Fluke 77 Series III Manuale utente

77 Series III

Multimeter

Service Manual

PN 800604

November 1998 Rev.1, 11/99

All product names are trademarks of their respective companies.

Table of Contents

Chapter Title Page

1 Introduction 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

2 Theory 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 Conditioning .............................................. 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

3 Maintenance ................................................................ 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. Performance 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

77 Series III

Service Manual

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

3-15. 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

4 List of Replaceable Parts............................................ 4-1

4-1. Introduction ................................................................. 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

5 Schematic Diagrams................................................... 5-1

iii

List of Tables

Table Title Page

1-1. Specifications ..................................................................... 1-5

2-1. S1 Function Codes.............................................................. 2-6

3-1. Recommended 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

77 Series III

Service Manual

List of Figures

Figure Title Page

2-1. Overview ............................................................................ 2-3

2-2. AC and A/D Converter....................................................... 2-7

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

77 Series III

Service Manual

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 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 could 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 power 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. 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 manual. 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 Cover

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 appears 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

Contents Page

1-1. Introduction.................................................................. 1-3

1-2. Organization of the Service Manual............................ 1-3

1-3. Conventions ................................................................. 1-4

1-4. Specifications............................................................... 1-4

Indice

Manuali Multimetro popolari di altre marche

Agilent Technologies

Agilent Technologies 34420A Manuale utente

Hameg

Hameg HM 8012 Manuale utente

Mastech

Mastech MY70 Manuale utente

Steren

Steren MUL-300 Manuale utente

Somogyi Elektronic

Somogyi Elektronic home SMA 92 Manuale utente

Gossen MetraWatt

Gossen MetraWatt METRAmax 6 Manuale utente

PeakTech

PeakTech 4000 Manuale per l'uso e la cura

YOKOGAWA

YOKOGAWA 90050B Manuale utente

Gossen MetraWatt

Gossen MetraWatt METRALINE DMM16 Manuale utente

Tempo Communications

Tempo Communications MM200 Manuale utente

Elenco Electronics

Elenco Electronics CM-1555 Manuale utente

Mastech

Mastech MS8238C Manuale utente

SDAR

SDAR 830A, 830B, 830D, 830C Manuale utente

RS PRO

RS PRO RS-9519BT Manuale utente

BGS technic

BGS technic 8890 Manuale utente

Amprobe

Amprobe Hexagon 60 Manuale utente

Morris

Morris 57074 Manuale utente

Agilent Technologies

Agilent Technologies 34450A 5 Digit Multimeter Manuale utente