FLUKE 88 电路图.pdf

88 Automotive Meter Service Manual For IEC 61010 CAT II Meters Only PN 666856 November 1998 Rev.1, 11/99 1998, 1999 Fluke Corporation. All rights reserved. Printed in U.S.A. All product names are trademarks of their respective companies. RadioFans.CN 收音机爱 好者资料库 LIMITED WARRANTY a Caution identifies conditions and actions that might damage the meter. International electrical symbols used on the meter are shown below. W Warning To avoid possible electric shock or personal injury: Do not use the meter if it is damaged. Before use, inspect the case for cracks or missing plastic. Pay particular attention to the insulation surrounding the connectors. Always turn off power to the circuit before cutting, unsoldering, or breaking the circuit. Small amounts of current can be dangerous. Inspect the test leads for damaged insulation or exposed metal. Check test lead continuity. Replace damaged leads. To avoid damage or injury, never use the meter on unprotected circuits that exceed 4800 volt-amps. Do not use the meter if it operates abnormally. Protection may be impaired. When in doubt, have the meter serviced. Do not operate the meter around explosive gas, vapor or dust. Do not apply more than 300 V dc or ac rms (sine) between terminals or between any terminal and earth ground. Before each use, verify the meters operation by measuring a known voltage. When servicing the meter, use only specified replacement parts. Use caution when working above 30 V ac rms, 42 V ac peak, or 60 V dc. Such voltages pose a shock hazard. Keep your fingers behind the finger guards on the probe when making measurements. Connect the common test lead before connecting the live test lead. Disconnect the live test lead first. Remove test leads from the meter before opening the case. Use only a single 9 V battery, properly installed in the meter case, to power the meter. Follow all equipment safety procedures. Before measuring current, check the meters fuses (see “How to Test the Fuse”). RadioFans.CN 收音机爱 好者资料库 Safety-2 Never touch the probe to a voltage source when the test leads are plugged into the 10 A input jack. Always use clamp-on probes (dc current clamps) when measuring current exceeding 10 A. DO NOT connect thermocouple to voltages exceeding 30 V. Always use a high voltage probe to measure voltage if peak voltage might exceed 300 V. To avoid false readings, which could lead to possible electric shock or personal injury, replace the meters battery as soon as the low battery indicator (N) appears. To avoid fire hazard, only use a fuse identical in type, voltage rating, and current rating to that specified on the fuse rating label located on the case bottom. Do not operate the meter if it is disassembled. Always operate the meter with the case top and bottom properly assembled. Disassembly procedures and warnings are in the 78 Automotive Service Manual. Service procedures are for qualified personnel only. Caution To avoid possible damage to the meter or to equipment under test: Disconnect the power to the circuit under test and discharge all high voltage capacitors before testing resistance, continuity or diodes. Use the proper function and range for your measurement applications. When measuring current, turn off circuit power before connecting the meter in the circuit. Remember to place the meter in series with the current. Symbols SymbolMeaning Important information. See manual. Ground Fuse Double insulation (Protection Class II) Conforms to European Union directives i Table of Contents ChapterTitlePage 1Introduction and Specifications. 1-1 1-1.Introduction. 1-3 1-2.Organization of the Service Manual. 1-3 1-3.Conventions. 1-4 1-4.Specifications. 1-4 2Theory of Operation. 2-1 2-1.Introduction. 2-3 2-2.Functional Block Description. 2-3 2-3.Detailed Circuit Description . 2-5 2-4.Input Overload Protection. 2-5 2-5.Rotary Switch. 2-5 2-6.Input Signal Conditioning Circuits. 2-5 2-7.Volts. 2-6 2-8.Ohms. 2-6 2-9.Analog Section of Integrated Meter IC (U4). 2-6 2-10.Microcomputer Control . 2-8 2-11.Peripherals to U4. 2-9 2-12.AC Buffer. 2-10 2-13.AC Converter. 2-10 2-14.Active Filter. 2-10 2-15.A/D Converter . 2-10 2-16.Beeper. 2-10 2-17.Reference Voltage . 2-10 2-18.Power Supply. 2-10 2-19.Display. 2-11 2-20.Rotary Knob Switch and Potentiometer . 2-11 3Maintenance. 3-1 3-1.Introduction. 3-3 3-2.Required Tools and Equipment. 3-3 3-3.Operator Maintenance. 3-4 3-4.Disassembing the Case. 3-5 3-5.Removing and Reinstalling the Circuit Assembly. 3-5 88 Service Manual ii 3-6.Reassembling the Case. 3-6 3-7.Replacing the Battery. 3-7 3-8.Testing Fuses . 3-7 3-9.Replacing Fuses. 3-7 3-10.Cleaning. 3-8 3-11.Input Terminals. 3-8 3-12.Function Encoding Potentiometer. 3-8 3-13.Performance Test. 3-9 3-14.Testing the Display. 3-9 3-15.Testing Function Selection (Rotary Switch). 3-10 3-16.Testing the AC Voltage Function. 3-10 3-17.Testing the Frequency Counter Function. 3-11 3-18.Testing Frequency Sensitivity and Trigger Level. 3-12 3-19.Testing the DC Voltage Function. 3-12 3-20.Testing the DC mV Function. 3-13 3-21.Testing the Ohms Function. 3-13 3-22.Testing the Diode Test Function. 3-13 3-23.Testing the mA Functions. 3-13 3-24.Testing the Amp Functions. 3-14 3-25.Testing the Inductive Pickup. 3-14 3-26.Calibration. 3-18 3-27.Troubleshooting the Power Supply. 3-19 3-28.Common (Shunt) Regulator Troubleshooting. 3-21 3-29.VDD (Series) Regulator Troubleshooting. 3-23 3-30.Troubleshooting a Function Selection Malfunction. 3-23 3-31.Meter Does Not Turn Off (Problem 1). 3-24 3-32.Meter Enters Wrong Function (Problem 2). 3-24 4List of Replaceable Parts . 4-1 4-1.Introduction. 4-3 4-2.How to Obtain Parts. 4-3 4-3.Manual Status Information. 4-3 4-4.Newer Instruments. 4-4 4-5.Service Centers. 4-4 4-6.Parts Lists. 4-4 5Schematic Diagrams. 5-1 iii List of Tables TableTitlePage 1-1.Summary of Accuracy Specifications. 1-5 2-1.Typical Voltage Levels and Tolerance. 2-11 3-1.Required Equipment. 3-3 3-2.Function Selection Test. 3-10 3-3.AC Voltage Test. 3-11 3-4.Frequency Test. 3-11 3-5.Frequency Counter Sensitivity and Trigger Level Tests. 3-12 3-6.DC Voltage Test. 3-12 3-7.Ohms Test. 3-13 3-8.Milliamp Tests. 3-14 3-9.Amp Tests. 3-14 3-10. Functional Description of Power Supply Components . 3-20 3-11. Voltage Levels. 3-20 4-1.Fluke 88 Final Assembly. 4-5 4-2.A1 Main PCA. 4-7 88 Service Manual iv v List of Figures FigureTitlePage 2-1.Overall Functional Block Diagram. 2-4 2-2.A/D Conversion. 2-8 2-3.Function-Encoding Switch . 2-12 3-1.Battery and Fuse Replacement . 3-4 3-2.Assembly Details. 3-6 3-3.Display Test. 3-9 3-4.Setup for Inductive Pickup Test . 3-16 3-5.Waveform for Inductive Pickup Test. 3-17 3-6.Calibration Adjustment Points. 3-19 3-7.Simplified Power Supply Schematic. 3-22 4-1.Fluke 88 Final Assembly. 4-6 4-2.A1 Main PCA. 4-9 5-1.A1 Main PCA. 5-3 88 Service Manual vi 88 AUTOMOTIVE METER MIN MAXRANGEHOLD H %DUTYALERT ZERO RPM AVGH M k 4000 mV 2024631082468420 TRIG _ + _ + AUTORANGERECORDMAXMINAVG ACDC m s % m V A + T Hz RPM12 POWER-UP OPTIONS PRESS 2 SEC. WHILE TURNING METER ON LOW, OHMS/HIGH RESOLUTION DISABLE AUTOMATIC POWER-OFF AUTORANGE VDC, VAC HI IMPENDANCE mV DC INPUT TURN OFF BEEPER TEST ROTARY SWITCH HI ACCURACY, 1 SEC. RESPONSE ZERO MIN MAX RANGE HOLD ALERT RPM WARNING TO AVOID ELECTRICAL SHOCK REMOVE TEST LEADS BEFORE OPENING CASE TO PREVENT DAMAGE OF INJURY INSTALL QUICK ACTING FUSES WITH AMP/VOLT RATINGS SHOWN. POWER-UP OPTIONS DISPLAY PUSHBUTTONS ROTARY SWITCH ELECTRICAL SHOCK AND FUSE WARNINGS BATTERY TYPE BACK FUSE RATINGS SKID RESISTANT FEET INPUT TERMINALS FRONT 9V NEDA 1604 F 44/100A 1000V MIN INTERRUPT RATING 10 000A F 11A 1000V MIN INTERRUPT RATING 17 000A FLUKE CORPORATION MADE IN USA PAT. RE. 34,428 DES. 314,715 DES. 312,534 4,217,543 4,556,867 4,532,470 5,073,757 4,940,204 4,951,834 PRODUCT SERVICE OFF RPM AmACOMRPM V 400mA FUSED 10A FUSED Hzms-PULSETRIGGERSMOOTH mV V V mA A mA A + 300V CATII LR44340 aad01f.eps Frontispiece 1-1 Chapter 1 Introduction and Specifications TitlePage 1-1.Introduction.