FLUKE 77 III Service 电路图.pdf

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1、 77 Series III Multimeter Service Manual PN 800604 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 i Table of Contents ChapterTitlePage 1Introduction and Specificati

2、ons. 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 Description . 2-3 2-4.Voltage Signal Conditioning . 2-3 2-5.Current Conditi

3、oning . 2-4 2-6.Ohms . 2-4 2-7.Additional Circuitry . 2-4 2-8.AC Converter . 2-5 2-9.Active Filter . 2-5 2-10.Rotary Switch . 2-5 2-11.A/D Conversion . 2-5 3Maintenance . 3-1 3-1.Introduction . 3-3 3-2.PCA Access and General Maintenance . 3-3 3-3.Display Access . 3-4 3-4.Cleaning . 3-4 3-5.Performan

4、ce Test . 3-7 3-6.Initial Procedure . 3-7 3-7.DC Voltage Test . 3-7 3-8.AC Voltage Test . 3-8 3-9.Resistance Test . 3-8 RadioFans.CN 收音机爱 好者资料库 77 Series III Service Manual ii 3-10.Diode Test . 3-9 3-11.DC mA Test . 3-10 3-12.DC Amps Test . 3-11 3-13.Calibration . 3-11 3-14. Troubleshooting . 3-11 3

5、-15.Supplemental Troubleshooting Procedures . 3-13 3-16.Checking the Crystal Oscillator . 3-13 3-17.Checking The Reference Voltage . 3-13 3-18.Checking Display Drive Voltage . 3-13 3-19.Checking Beeper Drive Signal . 3-13 3-20.Tracing the VDC Signal Path . 3-13 4List of Replaceable Parts. 4-1 4-1.In

6、troduction . 4-3 4-2.How to Obtain Parts . 4-3 4-3.Newer Instruments . 4-3 4-4.Service Centers . 4-3 4-5.Manual Status Information . 4-4 4-6.Parts Lists . 4-4 5Schematic Diagrams. 5-1 RadioFans.CN 收音机爱 好者资料库 iii List of Tables TableTitlePage 1-1.Specifications. 1-5 2-1.S1 Function Codes. 2-6 3-1.Rec

7、ommended Test Equipment. 3-3 3-2.DC Voltage Test. 3-8 3-3.AC Voltage Test. 3-8 3-4.Resistance Test. 3-10 3-5.DC mA Test. 3-11 3-6.DC Amps Test. 3-11 4-1.Final Assembly. 4-5 4-2.A1 Main PCA. 4-7 5-1.Abbreviations . 5-3 v List of Figures Figure TitlePage 2-1.Overview . 2-3 2-2.AC and A/D Converter. 2-

8、7 3-1.Assembly Details. 3-6 3-2.Troubleshooting Tree. 3-12 4-2.A1 Main PCA. 4-9 5-1.A1 Main PCA. 5-4 SAFETY-1 OPERATOR SAFETY INFORMATION This instrument has been designed and tested in accordance with IEC Publication 348, Safety Requirements for Electronic Measuring Apparatus. This manual contains

9、information and warnings which have to be followed by the user to ensure safe operation and to retain the instrument in safe condition. Warning statements identify conditions or practices that could result in personal injury or loss of life. Caution statements identify conditions or practices that c

10、ould result in damage to the equipment or other property. Never use the meter if the meter or test leads look damaged. Always turn off power to the circuit before cutting, unsoldering, or breaking the circuit. Small amounts of current can be dangerous. Never measure resistance in a circuit when powe

11、r is applied to the circuit. Never touch the probes to a voltage source when the test leads are plugged into the 10A or 300 mA input jack. Never apply more than 1000V dc or ac rms (sine) between any input jack and earth ground. Always be careful when working with voltages above 60V dc or 30V ac rms.

12、 Such voltages pose a shock hazard. Always keep your fingers behind the finger guards on the probe when making measurements. Always use a high voltage probe to measure voltage if the peak voltage might exceed 1000V. SAFETY-2 Symbols Marked on Equipment DANGER High Voltage Attention refer to the manu

13、al. This symbol indicates that information about the usage of a feature is contained in the manual. IFuse information Use the Proper Fuse To avoid fire hazard, use only the fuse identical in type, voltage rating, and current rating as specified on the case bottom fuse rating label. Do Not Remove Cov

14、er Always operate the meter with case top and bottom properly assembled. Access procedures and the warnings for such procedures are contained in this Service Manual Service procedures are for qualified service personnel only. Do Not Attempt to Operate if Protection May be Impaired If the meter appea

15、rs damaged or operates abnormally, protection may be impaired. Do not attempt to operate it. When is doubt, have the instrument serviced. 1-1 Chapter 1 Introduction and Specifications ContentsPage 1-1.Introduction.1-3 1-2.Organization of the Service Manual.1-3 1-3.Conventions .1-4 1-4.Specifications

16、.1-4 Introduction and Specifications Introduction1 1-3 1-1. Introduction This manual presents service information for the Fluke 77 Series III Multimeter. The manual includes a theory of operation, general maintenance procedures, performance tests, calibration procedures, troubleshooting information,

17、 a list of replaceable parts, and schematic diagrams. A meter under warranty will be promptly repaired or replaced (at Flukes option) and returned at no charge. See the registration card for warranty terms. To locate an authorized service center, visit us on the World Wide Web: or call using any of

18、the phone numbers listed below: USA: 1-888-99-FLUKE (1-888-993-5853) Canada: 1-800-36-FLUKE (1-800-363-5853) Europe: +31 402-678-200 Japan: +81-3-3434-0181 Singapore: +65-738-5655 Anywhere in the world: +1-425-446-5500 1-2. Organization of the Service Manual The following descriptions briefly descri

19、be each chapter in the manual. Chapter 1Introduction and Specifications This chapter describes use of the Service Manual and application of special terminology (conventions) to describe the meters circuitry. A complete set of specifications appears at the end of this chapter. Chapter 2Theory of Oper

20、ation This chapter first categorizes instrument circuitry into functional blocks, with a description of each blocks 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 an

21、d repair procedures defined in Section 3. Chapter 3Maintenance Provides complete maintenance information, from general maintenance and cleaning instructions to detailed troubleshooting and repair procedures to the component level. Troubleshooting and repair procedures rely heavily on both the Theory

22、 of Operation presented in Chapter 2 and the Schematic Diagrams shown in Section 5. Chapter 4List of Replaceable Parts Includes parts lists for all standard assemblies. Information on how and where to order parts is also provided. Chapter 5Schematic Diagrams Includes schematic for the A1 Main PCA. 7

23、7 Series III Service Manual 1-4 1-3. Conventions Through the manual, certain notational conventions are used. A summary of these conventions follow: Instrument Reference The Fluke 77 Series III Multimeter is also referred to throughout this manual as “the meter”. Printed Circuit Assembly The term “p

24、ca” is used to represent a printed wiring board and its attached parts. Circuit Nodes Individual pins or connections on a component are specified by a dash (-) following the component reference designator. For example, pin 19 of U30 would be U30-19. User Notation Generally, push buttons, function po

25、sitions, input terminals, and display notation are presented in this manual as they are seen on the meter. Special terms (mnemonics) used in text descriptions of meter circuitry correspond to terms used on the schematic diagrams in Chapter 5. 1-4. Specifications Specifications for the meters are pre

26、sented in Table 1-1. Introduction and Specifications Specifications1 1-5 Table 1-1. Specifications Maximum Voltage Between any Terminal and Earth Ground Rated voltage DisplayDigital: 3,200 counts, updates 2.5/sec Analog: 31 segments, updates 25/sec Response Time of Digital DisplayV ac 2 s V dc 1 s 1

27、s to 320 k, 2s to 3.2 M, 10 s to 32 M Operating Temperature0C to 50C Storage Temperature-40C to 60C Temperature Coefficient0.1 x (specified accuracy)/C (28C) Electromagnetic Compatibility In RF field of 3 V/m on all functions. Total accuracy = Specified accuracy + 0.1% of range. Relative Humidity ex

28、cept 32 M range 32 M range only 0% to 90% (0C to 35C) 0% to 70% (35C to 50C) 0% to 80% (0C to 35C) 0% to 70% (35C to 50C) AltitudeOperating: 2000 meters Storage: 12,000 meters Battery Type9 V NEDA 1604 or 6F22 or 006P, or NEDA 1604A or 6LR61 Battery Life2000 hrs typical with alkaline 1600 hrs typica

29、l with carbon zinc Continuity Beeper4096 Hz Shock, Vibrationper MIL-T-PRF 28800F Class III, Sinusoidal, Non Operating Size (H x W x L)3.7 cm x 8.9 - 7.8 cm x 19 cm (1.5 in x 3.5 - 3.1 in x 7.49 in) Weight365 g (12.9 oz) Safety600 V CAT III and 1000 V CAT II per ANSI/ISA S82.01-1994, EN 61010-1: 1993

30、, CSA C22.2 No 1010.1-92, UL 3111-1. EMC RegulationsEN 61326-1 1997. Certifications/Listings 77 Series III Service Manual 1-6 Table 1-1. Specifications (cont) FunctionRangeAccuracy L 3.200 V 32.00 V 320.0 V 1000 V (0.3%+1) (0.3%+1) (0.3%+1) (0.4%+1) mL 320.0 mV(0.3%+1) K (45 to 500 Hz, 3.2 V range.

31、Other ranges 45 to 1 kHz) 3.200 V 32.00 V 320.0 V 1000 V (2%+2) (2%+2) (2%+2) (2%+2) e 320.0 3200 32.00 k 320.0 k 3.200 M 32.00 M (0.5%+3) (0.5%+1) (0.5%+1) (0.5%+1) (0.5%+1) (2.0%+1) G R2.0 V(1% typical) FunctionRangeAccuracyBurden Voltage (typical) ? (45 Hz to 1 kHz) 32.00 mA, 320.0 mA 10.00 A * (

32、2.5%+2) (2.5%+2) 6 mV/mA 50 mV/A A 32.00 mA, 320.0 mA 10.00 A * (1.5%+2) (1.5%+2) 6 mV/mA 50 mV/A * 10 A continuous, 20 A for 30 seconds maximum. Introduction and Specifications Specifications1 1-7 Overload protection for all functions and ranges: Rated voltage. FunctionInput Impedance (Nominal) L,

33、mL, K10 M, 120 dB at dc, 50 Hz, or 60 Hz60 dB at 50 Hz or 60 Hz K60 dB dc to 60 Hz Open Circuit Test VoltageFull Scale Voltage To 3.2 M 32 M e 3.1 V dc 2.8 V dc (typical) 440 mV dc 420 mV dc (typical) 1.4 V dc 1.3 V dc (typical) Open Circuit Test VoltageFull Scale Voltage G R3.1 V dc2.0 V dc Short C

34、ircuit Current (typical) e300 A G R400 A GVFCurrent (typical) 0.0 V 0.6 V 1.2 V 2.0 V 0.4 mA 0.3 mA 0.2 mA 0.1 mA 2-1 Chapter 2 Theory of Operation ContentsPage 2-1.Introduction. 2-3 2-2.Functional Block Description. 2-3 2-3.Detailed Description. 2-3 2-4.Voltage Signal Conditioning. 2-3 2-5.Current

35、Conditioning. 2-4 2-6.Ohms. 2-4 2-7.Additional Circuitry. 2-4 2-8.AC Converter . 2-4 2-9.Active Filter . 2-5 2-10.Rotary Switch. 2-5 2-11.A/D Conversion. 2-5 Theory of Operation Introduction2 2-3 2-1. Introduction This chapter contains a brief overview of the 77 Series III Multimeter, followed by a

36、more detailed explanation of operation. 2-2. Functional Block Description The heart of the instrument consists of a two-chip CMOS system: U1, a primarily analog IC, and U2, a calculator-style microcomputer (see Figure 2- 1). OHMS 300 mV DCV ACV OFF ACmV DCmV A/D J1 Input Signal Conditioning Range and Function Control To Bar