurement Processor resides within a plastic shield on the top of the Main PCA Although having the appearance of a dark gray piece of plastic this shield is electrically conductive treat it as you would any other conducting surface On the bottom of the Main PCA the Analog Measurement Processor is protected with a metallic shield Press the conductive plastic shield into place on the top of the Main PCA From the bottom of the Main PCA install the metallic shield K Avoid contacting any circuit traces during this procedure Then replace the single Phillips head screw J securing the metallic shield 3 30 Install the Main PCA 1 Prior to installing the Main verify the following e If necessary reinstall the transformer insulator I tabs down around the right side of the transformer Once the insulator is in place pull each tab through the Main PCA from bottom side with a needle nose pliers e If the nylon standoff L used between the Main PCA and the metallic shield surrounding the Analog Measurement Processor has been removed verify that proper orientation is maintained during installation The standoff end with the shorter beveled indent fits into the metallic shield Press the standoff end with the wider straighter indent into the Main PCA with a 3 16 nut
70. wave when an input is being measured Check the 1 1 V reference 1 2 to AITP1 1 1 V In general check that the relays are getting the proper drive signals and that they are in the correct position The 10 A current shunt A1R3 or the mA current shunt A1R2 can be used as a convenient COMMON test point 5 10 Uart Test This test checks both the optoisolators A1U3 and A1U4 and the Analog Measurement Processor A1U1 UART circuitry The Main Processor A1U6 first sends a break signal 5 V dc logic high to A1U1 then waits for a break signal in response from A1U1 Once this occurs 106 commands 101 to remove its break signal response 5 13 45 Service Manual To initiate the UART test hold the button down for three seconds If the test passes PASS is shown in the secondary display If the test fails FAIL is shown in the secondary display The test is run repeatedly updating the PASS or FAIL display each time An oscilloscope can thereby be used to trace the rectangular wave forms across optoisolators AIU3 and A1U4 To exit the UART Test turn the meter off wait three seconds then turn the meter back on 5 11 DC Volts Troubleshooting Put the meter in the 300 mV 3 V range and apply an input Then trace this signal as described in Table 5 3 5 12 AC Volts Troubleshooting Apply a signal with the multimeter set for the 300 mV ac range Then trace this signal as described in Table 5 4 5 13
71. 0 2 9990 30 V 30 V 30 010 29 990 300 V 300 V 300 10 299 90 1000 V 1000 V 1000 5 999 5 30 V 30 V 29 990 30 010 300 V 300 V 299 90 300 10 1000 V 1000 V 999 5 1000 5 300 mV short lt 075 15 1 2 14 87 15 13 100 2 13 75 16 25 300 1 kHz 299 30 300 70 100 kHz 284 50 315 50 3V 3 0 V 1 kHz 2 9930 3 0070 30 V 30V 1 kHz 29 930 30 070 300 V 300 V 1 kHz 299 30 300 70 750V 750 V 1 kHz 747 5 752 5 Using decades of 3 300 Q short 0 00 0 04 300 Q 299 83 300 19 3ko short 0 000 0 0002 3 kQ 2 9983 3 0017 30 kQ 30 kQ 29 983 30 017 300 300 299 83 300 17 3 MQ 3 MQ 2 9980 3 0020 30 30 MQ 29 922 30 078 300 MQ 300 MQ 294 0 306 0 Using decades of 1 9 300 Q short 0 00 0 04 190 Q 189 88 190 14 4 5 45 4 6 Table 4 2 Performance Tests for Volts Diode Test Ohms Frequency Functions cont 10 100 kHz 0 1to10V_ 10 kHz 9 994 10 006 Use either 2 wire compensation on the 5700A or the relative REL mode on the 45 Optional test points that can be used if standards are available All measurement rates are in medium speed unless otherwise specified Function Range Rate Input Frequency Display Level 3k Q short 0 0000 0 0002 1 9 KQ 1 8988 1 9012 30 kQ 19 KQ 18 988 19 012 300 kQ 190 189 88 190 12 3 MQ 1 9 1 8987 1 9013 30 MQ 19 MQ 18 949 19 051 300 190 MQ 186 2 193 8
72. 1 2 2 Er 5 Bgg 5 PE t en a GS or CKT1 TP2 5 in C 5 5 50 ss i 2 2 45 4002 qb32f eps Chapter 7 Option 01 Battery Pack m tho PR Pa Pod gi Pie t pad gera edo Theory of Operation iet eL Functional Block 1 Switching Power 5 Cycle Float Charge Rate Switch esses Low Battery Indicator Detector eese Low Battery Constant Voltage Trickle Charger eee Other ctim ei tret ede xe Fe ase Food tus General Maintenance i tede le eda Lee ee Eee pet ea 2 Install ati T P rformance General nee e Rc aee Low Battery Indicator Detector and Low Battery Disconnect Test Cycle Float Charge Rate Switch iea Troubleshooting sense Additional Schematic Diagt iri ue op aet Listof Replaceable Parts rtr oett hee toten re
73. 1 form a filter network to reduce the amplitude of current pulses generated by the switching of the inverter transistors The secondary windings of A1T2 are used for three sets of supply voltages The first winding of 1 2 secondary provides out guard outputs using the following rectifier diodes and filter capacitors to provide the required voltages for the display and the battery trickle charger circuit e 1 11 and A1C45 30 V supply e 1 12 and A1C47 5 V supply A1CR10 and A1C46 30 V source for the battery trickle charger Next an isolated secondary winding provides the various in guard supplies Dual diodes 1 8 1 9 and capacitors A1C43 and A1C44 are the rectifiers and filters for the in guard 5 25 V and 5 25 V supplies Dual diode AICR7 and capacitor A1C42 are the rectifier and capacitor for the relay 5 25 V dc supply A third transformer winding provides the heater power FIL1 FIL2 for the vacuum fluorescent display Zener diode and resistor 1 55 bias this winding at approximately 5 volts more positive than the 30 V supply 2 18 Analog Measurement Processor Refer to Figure 2 2 for an overall picture of the Analog Measurement Processor chip and its peripheral circuits Table 2 1 describes Analog Measurement Processor chip signal names The Analog Measurement Processor 101 is a 68 pin CMOS device that under control of the Main Processor A1U6 performs the following func
74. 2 Make sure the meter is turned off and unplugged from the power outlet Remove the screw on the bottom of the meter case and the two screws from the rear bezel as shown in Figure 8 1A While holding the front panel slide the case and rear bezel off the chassis see Figure 8 1B At this point the rear bezel is not secured to the case Using needle nose pliers disconnect the 24 line cable assembly at the IEEE 488 PCA by alternately pulling up on each end of its connector See Figure 8 2 Refer to Figure 8 3 for the remaining steps Remove the panhead Phillips screw at the rear of the IEEE 488 PCA Using needle nose pliers detach the two ribbon cables at the front part of the 488 PCA Alternately pull up on each end of the cable connectors Option 05 IEEE 488 Interface 8 Performance Testing 6 Remove the IEEE 488 PCA disengaging the assembly from both the small slot in the side of the meter and the plastic standoff at the front corner of the assembly 8 12 Installing the IEEE 488 Interface Option Use the following procedure to install the IEEE 488 Interface Option 1 Turn the meter off and unplug the power connection 2 Check that the plastic standoff remains in the appropriate hole in the meter narrow end of the standoff down see Figure 8 3 3 If necessary install the two ribbon cables the IEEE 488 PCA Each cable fits in only one socket and in only one direction Make sure the cables lock f
75. 2 7 goes high If the battery pack option is not installed the pull up resistor on the Main Circuit Assembly pulls the battery line high to keep the low battery indicator turned off 7 8 Low Battery Disconnect The Low Battery Disconnect uses FET switch Q2 The FET gate is driven by a latching circuit comprised of Q12 Q13 and VR4 7 5 45 When the power switch is first turned on pulse through C15 turns 13 which then turns on Q3 With the Q3 collector voltage now near its emitter voltage and the FET gate near the battery voltage the FET switch is on At the same time Q12 is turned on its collector pulls down the base of Q3 latching the circuit on When the voltage between the base of Q12 and the anode of VR4 drops below 6 9 volts battery voltage of about 7 0 volts Q12 cannot be maintained on due to the 6 2 V zener diode in its emitter circuit and the circuit unlatches itself The gate of Q3 then goes to zero and turns off disconnecting the battery pack If the battery pack charge is low this circuit does not latch and the battery pack is protected from being deeply discharged 7 9 Constant Voltage Trickle Charger The Constant Voltage Trickle Charger uses a voltage regulator set at 9 25 volts The output voltage is set by the values of R38 R40 and the setting of R39 The 30 volt supply on the Main Circuit Assembly provides the source for the regulator Trickle charging occurs only w
76. 45 The problem is probably a short on A5P2 or A5P3 the Microprocessor on the Main Assembly is prevented from accessing ROM and RAM correctly Two extender cables are available PN 867952 and 867957 to assist during troubleshooting e first thing to check is whether GND is shorted to either VCC2 on the IEEE Assembly The short may also be an interface signal to either VCC GND or another interface signal The logical signals to check are DATA 7 0 ADD 15 0 RD WR E and RESET e The short may be due to a CMOS input that has been damaged from static discharge the short is then detectable only when the circuit is powered up Use an oscilloscope to check activity on each of the interface signals Verify that signals are able to transition normally between 0 and 5V 8 16 Communication Problems 8 17 Failure to Select IEEE 488 Interface Option IEEE 488 Interface selection procedures are described in Chapter 3 8 10 Option 05 IEEE 488 Interface 8 Troubleshooting If the IEEE 488 Interface Option is not detected by Fluke 45 software there may be a problem with the OPS or signal The IEEE Interface Option grounds the OPS signal 5 2 18 which is normally pulled up to VCC on the Fluke 45 Main Assembly The Microprocessor determines that the IEEE 488 Interface Option is not installed if OPS A1U6 29 is detected high Further software does not allow the IEEE 488 Interface Option to be selected
77. 45 ADDC 4 900652 __ 5 14 5 A4 65 48 ADD S ADDIG 4 157 DISRX AS IRQ2 42 ADD 6 ADDC0 15 7 3 18 DISTX n6 0 5 T 146 7 RDD B 25 TO DISPLAY RESETS 44 appt a 24108 10 RESET ADD 1 9 A 810 BOARD aig 8 BDD iD ADDCO 53 41 ADD 11 12 2 Al 1140 12 800013 26 412 ADOL AI 213 8005 15 59 800013 8 0 14 27 38 800014 820015 1 622 HE MIN TCR Ris 800623 FIL2 215 8DDCis ADD 8 FIL1 ADD 9 ADDC10 ADD 11 ADD 12 ADD 13 ADD 14 ADD 14 ADD 15 ADD 13 WRe 270512 aq r j FN S dun LOW BATTERY gt 5 DATAC7 ADD 0 1592 DATAC6 DATACO 1 2 DATACS DATAC 4 DATACS DATAC2 DATAC1 E DRTRCOD ale a 11 00 parasi 120 2 2 35 DRTR CO 7 pataca 150 DRTa 4 16 D DATA CS 12104 DRTRC6 18105 19106 80060 0 ABD 1 9 ni 10 RS esa 15 800 5 27 ADD 4 6 5 5144 ADD 6 4 800 7 3 ADD B 0 9 24
78. 57 RES CERM 910 5 125W 200PPM 1206 769257 1 R 58 RES CF 1K 5 0 25W 780585 1 RT 1 THERMISTOR DISC POS 1 1K 20 25 C 602995 1 RV 1 2 3 VARISTOR 910V 10 1 0 MA 876193 3 6 9 45 Service Manual Table 6 3 A1 Main PCA cont Reference Designator Description INDUCTOR FXD DUAL EE24 25 0 4MH 1 2A 817379 TRANSF INV 5VDC 30KHZ 6KV ISO EE375 817395 MERCURY SATURN ASSY TESTED PLASTIC 776195 IC ARRAY 7 NPN DARLINGTON PAIRS SOIC 821009 ISOLATOR OPTO LED TRANSISTOR 688314 IC NMOS 64 X 16 BIT EEPROM 822353 IC CMOS 8 BIT MPU 1 2 256 RAM PLCC 821298 IC CMOS RS232 DRIVER RECEIVER SOIC 821538 EPROM PROGRAMMED 27 512 857797 IC CMOS AND NOR GATES SOIC 837203 IC CMOS 8K X 8 STATIC RAM 120NS SOIC 851795 IC VOLT REG ADJ SWITCHING REGULATOR 821215 IC MICROPROCESSOR RESET CIRCUIT 602920 ZENER TESTED 857201 ZENER UNCOMP 6 0V 5 20MA 0 2W SOT 837161 23 837179 ZENER UNCOMP 5 1V 5 20MA 0 2W SOT 834929 23 834945 WIRE ASSY H 834911 WIRE ASSY FUSE 834937 WIRE ASSY INPUT 10A CUR 650390 WIRE ASSY L 570606 CRYSTAL 3 84MHZ 0 05 HC 18 U 851100 CRYSTAL 3 6864MHZ 0 005 HC 18U 847363 RES NET THN F TESTED 833921 RES NET THK FILM TESTED 849984 RES NET THN FILM TESTED RES NET THK FILM TESTED 1 Fusible resistor To ensure safety use exact replacement only A E E E lt lt lt lt CC 0 0 0 0 0 0 0 0 0 0 0
79. 6 A1TP17 5 0 to 6 0 V dc VLOAD A1TP15 A1TP17 28 5 to 32 0 V dc Display PCA Out Guard Circuits A2TP3 or A2U1 42 4 85 to 5 35 V dc A2TP3 or A2U1 42 5 0 to 6 0 V dc A2TP3 or A2U1 42 28 5 to 32 0 V These points are at Common Ground is also used in the meter but in relation to Out Guard circuits only For example the A2 Display PCA uses Ground 5 7 5 Volt Switching Supply Use an oscilloscope to troubleshoot the 5 volt switching supply Check the waveform at either A1U11 pin 6 switch transistor collector or ATTI pin 2 to determine the loading on the 5 volt switching supply Normal load The waveform is a square wave with a period of approximately 20 to 25 us and an ON voltage is low duty ratio of about 0 35 when the line voltage is about 120 V ac The amplitude is usually about 15 V p p The positive going edge of the waveform will be fuzzy as the duty ratio is varying to compensate for the ripple of the raw supply and the pulsing load due to the switching of the inverter See Figure 5 2 e Very Light or No Load The OFF interval voltage is high part of the waveform will have a damped ringing sine wave of 2 to 10 cycles Heavy Load or Shorted The waveform is a square wave with a very low ON duty ratio approximately 0 1 If no square wave signal is present the functioning of the oscillator can be checked by looking at the waveform at A1U11 pin 3 Use the oscilloscope with ac coupling to
80. 9 EEROM Calibration Constants 0 97025 to 1 03775 VDC range 1 0 97025 to 1 03775 VDC range 2 0 97267 to 1 04554 VDC range 3 0 96782 to 1 04035 VDC range 4 0 96792 to 1 04045 VDC range 5 0 9975 to 1 0025 100 mV gain 0 9975 to 1 0025 320 mV gain 0 9975 to 1 0025 3 2 V gain 100 to 100 VAC offset range 1 0 9725 to 1 0275 VAC range 1 100 to 100 VAC offset ranges 2 through 4 0 9725 to 1 0275 range 2 0 9725 to 1 0275 VAC range 3 0 9725 to 1 0275 VAC range 4 0 9725 to 1 0275 VAC range 5 0 9500 to 1 0500 ADC range 1 0 9500 to 1 0500 ADC range 2 0 9500 to 1 0500 ADC range 3 0 9225 to 1 0775 AAC range 1 0 9225 to 1 0775 AAG range 2 100 to 100 AAC offset range 3 24 16 IO IO IO IO IO IO IO IO 2 CO Io 0 9225 10 1 0775 0 9990 to 1 0090 1 0000 to 1 0100 1 0040 to 1 0140 0 9990 to 1 0090 0 9990 to 1 0090 0 9990 to 1 0090 0 9886 to 1 0035 0 9910 to 1 0010 0 9999 to 1 0001 10 0 to 10 0 1 0000 to 1 0006 AAC range 3 OHMS range 1 OHMS range 2 OHMS range 3 OHMS range 4 OHMS range 5 OHMS range 6 Slow Siemens Medium and Fast Siemens Frequency calibration Slow offset Slow negative gain 4 21 45 4 22 Chapter 5 Diagnostic Testing and Troubleshooting Title 521 Introduction rr V
81. CK MAG SS 6 32 500 853986 2 H 15 16 SCREW FH P LOCK STL 8 32 375 114116 2 J 1 PWR PLUG PANEL 6 3A 250V 3 WIRE 780817 1 J 2 PWR PLUG PART FUSE HOLDER 780825 1 MP 1 PAD TRANSFER FRONT PANEL CE 609427 1 MP 2 PAD TRANSFER CHASSIS 835496 1 MP 3 ASSEMBLY WINDOW 784793 1 MP 4 GROMMET EXTRUDED POLYETHYLENE 085 854351 1 MP 5 DECAL REAR PANEL CE 609419 1 MP 6 INSULATOR TRANSFORMER 852413 1 MP 7 5 5 180 RND NYL 125 844845 1 8 STANDOFF FEMALE 874748 1 MP 9 RECEPTACLE FUSE 824607 1 MP 10 ROD POWER SWITCH 784827 1 MP 11 SHIELD TOP 784819 1 MP 12 SHIELD BOTTOM 791590 1 MP 13 CASE OUTER 784769 1 MP 14 15 CASE FOOT BLACK 824433 2 MP 16 BEZEL REAR 885889 1 MP 17 MOUNTING PLATE HANDLE LEFT 857248 1 MP 18 MOUNTING PLATE HANDLE RIGHT 857243 1 MP 19 HANDLE PAINTED 848205 1 MP 20 COVER IEEE 791616 1 MP 29 TEST LEAD ASSY TL70A 855820 1 MP 32 LABEL ADHES PAPER 4 750 3 1875 854104 1 MP 38 STANDOFF MALE 874743 1 MP 40 SCREW PH 4 14 312 642931 1 5 1 SWITCH PUSHBUTTON DPDT PUSH PUSH 836361 1 5 2 KEYPAD ELASTOMERIC 855994 1 T 3 TRANSF PWR 35W 90 264VAC 14 6 43VAC 609088 1 TM 1 FLUKE 45 USER MAN ENGLISH 855981 1 TM 2 FLUKE 45 USER MAN GERMAN FRENCH 856034 1 1 CABLE ASSY RS232 848192 1 1 W 2 WIRE ASSY GROUND 834952 1 W 4 CABLE ASSY FLAT 20 COND MICROMOD 2 IN 852157 1 W 5 CORD LINE 5 15 IEC 3 18AWG SVT 7 5 FT 284174 1 1 For 250 V order part number 769422 6 5 45 Service Manual Sheet 1 of 2 05 OPTION SE
82. Diagnostic Testing and Troubleshooting Analog Troubleshooting Note When making voltage measurements in the inverter circuit remember that there are two separate grounds The out guard ground is the GRD test point and the in guard ground or common is the common test point The normal input current to the inverter supply is about 210 mA or 1 05 V across 1 46 5 9 Analog Troubleshooting Analog circuit problems are evidenced by Error 8 or Error 9 in the display These errors signify either that the Main Processor A1U6 is not communicating with the in guard circuitry or that the Analog Measurement Processor A1U1 is not functioning correctly First check the in guard power supplies referenced to common Power Supply Testpoint Range VDD 1 10 4 95 to 5 45 dc VSS 1 12 4 95 to 5 45 V dc 4 7 to 5 35 4 7 to 5 35 Check the out guard to in guard communication for activity whenever front panel button is pressed If necessary press a button repeatedly while looking for the following communication activity 1 8 GROUND to VCC pulses A1TP4 COMMON to VDD pulses Check the in guard to out guard communication 1 5 VDD to 0 7 V above COMMON pulses 1 7 GROUND to VCC pulses Check the crystal oscillator referenced to COMMON 3 84 MHz sine wave 260 ns period Check the integrator waveform referenced to COMMON A1U1 45 should be a triangle
83. Disconnect circuit interrupts meter loading on the battery pack when battery pack voltage drops below approximately 7 0 V This action prevents deep discharge of the batteries e Constant Voltage Trickle Charger When the meter is operated on line power the charge on the battery pack is maintained with the Constant Voltage Trickle Charger 9 25 V output 7 3 7 2 weibeig 2 uondo 1 1 4 sde jeeqb LINE RAW 51 SUPPLY 5 A OFF T 1 7 gt MAIN SWITCHING SUPPLY SWITCHING POWER SUPPLY TO MICROPROCESSOR jm LOW BATTERY INDICATOR MAIN J1 8 Feedback path for controlling _ _ POWER switching supply output voltage SUPPLY in Float Charge mode Feedback path for controlling 1 switching supply output voltage in Cycle Charge mode CKT 30V CYCLE FLOAT CHARGE RATE SWITCH J1 5 TRICKLE CHARGER CR9 F1 CR5 LOW BATTERY DISCONNECT Q2 J1 6 TO 1 5 amp C27 ON MAIN enuey Sv Option 01 Battery Pack Theory of Operation 7 5 Switching Power Supply The switching power supply regulates the output voltage with a pulse width modulating technique that varies the on time of the FET switch Q5 The controller chip for this process U4 contains
84. E FIGURE 8 5 MP13 tc 2 a 01 OPTION SEE SHEET 2 OF 2 qb28c eps Figure 6 1 Final Assembly 6 6 Figure 6 1 Final Assembly cont List of Replaceable Parts Parts 45 Sheet 2 of 2 qb29c eps 6 6 7 45 Service Manual 6 8 gt gt CR CR CR CR CR CR cccc MP MP MP MP Reference Designator 2 3 5 9 19 22 25 49 50 17 18 4 6 42 44 7 10 8 12 13 14 16 15 20 21 26 37 40 27 28 29 30 31 32 36 47 33 34 35 41 3 9 10 12 1 wo 0 00 14 0 3 Table 6 3 A1 Description TRUE RMS PCA AMP JFET INPUT DECOMP SOIC CAP POLYES 0 1UF 10 1000V CAP CER 4 7PF 0 25pF 50V COG 1206 CAP CER 0 1UF 10 25V X7R 1206 CAP CER 4 3PF 10 50V COG 1206 CAP AL 470UF 20 10V SOLV PROOF CAP POLYES 0 47UF 10 50V CAP 2 2uF CAP POLYPR 0 12UF 10 50V CAP POLYPR 0 033UF 10 63V CAP TA 2 2UF 10 35V CAP CER 15PF 10 50V COG 1206 CAP CER 0 047UF 20 50V X7R 1206 CAP AL 4700UF 20 35V SOLV PROOF CAP CER 33PF 10 50V C0G 1206 CAP CER 1800PF 10 50V COG 1206 CAP CER 0 047UF 10 100V X7R CAP AL 10UF 20 63V SOLV PROOF CAP AL 220UF 20 50V SOLV PROOF CAP AL 47UF 20 50V SOLV PROOF CAP AL 2 2UF 20 50V SOLV PROOF CAP CER 100PF
85. FLUKE 45 Dual Display Multimeter Service Manual For IEC 1010 Meters Only PN 609203 March 1999 1999 Fluke Corporation All rights reserved Printed in U S A All product names are trademarks of their respective companies LIMITED WARRANTY amp LIMITATION OF LIABILITY Each Fluke product is warranted to be free from defects in material and workmanship under normal use and service The warranty period is one year and begins on the date of shipment Parts product repairs and services are warranted for 90 days This warranty extends only to the original buyer or end user customer of a Fluke authorized reseller and does not apply to fuses disposable batteries or to any product which in Fluke s opinion has been misused altered neglected or damaged by accident or abnormal conditions of operation or handling Fluke warrants that software will operate substantially in accordance with its functional specifications for 90 days and that it has been properly recorded on non defective media Fluke does not warrant that software will be error free or operate without interruption Fluke authorized resellers shall extend this warranty on new and unused products to end user customers only but have no authority to extend a greater or different warranty on behalf of Fluke Warranty support is available if product is purchased through a Fluke authorized sales outlet or Buyer has paid the applicable international price Fluke reserves the right t
86. IN 831511 TRANSISTOR SI PMOS 1W D PAK 836544 RES CERM 5 1K 5 125W 200PPM 1206 746560 RES CERM 47K 5 125W 200PPM 1206 746685 RES CERM 220 5 125W 200PPM 1206 746347 ll n ln n qw i IC CMOS QUAD INPUT NOR GATE SOIC 830711 IC CMOS OCTAL BUS TRANSCEIVER SOIC 742577 IC CMOS OCTL LINE DRVR SOIC 801043 IC CMOS 8 INPUT NAND GATE SOIC 830729 IC NMOS GPIB CONTROLLER PLCC 887190 IC LSTTL OCTAL GPIB XCVR SOIC 831651 IC LSTTL OCTAL GPIB XCVR SOIC 831669 IC CMOS DUAL D F F EDG TRG SOIC 782995 Option 05 IEEE 488 Interface 8 List of Replaceable Parts m oo m Figure 8 6 5 488 Interface qb44c eps 8 15 45 Chapter 9 Schematic Diagrams PCA AZ Display ATAI True Rms A4 Battery 5 488 Interface 9 1 45 er 8191 Lidl
87. J3 1 The logic common return GND is through A5J2 20 8 6 Address Decoding Circuit When a memory read or memory write cycle intended for the IEEE 488 Controller A5U6 is in progress the 13 address bits ADD 15 through ADD 3 from A1U6 are decoded 501 502 505 to generate an active low chip select signal The chip select signal A5U5 8 goes low when two events occur OPTS W A5J3 12 is near 5 2V VEE and the address bus indicates that the Microprocessor is accessing memory between addresses 0028 and 002F hexadecimal inclusive When the Fluke 45 is Operating on battery power the Microprocessor turns off the power to the 488 Assembly by driving the OPTS W signal A5J3 12 to VCC This signal drives A5U1 6 to about 4 3V through 5 1 disabling the Address Decoding Circuit 8 3 45 8 7 Isolation Circuits The Isolation Circuits allow the Microprocessor to turn off power to ASU6 A5U7 and A5U8 components These three components consume the majority of the power on the IEEE 488 Assembly normal meter operation on batteries is extended by approximately 10046 with this power isolation scheme The Microprocessor determines that the IEEE 488 Assembly is installed in the meter by checking the state of the OPS signal A5J2 18 This signal is pulled up to VCC by resistor AIR39 and is shorted to logic ground on the IEEE 488 Assembly If A1U6 29 is low the Micropro
88. N LAST USED NOT USED 45 1005 qb54sc tif Figure 9 5 A5 IEEE 488 Interface PCA cont 9 15 45 Series Service Manual 1 100 MW and 300 mq range 2 14 5 5 volt switching supply converter 2 17 ac 2 14 ac volts calibration computer interface 4 18 ac volts calibration front panel 4 9 ac volts troubleshooting 2 15 active filter additional tests 7 14 address decoding circuit 8 3 alternate ohms calibration computer interface 4 19 alternate ohms calibration front panel 4 13 amps 2 15 analog measurement processor 2 3 2 7 analog troubleshooting 5 13 analog to digital a d converter 2 3 assemble the front panel assembly 3 12 assembly procedures 3 10 B battery pack option 01 beeper drive circuit calibration 7 12 calibration failures 5 19 calibration interrelationships 5 21 Index calibration using the computer interface 4 14 calibration related components 5 20 cleaning 3 4 communication problems 8 10 concluding calibration using the computer interface 4 19 constant voltage trickle charger 7 6 continuity hysteresis threshold calibration computer interface continuity hysteresis threshold calibration front 4 13 conventions current input fuses 3 4 cycle float charge rate switch cycle float charge rate switc
89. ONSEQUENTIAL DAMAGES OR LOSSES INCLUDING LOSS OF DATA WHETHER ARISING FROM BREACH OF WARRANTY OR BASED ON CONTRACT TORT RELIANCE OR ANY OTHER THEORY Since some countries or states do not allow limitation of the term of an implied warranty or exclusion or limitation of incidental or consequential damages the limitations and exclusions of this warranty may not apply to every buyer If any provision of this Warranty is held invalid or unenforceable by a court of competent jurisdiction such holding will not affect the validity or enforceability of any other provision To locate an authorized service center visit us on the World Wide Web www fluke com or call Fluke using the phone numbers listed below USA and Canada 1 888 99 FLUKE 1 888 993 5853 Europe 31 402 678 200 Japan 81 3 3434 0181 Singapore 65 738 5655 Anywhere in the world 1 425 356 5500 Fluke Corporation Fluke Europe B V P O Box 9090 P O Box 1186 Everett WA 98206 9090 5602 BD Eindhoven U S A The Netherlands 5 94 Table of Contents Chapter Title 1 Introduction and Specifications 1 1 1 2 Operating Instructions i ob Re Eee ote rbd 1 3 Options and ded ret edo eode e eR 1 4 Organization of the Service Manual 2 2 1 5 5 2 1 6 Specifications sa 2 T
90. Ohms Troubleshooting Use a meter with high input impedance to measure the open circuit voltage for each ohms range listed below If a high input impedance meter is not available the following checks can be made on the 30 lower ranges only RANGE VOLTAGE 300 Q 3 KQ 1 3 V 30 kO 1 3 V 300 1 3 V 3 MQ 1 3 V 30 MQ 300 MQ With failures with these tests suspect components 1 5 AIRTI A1K2 AIQI 171 and 101 Now check the signal path at the following points W1 101 23 OVS AIUI 58 AFI and 101 56 Suspect components for these checks are 1 6 A1R7 and Table 5 3 DC Volts Troubleshooting A1U1 23 OVS Input signal A1W1 A1R6 A1R7 A1K1 A1U1 58 AFI Input signal active filter input A1U1 A1U1 56 Input signal active filter output A1U1 A D low path Check continuity among A1U1 13 RRS and A1R9 A1K2 COMMON Diagnostic Testing and Troubleshooting Digital Troubleshooting Table 5 4 AC Volts Troubleshooting 122 1 Input signal 1 5 A1R5 1 1 A1K3 A1U1 2 ACBO Amplified input input x 2 5 A1U1 A1R11 A1R14 A1Q2 A1Q8 A1Z2 A1AR1 1 7 A1R16 1 17 A1U1 68 RMSI Amplified input A1U1 A6U1 14 Amplified input A6U1 124 2 DC equivalent of amplified input A6U1 A1U1 61 RMSF DC equivalent of original input 124 1 19 A1C10 5 14 Digital Troubleshooting At power up if the display does not light
91. R 5 2 Servicing Surface Mount Assemblies 5 3 Error Codes usui GRE EUR 5 4 General Troubleshooting Procedures eene 5 5 Power Supply Troubleshooting eee 5 6 Raw DC Supply niter ir 5 7 5 Volt Switching 5 8 EP 5 9 Analog Troubleshooting eese eene 5 10 5 11 DC Volts Troubleshooting eene 5 12 AC Volts Troubleshooting eene 5 13 Ohms Troubleshooting eee enne 5 14 Digital Troubleshooting eee 5 15 Display Assembly Troubleshooting eene 5 16 Calibration Failure S 5 17 Introduction rettet dani e tese 5 18 Calibration Related 5 19 Calibration Interrelationships eene 5 20 Retrieving Calibration Constants eese 5 21 Replacing the EEROM 5 45 5 2 Diagnostic Testing and Troubleshooting Introduction 5 1 Introduction The Fluke 45 provides error code information and semi modular design to aid in troubleshooting This chapter explains the error codes and describes procedures needed to isolate a problem to a specific functional area Finally troubleshooting hints fo
92. Schmitt Trigger NAND gate A2U6 12 The output of this gate A2U6 11 then drives the active high reset signal RESET to the rest of the system When the voltage on A2C3 is below the input threshold of A2U6 12 A2U6 11 is high As soon as A2C3 charges up to the threshold of A2U6 12 A2U6 11 goes low The RESET signal drives NAND gate inputs A2U6 1 and 206 2 to generate the active low reset signal RESET at A2U6 3 When the RESET signal transitions from high to low A2U5 1 the Watchdog Timer is triggered initially causing A2U5 13 to go high This half of the dual retriggerable monostable multivibrator uses timing components A2R2 and A2C2 to define a nominal 4 75 second watchdog timeout period Each time a low to high transition of DISTX is detected on A2U5 2 capacitor A2C2 is discharged to restart the timeout period If there are no low to high transitions on DISTX during the 4 75 second period A2U5 13 transitions from high to low triggers the other half of A2US and causes output A2U5 12 to go low A2U5 12 is then inverted by A2U6 to drive the RESET signal high causing system reset The low duration of 20 5 12 is determined by timing components 271 and A2C4 and is nominally 460 us When A2U5 12 goes high again RESET goes low to retrigger the Watchdog Timer 2 47 Display Controller with FIP 2 22 The Display Controller is a 4 bit single chip microcomputer with high voltage outputs that drive a vacuum fluorescent display directly
93. The meter power switch A1S1 is also connected in the output of the Raw DC Supply it connects the Raw DC Supply either to the 5 V Switching Supply when the meter is ON or to the Battery Charger Switching Supply through A1J1 7 when the meter is OFF 2 16 5 Volt Switching Supply The 5 Volt Switching Supply incorporates A1U11 controller device and several external components Operating on an input of 7 5 V dc to 35 V dc the 5 volt Switching Supply uses a pulse width modulation technique to regulate its output at 5 1 V dc The nominal switching frequency is 40 kHz With the controller the output voltage is controlled by varying the duty cycle ON time of the switch transistor in 1011 Controller device 1011 contains the supply reference oscillator switch transistor pulse width modulator comparator switch drive circuit current limit comparator and current limit reference Resistors AIRA1 and A1R42 in conjunction with the reference circuit set the input levels to the pulse width modulating comparator Resistors 1 35 in parallel with 1 41 and A1R36 in parallel with 1 42 are used in production to adjust the 5 1 V supply output Removing A1R35 decreases the output by approximately 5 Removing A1R36 increases the output by approximately 7 Within the controller the output of the comparator is combined with the oscillator signal to form the drive signal for the switch transistor Diode AICR6 operates as a complemen
94. ace to start The following chapter descriptions serve to introduce the manual Chapter 1 Introduction and Specifications Introduces the Fluke 45 Dual Display Multimeter describing its features options and accessories This chapter also discusses use of the Service Manual and the various conventions used in describing the meter s circuitry Finally a complete set of specifications is presented 1 4 Introduction and Specifications 1 Conventions Chapter 2 Theory of Operation This chapter first categorizes meter circuitry into functional blocks with a description of each block s role in overall operation A detailed circuit description is then given for each block These descriptions explore operation to the component level and fully support troubleshooting procedures defined in Chapter 5 Chapter 3 General Maintenance Provides maintenance information covering handling cleaning and fuse replacement Access and reassembly procedures are also explained in this chapter Chapter 4 Performance Testing and Calibration This chapter provides performance verification procedures that are tied to the specifications presented in Chapter 1 To maintain these specifications a full calibration procedure is also presented Chapter 5 Diagnostic Testing and Troubleshooting The troubleshooting procedures presented in this chapter rely closely on both the Theory of Operation presented in Chapter 2 and the Schematic Diagrams shown in C
95. ally the Digital Kernel Microprocessor performs the following functions Executes the instructions in ROM Stores temporary data in RAM Store meter configuration and calibration data in EEROM Communicates with the Analog Measurement Processor via the Serial Communication Guard Crossing block Communicates with the Display Controller to display readings and user interface information Scans the user interface keyboard found on the Display Assembly Communicates via the RS 232 interface and optional IEEE 488 interface 2 10 Display Assembly The Display Assembly controller communicates with the main Microprocessor over a three wire communication channel Commands from the Microprocessor inform the Display Controller how to modify its internal display memory The Display Controller then drives the grid and anode signals to illuminate the required segments on the Display The A2 Display Assembly requires power supply voltages from the Power Supply and a clock signal from the A1U6 Microprocessor 2 11 IEEE 488 Interface Option 05 Theory of operation for the IEEE 488 Interface Option 05 is presented in Chapter 8 of this manual The related schematic diagram is found in Chapter 9 2 12 Battery Pack Option 01 Chapter 7 of this manual contains the theory of operation for the Battery Pack Option 01 Refer to Chapter 9 for the related schematic diagram 2 13 Detailed Circuit Description 2 14 Power Supply Circuit Descriptio
96. alue prompt may be set to the value available In the following procedure the Fluke 5700A Multifunction Calibrator is used as the ohms source with input values of 190 1 9 19 190 and 1 9 Note If you are using an ohms calibrator without active 2 wire compensation take a zero ohms measurement before entering calibration mode Use the test leads that will be used for ohms calibration Record this zero ohms value The CALREF xxx xx command tells the Fluke 45 to calibrate to the exact ohms value of the calibrator resistance For the 290 Q and 2 9 steps xxx xx should be the calibrator value plus the recorded zero ohms value 1 Connect the Ohms Calibrator to the Fluke 45 VO and COM inputs Then send CAL 7 4 18 Performance Testing and Calibration 4 Calibration Using the Computer Interface Note that the 300 and 3 MQ ranges are quite sensitive to noise Any movement of the input leads or movement of the hands or body in the vicinity of the leads can cause noisy readings Use shielded leads during this calibration Verify these two calibration points for accuracy at the conclusion of the calibration procedure 2 Complete steps 25 through 29 in Table 4 7 Then clear the ohms source 4 27 Continuity Hysteresis Threshold Calibration Computer Interface 1 Connect the DC Volts Calibrator to the Fluke 45 and COM inputs Then send CAL 8 2 Complete steps 30 and 31 in Table 4 7 and clear
97. amps Calibration 29 000 mA DC 29 mA dc 100 00 mA DC 100 mA dc AC Milliamp Calibration 20 29 000 mA AC 29 mA 1 kHz 3s 21 100 00 mA AC 100 mA 1 kHz 3s DC and AC Amps Calibration 22 10 000 A DC 10A DC 3s 23 2 000 A AC 2 A 1 kHz 5s 24 10 000 A AC 10 A 1 kHz 5s Performance Testing and Calibration 4 Front Panel Calibration Table 4 5 Front Panel Calibration cont Ohms Calibration Initial Meter Cal 5700A Source Edit Ts 2 Prompt Meier Setiling Time Prompt Output Before Pressing 290 00 Q 5700A Display 1s 2 9000 kQ 4 1s 29 000 kQ 2s 290 00 kQ 3s 2 9000 MQ 3 Continuity Hysteresis Threshold Calibration 2 Source Output Meter Settling Time Before Pressing AUTO Prompt 0 000 V 0 000 mV 1s 0 020 V 20 00 mV 1s Frequency Calibration 190 source calibrates the 300 range on the Fluke 45 to 0 06 2 digits 0 02 For calibration of this range to 0 05 2 digits 0 02 use a 290 Q source and the procedure detailed under Alternate Ohms Calibration Front Panel This procedure can also be used with appropriate discrete resistor values such as a decade box on all ranges Note that the 300 kQ and 3 MQ ranges are quite sensitive to noise Any movement of the input leads or movement of the hands or body in the vicinity of the leads can cause noisy readings This causes an error in the calibration if the button is pushed during a bad reading To avoid this use shielded leads duri
98. an full scale 0 01 must be added to the Fluke 45 300 and 100 range accuracy to arrive at the new specification Note that the first three calibration points 0 90 mV and 90 mV cannot be edited Also to provide accuracy at full range calibration is not recommended below one third of full range 10000 counts Table 4 6 Specifications Increase with Different Calibration Points Cal Point In Display Counts Function 20000 19000 10000 DC AC 300 0 100 Q kO MO 4 17 Calibration Using the Computer Interface 4 18 Setup Before performing this type of calibration make sure that computer interface connections are made to the Fluke 45 Then verify the ac power connection to the Fluke 45 and turn the meter on 4 19 RS 232 Interface 4 14 For RS 232 interface operation use the following procedure from the front panel 1 Press 210 then press RATE 2 Use ES to scroll to the desired baud rate Then press to select the displayed rate 3 Use ES to scroll to the desired parity E for even Odd for odd or no for none Then press to select the displayed parity 4 Use S or 57 to display OFF or On for command echo mode Then press to make the selection 5 Sendthe following command from the computer interface IDN lt CR gt 6 Check for a response in the following format FLUKE 45 nnnnnnn n n Dn n lt CR gt lt LF gt gt lt CR gt lt LF gt where nnnnnnn is the multimete
99. atic discharge 6 2 How to Obtain Parts Electrical components may be ordered directly from the manufacturer by using the manufacturers part number or from the Fluke Corporation and its authorized representatives by using the part number under the heading FLUKE STOCK NO Parts price information is available from the Fluke Corporation or its representatives Prices are also available in a Fluke Replacement Parts Catalog which is available on request In the event that the part ordered has been replaced by a new or improved part the replacement will be accompanied by an explanatory note and installation instructions if necessary To ensure prompt delivery of the correct part include the following information when you place an order e Instrument model and serial number e Part number and revision level of the pca containing the part e Reference designator e Fluke stock number e Description as given under the DESCRIPTION heading e Quantity 6 3 45 6 4 6 3 How to Contact Fluke To contact Fluke visit Fluke s web site at www fluke com or call one of the following telephone numbers USA and Canada 1 888 99 FLUKE 1 888 993 5853 Europe 31 402 678 200 Japan 81 3 3434 0181 Singapore 65 738 5655 Anywhere in the world 1 425 356 5500 6 4 Manual Status Information The Manual Status Information in Table 6 1 defines the assembly revision levels that are documented in the manual
100. become part of an automated instrumentation system 8 2 Theory of Operation 8 3 Functional Block Description The IEEE 488 Assembly A5 requires power supply voltages address data and control signals from the Fluke 45 Main Assembly A1 to operate The A5 assembly implements the circuitry necessary to satisfy the IEEE 488 1 standard for programmable instrumentation 8 4 Detailed Circuit Description The IEEE 488 Assembly comprises the following functional blocks the Main Assembly Connectors the Address Decoding Circuit the Isolation Circuits the IEEE 488 Controller and the IEEE 488 Transceivers and Connector These five blocks described in the following paragraphs Signal names mentioned during this discussion are ACON AC line power on IRQ2 IEEE 488 interrupt request OPSIEEE 488 option sense OPTSW 488 option power switch control signal 8 5 Main Assembly Connectors The IEEE 488 Assembly interfaces with the Main Assembly through two ribbon cables that mount to the 14 position and 20 position connectors on each assembly The 20 pin connector A5J2 routes the 16 bit address bus from the Microprocessor A1U6 to the circuitry on the IEEE 488 Assembly The 14 position connector A5J3 passes the eight bit data bus and memory control signals between the two assemblies The IEEE 488 Assembly is powered by the 5 2V power supply VCC from the Main Assembly VCC is connected to the IEEE 488 Assembly via A5
101. c and 5 25 V dc Within the Power Supply the Raw DC Supply converts ac line voltage to dc levels and the 5 V Switching Supply converts this raw dc to 5 V 0 25 V dc which is used by the Inverter in generating the above mentioned outputs 2 4 Analog Measurement Processor The Analog Measurement Processor A1U1 provides input signal conditioning ranging a d conversion and frequency measurement This custom chip is controlled by the Main Processor A1U6 with communication carried out over a special serial interface 2 5 Input Protection Circuit Input protection safeguards the meter against a number of over voltage and over current conditions Depending on the type of input protection circuits or fuses are used 2 6 Input Signal Conditioning The input signal voltage current or resistance must be scaled or conditioned to a dc voltage that can be measured by the a d converter High dc voltage levels must be attenuated Resistances currents and ac voltages must be converted to a representative dc voltage DC type measurements dc volts dc current ohms and diode test are then filtered by an active filter AC measurements ac volts and ac current are passively filtered after being converted to a dc voltage 2 7 Analog to Digital A D Converter The voltage level from the signal conditioning circuits charges or integrates a capacitor for an exact amount of time The capacitor discharge time which is proportional to the leve
102. cessor assumes that the IEEE 488 Assembly is installed If the ACON signal A1U6 33 is low indicating operation on ac power the Microprocessor drives A1U6 28 high As a result the OPTSW signal A1U7 3 is driven to VEE and transistor 5 1 turns on This transistor passes current from the VCC power supply to the VCC2 power supply to bias ASU6 A5U7 and 508 Normally VCC2 is approximately 0 1V less than VCC When OPTSW A5J3 12 is near VCC battery operation diode ASCRI and pulldown resistor A5R1 cause the non inverting octal tri state buffer A5U4 to be tri stated off by holding inputs 504 1 and A5U4 19 near VCC This octal buffer isolates six Microprocessor outputs ADD 2 ADD 1 ADD 0 WR RD and E clock from the IEEE 488 Controller A5U6 when the meter is operating on batteries 504 also buffers the chip select signal A5U5 8 that goes to A5U6 and the interrupt output signal from 506 10 The eight bit data bus from the Microprocessor is isolated from 506 an octal bus transceiver with tri state outputs A5U3 This transceiver is enabled only when the Address Decoding Circuit detects that a memory cycle for the IEEE 488 Assembly is in progress and A5U3 19 is driven low If the memory cycle is a read cycle the R W signal A5U3 1 is high and the transceiver buffers the eight bit data from A5U6 to 106 If the memory cycle is a write cycle the signal A5U3 1 is low and the transceiver buffers the eigh
103. ch the two ribbon cables at the front of the IEEE 488 PCA Alternately pull on each end of the cable connector Do not remove these cables at their Main PCA connections Note The 488 ribbon cables are not interchangeable with the Display Assembly ribbon cable Connectors on these cables are aligned differently allowing for proper cable routing 4 Remove the IEEE 488 PCA disengaging the board from both the small slot in the side of the meter chassis and the plastic standoff at the front corner of the board 3 20 Remove the Main PCA With the IEEE 488 option and the Display Assembly removed the Main PCA can be removed with the following procedure 1 Remove the power switch activator rod E in Figure 3 5 from the bottom of the Main PCA 2 Detach the transformer connector right rear corner of the Main PCA F in Figure 3 5 and the RS 232 connector center of the Main PCA G in Figure 3 5 If the Battery Option is installed detach its connector at the center rear of the Main PCA 3 Now remove the securing screw near the battery connector in Figure 3 5 and slide the Main PCA forward Match the pca edge indentations to the guide tabs on each chassis side then lift the Main PCA up and away from the chassis To remove the transformer insulator center rear of the Main PCA I in Figure 3 5 detach the two tabs and pull up 3 21 Remove the Analog Measurement Processor Shields The Analog Measurement Proc
104. ct 33Q 5W load resistor in parallel across the output of a variable voltage power supply e Disconnect the battery charger wires from the battery e Connect the simulator to the battery charger wires Install 0 1Q shunt resistor in series with the red wire e Connect a voltmeter across the shunt resistor to measure the voltage drop across and the charging current through the resistor Option 01 Battery Pack Calibration 3 With no ac line power applied to the meter adjust the variable voltage power supply for 8 5 V output 4 Now apply ac line power and check that the charging current is greater than 250 mA Slowly increase the variable voltage supply output Check for the following The charging current decreases as the supply voltage approaches 10 V dc The current should continue to decrease as the voltage increases until the current is between 60 and 80 mA With any additional decrease in current increase of the supply voltage the current should suddenly jump to a low value less than 0 5 mA When the variable voltage supply output is reduced to 9 35 V dc the current should be between 5 and 15 mA OPTIONAL VOLTMETER METER TO MEASURE TO MONITOR A BATTERY VOLTAGE CHARGING CURRENT O O O 1 1 L3 rcu SHUNT POWER SUPPLY 0 TO 15V 2
105. d qb12f eps Figure 3 1 Replacing the Line Fuse F3 3 5 45 3 6 F1 Fuse 500 mA 250V Fast Blow 1500 A Minimum Breaking Capacity Front Panel Input Terminal 100 mA Input Socket Fuse Holder To remove push in and turn counter clockwise To insert reverse this procedure qb13f eps Figure 3 2 Replacing the External 100 mA Input Fuse F1 Table 3 1 Fuses Description Fluke Part No 100 Input Fuse 500 mA 250 V fast blow 1500 A breaking 838151 capacity 10 A Input Fuse F 11 A 1000 V fast blow 17 000 breaking 943118 capacity Line Fuse T 125 mA 250 V slow blow 822254 100 mA Input Fuse F440 mA 1000 V 10 000 A minimum interrupt 943121 3 13 Replacing the 10 A Input Jack Fuse F2 The 10 A input jack is protected by an 11 A fuse F2 located inside the meter The following procedure explains how to access and change this fuse This procedure can also be used to change F5 1 3 Remove the single Phillips head screw the bottom of the case and the Phillips head screw on each side of the rear bezel ZA Warning Opening the case may expose hazardous voltages Always disconnect the power cord and measuring inputs before opening the case Remove the bezel and slip the case back from the front of the meter The fuse and fuse clip are visible at the front of the main printed circuit assembly pca near the input termi
106. d medium and slow rates 45 1 8 Maximum Functional Input 1000 V dc or peak ac on any range True Rms AC Voltage AC Coupled Resolution 300 mV 10 uV 100 pV 3V 100 uV 1mV 30 V 1 10 mV 300 V 10 mV 100 mV 750 V 100 mV 1 100 mV 1gV 1000 mV 10 uV 10V 100 uV z 5 100 V 1 750 V 10 mV Accuracy Max Input Frequency Linear Accuracy dB Accuracy Power at Upper Freq Medium Slow Med 20 50 Hz 1 100 1 10 50 Hz 10 kHz 0 2 100 0 2 10 0 4 10 750 V 10 20 kHz 0 5 100 0 5 10 20 50 kHz 2 200 2 20 50 100 kHz 5 500 5 50 10 50 200 V Error in power mode will not exceed twice the linear accuracy specification Accuracy specifications apply within the following limits based on reading rate Slow Reading Rate Between 15 000 and 99 999 counts full range Medium Reading Rate Between 1 500 and 30 000 counts full range Fast Reading Rate Between 150 and 3 000 counts full range Decibel Resolution Resolution Slow amp Medium Fast 0 01 dB 0 1 dB Introduction and Specifications 1 Specifications Input Impedance 1 MQ in parallel with lt 100 pF Maximum Crest Factor 3 0 Common Mode Rejection Ratio gt 60 dB at 50 or 60 Hz 1 kQ unbalanced medium rate Maximum Input 750 V rms 1000 V peak 2 10 Volt Hertz product any range normal mode input 1 x 10 Volt Hertz product
107. d Circuit Description A1C4 A1C5 and A1C6 provide a filtered power supply for the ac buffer the ac buffer switching JFETs and the rms converter 2 26 Current through A1R2 develops a voltage that is proportional to the input This dc voltage is routed through A1R4 to the active filter then to the a d converter The 100 mA current range uses the 3 V range of the a d converter See Figure 2 6 2 27 ACmA In relay A1K3 connects the ac voltage developed across A1R2 to the ac buffer The signal is then conditioned as described for ac volts 2 28 Amps The dc voltage output of the 10 amp shunt A1R3 is routed directly to the a d converter through the Analog Measurement Processor OVS input pin 23 For ac amps the ac voltage output of the shunt is routed to the rms converter through Analog Measurement Processor switches S35 and 537 2 29 Diode Continuity Test In Diode Test the meter front end is in the 300 ohm range configuration The a d converter measures the dc voltage at the binding posts through the OVS input pin 23 For the continuity function the frequency continuity comparator senses the signal through Analog Measurement Processor switches 535 and 541 The comparator toggles when the input goes below about 20 mV 2 30 Frequency The frequency continuity comparator uses the ac volts ac mA output of the ac buffer as its input at the Analog Measurement Processor ACBO input pin 2 In the 10 A ac rang
108. d reading taken on the reference input Refer to Calibration Failures in Chapter 5 for more information Performance Testing and Calibration 4 Front Panel Calibration 4 7 Exiting Calibration Mode Calibration mode can be exited at any time by pressing the Cal Enable button However if this button is pressed prior to completion of all calibration points for any function no changes are made to nonvolatile calibration memory for that function If calibration mode is exited after completion of calibration of any function except VDC constants for other functions are not affected But remember whenever VDC is calibrated the calibration procedure for all other functions should be performed To exit the calibration mode press the Cal Enable button with a small screwdriver or equivalent blunt tipped object Avoid using sharper tipped objects such as pencils 4 8 DC Volts Calibration Front Panel To perform VDC calibration proceed as follows 1 Press the Cal Enable button for 3 seconds to enter the calibration mode Or if the meter is already in calibration mode but set for a different type of calibration press the button to return to VDC calibration Press the button to select the first prompt 0 000 mV DC for the VDC function Apply a shorting bar to the gt _ and COM inputs of the meter and allow 5 seconds for meter settling Note After voltage is applied to the MY input the meter can take up to 4 6 minute
109. ded in Chapter 9 of this manual 7 22 List of Replaceable Parts Figures 7 8 and 7 9 provide illustration for parts list in Tables 7 2 and 7 3 respectively Refer to Chapter 6 for parts ordering information 7 14 Option 01 Battery Pack List of Replaceable Parts Table 7 1 Option 01 Battery Pack Final Assembly Reference Description Fluke Total Designator Stock Qty No A 4 BATTERY 825885 1 BT 1 BATTERY LEAD ACID 8 0V 2 5AH 822262 1 H 1 4 SCREW PH P LOCK STL 6 32 250 152140 4 1 RETAINER BATTERY 828814 1 34 TAPE FOAM URETHANE ADHES 063 500 854539 1 TM 1 FLUKE 45 BATTERY KIT INST SHEET 856013 1 1 CABLE ASSY FLAT 10 COND MICROMOD 3 831552 1 1 BT1 H2 REF 45 01 T amp B qb39c eps Figure 7 8 Option 01 Battery Pack Final Assembly 7 15 45 Service Manual 7 16 Reference Table 7 2 A4 Battery Pack PCA Description Fluke Stock Total Qty Designator 2 23 20 20 A CAP CER 1800PF 10 50V COG 1206 CAP CER 33PF 10 50V C0G 1206 CAP AL 47UF 20 50V SOLV PROOF CAP AL 10UF 20 63V SOLV PROOF CAP AL 47UF 20 100V SOLV PROOF CAP AL 1000UF 20 16V SOLV PROOF CAP CER 0 22UF 80 20 50V Y5V 1206 CAP AL 2 2UF 20 50V SOLV PROOF DIODE SI SCHOTTKY BARRIER 40V 1A DIODE SI BVz275V IO2250MA
110. e the signal is routed to the comparator through Analog Measurement Processor switches 535 541 2 15 45 BUFFER CONVERTER ACTIVE FILTER RMS CONVERTER ACTIVE FILTER qbO6f eps Figure 2 6 DC mA and Amps Simplified Schematic 2 31 Active Filter Refer to Figure 2 7 The two pole active filter consisting of AIR21 1 22 A1C12 and A1C13 filters noise on the a d converter input signal for the DCV DCmA DCA OHMS kOHMS and Diode Test functions Resistor AIR22 provides a 200 kQ input impedance for the filter except as follows Resistors AIR6 and A1R7 provide the 200 kQ input impedance for the 100 mV dc 300 mV dc 1000 mV de 3 V dc ohms and kilohms ranges Resistor AIR10 and the 100 5 resistor in 171 provide the 200 impedance for the 10 V and 30 V dc ranges Resistor A1R4 provides the impedance for the two DCmA ranges Analog Measurement Processor switch 582 shorts out AIR21 during ranging Switch 587 shorts out AIR22 both during ranging and in the measurements listed above For the 1000 3 10 30 100 and 300 ranges the active filter is bypassed and switch S83 selects C14 as the filter 2 16 Theory of Operation 2 Detailed Circuit Description ACTIVE FILTER INPUT MW FILTER qb07f eps Figure 2 7 Active Filter Simplified Schematic 2 32 A
111. e grid drive signals GRID 0 10 must be at approximately VCC 4 85 to 5 35 V dc Fora digit to be disabled the drive must be at VLOAD 28 5 to 32 0 V dc 8 Ifasegment under each of several or all grids fails to be turned on or off properly one of the anode drive signals may not be connected properly from 201 to A2DSI When an anode signal is at VCC and a grid signal is at VCC then the corresponding segment on the display is illuminated 9 Ifthe Main Processor has difficulty recognizing front panel button presses the switch scanning signals SWRI through SWR6 A1U6 21 through 26 respectively should be checked When no switch contacts are being closed the switch scanning lines should have about 20 of resistance between each other through two 10 pullup resistors to VCC None of the switch scanning lines should be shorted directly to GND at any time unless one of the switches is closed 5 16 Calibration Failures 5 17 Introduction Calibration processes for both front panel and computer interface operation are described in Chapter 4 of this manual Generally a calibration failure is noted with an error beep and a displayed Error at the front panel and a device dependent error over the computer interface These indications occur if the input varies from what the meter expects to see 5 19 45 Service Manual by more than 15 After one second the meter reverts to normal operation in calibration mode Bef
112. ected to a bi directional I O port on the microprocessor Each successive column has one less switch This arrangement allows the unused interface signals to function as strobe signals when their respective column is driven by the microprocessor The microprocessor cycles through six steps to scan the complete Front Panel Switch matrix Table 2 5 shows the interface signal state and if the signal state is an output the switches that may be detected as closed In step 1 six port bits are set to input and the interface signal values are read In steps 2 through 6 the bit listed as output is set to output zero the other bits are read and bits indicated by a Z are ignored Each of the interface signals is pulled up to the 5 V dc supply by a 10 kQ resistor in network A2Z1 Normally the resistance between any two of the interface signals is approximately 20 Checking resistances between any two signals SWR1 through SWRO verifies proper termination by resistor network 271 2 44 Display The custom vacuum fluorescent display A2DS1 comprises a filament 11 grids numbered 0 through 10 from right to left on the display and up to 14 anodes under each grid The anodes make up the digits and annunciators for their respective area of the display The grids are positioned between the filament and the anodes The filament is driven by a 5 V ac signal that is centered on a 25 V dc level When a grid 15 driven to 5 V dc the electrons fr
113. ector attach the display ribbon cable connector A on the Main PCA 3 Attach the wires at the rear of the front panel input terminals Observe the following color coding e At the rear of the 100 mA input terminal carefully insert the spring attached to the white wire into the fuse holder e Using needle nose pliers connect the wires at the rear of the input terminals as follows VOSE Red COM Black 10 A Yellow e Install the front panel 100 mA input fuse 3 34 Install the Handle and Mounting Brackets Refer to Figure 3 4 during the following procedure Use a Phillips head screwdriver to attach the two handle mounting brackets Note that these brackets must be reinstalled in their original positions Therefore the inside of each bracket is labeled with an R or an in reference to the front view of the meter Now engage the handle Point the handle straight up Then pull out on each end of the handle to engage the respective pivot in its bracket Pull out slightly on both pivots to rotate the handle to the desired position 3 35 Install the Meter Case Reinstall the meter case checking that it seats properly in the front panel Attach the rear bezel with the two panhead Phillips screws and secure the case with the flathead Phillips screw in the bottom Refer to Figure 3 3 3 15 45 Chapter 4 Performance Testing and Calibration Title 4 1 Introduction
114. eding allow for settling time of at least 30 seconds with no input applied Apply Input Wait For Meter Settling Time Send 1 0 0000 mV dc 5s CALSTEP 2 90 000 mV dc 2s CALSTEP 3 90 000 mV dc 2s CALSTEP 4 900 00 mV dc 2s CALSTEP 5 90 000 mV dc 5s CALSTEP 6 290 00 mV dc 1s CALSTEP 7 2 9000 V 1s CALSTEP 8 29 000 V 1s CALSTEP 9 290 00 V 1s CALSTEP 10 1000 0 V de 1s CALSTEP Note Settling times mentioned here assume that steps 1 through 32 are followed in sequence If you have just calibrated dc volts steps 1 through 10 but do not follow the subsequent sequence a special settling period of 4 minutes may be required due to dielectric absorption caused by the 1000 V dc input in step 10 Examples of this requirement include re checking dc volts calibration going from step 10 back to step 1 or skipping to ohms calibration going from step 10 to step 25 AC Volts Calibration 29 000 mV ac 1 kHz 35 CALSTEP 290 00 mV ac 1 kHz 35 CALSTEP 290 00 mV ac 1 kHz 35 CALSTEP 2 9000 V ac 1 kHz 3s CALSTEP 29 000 V ac 1 kHz 3s CALSTEP 290 00 Vac 1 kHz 3s CALSTEP 750 00 1 2 36 CALSTEP DC Milliamps Calibration 18 29 000 mA DC 1s CALSTEP 19 100 00 mA DC 1s CALSTEP DC Amps Calibration 10 000 A DC 35 CALSTEP AC Amps Calibration CALSTEP CALSTEP Ohms Calibration Step Range Input Wait for Meter Settling Send Send Time 25 1 190 0 0 1s CALREF xxx xx CALSTEP 26 2
115. ents and assemblies in static shielding bags or containers Static shielding bags and containers protect components and assemblies from direct static discharge and external static fields Store components in their original packages until they are ready for use 3 7 Cleaning ANWarning To avoid electrical shock or damage to the meter never allow water inside the case To avoid damaging the meter s housing never apply solvents to the meter If the meter requires cleaning wipe it down with a cloth that is lightly dampened with water or a mild detergent Do not use aromatic hydrocarbons chlorinated solvents or methanol based fluids when wiping the meter 3 8 Fuse Test and Replacement 3 9 Line Fuse The line fuse a T 125 mA 250 V slow blow is located on the rear panel The fuse is in series with the power supply For replacement unplug the line cord and remove the fuse holder with fuse as shown in Figure 3 1 The meter is shipped with a replacement fuse 3 10 Current Input Fuses The 100 mA and 10 A inputs are protected by replaceable fuses The 100 mA input is protected by 2 fuses and F5 F1 is rated at 500 mA 250 V fast blow 1500 A minimum breaking capacity IEC 127 Sheet I and F5 is rated at 440 mA 1000 V 10 000 A minimum interrupt rating fast blow fuse e The 10 A input is also protected by fuse F2 rated at F 11 A 1000 V fast blow 17 000 A breaking capacity 3 11 Testing Current Input Fuses
116. er output 107 13 is 5 0 V dc Data Terminal Ready DTR is a modem control signal controlled by the Microprocessor This signal is an RS 232 output generated by driver A1U7 7 it is at 5 0 dc when the meter is powered up 2 36 Microprocessor The Microprocessor utilizes an eight bit data bus and a sixteen bit address bus to access memory locations in ROM A1U8 RAM A1U10 and the IEEE 488 option The upper three bits of the address bus are decoded by A1U9 to generate chip select signals for the ROM A1U9 6 and RAM A1U9 8 The Microprocessor enables the reading of memory by driving RD A1U6 67 low and writing of memory by driving WR A1U6 66 low The IEEE 488 option also makes use of the signal R W read when high write when low that is generated by A1U6 65 The Microprocessor operates with a memory cycle time of 1 085 us as determined by the 3 6864 MHz crystal 2 The system clock signal A1U6 68 is a square wave with a frequency of 921 6 kHz It is used by the Display Assembly and the IEEE 488 option assembly after being damped by series resistor A1R57 The Microprocessor uses synchronous communication to store and retrieve meter configuration and calibration information in the EEROM A1U5 See the EEROM description for more detailed information The Microprocessor communicates to the Display Controller using a synchronous three wire communication interface described in detail in the Display Controller Theory of
117. essor resides within a plastic shield on the top of the Main PCA Although having the appearance of a dark gray piece of plastic this shield is electrically conductive treat it as you would any other conducting surface On the bottom of the Main PCA the Analog Measurement Processor is protected with a metallic shield Access the Analog Measurement Processor with the following procedure 3 9 45 Service Manual e Working from the bottom of the Main PCA remove the single Phillips head screw J in Figure 3 6 securing the metallic shield then lift the plastic shield M away from the top of the Main PCA e If necessary remove the metallic shield K Avoid contacting any circuit traces during this procedure First rotate the shield toward the pca edge then pry the shield free from its nylon standoff L 3 22 Remove the Rms PCA The rms is soldered in place the Main PCA within the Analog Measurement Processor shield For access procedures refer to Remove the Analog Measurement Processor Shields Use standard desoldering techniques e g solder sucker or solder wick when removing this assembly 3 23 Remove the Battery Option Use the following procedure to remove the Battery Option Refer to Figures 7 2 and 7 3 Chapter 7 to identify features and techniques mentioned here If necessary refer to Chapter 7 for a detailed description of Battery Option removal 1 Disconnect the flat white battery option connec
118. fully slide the battery kit into the area reserved for it in the back of the meter as shown in Figure 7 4 Make sure that both the retaining slots line up and the mounting holes mate Do not pinch wires running from the circuit assembly to the battery pack terminals 4 Secure the battery kit with two 6 32 x 1 4 panhead Phillips screws Attach the flat white connecting cable at the Battery Pack Option circuit board see Figure 7 3 The single blue line of the cable should be to the rear of the meter Align the plastic socket on the cable end then seat it securely in place 6 Reinstall the meter case to seat properly in the front panel Attach the rear bezel with the two panhead Phillips screws and secure the case with the flathead Phillips screw in the bottom 7 7 45 7 To ensure that the battery kit is properly installed turn the meter ON before connecting the power cord If the meter does not turn on the battery pack may be in the discharged state Charge the battery pack for 16 hours then retest m 6 32 x W PANHEAD SCREWS RETAINING SLOTS MOUNTING HOLES qb35c eps Figure 7 3 Installing the Battery Kit 7 8 Option 01 Battery Pack Performance Testing MAIN CIRCUIT BOARD qb34c eps Figure 7 4 Battery Pack Option Connecting Cable 7 14 Performance Testing 7 15 General Operability The following performance verification assumes the following initial setup configuration
119. g display may be the result of a hardware or software problem that is not a direct functional part of the Display Assembly Consult the General Troubleshooting Procedures found earlier in this chapter for procedures to isolate the fault to the Display Assembly Use the following discussion of display software operation when troubleshooting problems within a known faulty Display Assembly A Display Extender Cable is available PN 867952 for use during troubleshooting Figure 5 4 shows the timing of communications between the main processor and the display controller The Display Controller reads the DTEST and LTE inputs to determine how to initialize the display memory DTEST and LTE default to logic 1 and logic 0 respectively to cause all display segments to be initialized to on DTEST is connected to test points 2 and LTE is connected to 2 5 Either test point can be jumpered to VCC A2TP6 or GND A2TP3 to select other display initialization patterns Display Test Patterns 1 and 2 a mixture of on and off segments with a recognizable pattern to aid in troubleshooting problems involving individual display segments When either of the special display patterns is selected the beeper is also sounded for testing without interaction with the main processor Table 5 5 indicates the display initialization possibilities Figures 5 5 and 5 6 show grid and anode assignments for primary and secondary displays respectively
120. gnals to the option The 20 position connector A1J2 routes the 16 bit address bus and the WR memory control signal to the option This connector also routes the IEEE 488 interrupt and option sense signals from the option See Chapter 8 for further information 2 41 Display Assembly Display Assembly operation classified into six functional circuit blocks the Main Assembly Connector the Front Panel Switches the Display the Beeper Drive Circuit the Watchdog Timer Reset Circuit and the Display Controller These blocks are described in the following paragraphs 2 42 Main Assembly Connector The Main Assembly Connector is a 20 pin connector A2J1 that provides the interface between the Main Assembly and the other functional blocks on the Display Assembly Seven of the connector pins provide the necessary connections to the four power supply voltages 30 V dc 5 V dc 5 V dc and 5 V ac Six pins are used to provide the interface to the Front Panel Switches 25 1 through A2SWR6 The other seven signals interface the Microprocessor to the Display Controller and pass the reset signals between the assemblies 2 43 Front Panel Switches The microprocessor scans the 19 Front Panel Switches 251 through 2518 and 2521 using only six interface signals plus the ground connection already available 2 20 Theory of Operation 2 Detailed Circuit Description from the power supply These six signals SWRI through SWR are conn
121. h test D dc and ac amps calibration computer interface 18 dc and amps calibration front 4 11 and milliamp calibration front panel and ac milliamps calibration computer interface dc volts 2 12 volts calibration computer interface dc volts calibration front panel 4 9 dc volts troubleshooting detailed circuit description 8 3 digital 2 5 digital troubleshooting 5 15 diode continuity test disassembly procedures 3 7 disconnect miscellaneous chassis components 3 10 display 2 21 display assembly 2 5 2 20 display assembly troubleshooting 5 17 Service Manual display controller with FIP 2 22 E editing the prompt for different calibration points 4 13 eerom entering calibration mode 4 8 error codes exit calibration mode exiting calibration mode F failure to enter remote 8 11 failure to generate a service request 8 12 failure to generate an end or identify eoi failure to handshake on ieee 488 bus ad receive multiple character commands 8 12 failure to select ieee 488 option 8 10 failure to transmit query 8 12 frequency 2 15 frequency calibration computer interface 4 19 frequency calibration front panel 4 13 front panel calibration front panel switches 2 20 functional block description 7 3 8 3 3 4 fuse test and replacement
122. handle mounting brackets then rotate the handle up over the display With the handle pointing straight up pull out and disengage one pivot at a time 3 7 45 Use a Phillips head screwdriver to remove the two handle mounting brackets Note that these brackets must be reinstalled in their original positions Therefore the inside of each bracket is labeled with an or an L referenced to the front view of the meter qb15c eps Figure 3 4 Removing the Handle and Handle Mounting Brackets 3 17 Remove the Front Panel Assembly Remove all leads connected to the input terminals Then remove the front panel 100 mA fuse Using needle nose pliers disconnect the wires at the rear of the COM and 10 A input terminals At the rear of the 100 mA terminal carefully dislodge and withdraw the spring attached to the white wire from the fuse holder Locate the display ribbon cable connector on the Main PCA in Figure 3 5 Using needle nose pliers disconnect this cable by alternately pulling up on each end of its connector Avoid breaking the alignment tabs on the Main PCA half of this connection Now remove the Front Panel Assembly by releasing the four snap retainers in Figure 3 5 securing it to the chassis 3 18 Remove the Display PCA The Display PCA is held in place with a set of tabs around its periphery In sequence release the tabs along the top left side and right side Then
123. hapter 9 Chapter 3 provides access information Chapter 6 List of Replaceable Parts Includes parts lists for all standard assemblies Information on how and where to order parts is also provided Chapter 7 Option 01 Battery Pack Each option is allocated a separate chapter 7 for the Battery Pack Option 01 and 8 for the IEEE 488 Interface Option 05 Option 15 incorporates both Options 01 and 05 Chapter 7 includes the full range of Service Manual topics specifications theory of operation maintenance list of replaceable parts etc for the Battery Pack option Schematic diagrams for the options are found in Chapter 9 Chapter 8 Option 05 IEEE 488 Interface Includes the full range of Service Manual topics specifications theory of operation maintenance list of replaceable parts etc for the IEEE 488 Interface option Schematic diagrams for the options are found in Chapter 9 Chapter 9 Schematic Diagrams Includes schematic diagrams for all standard and optional assemblies A list of mnemonic definitions is also included to aid in identifying signal name abbreviations 1 5 Conventions Throughout the manual set certain notational conventions are used A summary of these conventions follows e Instrument Reference The Fluke 45 Dual Display Multimeter is usually called the meter e Printed Circuit Assembly 45 Service Manual The term pca is used to represent a printed circuit assembly and its attached par
124. he 24 line cable assembly to the IEEE 488 circuit board 3 32 Assemble the Front Panel Assembly As appropriate use the following steps to assemble the Front Panel Assembly 1 Clean the lens D with deionized air and if necessary isopropyl alcohol Then gently snap the lens into the front panel tabs Install the elastomeric keypad assembly Make sure that the four front panel guide pins protrude through the keypad On the Display PCA clean the display with deionized air and if necessary isopropyl alcohol Slide the Display PCA into the bottom securing tabs on the back of the Front Panel Assembly Then gently snap the pca into the remaining tabs along its periphery Note The Display PCA provides a space for a center securing screw If the peripheral tabs are intact this screw is not necessary If some of the tabs are broken the screw can be used as an additional securing device Connect the 20 pin cable connector A to the Display PCA General Maintenance Assembly Procedures Figure 3 5 Assembly Details qb16c eps 3 3 13 Mii LI Figure 3 5 Assembly Details cont General Maintenance 3 Assembly Procedures 3 33 Install the Front Panel Assembly Use the following procedure when installing the Front Panel Assembly 1 Snap the Front Panel Assembly into place in the four tab retainers 2 Observing the alignment orientation provided by tabs on the conn
125. he probes should make contact only with the pads in front of the component leads With the close spacing involved ordinary test probes can easily short two adjacent pins an SMT This Service Manual is a vital source for component locations and values With limited space on the circuit board chip component locations are seldom labeled Figures provided in Chapter 6 of this manual provide this information Also remember that chip components are not individually labeled keep any new or removed component in a labeled package Surface mount components are removed and replaced by reflowing all the solder connections at the same time Special considerations are required e Use a solder tool with regulated hot air to melt the solder there is no direct contact between the tool and the component e Surface mount assemblies require rework with wire solder rather than with solder paste A 0 025 inch diameter wire solder composed of 63 tin and 37 lead is recommended A 60 40 solder is also acceptable A good connection with SMT requires only enough solder to make a positive metallic contact Too much solder causes bridging while too little solder can cause weak or open solder joints With SMT the anchoring effect of the through holes is missing solder provides the only means of mechanical fastening Therefore the pca must be especially 5 3 45 Service Manual 5 4 clean to ensure a strong connection An oxidized pca pad causes t
126. he solder to wick up the component lead leaving little solder on the pad itself 5 3 Error Codes At reset the Fluke 45 software attempts power up self tests and initialization of ROM RAM Display EEROM and measurement hardware Self test failures are reported on the display with error in the secondary display and an error code 1 9 in the primary display Several of these error codes might never be displayed Certainly errors 4 and 5 which signify a faulty or dead display could not be reported in the normal displayed manner Other errors might not appear on the display Therefore the following two additional methods exist for accessing error information The computer interfaces can be used to determine self check status using the TST query Note that the extent of the error producing damage could also cause the meter to halt before the computer interfaces are operational The keyboard scan lines A1U6 SWR1 5 which are also used as status indicators can be checked as a last resort for accessing error information The software sets SWRI A1U6 21 low to indicate that the basic operation of the processor ROM and ROM decode circuitry is intact SWR2 A1U6 22 is set low if the ROM check passes SWR3 A1U6 23 is set low if the external RAM A1U10 check passes and SWR4 A1U6 24 is set low if the internal RAM A1U6 check passes Then if the display self check passes 5 5 A1U6 25 is set low to indicate that the display
127. hen the meter is operated on line power If trickle charging occurs when the battery pack is low R2 limits charging current to about 15 mA maximum When the meter is operated solely on battery pack power the charger is disconnected from the battery pack A logic level signal ACON from the Main Circuit Assembly 11 5 is maintained high and the output of comparator U2 1 goes low pulling U1 1 to common and setting the U1 2 output at 1 25 volts CR4 is thus reversed biased disconnecting the charger from the battery pack 7 10 Other Circuits During the various modes of operation switching diodes provide the required battery pack connections During battery pack operation of the meter CR3 connects the battery pack to the switching supply on the Main Circuit Assembly During charging line power connected CR5 connects the battery pack to the charging circuit If line power is disconnected CR9 disconnects the battery pack from the charging circuit The 5 amp battery pack fuse opens if either the battery pack is connected with the wrong polarity or if the battery pack output is shorted on the battery pack circuit board 7 11 General Maintenance 7 12 Removal 7 6 Use the following instructions to remove the Battery Pack Option from the meter 1 Make sure the meter is turned off and unplugged from the power outlet 2 Remove the screw from the bottom of the case and the two screws from the rear bezel as shown in Figure 7 2 deta
128. heory of Operation neeendseneeseanacneeeetancnieae 2 1 20 a trade eo ced 2 2 Functional Block 1 2 3 Power Supply 2 4 Analog Measurement Processor sss 2 5 Input Protection Circuit 2 6 Input Signal Conditioning esee 2 7 Analog to Digital A D Converter eene 2 8 Serial Communication Guard Crossing 2 9 Digital Kernel oir a ete nt eee eta 2 10 Display Assembly optet Rete iN e ee Yee dta aoa 2 11 IEEE 488 Interface Option 05 2 12 Battery Pack Option 01 5 ertt tint ttt leen 2 13 Detailed Circuit ene 2 14 Power Supply Circuit Description seen 2 15 Raw DC Supply Pro eee eed es esee cedo 2 16 5 Volt Switching 2 17 niis EE 2 18 Analog Measurement Processor 2 19 Input 2 20 Input Signal Conditioning eere 2 21 RELAYS m 2 22 DG c ai 2 23 OTS E EA 2 24 100 MQ 300 MQ 00 040021101 2 25 45 Service Manual 2 26
129. ibration depends on various combinations of components in and around the Analog Measurement Processor The major components are Rms Converter 1 1 e AC Buffer AIARI Shunt Resistors AIR2 AIR3 Zener Reference AIVRI e Divider Network DC Ohms 171 e Integrate Resistors Reference Divider 173 e AC Divider Network A1Z2 Rms Converter Network 174 Calibration of the Fluke 45 utilizes a building block approach individual components are calibrated separately and the appropriate calibration building blocks are assembled later for correction of any particular measurement function range and rate Calibration steps are grouped by function with dc volts being first Therefore the calibration constants are partitioned to allow for some independence in the correction of the various measurement functions For example if the zener reference and divider needed replacing it would be necessary to recalibrate dc volts only ac volts would not be affected Table 5 6 identifies components that are unique to each calibration step Table 5 7 provides a different approach relating components that are common to a group of calibration steps Diagnostic Testing and Troubleshooting Calibration Failures 5 19 Calibration Interrelationships If you suspect calibration errors but the meter does not exhibit the symptoms mentioned above verify that you are observing the following calibration rules e Stored dc volts calibration constants i
130. il A While holding the front panel slide the case and rear bezel off the chassis See Figure 7 2 detail B At this point the rear bezel is not secured to the case 3 Locate the flat white battery pack option cable connector at the Main PCA see Figure 7 3 Use needle nose pliers to detach this connection alternately pull up on each end of this connector Option 01 Battery Pack General Maintenance Mounting Screw 2 Rear Bezel Grounding Screw 2 Chassis qb14f eps Figure 7 2 Removing the Case 4 Remove the two 6 32 x 1 4 panhead Phillips screws securing the Battery Pack Option see Figure 7 4 5 Carefully slide the Battery Pack Option out of the meter as shown in Figure 7 4 Do not pinch the wires running from the circuit board to the battery terminals Caution To prevent damage to the meter when servicing the Main PCA unplug the battery pack ribbon cable at the Main PCA or disconnect the wires to the battery pack 7 13 Installation Use the following instructions to install the Battery Kit Option Refer to the Instruction Sheet PN 856013 supplied with the Battery Kit for the more detailed instructions required with an initial installation of the Battery Kit Option 1 Make sure the meter is turned off and disconnected from line power 2 With the meter disconnected from line power discharge the power supply capacitor by turning the meter on After five seconds turn the meter off 3 Care
131. irmly in place 4 Attach opposite ends of the ribbon cables onto the Fluke 45 Main PCA Install the IEEE 488 in the Fluke 45 with the dual ribbon cables facing the front of the meter The IEEE 488 PCA slips into the small slot in the side of the meter The end of the plastic standoff fits into the hole in the IEEE 488 PCA Make sure the IEEE 488 is firmly gripped against the retainer the standoff The rear of the IEEE 488 should rest upon the support just forward of the transformer Secure the rear of the IEEE 488 PCA with the panhead Phillips screw Connect the 24 line cable assembly to the IEEE 488 PCA See Figure 8 2 8 Reinstall the meter case so it seats properly in the front panel Attach the rear bezel with the two panhead Phillips screws and secure the case with the flathead Phillips screw in the bottom 8 13 Performance Testing Use the performance test program in Figure 8 1 to verify operation of the IEEE 488 Interface This program is written for use with the Fluke 182A Instrument Controller and its interpreted BASIC language The program may be adapted to the language of any IEEE 488 controller This performance test communicates to a meter that has been configured for IEEE 488 operation at address 0 Lines 160 and 170 initialize the IEEE 488 bus and send selective device clear to the meter A multiple byte command is sent to the meter by line 190 to clear the meter status Another command seque
132. is signal is present the problem is probably on the Display PCA Refer to Display Assembly Troubleshooting elsewhere in this chapter e Ifthe E clock is something other than a 921 6 kHz square wave isolate the digital chapter of the Main PCA by disconnecting the Display PCA at J4 Then check the E clock again and refer to Digital Troubleshooting elsewhere in this chapter for further problem isolation 5 5 Power Supply Troubleshooting 5 6 Raw DC Supply With the meter off but connected to line power check for approximately 16 V at 120 ac line voltage between the ground test point and the cathode of either 1 2 or ATCR3 If necessary check for transformer secondary voltage of approximately 24 V ac With the meter on check for 19 V dc from 1011 pin 8 to the ground test point This voltage is approximately 5 volts greater than the raw supply voltage when the switching supply is operating properly The controller IC A1U11 starts operating when its supply voltage is approximately 2 5 V dc Diagnostic Testing and Troubleshooting Power Supply Troubleshooting Table 5 2 Power Supplies CCS Main PCA In Guard Circuits 10 A1R2 A1R3 4 95 to 5 45 12 A1R2 A1R3 4 95 to 5 45 V A1R2 A1R3 4 7 to 5 35 V A1R2 A1R3 4 7 10 5 35 Main PCA Out Guard Circuits VCC A1TP18 A1TP17 4 85 to 5 35 V dc VEE A1TP1
133. it Q4 R18 and R19 in the feedback path of the switching power supply 7 6 Cycle Float Charge Rate Switch The Cycle Float Charge Rate Switch monitors the charging current supplied to the battery pack during charge when the meter is de energized If the current is 60 mA to 80 or higher the charging voltage is increased to about 9 8 V This level of current causes a voltage drop across R28 that is sufficient to turn Q6 and Q7 on connecting one end of R22 to common The resulting current through R22 modifies feedback to the switching supply causing the increased output voltage As the battery pack charge reaches about 90 of capacity the charge current at 9 8 volts drops below 60 to 80 mA Q6 and Q7 turn off and the charging voltage decreases to 9 35 volts the trickle charge level for the battery pack Diode CR10 clamps the voltage across R28 to about 0 8 V maximum 7 7 Low Battery Indicator Detector The Low Battery Indicator Detector uses comparator U2 7 Bandgap reference VR2 is connected to the inverting input of the comparator while the divided down battery voltage is connected to the noninverting input Resistor R16 provides the comparator with a hysteresis of approximately 0 25 V The comparator output is an open collector transistor connected to pull up resistor R45 on the Main Circuit Assembly When the battery pack voltage falls below about 7 7 V U2 7 goes low When the battery pack voltage rises above about 8 0 volts U
134. itchin Supply erp eer i ee e etus e lodo see Processor Timing Display Controller to Microprocessor Primary Secondary Display numen e Final Assembly True Rms aue bet rrt torneo rcr cte ees bee dnce A2 Display PC A iore oec etn eria COD ea gebe Battery Pack Option Functional Block Diagram eee Removing the ND Installing the Battery iere tree eren eiat rete erase e aee Battery Pack Option Connecting Cycle Float Charge Rate Switch Test essere Unplugging the Battery Pack Connectors Test Points and Adjustments esee Option 01 Battery Pack Final Assembly eee 45 Service Manual 59 _ amp PCA 7 1 8 1 2188885 EEEE 8 2 IEEE 488 Interface 8 3 488 Module 8 4 IEEE 488 Interface Performance 8 5 Option 05 IEEE 488 Interface Final Assembly 8 6 5 IEEE 488 Interface 9 1 PCA 9 2
135. l a shock Most electronic components manufactured today can be degraded or destroyed by ESD While protection networks are used in CMOS devices they can only reduce not eliminate component susceptibility to ESD ESD may not cause an immediate failure in a component a delayed failure or wounding effect is caused when the semiconductor s insulation layers or junctions are punctured The static problem is thus complicated in that failure may occur anywhere from two hours to six months after the initial damage 3 3 45 Service Manual 3 4 Two failure modes are associated with ESD First a person who has acquired a static charge can touch a component or assembly and cause a transient discharge to pass through the device The resulting current ruptures the junctions of a semiconductor The second failure mode does not require contact with another object Simply exposing a device to the electric field surrounding a charged object can destroy or degrade a component MOS devices can fail when exposed to static fields as low as 30 volts Observe the following rules for handling static sensitive devices 1 Handle all static sensitive components at a static safe work area Use grounded static control table mats on all repair benches and always wear a grounded wrist strap Handle boards by their nonconductive edges only Store plastic vinyl and Styrofoam objects outside the work area 2 Store and transport all static sensitive compon
136. l of the unknown input signal is measured by the digital circuits in the Analog Measurement Processor and sent to the microprocessor 2 8 Serial Communication Guard Crossing This functional block provides a high isolation voltage communication path between the Digital Kernel and the Analog Measurement Processor This bi directional communication circuit also requires power supply voltages from the Power Supply block 2 3 45 Service Manual Input Protection Input Signal Conditioning Analog Measurement Processor A D Converter Serial Communication Crossing Vacuum Fluorrescent Display ae R Display Controller gt IEEE 488 Front Panel e Option 05 Switches EEPROM Calibration Constants Display Assembly Digital Kernel 2 4 Battery Assembly Option 01 Power Supply gt 5Vac gt 5 2 gt 30 5 25 Vdc 5 25 Vdc Figure 2 1 Overall Functional Block Diagram qb01 eps Theory of Operation 2 Detailed Circuit Description 2 9 Digital Kernel The Digital Kernel functional block is responsible for the coordination of all activities within the meter This block requires power supply voltages from the Power Supply and reset signals from the Display Assembly Specific
137. lead and source zero resistance on the 300 Q range by sending VAL 3 Record the response This value is used if you elect to perform the Alternate Ohms Calibration 4 Now continue on with the calibration procedures in the following paragraphs 4 17 45 4 22 DC Volts Calibration Computer Interface 1 Connect the DC Calibrator to the Fluke 45 VO and inputs Then send CAL 1 2 Complete steps 1 through 10 in Table 4 7 Then clear the dc volts source 4 23 AC Volts Calibration Computer Interface 1 Connect the AC Calibrator to the Fluke 45 and COM inputs Then send CAL 2 2 Complete steps 11 through 17 in Table 4 7 Then clear the ac volts source 4 24 DC and AC Milliamps Calibration Computer Interface 1 Connect the mA Calibrator to the Fluke 45 100 mA and COM inputs Then send CAL3 2 Complete steps 18 and 19 in Table 4 7 Now send CAL 4 4 Complete steps 20 and 21 in Table 4 7 Then clear the milliamp source 4 25 DC and AC Amps Calibration Computer Interface 1 Connect the Amps Calibrator to the Fluke 45 10 A and COM inputs Then send CAL 5 2 Complete step 22 in Table 4 7 Clear the dc amps source Then send CAL 6 4 Complete steps 23 and 24 in Table 4 7 and clear the amps source 4 26 Ohms Calibration Computer Interface If you do not have the value resistors 290 2 9 29 etc required by the Fluke 45 calibration prompts the requested v
138. led below although discrete resistor values can be used for all ranges Lead and source zero resistances are only taken into account for the lowest two ranges 300 and 3 1 Connect the ohms source to the meter Apply zero ohms 2 Measure and record the residual lead and source zero resistance on the 3000 range 3 Add the value from the lead and source zero resistance from step 2 above to the certified value of the source resistor 4 Setthe meter to the calibration mode press the Cal Enable button Select ohms calibration 5 Using the editor buttons edit the meter display prompt to the value calculated in step 3 6 Press to calibrate this range 4 14 Continuity Hysteresis Threshold Calibration Front Panel Perform the calibration as follows 1 If the meter is already in calibration mode press the 225 button to select V gt calibration Otherwise select calibration mode first press Cal Enable button for three seconds then select V gt calibration by pressing the 25 button seven times 2 Connect the output of the dc voltage source to the VO gt and COM input of the meter 3 Apply the outputs indicated in Table 4 5 and calibrate using the button 4 15 Frequency Calibration Front Panel If the meter is already in calibration mode press the CJ button to select Hz calibration Otherwise select calibration mode first press Cal Enable button for three seconds then select Hz calibrati
139. lternate Ohms Calibration Front 4 14 Continuity Hysteresis Threshold Calibration Front Panel 4 15 Frequency Calibration Front Panel eese 4 16 Editing the Prompt for Different Calibration Points 4 17 Calibration Using the Computer 4 18 NM 4 19 RS 232 Interface 25544444 24442204 14524201 80 ae 4 20 IBBE 488 iie one 4 21 The Calibration Procedure eese 4 22 DC Volts Calibration Computer Interface 2 4 23 AC Volts Calibration Computer Interface 4 24 DC and AC Milliamps Calibration Computer Interface 4 25 DC and AC Amps Calibration Computer Interface 4 26 Ohms Calibration Computer 2 esee 4 27 Continuity Hysteresis Threshold Calibration Computer Interface 4 28 Frequency Calibration Computer 4 29 Concluding Calibration Using the Computer Interface 4 30 Alternate Ohms Calibration Computer Interface Diagnostic Testing and Troubleshooting CA CA CA CA CA CA CA Ree
140. ly The battery has a typical operating time of eight hours and is fully operable at ambient temperatures between 0 and 50 C The IEEE 488 Interface Kit Option 05 consists of a printed circuit assembly connecting cables and mounting hardware This option provides full programmability external trigger input and automated calibration The 488 computer interface command set is identical to the RS 232 interface commands wherever possible e Option 15K combines Options 01K and 05K as a single kit 45 Service Manual The Fluke 45 Dual Display Multimeter can be mounted in a standard 19 inch rack panel on either the right hand or left hand side using the Fluke 00 200 634 Rack Mount Kit Accessories for the Fluke 45 are listed in Table 1 1 Table 1 1 Accessories Model Description C40 Soft carrying case Provides padded protection for the meter Includes a pocket for the manual and pouch for the test leads and line cord 00 200 Rackmount Kit Allows meter to be mounted on either the right or left side of a standard 634 19 inch rack RS40 RS 232 terminal interface cable Connects other Fluke 45 to any terminal or printer with properly configured DTE connector DB 25 female pins including an IBM PC IBM PC XT or IBM PS 2 models 25 30 50 P60 70 and 80 RS41 RS 232 modem cable Connects the Fluke 45 to a modem QuickStart a PC software package simplifies operation of the Fluke 45 whe
141. make this measurement This waveform should be a sawtooth signal with an amplitude of 0 5 V p p and a period of approximately 20 to 25 us The output current of the 5 volt switching supply can be determined by measuring the voltage across the current limit current sense resistors AIRA7 1 48 AIR49 The current shunt is approximately 0 167 ohms With line voltage at 120 V ac typical voltages across the current sense resistors are as follows e Meter without options 42 mV e Meter with IEEE 488 Interface Option 72 mV 45 Service Manual Meter with Battery Option Line Operation 54 mV Battery Operation 43 mV e Meter with IEEE 488 Interface and Battery Options Line Operation 85 mV Battery Operation 43 mV NORMAL LOAD ON 5V SUPPLY NO LOAD OR VERY LIGHT LOAD ON 5V SUPPLY i 5V SUPPLY OUTPUT SHORTED HEAVY LOAD ON 5V SUPPLY qb23f eps Figure 5 2 Volt Switching Supply 5 8 Inverter Use an oscilloscope to troubleshoot the inverter Check for a 9 6 V p p signal with a period of approximately 30 to 40 us across the primary winding of the inverter transformer A1T2 If this signal is measured with reference to ground the amplitude of the square wave should be approximately 4 8 V p p
142. n Press the 25 button to select mA AC calibration Connect the ac milliamps source to the 100 mA and COM inputs 4 9 45 Service Manual 6 Apply the ac milliamp outputs indicated in Table 4 5 steps 20 and 21 and calibrating each step by pressing the button Table 4 5 Front Panel Calibration Note Before proceeding allow for settling time of at least 30 seconds with no input applied Meter Cal Prompt Meter Settling Time Before Pressing DC Volts Calibration 0 000 mV DC short 90 000 mV DC 90 mV 90 000 mV DC 90 mV 900 00 mV DC 900 mV dc 90 000 mV DC 90 mV 290 00 mV DC 290 mV 2 9000 V DC 2 9 V 29 000 V DC 29 V dc 290 00 V DC 290 V dc 1000 0 V DC 1000 V dc A Note Settling times mentioned here assume that steps 1 through 32 are followed in sequence If you have just calibrated dc volts steps 1 through 10 but do not follow the subsequent sequence a special settling period of 4 minutes may be required due to dielectric absorption caused by the 1000 V dc input in step 10 Examples of this requirement include re checking dc volts calibration going from step 10 back to step 1 or skipping to ohms calibration going from step 10 to step 25 AC Volts Calibration 29 000 mV AC 29 mV 1 kHz 290 00 mV AC 290 mV 1 kHz 0 2900 V AC 290 mV 1 kHz 2 9000 V AC 2 9 V 1 kHz 29 000 V AC 29 V 1 kHz 290 00 V AC 290 V 1 kHz 750 00 V AC 750 V 1 kHz DC Milli
143. n The Power Supply consists of the following three functional sections Raw DC Supply The Raw DC Supply converts line voltage 90 V to 264 V ac to a dc output of 7 5 V to 5 V 5 V Switching Supply The 5 V Switching Supply converts the Raw DC Supply output to 5 1 V 0 25 V dc Inverter Using the 5 V Switching Supply output the Inverter generates the 30 V dc 5 V dc and 5 V ac supply levels needed for the vacuum fluorescent display Also the 2 5 45 Service Manual 2 6 Inverter provides isolated positive and negative 5 25 V outputs for the in guard circuitry 2 15 Raw DC Supply The Raw DC Supply uses a power transformer A1T3 that operates on input line voltages ranging from 90 V to 264 V ac Since there is no power switch in the transformer input circuit the Raw DC Supply is energized whenever the meter is connected to line power The transformer uses an internal 275 V ac MOV metal oxide varistor to clamp line transients This MOV normally acts as an open circuit when the peak voltage exceeds approximately 400 V the MOV turns on and working with the line impedance in series with the line fuse limits the transient peak voltage to 400 to 500 V All line voltages use a T 0 125 A 250 V slow blow fuse On the secondary side of the transformer the output is rectified by diodes 1 2 and and filtered by capacitor A1C27 In addition A1C26 reduces rectifier diode switching emi emissions from the meter
144. n using the RS 232 computer interface Readings are recorded in files that can be accessed by Lotus 1 2 3 dBase and other graphics packages Y8021 Shielded IEEE 488 one meter 39 4 inches cable with plug and jack at each end Y8022 Shielded IEEE 488 two meter 78 8 inches cable with plug and jack at each end Y8023 Shielded IEEE 488 four meter 13 feet cable with plug and jack at each end QuickStart 45 is a trademark of Fluke Corporation Lotus is a registered trademark of Lotus Development Co dBase Ill is a registered trademark of Ashton Tate IBM PC and IBM PC XT are registered trademarks of International Business Machines 1 4 Organization of the Service Manual This manual focuses on component level repair of the Fluke 45 Dual Display Multimeter To that end manual chapters are often interdependent effective troubleshooting may require not only reference to the troubleshooting procedures in Chapter 5 but also some understanding of the detailed Theory of Operation in Chapter 2 and some tracing of circuit operation in the Schematic Diagrams presented in Chapter 9 Often scanning the table of contents will yield an appropriate place to start using the manual A comprehensive table of contents is presented at the front of the manual local tables of contents are also presented at the beginning of each chapter for ease of reference If you know the topic name the index at the end of the manual is probably a good pl
145. nals Carefully remove the fuse and install a properly rated replacement General Maintenance 3 Disassembly Procedures 3 14 Disassembly Procedures The following paragraphs describe disassembly of the Fluke 45 in sequence from the fully assembled meter to the chassis level Start and end your disassembly at the appropriate heading levels 3 15 Remove the Meter Case Use the following procedure to remove the meter case 1 Make sure the meter is turned off and unplugged from the power outlet 2 Discharge the power supply capacitor by turning on the meter with the meter unplugged from the power line After five seconds turn the meter off 3 Remove the screw from the bottom of the case and remove the two screws from the rear bezel as shown in Figure 3 3 section A While holding the front panel slide the case and rear bezel off the chassis See Figure 3 3 section B At this point the rear bezel is not secured to the case Caution If the Main PCA is to be serviced and the Battery Option is installed first unplug the battery ribbon cable from the Main PCA or disconnect the wires to the battery This measure prevents damage to the meter when you are servicing the Fluke 45 Main PCA Mounting Screw 2 Rear Bezel _ Grounding Screw 2 Chassis qb14f eps Figure 3 3 Removing the Case 3 16 Remove Handle and Mounting Brackets Refer to Figure 3 4 during this procedure Pull each handle pivot out slightly at the
146. nce including a query is sent to the meter by line 210 the meter asserts Service Request SRQ to signal that a response is available Lines 530 through 560 first poll the meter for status then input the response from the meter Lines 230 through 270 test for proper operation and print the results 8 9 45 Service Manual 140 0 instrument IEEE address 150 55 1 initialize spl response 160 TERM terminate input only on EOI 170 INIT PORT 0 initialize IEEE 488 bus 180 CLEAR IA selective device clear 190 PRINT IA cls clear instrument status 200 ON SRQ GOTO 530 enable SRQ interrupt 210 PRINT IA cls sre 16 idn 580 on Message Available 220 WAIT 500 FOR SRO allow time to execute commands 230 IF 5 gt 0 THEN 260 240 PRINT Instrument failed to generate a Service Request 250 STOP 260 PRINT Serial Poll S should be 80 270 PRINT Identification Query Response R 280 STOP 500 510 Service Request interrupt 520 530 S 5 5 get instrument serial poll status 540 IF S AND 16 THEN 550 ELSE 560 550 INPUT LINE if MAV set get the response 560 RESUME 230 end of SRQ interrupt 999 END Figure 8 4 IEEE 488 Interface Performance Test 8 14 Troubleshooting 8 15 Power up Problems The following discussion identifies probable fault areas if the installation of an IEEE 488 Interface Option causes power up failure for the Fluke
147. nfluence constants for several other functions If dc volts 16 recalibrated these other functions must be recalibrated This interrelationship is explained in Table 5 8 e Independent calibration of any function except dc volts results in the storage of correcting calibration constants for that function only e Once calibration is begun all steps for that function must be completed before the calibration constants are stored If all steps are not completed and the procedure is terminated only calibration constants for previously completed functions are stored 5 20 Retrieving Calibration Constants If a calibration error is suspected the stored constant can be retrieved and verified over the computer interface This information can be specified by the number of the constant Table 5 9 lists the calibration constant numbers Use the following format CALCONST xx where xx denotes the calibration constant number Except for constants 9 11 21 and 32 the response format is 1 X0 XXXXXXX 5 21 Replacing the EEROM A1U5 The EEROM provides non volatile storage for the serial number of the meter meter configuration and calibration information If the EEROM is replaced during repair the new EEROM should be programmed with the 7 digit serial number found on the rear panel of the meter Use the following command to program the serial number into the EEROM SERIAL xxxxxxx denotes the 7 digit serial numbe
148. ng this calibration and hold very steady for several seconds with your index finger resting on the button before pressing it These two cal points should be verified for accuracy at the conclusion of calibration 4 11 DC and AC Amps Calibration Front Panel The dc and ac amps calibration requires a boost amplifier or transconductance amplifier capable of 10 A output at both de and 1 kHz 1 If the meter is already in calibration mode press the CJ amp button to select DC calibration Otherwise select calibration mode first press Cal Enable button for three seconds then select A DC calibration by pressing the 5 button four times 2 Connect the output of the boost amplifier to the 10 A and COM inputs of the meter Apply the dc amp output indicated in Table 4 5 step 22 and calibrate using the button Select A AC calibration on the meter by pressing the button once Apply the two ac amp outputs called for in steps 23 and 24 of Table 4 5 calibrating each step by using the button 4 12 Ohms Calibration Front Panel If you do not have the value resistors 290 Q 2 9 kQ 29 kQ etc required by the Fluke 45 calibration prompts the requested value prompt must be edited to the value available See Editing the Prompt for Different Calibration Points later in this 45 chapter the following procedure the Fluke 5700 Multifunction Calibrator is used as the ohms source with in
149. nput divider ohms reference network 17 GRD Guard 18 V2F Tap 2 active filter input on the DCV input divider ohms reference network 19 V2 2 on the DCV input divider ohms reference network 20 GRD Guard 21 VO Tap 0 on the DCV input divider ohms reference network 22 GRD Guard 23 OVS Ohms and volts sense input 24 GRD Guard 25 AGND1 Analog ground 1 26 not used 27 DGND Digital ground 28 FCO Function control 0 29 FC1 Function control 1 30 FC2 Function control 2 31 FC3 Function control 3 32 FC4 Function control 4 33 FC5 Function control 5 34 FC6 not used 35 FC7 not used 36 OSCIN Crystal oscillator input 37 OSCO Crystal oscillator output 38 MRST Master reset 39 AS Analog send 40 AR Analog receive 41 SK Serial clock 42 CS Chip select 43 BRS Baud rate select 44 VSS 5 V 45 INT Integrator output 46 SUM Integrator summing node 47 B 1 Buffer output 100 mV range 48 B 3 Buffer output 300 mV range 49 B1 Buffer output 1000 mV range 50 B3 Buffer output 3 V range 2 9 45 Service Manual Table 2 1 Analog Measurement Processor Pin Name Description cont Pin Name 51 VREF A D reference plus 52 VREF A D reference minus 53 RAO A D reference amplifier output 54 RA A D reference amplifier noninverting input 55 RA A D reference amplifier inverting input 56 AFO Active filter output 57 MOF Megohms filter 58 AFI Ac
150. o invoice Buyer for importation costs of repair replacement parts when product purchased in one country is submitted for repair in another country Fluke s warranty obligation is limited at Fluke s option to refund of the purchase price free of charge repair or replacement of a defective product which is returned to a Fluke authorized service center within the warranty period To obtain warranty service contact your nearest Fluke authorized service center or send the product with a description of the difficulty postage and insurance prepaid FOB Destination to the nearest Fluke authorized service center Fluke assumes no risk for damage in transit Following warranty repair the product will be returned to Buyer transportation prepaid FOB Destination If Fluke determines that the failure was caused by misuse alteration accident or abnormal condition of operation or handling Fluke will provide an estimate of repair costs and obtain authorization before commencing the work Following repair the product will be returned to the Buyer transportation prepaid and the Buyer will be billed for the repair and return transportation charges FOB Shipping Point THIS WARRANTY IS BUYER S SOLE AND EXCLUSIVE REMEDY AND IS IN LIEU OF ALL OTHER WARRANTIES EXPRESS OR IMPLIED INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE FLUKE SHALL NOT BE LIABLE FOR ANY SPECIAL INDIRECT INCIDENTAL OR C
151. om A5U6 10 during attempts to communicate with the meter Each byte received with the ATN signal A5U6 31 high should cause the interrupt signal to go low Follow the interrupt signal through A5U4 and verify that it arrives at A5J3 properly If the interrupt is not detected by 106 it will remain low indefinitely ASU6 10 will only go high when both the interrupt is detected and the received byte is removed from A5U6 by A1UG 8 21 Failure to Transmit Query Responses Check that TE A5U6 24 goes high when the interface is addressed to talk This signal must go high to allow the bus interface transceivers to change the direction of DIOI through DIOS EOI DAV NRFD and NDAC Verify that each of these signals passes through A5U7 and ASUS properly 8 22 Failure to Generate an End or Identify EOI When the IEEE 488 Interface Option sends the Line Feed termination character with a message the EOI signal should also be set true When EOI is true ASU6 30 should go low Follow this signal from A5J1 through A5U8 to A5U6 8 23 Failure to Generate a Service Request SRQ When a Service Request is being generated ASU6 32 should be low Follow this signal through A5US to connector A5J1 When a Serial Poll SPL is performed by the IEEE 488 bus controller ASU6 32 will go high again Note If the meter is in the remote state without front panel lockout i e a service request can be sent from the front panel by pressing
152. om the filament are accelerated toward the anodes that are under that grid Anodes under that grid that are also driven to 5 V dc are illuminated but the anodes that are driven to 30 V dc are not Grids are sequentially driven to 5 V dc one at a time The sequence is from GRID 0 to GRID 10 which is right to left as the display is viewed 2 45 Beeper Drive Circuit The Beeper Drive circuit is controlled by U1 A 3 6 kHz square wave appears at the PPO output of U1 and across the parallel combination of A2LS1 and 2 10 causing the beeper to resonate Table 2 5 Front Panel Switch Scanning Interface Signal States or Key Sensed Stee swas swa swa 2 17 2 10 A2Sn indicates switch closure sensed 0 indicates strobe driven to logic 0 Z indicates high impedance input state ignored 2 46 Watchdog Timer and Reset Circuit This circuit provides active high and active low reset signals to the rest of the system at power up or a system reset if the Microprocessor does not communicate with the Display Processor for a 5 second period The Watchdog Timer and Reset Circuit is comprised of 2 21 45 dual retriggerable monostable multivibrator A2U5 NAND gates from A2U6 diode A2CR3 and various resistive and capacitive timing components At power up capacitor A2C3 begins to charge up through resistor A2R3 The voltage level on A2C3 is detected by an input of
153. on any range common mode input AC DC Voltage Accuracy Total Measurement Error will not exceed the sum of the separate accuracy specifications plus 1 display count Refer to the table under Maximum Allowable AC Voltage While Measuring DC Voltage or AC DC Voltage located on page 1 6 Note When measuring AC DC or any dual display combination of AC and DC in the fast reading rate the Fluke 45 may show significant reading errors This results from a lack of filtering on the DC portion of the measurement for the fast reading rate To avoid this problem use only the slow and medium reading rates for AC DC or AC and DC combinations Maximum Frequency of AC Voltage Input While Measuring AC Current When the meter makes ac current and ac voltage measurements using the dual display the maximum frequency of the voltage input is limited to the maximum frequency of the current function For example if you are making an ac current measurement on the 10 A range the maximum frequency of the voltage input must be less than 2 kHz DC Current Range Resolution Burden Accuracy Voltage 0 05 3 0 05 2 0 2 5 05 15 0 05 5 0 2 7 Typical at full range 45 Maximum Input mA 300 mA dc rms Protected with 500 mA 250 V IEC 127 sheet I fast blow fuse and a 440 mA 1000 V fast blow fuse A 10 A dc rms continuous or 20 A dc or rms for
154. on by pressing the 25 button eight times Complete step 32 of Table 4 5 4 16 Editing the Prompt for Different Calibration Points Except for the first three prompts in VDC 0 000 mV 490 000 and 90 000 mV are calibration constants the Fluke 45 can be calibrated using calibration points other than the prompted values To do this you must edit the prompt to the reference source value as follows 1 Press the editor button This intensifies the left most digit of the numeric display and turns the EDIT annunciator on 2 Press the 25 editor button to increment the intensified digit from 0 9 Press the amp editor button again to intensify the next digit to be edited 4 Once the edited value is equal to the reference source value push the button to exit the edit mode Holding down the editor buttons causes continual incrementing until the button is released 4 13 45 Service Manual For calibration at points other than full scale you must account for the effect of non linearity and noise on the accuracy specifications This effect is expressed as a percentage added to the Fluke 45 specification Table 4 6 shows additional errors to be added to the specifications when calibration is conducted at points other than full range For example if ohms is calibrated using decades of 1 9 190 Q 1 9 kQ etc the additional error on the 300 Q and 100 ranges is 0 01 Therefore since calibration has been performed at less th
155. on the battery pack option circuit assembly Adjust rear potentiometer R20 top of the battery pack option circuit assembly until the voltmeter across the test points reads 9 35 volts With the meter connected to line power and turned off the charging voltage reads approximately 9 35 volts 7 Disconnect the line cord from the meter 8 Remove the 1800 Q resistor and plug the battery pack connector wires back into the battery pack the red wire to and the black wire to 9 To ensure the battery pack connector wires are properly connected and the battery kit is properly installed turn the meter ON without plugging in the power cord Option 01 Battery Pack Troubleshooting View from bottom of instrument Black Battery Connectors qb37f eps Figure 7 6 Unplugging the Battery Pack Connectors 7 19 Troubleshooting Troubleshooting can be facilitated by removing the Battery Pack Option and connecting the Battery PCA with an extender cable Fluke Part Number 854245 Refer to the removal instructions provided earlier in this chapter With the meter off but plugged into line power check for approximately 16 V dc at 120V ac line raw dc supply between the ground test point and the cathode of either 1 2 or A1CR3 If necessary check for transformer secondary voltage of approximately 24 V ac Use an oscilloscope to trace the waveforms associated with the switching power supply e Wi
156. onnect to the last two pins on each end of A2DS1 These signals should be 5 0 V ac centered on a 25 V dc level and FIL2 should be 180 degrees out of phase If the dc bias of the filament signals is not at about 25 V dc the display segments that should be off will show a shadowing or speckling effect Note It may be necessary to disable the watchdog reset by jumpering 2 105 3 105 11 to GND A2TP3 to verify the following items 3 Check the clock signal at AZTP2 This signal should be 4 19 MHz 238 us per cycle If the signal is not 4 19 MHz the ceramic resonator U2 is probably defective 4 Check the state of the RESET signal A2UI 1 This signal should be low once the reset time is completed after power up 5 Verify that the DISRX signal A2U1 39 goes low after RESET A2UI 1 goes low If this sequence does not occur communication to the Main Processor is held off with the DISRX signal high If DISRX stays high but is not shorted to VCC A2U1 must be faulty 6 Verify activity for both the DISTX and DSCLK signals These signals are driven by the Main Processor and must be transitioning for the Display Controller to receive commands from the Main Processor 7 Ifall segments of a particular digit do not turn on at power up the grid drive from 201 may not be connected properly to A2DS1 Grids are numbered from 0 to 10 left to right as the display is viewed For a digit to be enabled the respectiv
157. or lights up and fails to report errors or begin operation use the following troubleshooting procedures First check the state of SWR1 A1U6 21 If this status line is less than 0 8 V basic processor operation is intact Examining SWR2 through SWR5 A1U6 22 through 25 respectively should indicate how far the software progressed before finding an error If the state of SWRI is not less than 0 8 V the problem may be the 6303Y Processor 106 the ROM RAM decode circuitry A1U9 the ROM 108 RAM A1U10 or the address data lines among these parts Note The functions of SWR1 through SWR5 as power up status lines only persist for 2 to 3 seconds These functions end when the keyboard scanner begins operation if it can Extremely difficult cases may require the use of an oscilloscope triggered on the falling edge of SWRI to examine the states of SWR2 through SWRS To determine the relative health of the 6303 Y Main Processor 106 first check for valid E clock at pin 68 The default for the E clock after reset is a rectangular wave with a period of 1 628 us and a duty cycle of about 67 If the processor is able to fetch instructions from the ROM the software initializes the processor and the E clock becomes a square wave with a period of 1 085 us Since this initialization occurs almost immediately with a working meter the resulting square wave on the E clock line is a good indication that the software has
158. ore suspecting a fault with the Fluke 45 verify that the calibration is being conducted properly e Check the connections between the source and the meter Are all the connections in place e Check the output of the calibration source Does it equal the value called for by this calibration step e Check the calibration source Is it in operate mode Has it reverted to standby If the calibration setup is correct a faulty component within the Fluke 45 may be causing the failure Each measurement function depends on a combination of components in and around the Analog Measurement Processor A1U1 Basic dc measurements depend on the zener reference reference divider network 173 and integrate resistors A1Z3 Resistance measurements and dc measurements above three volts additionally depend on the resistors in the divider network A1Z1 AC measurements depend on the ac divider network A1Z2 ac buffer ATARI and rms converter 1 as well as the basic dc measurement components Note The Fluke 45 utilizes three measurement rates slow medium and fast Two sets of measurement ranges are used one for the medium and fast rates and one for the slow rate Whenever the meter is powered up or put in calibration mode the medium rate is selected During calibration the slow rate is selected automatically as required by the calibration step 5 18 Calibration Related Components 5 20 Measurement function cal
159. ostic routines and descriptive error codes However these features are somewhat limited and do not provide in depth troubleshooting tools The Fluke 45 incorporates a semi modular design determining modules not related to a problem constitutes the first step in the troubleshooting process Disconnect the Battery Option cable at the Main PCA Disconnect the IEEE 488 Interface Option at P2 and P3 on the IEEE 488 Interface PCA If either of these assemblies is causing the meter failure refer to troubleshooting information in Chapters 7 and 8 7 for the Battery Pack Option 8 for the IEEE 488 Interface Option Measuring the power supplies helps to isolate a problem further Refer to Table 5 2 and Figure 5 1 for test point identification and readings If power supply loading is suspected disconnect the Display PCA at J4 on the Main PCA If this action solves the loading problem proceed to Display Assembly Troubleshooting elsewhere in this chapter Otherwise refer to Power Supply Troubleshooting If the power supplies appear good check the E clock signal to determine whether the Main PCA or the Display PCA is causing the problem A correct display depends on the E clock signal Missing segments intensified digits a strobing display or a blank display can be caused by a faulty E clock Use an oscilloscope to check for E clock at microcomputer 106 pin 68 Look for a 921 6 kHz square wave that transitions from 0 to 5 V dc VCC e If th
160. oximately 003 Q Ohms Typical Current Resolution Accuracy Full Scale Through the Voltage Unknown Medium 10 100 0 05 2 0 020 0 25 1 3 kQ 100 mQ 10 0 05 2 0 24 120 pA 30 10 100 0 05 2 0 29 14 300 100 100 Q 0 05 2 0 29 1 5 3 MQ 1000 1 0 06 2 0 3 150 pA 30 MQ 1 2 0 25 3 2 25 320 pA 300 5 100 1 2 2 0 320 1000 1 0 05 8 0 020 0 09 1 1000 Q 10 0 05 8 0 020 0 10 12 10 100 mo 0 05 8 0 11 14 100 10 0 05 8 0 11 1 5 1000 10 gt 0 06 8 0 12 150 pA 10 MQ 1000 0 25 6 1 5 150 pA 100 100 2 2 2 75 320 pA Because of the method used to measure resistance the 100 MQ slow and 300 MQ medium and fast ranges cannot measure below 3 2 MQ and 20 MQ respectively UL underload is shown on the display for resistances below these nominal points and the computer interface outputs 1E 9 1 45 Open Circuit Voltage 3 2 volts maximum on the 100 Q 300 Q 30 MQ 100 MQ and 300 MQ ranges 1 5 volts maximum on all other ranges Maximum Rated Input Input Protection 1000 dc or rms ac on all ranges Diode Test Continuity Maximum Reading Resolution Slow 999 99 mV Medium 2 5 V Fast 2 5V Test Current Approximately 0 7 mA when measuring a forward biased junction Audible Tone
161. pecifications Temperature Coefficient 0 1 times the applicable accuracy specification per degree for 0 C to 18 C and 28 C to 50 C Electromagnetic Compatibility In an RF field of 1 V m on all ranges and functions Total Accuracy Specified Accuracy 4 of range Performance above 1 V m is not specified Operating Temperature 0 C to 50 C Storage Temperature 40 C to 70 C Elevated temperature storage of battery will accelerate battery self discharge Maximum storage time before battery must be recharged 20 25 1000 days 50 180 days 70 C 40 days Relative Humidity To 90 at 0 C to 28 C non condensing To 80 at 28 C to 35 C To 70 at 35 C to 50 C except to 70 at 0 C to 50 C for the 1000 3 MQ 10 MQ 30 100 MQ and 300 MQ ranges Altitude Operating 0 to 10 000 feet Non operating 0 to 40 000 feet Vibration 3G 55 Hz Shock Half sine 40G Per Mil T 28800D Class 3 Style Bench Handling Per Mil T 28800D Class 3 General Common Mode Voltage 1000 V dc or rms ac maximum from any input to earth Introduction and Specifications Specifications Size 9 3 cm high 21 6 cm wide 28 6 cm deep Weight Net 2 4 kg without battery 3 2 kg with battery Shipping 4 0 kg without battery 4 8 with battery Power 90 to 264 V ac no switching required 50 and 60 Hz 15 VA maximum Safety Compliant with the following standards ANSI ISA 582 01 1994 CAN CS A C22
162. put values of 190 Q 1 9 19 190 and 1 9 MQ 1 If the meter is already in calibration mode press the CJ amp button to select calibration Otherwise select calibration mode first press Cal Enable button for three seconds then select calibration by pressing the button six times 2 Connect the ohms source to the meter in a four wire configuration Refer to Figure 4 1 3 On the 5700A select 2 wire compensation ON with external sense Then program the 5700A for the output in step 25 of Table 4 5 4 Edit the meter prompt display to read the same value as the 5700A output display On the meter press the button to calibrate this step Then continue with steps 26 through 29 in Table 4 5 CAUTION USE CONNECTIONS WITH EXPOSED PLUG TIPS FOR THE OHMS FUNCTION ONLY 27 EXT TRG mA L DCAC UNCA LI Lf Ll MkQHz 10 THRESH ADDR POWER qb18f eps Figure 4 1 Four Wire Configuration Performance Testing and Calibration 4 Front Panel Calibration 4 13 Alternate Ohms Calibration Front Panel The following procedure can be used with discrete resistor values such as a decade box On the 300 Q range this alternate procedure uses 290 Q source and yields specification of 0 05 2 digits 0 02 Q Alternate calibration of this range is detai
163. r Note once entered the serial number cannot be changed 5 21 45 Table 5 6 Calibration Steps and Related Components Related Components 100 mV 0 0000 V A1VR1 123 100 mV 0 0900 V A1VR1 123 100 mV 0 0900 V A1VR1 123 1000 mV 0 9000 V 1 100 mV 0 0900 V A1VR1 123 300 0 2900 V A1VR1 123 2 9000 V A1VR1 123 30V 29 000 V A1VR1 A1Z1 123 300 V 290 00 V A1VR1 A1Z1 123 1000 V 1000 0 V A1VR1 A1Z1 123 1 2 3 4 5 6 7 8 9 0 0290 V A1A1 A1VR1 122 123 124 0 2900 1 A1VR1 122 123 124 0 2900 A1A1 A1VR1 122 123 124 2 9000 1 A1VR1 122 123 124 29 000 V 1 A1VR1 122 123 124 290 00 V 1 121 122 123 124 750 00 V 1 121 122 1 73 124 mA 18 30 29 000 mA A1R2 A1VR1 143 A1F1 19 100 mA 100 00 mA A1R2 A1VR1 143 A1F1 AC mA 20 30 mA 29 000 mA A1A1 A1R2 A1VR1 A1Z2 A1Z3 124 A1F1 21 100 mA 100 00 mA A1A1 A1R2 A1VR1 122 A1Z3 124 A1F1 DCA 10 000 A A1R3 A1VR1 A1Z3 A1F2 ACA 23 10A 2 0000 A 1 A1R3 124 A1F2 24 10A 10 000 A A1A1 A1R3 A1VR1 1743 A1Z4 A1F2 190 00 Q A1Z1 A1Z3 1 9000 121 123 19 000 121 A1Z3 190 00 121 123 1 9000 121 A1Z3 Continuity Hysteresis Threshold 30 0 000 mV AiU1 31 20 00 mV A1U1 Frequency 2000 Vpp ion Ai 5 22
164. r each functional area are presented But first if the meter fails check the fuses and replace as needed If the problem persists verify that you are operating the meter correctly by reviewing the operating instructions found in the User s Manual A Warning Opening the case may expose hazardous voltages Always disconnect the power cord and measuring inputs before opening the case And remember that repairs or servicing should be performed only by qualified personnel Required equipment is listed in Chapter 4 of this manual Signal names followed by a are active asserted low Signal names not so marked are active high 5 2 Servicing Surface Mount Assemblies The 45 Dual Display Multimeter incorporates Surface Mount Technology SMT for printed circuit assemblies pca s Surface mount components are much smaller than their predecessors with leads soldered directly to the surface of a circuit board no plated through holes are used Unique servicing troubleshooting and repair techniques are required to support this technology The information offered in the following paragraphs serves only as an introduction to SMT It is not recommended that repair be attempted based only on the information presented here Since sockets are seldom used with SMT shotgun troubleshooting cannot be used a fault should be isolated to the component level before a part is replaced Surface mount assemblies are probed from the component side T
165. r serial number identifies the main software version identifies the display software version and gt is the RS 232 prompt Performance Testing and Calibration 4 Calibration Using the Computer Interface If echo mode is ON the response to the CALSTEP command called for in Table 4 7 step 12 appears in the form CALSTEP lt CR gt lt LF gt 290 00E 3 lt CR gt lt LF gt gt lt CR gt lt LF gt where gt is the prompt returned by the Fluke 45 The response to CALREF also follows this format 4 20 IEEE 488 Interface For IEEE 488 interface operation use the following front panel procedure 1 Press 2ND then press RATE 2 Use to scroll to IEEE Then press to enable the IEEE 488 interface 3 Send the following to the meter over the IEEE 488 bus Note The following example uses Fluke BASIC commands entered from a Fluke 1722A Instrument Controller Syntax may vary for other controllers INIT PORT 0 lt CR gt CLEAR PORT lt gt PRINT lt address of meter IDN CR INPUT LINE lt address of meter gt AS lt CR gt PRINT 5 lt gt 4 Check for the following response format FLUKE 45 nnnnnnn n n Dn n where nnnnnnn is the multimeter serial number identifies the main software version and identifies the display software version 4 15 45 Service Manual 4 16 Table 4 7 Calibration Using the Computer Interface Note Before proce
166. re to the CRC If an error is determined the meter configuration is set to factory default and Error 6 is displayed Error 7 1 05 calibration data corrupted The EEROM is divided into two storage areas the default meter configuration storage and calibration data storage Each area uses a Cyclic Redundancy Checksum against which the data is checked on power up In addition the calibration data includes parity information for each calibration constant which is also checked If the meter configuration check finds an error the meter configuration is set to factory defaults and Error 6 is reported If the parity check or the calibration data checksum finds an error the front panel UNCAL annunciator is turned on and Error 7 is reported Note Errors 6 and 7 should always appear the first time a meter is powered up with a new ized Error 7 continues to appear at subsequent power ups until the meter is fully calibrated Analog Measurement Processor A1U1 dead Error 9 Measurement self check failed The Analog Measurement Processor is programmed to do self test measurements If the Analog Measurement Processor does not respond it is considered dead 5 5 45 ASWY NLYV ZOSWY esvid SINHSSA LOSWY ISINH NIV OVSSA s ON O 2 6 S 9 2 8 6
167. ress data lines among the 6303Y Main Processor ROM RAM and IEEE option connector If SWRI A1U6 21 SWR2 A1U6 22 transition low but SWR3 A1U6 23 remains high the problem is with the RAM decode circuitry A1U9 the external RAM A1U10 or the address data control lines between the RAM and the 6303Y Main Processor To check the RAM decode circuitry verify that A1U9 8 is transitioning low and that these transitions correspond approximately to the low going transitions of WR A1U6 66 It may be necessary to continually reset power on the meter to check these lines since the activity probably halts quickly when the meter software goes awry Verify that the signal on A1U9 8 also appears at the RAM Chip Enable A1U10 20 If the RAM Diagnostic Testing and Troubleshooting Display Assembly Troubleshooting Chip Enable is present the problem is with either the RAM itself or the address data RD lines between the 6303 Y Main Processor and the external RAM Figure 5 3 shows the timing relationships of the 6303Y Main Processor lines LIR and WR to the system clock E and the address lines 0 15 The ROM and RAM Chip Enables correspond to the active low region shown for the address lines 5 15 Display Assembly Troubleshooting The following discussion is helpful if it has been determined that the Display Assembly is faulty This initial determination may not be arrived at easily since an improperly operatin
168. s to settle to zero within one microvolt once the voltage is removed For this reason no voltage should be applied to the input for 4 minutes before doing zero mV cal Push the button to calibrate the meter zero mV calibration point Remove the short and connect the dc volts source to the gt _ and COM inputs of the meter Complete calibration steps 2 through 10 in Table 4 5 4 9 AC Volts Calibration Front Panel To perform ac volts calibration proceed as follows 1 If the meter is already in calibration mode press the 259 amp button to select VAC calibration Otherwise select calibration mode first press Cal Enable button for three seconds then select VAC calibration by pressing the button once Connect the ac source to the and COM inputs of the meter For each of steps 11 through 17 Table 4 5 apply the source output indicated and calibrate the meter by pressing the button 4 10 DC and AC Milliamp Calibration Front Panel Perform the and ac milliamps calibration as follows 1 If the meter is already in calibration mode press the GS or button to select mA DC calibration Otherwise select calibration mode first press Cal Enable button for three seconds then select mA DC calibration by pressing the button twice Connect the de milliamps source to the 100 mA and COM inputs Apply the milliamp outputs indicated in Table 4 5 steps 18 and 19 and calibrate the meter with the butto
169. signal high the microprocessor waits indefinitely New data is written to a register only after old data in that register is erased After each such erase or write cycle the microprocessor polls the status of EEROM by setting Chip Select A1U5 2 high and checking the state of the Data Out signal A1U5 6 If Data Out is low the erase write cycle is still in progress If Data Out is high the EEROM is ready for another command 2 38 RAM The RAM is a 8192 x 8 bit device that provides the temporary data storage used by the operating software of the meter The chip select for this device A1U10 20 goes low for any memory cycle between hexadecimal addresses 2000 and 3FFF The RD signal from the Microprocessor enables the reading of data when it is low and the WR signal writes data into the RAM when it is low 2 39 ROM The ROM provides the instruction storage for the Microprocessor The chip select for this device A1U8 20 goes low for any memory cycle between hexadecimal addresses 4000 and FFFF accessing 48 kbytes Whenever this device is chip selected the instruction in the addressed location is output to the data bus and read by the Microprocessor 2 40 IEEE 488 Option Connections The interconnection to the IEEE 488 option is implemented by two ribbon cables that mount to the 14 position and 20 position connectors on the Main PCA The 14 position connector A1J3 routes the 8 bit data bus RD E RESET and OPTS W si
170. sis General Maintenance 3 Assembly Procedures 2 Replace the RS 232 connector O on the rear of the chassis Use a 3 16 inch nut driver to tighten the connector hardware Also attach the ground wire at its chassis connection 3 Replace the power transformer along the right side of the chassis Use four 6 32 x 25 FHU screws N inserted from the exterior of the meter Snap the power plug into position Use needle nose pliers to replace the interior connections at the power plug 3 27 Install the Battery Option Installation is fully described in both the instruction sheet supplied with the Battery Option and in Chapter 7 of this manual The following procedure presents installation essentials Figures 7 2 and 7 3 can be used in identifying features and techniques mentioned here 1 Carefully slide the battery kit into the area reserved for it in the back of the meter Make sure that both the retaining slots line up and the mounting holes mate Do not pinch wires running from the circuit assembly to the battery terminals 2 Secure the battery kit with two 6 32 x 1 4 panhead Phillips screws Attach the flat white connecting cable at the Battery Option PCA The single blue marking line of the cable should be to the rear of the meter Align the plastic socket on the cable end then seat it securely in place 3 28 Install the Rms PCA With the Analog Measurement Processor shields removed solder the Rms PCA into place on
171. sistance to the certified value of the source resistor Lead and source zero resistance is the value obtained with the VAL command immediately prior to entering dc volts calibration Use this total value as xxx xx in the following command CALREF xxx xx 2 Now send CALSTEP 4 19 45 Service Manual 4 20 CALCLR CALCONST xx CALREF CALREF xxx xx CALSTEP EEREG xx Table 4 8 Calibration Mode Computer Interface Commands Start calibration of a new function where x 1 through 9 defined as follows VDC calibration VAC calibration DC Milliamps calibration AC Milliamps calibration DC Amps calibration AC Amps calibration Ohms calibration Frequency comparator Frequency calibration Reset all calibration constants to nominal values destroying present calibration Return the value of the calibration constant indicated by xx See Table 4 9 Return the present calibration reference Calibrate to the exact value xxx xx rather than the nominal expected cal value Return the calibrated value of the input Return the contents of the specified EEROM register xx The following additional computer interface commands be used Calibration Mode Use of any other command results in an execution error BUTTON FORMAT LOCS LWLS REMS RWLS SERIAL FORMAT VAL VAL1 Performance Testing and Calibration 4 Calibration Using the Computer Interface Table 4
172. slide the pca up and out away from the bottom tabs Note The Display PCA provides a space for a center securing screw If the peripheral tabs are intact this screw is not necessary If some of the tabs are broken the screw can be used as an additional securing device The elastomeric Keypad Assembly C on Figure 3 5 can now be lifted away from the Front Panel Assembly Remove the display window D on Figure 3 5 by releasing the two snaps along its inside bottom edge Use a gentle levering action between each snap and an adjacent edge on the Display Assembly 3 8 General Maintenance 3 Disassembly Procedures Caution Avoid using ammonia or methyl alcohol cleaning agents on either the Front Panel of the display window These types of cleaners can damage surface features and markings Use an isopropyl based cleaning agent or water to clean the Front Panel and the display window 3 19 Remove the IEEE 488 Option Chapter 8 of this manual provides a detailed removal procedure for the IEEE 488 option The following removal instructions provide the essentials of this procedure If necessary refer to the complete procedure in Chapter 8 paying particular attention to Figures 8 2 and 8 3 1 Use needle nose pliers to disconnect the 24 line cable assembly at the IEEE 488 PCA Alternately pull on each end of the cable connector 2 Remove the panhead Phillips screw at the rear of the IEEE 488 PCA Use needle nose pliers to deta
173. suming that 506 33 is always high Table 8 1 describes the transceiver direction control The IEEE 488 Transceivers connect to a 24 position connector which mates with the ribbon cable leading to the IEEE 488 connector mounted at the rear of the meter chassis 8 5 45 Table 8 1 IEEE 488 Transceiver Control 0101 0108 Receiver Transmitter SRQ Transmitter Transmitter ATN Receiver Receiver EOI Receiver Receiver 0 Receiver Transmitter ATN 1 DAV Receiver Transmitter Transmitter Receiver Transmitter Receiver IFC Receiver Receiver REN Receiver Receiver Mounting Screw 2 Rear Bezel Grounding Screw 2 Chassis qb14f eps Figure 8 1 Disassembly 8 6 Option 05 488 Interface Theory of Operation 24 LINE CABLE ASSEMBLY RETAINING SCREWS qb41c epc Figure 8 2 IEEE 488 Interface Connector 8 8 7 45 8 8 6 32 x PANHEAD SCREW RIBBON CABLES REMOVE PLASTIC PLUG FROM CASE PLASTIC STANDOFF qb42c eps Figure 8 3 IEEE 488 Module Assembly 8 10 General Maintenance 8 11 Removing the IEEE 488 Interface Option The following instructions can be used for access and servicing IEEE 488 Interface Option that is already installed in a Fluke 45 Dual Display Multimeter For initial installation refer to the Instruction Sheet PN 856005 provided with the option 1
174. t bit data from A1U6 to A5U6 8 8 488 Controller 8 4 The IEEE 488 Controller A5U6 is an integrated circuit that performs the transfer of information between the IEEE 488 standard bus and the Microprocessor Once it has been programmed by the Microprocessor via the eight register microprocessor interface 506 performs IEEE 488 bus transactions independently until it must interrupt the Microprocessor for additional information or data The IEEE 488 Controller is clocked by a 921 6 kHz square wave clock This clock A5U4 5 is generated by buffering the E clock A5U4 15 from the Microprocessor The IEEE 488 Controller uses this clock to run the internal state machines that handle IEEE 488 bus transactions The IEEE 488 Controller can be given a hardware reset with either of the following two methods e If the system reset signal RESET A5J3 14 goes high or if OPTSW A5J3 12 goes high then NOR gate output A5U2 10 goes low and the D flip flop Q output ASU9 9 goes low This flip flop output drives the reset input A5U6 22 forcing the IEEE 488 Controller into its reset state e When the meter is initially powered up both RESET and OPTSW are high forcing the IEEE 488 Controller reset input A5U6 22 to be low As long as OPTSW is high VCC2 is near ground and A5U6 is not biased so ASU6 22 is held low to avoid sourcing current into ASU6 22 while A5U6 is unbiased Option 05 488 Interface 8 Theory of Operation
175. tary switch with the switch transistor Dual inductor A1T1 is a magnetic device that regulates current pulses as the switch transistor is turned on and off A current shunt A1R47 1 48 and 1 49 senses the overall current flowing through diode 1 5 and the switch transistor of A1U11 If this current rises too high the duty cycle ON time of the switch transistor is reduced to current limit the supply Capacitor A1C33 serves as a filter capacitor and energy storage device and A1C34 and A1C35 the output filter capacitors The boost circuit A1CR4 and A1C32 supplies the controller AIU11 with sufficient supply voltage when the switching supply input is low For example this condition may occur when the meter is operating on low line voltage Resistor A1R40 and capacitors A1C28 and A1C29 are needed for proper dynamic performance of the switching supply Capacitor A1C30 sets the operating frequency of the supply Theory of Operation 2 Detailed Circuit Description 2 17 Inverter The inverter uses transistors 1010 1011 1012 and A1Q13 connected to form an astable 30 kHz multivibrator The operating frequency and drive to the transistors are determined by the values of the interconnecting resistors and capacitors The inverter transformer A1T2 primary is connected across the collectors of the multivibrator transistors the primary winding is thereby driven by a symmetrical square wave Resistor A1R46 and capacitor 1 4
176. th equipment meeting the minimum specifications given in Table 4 1 The following paragraphs first present a basic calibration procedure for use with front panel control This is followed by a description of editing prompts for different calibration points then by a description of calibration using the IEEE 488 or RS 232 computer interface 4 5 Introduction The basic calibration consists of sets of steps for DC Volts AC Volts DC and AC Milliamps DC and AC Amps Ohms Continuity Hysteresis Threshold and Frequency Normally it is recommended that the entire calibration procedure be performed However it is possible to calibrate any function individually This might be useful during troubleshooting when looking for a problem in a specific function Whenever the VDC function is calibrated the entire calibration procedure for all functions should be performed Any function except VDC can be calibrated independently without affecting calibration of another function If calibration of any function is discontinued prior to completion no changes are made to nonvolatile calibration memory for that function Some calibration steps take longer to execute than others When the Fluke 45 is executing a calibration step it ignores all of the front panel buttons and postpones execution of all computer interface commands 4 7 45 4 6 Entering Calibration Mode 4 8 Always begin the calibration procedure as follows
177. th the line voltage at 120 V ac check the waveform at the drain of FET Q5 This signal should be a 25 V p p square wave with the negative part at zero volts a period of 20 to 25 us and an ON duty ratio of 20 to 50 This square wave may exhibit a damped sine wave two to ten cycles ringing on the trailing half of the positive portion The sine wave amplitude should be from 10 to 20 V p p Check fora 15 V square wave at the gate of Q5 e Check for a 14 V square wave at U4 5 e Check for a 0 5 V sawtooth waveform with a period of 20 to 25 us at U4 3 Make sure that the oscilloscope is ac coupled for this measurement Troubleshoot other sections of the Battery Pack Option assembly by making dc voltage measurements For circuit common use the GND test point on the main circuit board or the common end of R30 on the Battery Pack PCA Note that the battery pack negative terminal is not connected to common when the low battery disconnect circuit turns off Q2 7 13 45 POSITIVE LEAD NEGATIVE LEAD qb38c eps Figure 7 7 Test Points and Adjustments 7 20 Additional Tests The Low Battery Indicator Detector Low Battery Disconnect Test and the Cycle Float Charge Switch Test described earlier under Performance Testing can also be used as fault isolation aids in troubleshooting the Battery Pack Option 7 21 Schematic Diagram The schematic diagram for the Battery Pack Option is inclu
178. the Rims PCA teste niet oap ha Remove the Battery Option Disconnect Miscellaneous Chassis Components Assembly reni tenete Parodi erm ie er epa Rog EE Install Miscellaneous Chassis Components esee Install the Battery 2 420444 4 00 00 Install the Rims PON rete retenta Rer rH Install the Analog Measurement Processor Shields Install the Lr ree Ee reddo Install the TEEE 488 Option eese Assemble the Front Panel Install the Front Panel Assembly eene Install the Handle and Mounting Brackets 2 2 Install the Meter Case tie eerte eder 45 3 2 General Maintenance 3 Introduction 3 1 Introduction This provides handling cleaning fuse replacement disassembly and assembly instructions 3 2 Warranty Repairs and Shipping Information If your meter is still under warranty see the warranty information at the front of this manual for instructions on returning the unit A list of Fluke telephone numbers and our website address can be found at the end of the warranty information and in Chapter 6 3 3 General Maintenance Information 3 4 Required Eq
179. the IEEE 488 interface optional The meter is fully programmable for use on the IEEE Standard 488 1 1987 The meter is also designed in compliance with supplemental standard TEEE 488 2 1987 e True rms ac e AC DC rms calculated e Frequency measurements to greater than 1 MHz e 1 uV sensitivity in volts dc e Decibels with variable reference impedance and audio power measurement capability e compare mode to determine if a measurement is within above or below a designated range e 100 000 30 000 and 3 000 selectable count resolution with reading speeds of 2 5 5 and 20 readings per second rps respectively e Built in self tests with closed case calibration no internal adjustments 1 2 Operating Instructions Full operating instructions are provided in the Fluke 45 Users Manual Reference to these instructions may be necessary during some of the maintenance and repair procedures presented in this Service Manual For quick references an operating instruction summary is presented on the inside of the front cover of the Service Manual For more detailed information refer to the Users Manual 1 3 Options and Accessories Three options are available These options can be installed either at the factory or in the field The following discussions pertain to the field installable option kits e The Battery Kit Option 01K consists of a rechargeable 8 V lead acid battery with battery bracket and charger assemb
180. the source 4 28 Frequency Calibration Computer Interface 1 Connect the Frequency Calibrator to the Fluke 45 VO and COM inputs Then send CAL 9 2 Complete step 32 in Table 4 7 Then clear the frequency source 4 29 Concluding Calibration Using the Computer Interface At the conclusion of this type of calibration first make sure the source is cleared Then press the Cal Enable button on the meter to exit calibration mode Calibration mode can also be exited at any time by sending the RST command If this command is sent prior to completion of all calibration points for the selected function no changes are made to nonvolatile calibration memory for that function If calibration mode is exited after completion of calibration of any function except VDC constants for other functions are not affected But remember whenever VDC is calibrated the calibration procedure for all other functions should be performed 4 30 Alternate Ohms Calibration Computer Interface This procedure can be used with discrete resistor values such as a decade box On the 300 Q range this alternate procedure uses 290 Q source and yields a specification of 0 05962 digits 40 02 Alternate calibration of this range is detailed below although discrete resistor values can be used for all ranges Lead and source zero resistances are only taken into account for the lowest two ranges 300 and 3 1 Add the value of lead and source zero re
181. the two battery pack connectors Connect the voltmeter across the variable power supply Set the variable power supply to approximately 9 volts Now turn the meter ON and check for correct operation of the Low Battery Indicator symbol e While watching the display slowly lower the variable voltage power supply output Check that the low battery indicator symbol comes on at 7 7 40 25 e Now slowly increase the variable voltage supply output Check that the low battery indicator symbol goes out at about 8 V dc Check the Low Battery Disconnect point e With the meter still operating on the variable supply slowly lower the voltage and check that the meter goes OFF at about 7 0 V dc After the meter goes OFF slowly increase the voltage and check that the meter does not come ON before approximately 8 0 V dc Note The meter may not come on above 68 volts until the power is cycled There are no adjustments to set the Low Battery Indicator point or the Low Battery Disconnect point 7 17 Cycle Float Charge Rate Switch Test Use the following procedure to verify operation of the meter s Cycle Float Charge Rate Switch Note that this test is required only after repairs have been performed on the Cycle Float Rate Switch Test circuits 1 2 Turn the meter OFF For this procedure use a battery simulator as a substitute for the regular battery pack Connect this simulator shown in Figure 7 5 as follows e Conne
182. times per second grid strobing sequence is from GRID 0 to GRID 10 which results in right to left strobing of grid areas on the display Figure 2 10 shows grid control signal timing The single grid strobing process involves turning off the previously enabled grid outputting the anode data for the next grid and then enabling the next grid This procedure ensures that there is some time between grid strobes so that no shadowing occurs on the display Figure 2 11 describes the timing relationship between an individual grid control signal and the anode control signals m 1817 1 6 X BIT5 4 BIT 3 2 Y BIT 1 DISRX BIT7 Y BITS 2 BIT1 Clear to receive T Clear to receive 35 us 35 us qb09 eps Figure 2 9 Command Byte Transfer Waveforms Table 2 6 Display Initialization Modes A2TP4 Dtest A2TP5 LTE Power Up Display Initialization 1 1 All Segments OFF 1 0 Segments ON default 0 1 Display Test Pattern 1 0 0 Display Test Pattern 2 2 23 45 Grid Timing 5 368 ms 0 4 427 us O 427 us Grid 10 Cp 427 us 61 us qb10f eps Figure 2 10 Grid Control Signal Timing Grid Anode Timing 5V ov Grid X0 30V 5V MAN MM il Anode 14 0
183. ting cable at the Battery Option PCA 2 Remove the two 6 32 x 1 4 panhead Phillips screws securing the Battery Option 3 Carefully slide the Battery Option out of the meter Do not pinch the wires running from the pca to the battery terminals 3 24 Disconnect Miscellaneous Chassis Components The following procedures can be used to disconnect remaining hardware from the chassis 1 Use needle nose pliers to remove the internal connections at the line power plug 2 Remove the power plug by releasing its two snaps one at a time 3 Disconnect the power transformer by removing the four screws in Figure 3 5 that secure it to the right side of the chassis 4 Remove the RS 232 connector O on the rear of the chassis Use a 3 16 inch nut driver to loosen the connector securing hardware Also disconnect the ground wire at its chassis connection 5 Remove the IEEE connector 3 25 Assembly Procedures Generally assembly procedures follow a reverse sequence of disassembly procedures As some differences do apply assembly is described separately in the following paragraphs Begin assembly at the appropriate level as defined by the heading References are made to items in Figure 3 5 for assembly details of standard meter parts 3 26 Install Miscellaneous Chassis Components Use the following procedure to replace any items that have been removed from the basic chassis 1 Install the IEEE connector on the rear of the chas
184. tions e Input signal routing e Input signal conditioning e Range switching e Active filtering of dc type measurements The active filter is disabled for fast reading rate measurements e A D conversion e Support for direct volts direct current true rms alternating volts true rms alternating current ohms frequency and continuity diode test functions Two separate signal paths are used one for dc ohms and one for ac For dc the 3 V range and below are coupled directly to the a d converter higher voltages are attenuated For ohms the dc circuitry is augmented with an internal ohms source voltage regulator controlled through an extra set of switches For ac inputs are routed through the ac buffer with attenuation being controlled by the a d converter The a d converter uses a modified dual slope minor cycle method The basic measurement unit a minor cycle consists of a fixed time integrate period for the unknown input a variable reference integrate period a variable hold period and various short transition periods A minor cycle period equals 25 ms 2 7 45 p 12195 8 5 5 0 9 19 UMOYS 5 N IL JON m sienug Keay ZHW v8 9 L 16 96 ze ie oe 62 82 n soia ERA S uones Jeba
185. tive filter input 59 Filter amplifier inverting input 60 FAO Filter amplifier output 61 RMSF RMS output filtered 62 ARTN Analog return 63 not used 64 RMSO RMS converter output 65 BIAS2 Bias input 66 VSSF 5 filtered 67 BIAS1 Bias input 68 RMSI RMS converter input 2 19 Input Protection Input protection safeguards the meter against a number of over voltage and over current conditions The various input protection schemes are as follows e In the Voltage mode of operation MOVs AIRVI AIRV2 and AIRV3 clamp input voltage transients to about 1800 volts 1 5 and A1R6 limit the current In this mode 1 7 and the 10 MQ resistor in 171 protect e In the Ohms and Diode Test modes A1Q1 clamps voltage inputs of both polarities and ATR5 and thermistor limit the overload current With large overloads heats up and increases in resistance Components A1R9 and 171 protect e The 100 mA input is protected by fuses and F5 With this input A1R4 protects e The 10 A input is protected by fuse A1F2 with 1 8 protecting 101 2 20 Input Signal Conditioning The input signal voltage current or resistance must be scaled or conditioned to a form that can be measured by the a d converter High dc voltage levels must be attenuated Resistances currents and ac voltages must be converted to a representative dc voltage DC type
186. ts e Signal Logic Polarity On schematic diagrams a signal name followed by is active or asserted low Signals not so marked are active high e Circuit Nodes Individual pins or connections on a component are specified with a dash following the component reference designator For example pin 19 of U30 would be U30 19 e User Notation For front panel operation XXX An uppercase word or symbol without parentheses indicates a button to be pressed by the user Buttons can be pressed in four ways 1 Press a single button to select a function or operation 2 Press a combination of buttons one after the other 3 Press and hold down a button then press another button 4 Press multiple buttons simultaneously For computer interface operation XXX An uppercase word without parentheses identifies a command by name lt XXX gt Angle brackets around all uppercase letters mean press the lt XXX gt key xxx When associated with a keyword a lowercase word in parentheses indicates an input required by the user 1 6 Specifications The following contains the specifications for the Fluke 45 Dual Display Multimeter These specifications assume e 1 year calibration cycle e operating temperature of 18 to 28 C e Relative humidity not exceeding 90 non condensing Accuracy is expressed as percentage of reading counts Reading Rates and Display Counts Rate Readings per Second Full Range Displa
187. ual 1 4 other circuits 7 6 p performance testin performance tests power requirements power supply 3 power supply circuit descrip 5 10 power supply troubleshooting power up problems R ram 2 20 raw dc supply 2 615 10 relays 2 11 removal 7 6 remove handle and mounting brackets 3 7 remove the analog measurement processor shields 3 9 remove the battery option 3 10 Index continued remove the display 3 8 remove the front panel 3 8 3 9 remove the ieee 488 option remove the main pca remove the meter case remove the rms pea 3 10 removing the ieee 488 option replacing the 10 a input fuse replacing the 100 ma input fuse 3 51 required equipment 3 3 4 3 retrieving calibration constants 5 21 rom 2 20 rs 232 interface 2 19 4 14 schematic diagram 7 14 8 12 serial communication guard crossing 2 3 2 18 servicing surface mount assemblies 5 3 setup 4 14 specifications 1 6 static safe handling 3 3 switching power supply 7 5 T testing current input fuses the calibration procedure theory of operation 8 3 troubleshooting uart test 5 13 warranty repairs and shipping information watchdog timer and reset circuit 2 21 45 Service Manual
188. uipment Equipment required for calibration troubleshooting and repair of the Fluke 45 is listed in Table 4 4 3 5 Power Requirements A Warning To avoid shock hazard connect the meter power cord to a power receptacle with earth ground If you have not already done so plug the line cord into the connector on the rear of the meter The meter operates on any line voltage between 90 V ac and 264 V ac without adjustment and at any frequency between 45 and 440 Hz However the meter is only warranted to meet published specifications at 50 60 Hz The meter draws a maximum of 15 VA 3 6 Static Safe Handling All integrated circuits including surface mounted ICs are susceptible to damage from electrostatic discharge ESD Modern integrated circuit assemblies are more susceptible to damage from ESD than ever before Integrated circuits today can be built with circuit lines less than one micron thick allowing more than a million transistors on a 1 4 inch square chip These submicron structures are sensitive to static voltages under 100 volts This much voltage can be generated on a dry day by simply moving your arm A person can develop a charge of 2 000 volts by walking across a tile floor and polyester clothing can easily generate 5 000 to 15 000 volts during movement against the wearer These low voltage static problems are often undetected because a static charge must be in the 30 000 to 40 000 volt range before a person will fee
189. us that are buffered by 504 ADD 2 through ADD 0 select the register being accessed in ASU6 When a memory read cycle is performed chip enable A5U6 3 goes low and A5U6 5 DBIN goes high These actions enable 506 driving the contents of the selected register onto the data bus and through the data bus transceiver to the Microprocessor When a memory write cycle is performed chip enable A5U6 3 goes low and A5U6 4 WE goes first low and then high to latch the data being driven from the Microprocessor through A5U3 into the IEEE 488 Controller The IEEE 488 Controller interfaces to the IEEE 488 Transceivers using an eight bit data bus eight interface signals and two transceiver control signals A5U6 33 and A5U6 24 The controller in charge signal A5U6 33 which should always be high controls the direction of the SRQ ATN IFC and REN IEEE 488 transceivers in ASUS The talk enable output A5U6 24 is either low when the IEEE 488 Controller is not addressed to talk or high when the controller is addressed to talk This signal determines the direction of all IEEE 488 Transceivers except SRQ ATN IFC and REN 8 9 IEEE 488 Transceivers Connector The IEEE 488 Transceivers 5077 and A5U8 octal transceivers that are specifically designed to exhibit the proper electrical drive characteristics to meet the IEEE 488 standard These transceivers are configured to match the control signals available on the IEEE 488 Controller As
190. using sharp objects that might damage this button Refer to Table 4 8 for brief descriptions of calibration mode commands The CALREF xxx xx command tells the Fluke 45 to change the calibration prompt to the exact value of the input from the calibrator Use of this command is equivalent to the act of editing the calibration prompt from the front panel when other than exact calibration points are to be used The CALSTEP command normally returns the calibrated value of the input If the input is not within an anticipated range of the expected value 5 to 15 depending on the step a beep is sounded at the front panel a device dependent error is returned over the computer interface and the measured reading is returned The response to CALSTEP must be received before each new step can begin With some steps such as step 31 a noticeable delay may be encountered Before beginning calibration consider the functions that will be affected AC volts dc amps ac amps and ohms are all influenced by dc volts calibration If you calibrate dc volts you must re calibrate these other functions But calibration of ac volts dc amps ac amps and or ohms influences only the function being calibrated If you plan to include the ohms function in your calibration procedure determine the residual lead and source zero resistance before you place the meter in calibration mode Use the following procedure 1 Send OHMS RANGE 1 2 Measure the residual
191. y Counts Slow 2 5 99 999 Medium 5 30 000 Fast 20 3 000 Ohms full range will typically be 98 000 counts 1 6 Introduction and Specifications 1 Specifications Response Times Refer to Chapter 4 of the Users Manual for detailed information DC Voltage 0 02 2 0 025 2 0 02 2 0 025 2 0 02 2 0 025 2 0 02 2 0 025 2 0 02 2 0 025 2 100 mV 5 0 02 6 0 025 6 1000 10 uV 0 02 6 0 025 6 10V 100 uV 2 0 02 6 0 025 6 100 V 1 0 02 6 0 025 6 1000 V 10 mV 0 02 6 0 025 6 Input Impedance 10 MQ in parallel with lt 100 pF Note In the dual display mode when the volts ac and volts dc functions are selected the 10 MQ dc input divider is in parallel with the 1 MQ ac divider Normal Mode Rejection Ratio gt 80 dB at 50 or 60 Hz slow and medium rates gt 54 dB for frequencies between 50 440 Hz slow and medium rates gt 60 dB at 50 Hz fast rate Note Fast rate has no filtering Maximum Allowable AC Voltage While Measuring DC Voltage Peak Normal Mode Signal Range Max Allowable Peak AC Voltage NMRR gt 80dB NMRR gt 60 dB 300 mV 100 mV 20V 15V 15V 3V 1000 mV 20 V 15V 15V 30 V 10V 1000 V 50 V 300 V 300 V 100 V 1000 V 50 V 300 V 1000 V 1000 V 1000 V 200 V 1000 V NMRR is the Normal Mode Rejection Ratio Normal Mode Rejection Ratio at 50 or 60 Hz 0 1 Common Mode Rejection Ratio gt 90 dB at dc 50 60 Hz 1 KQ unbalance
192. y Voltage Accuracy 10 kHz 1 0 125 Boost Current Accuracy Fluke 5725A Amplifier r 10A 05 AC Amps 1 kHz 2 10 Decade General Resistance Accuracy Resistance Inc Source Model RDS 66A 0 0125 0 0125 0 0125 0 0125 0 0125 Note The 5700A Calibrator can be used for 0 05 accuracy rated on the 3 0 30 300 and 3 0 MQ ranges This calibrator can be used for 0 06 accuracy on the 100 Q and 300 Q ranges 4 3 45 Service Manual 4 3 Performance Tests 4 4 The following performance tests are provided to ensure that the meter is in proper operating condition If the meter fails any of the performance tests calibration adjustment and or repair is needed To perform these tests you will need a Fluke 5700A Multifunction Calibrator and a 5725A Amplifier or equipment meeting the minimum specifications given in Table 4 1 Each of the measurements listed in the following steps assumes the meter is being tested after a one hour warmup in an environment with an ambient temperature of 18 to 28 and a relative humidity of less than 90 70 for ranges The limits in Table 4 2 represent the 1 year calibration cycle Note All measurements listed in the performance test tables are made in the medium reading rate unless otherwise noted 1 Power up the meter and allow it to stabilize for one hour 2 Connect a cable from the Output VA HI and LO connectors of the 5700A to the and

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