Fluke ScopeMeter 123 Service Manual
123
Industrial ScopeMeter
Service Manual
4822 872 05375
August 1997, Rev. 3, 01/00
© 1997 Fluke Corporation. All rights reserved. Printed in the Netherlands
All product names are trademarks of their respective companies.
SERVICE CENTERS
To locate an authorized service center, visit us on the World Wide Web:
http://www.fluke.com
or call Fluke using any of the phone numbers listed below:
+1-888-993-5853 in U.S.A. and Canada
+31-402-678-200 in Europe
+1-425-356-5500 from other countries
Table of Contents
Chapter Title Page
1 Safety Instructions ............................................................................. 1-1
1.1 Introduction................................................................................................. 1-3
1.2 Safety Precautions....................................................................................... 1-3
1.3 Caution and Warning Statements................................................................ 1-3
1.4 Symbols....................................................................................................... 1-3
1.5 Impaired Safety........................................................................................... 1-4
1.6 General Safety Information......................................................................... 1-4
2 Characteristics ................................................................................... 2-1
2.1 Introduction................................................................................................. 2-3
2.2 Dual Input Oscilloscope.............................................................................. 2-3
2.2.1 Vertical ................................................................................................ 2-3
2.2.2 Horizontal ............................................................................................ 2-4
2.2.3 Trigger ................................................................................................. 2-4
2.2.4 Advanced Scope Functions.................................................................. 2-5
2.3 Dual Input Meter......................................................................................... 2-5
2.3.1 Input A and Input B ............................................................................. 2-5
2.3.2 Input A ................................................................................................. 2-8
2.3.3 Advanced Meter Functions.................................................................. 2-8
2.4 Miscellaneous ............................................................................................. 2-9
2.5 Environmental............................................................................................. 2-10
2.6 Service and Maintenance ............................................................................ 2-11
2.7 Safety .......................................................................................................... 2-11
2.8 EMC Immunity ........................................................................................... 2-12
3 Circuit Descriptions ........................................................................... 3-1
3.1 Introduction................................................................................................. 3-3
3.2 Block Diagram ............................................................................................ 3-3
3.2.1 Channel A, Channel B Measurement Circuits..................................... 3-4
3.2.2 Trigger Circuit ..................................................................................... 3-4
3.2.3 Digital Circuit ...................................................................................... 3-5
3.2.4 Power Circuit....................................................................................... 3-6
3.2.5 Start-up Sequence, Operating Modes .................................................. 3-7
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3.3 Detailed Circuit Descriptions...................................................................... 3-9
3.3.1 Power Circuit....................................................................................... 3-9
3.3.2 Channel A - Channel B Measurement Circuits ................................... 3-15
3.3.3 Trigger Circuit ..................................................................................... 3-20
3.3.4 Digital Circuit ...................................................................................... 3-25
4 Performance Verification ................................................................... 4-1
4.1 Introduction................................................................................................. 4-3
4.2 Equipment Required For Verification ........................................................ 4-3
4.3 How To Verify ............................................................................................ 4-3
4.4 Display and Backlight Test......................................................................... 4-4
4.5 Input A and Input B Tests ........................................................................... 4-5
4.5.1 Input A and B Base Line Jump Test.................................................... 4-6
4.5.2 Input A Trigger Sensitivity Test.......................................................... 4-7
4.5.3 Input A Frequency Response Upper Transition Point Test................. 4-8
4.5.4 Input A Frequency Measurement Accuracy Test ................................ 4-8
4.5.5 Input B Frequency Measurement Accuracy Test ................................ 4-9
4.5.6 Input B Frequency Response Upper Transition Point Test ................. 4-10
4.5.7 Input B Trigger Sensitivity Test .......................................................... 4-10
4.5.8 Input A and B Trigger Level and Trigger Slope Test.......................... 4-11
4.5.9 Input A and B DC Voltage Accuracy Test .......................................... 4-14
4.5.10 Input A and B AC Voltage Accuracy Test ........................................ 4-15
4.5.11 Input A and B AC Input Coupling Test............................................. 4-16
4.5.12 Input A and B Volts Peak Measurements Test.................................. 4-17
4.5.13 Input A and B Phase Measurements Test.......................................... 4-18
4.5.14 Input A and B High Voltage AC/DC Accuracy Test......................... 4-19
4.5.15 Resistance Measurements Test.......................................................... 4-20
4.5.16 Continuity Function Test ................................................................... 4-21
4.5.17 Diode Test Function Test .................................................................. 4-22
4.5.18 Capacitance Measurements Test ....................................................... 4-22
4.5.19 Video Trigger Test............................................................................. 4-23
5 Calibration Adjustment ...................................................................... 5-1
5.1 General ........................................................................................................ 5-3
5.1.1 Introduction.......................................................................................... 5-3
5.1.2 Calibration number and date................................................................ 5-3
5.1.3 General Instructions............................................................................. 5-3
5.2 Equipment Required For Calibration.......................................................... 5-4
5.3 Starting Calibration Adjustment ................................................................. 5-4
5.4 Contrast Calibration Adjustment ................................................................ 5-6
5.5 Warming Up & Pre-Calibration.................................................................. 5-7
5.6 Final Calibration ......................................................................................... 5-7
5.6.1 HF Gain Input A&B ............................................................................ 5-7
5.6.2 Delta T Gain, Trigger Delay Time & Pulse Adjust Input A................ 5-9
5.6.3 Pulse Adjust Input A (firmware V01.00 only) .................................... 5-10
5.6.4 Pulse Adjust Input B............................................................................ 5-11
5.6.5 Gain DMM (Gain Volt)....................................................................... 5-11
5.6.6 Volt Zero.............................................................................................. 5-13
5.6.7 Zero Ohm (firmware V01.00 only)...................................................... 5-13
5.6.8 Gain Ohm............................................................................................. 5-14
5.6.9 Capacitance Gain Low and High......................................................... 5-15
5.6.10 Capacitance Clamp & Zero................................................................ 5-15
5.6.11 Capacitance Gain............................................................................... 5-16
5.7 Save Calibration Data and Exit................................................................... 5-16
Contents (continued)
6 Disassembling the Test Tool............................................................. 6-1
6.1. Introduction................................................................................................ 6-3
6.2. Disassembling Procedures ......................................................................... 6-3
6.1.1 Required Tools .................................................................................... 6-3
6.2.2 Removing the Battery Pack ................................................................. 6-3
6.2.3 Removing the Bail ............................................................................... 6-3
6.2.4 Opening the Test Tool ......................................................................... 6-3
6.2.5 Removing the Main PCA Unit............................................................. 6-5
6.2.6 Removing the Display Assembly......................................................... 6-6
6.2.7 Removing the Keypad and Keypad Foil.............................................. 6-6
6.3 Disassembling the Main PCA Unit............................................................. 6-6
6.4 Reassembling the Main PCA Unit.............................................................. 6-8
6.5 Reassembling the Test Tool........................................................................ 6-8
7 Corrective Maintenance..................................................................... 7-1
7.1 Introduction................................................................................................. 7-3
7.2 Starting Fault Finding. ................................................................................ 7-4
7.3 Charger Circuit............................................................................................ 7-4
7.4 Starting with a Dead Test Tool ................................................................... 7-6
7.4.1 Test Tool Completely Dead................................................................. 7-6
7.4.2 Test Tool Software Does not Run. ...................................................... 7-7
7.4.3 Software Runs, Test Tool not Operative ............................................. 7-7
7.5 Miscellaneous Functions............................................................................. 7-8
7.5.1 Display and Back Light ....................................................................... 7-8
7.5.2 Fly Back Converter.............................................................................. 7-9
7.5.3 Slow ADC............................................................................................ 7-10
7.5.4 Keyboard.............................................................................................. 7-11
7.5.5 Optical Port (Serial RS232 Interface).................................................. 7-11
7.5.6 Channel A, Channel B Voltage Measurements ................................... 7-12
7.5.7 Channel A Ohms and Capacitance Measurements.............................. 7-13
7.5.8 Trigger Functions................................................................................. 7-14
7.5.9 Reference Voltages.............................................................................. 7-15
7.5.10 Buzzer Circuit.................................................................................... 7-15
7.5.11 Reset ROM Circuit (PCB version <8 only)....................................... 7-16
7.5.12 RAM Test .......................................................................................... 7-16
7.5.13 Power ON/OFF.................................................................................. 7-16
7.5.14 PWM Circuit...................................................................................... 7-17
7.5.15 Randomize Circuit............................................................................. 7-17
7.6 Loading Software........................................................................................ 7-17
8 List of Replaceable Parts................................................................... 8-1
8.1 Introduction................................................................................................. 8-3
8.2 How to Obtain Parts.................................................................................... 8-3
8.3 Final Assembly Parts .................................................................................. 8-4
8.4 Main PCA Unit Parts .................................................................................. 8-6
8.5 Main PCA Parts .......................................................................................... 8-7
8.6 Accessory Replacement Parts ..................................................................... 8-24
8.7 Service Tools............................................................................................... 8-24
9 Circuit Diagrams................................................................................. 9-1
9.1 Introduction................................................................................................. 9-3
9.2 Schematic Diagrams.................................................................................... 9-4
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10 Modifications ...................................................................................... 10-1
10.1 Software modifications ............................................................................. 10-1
10.2 Hardware modifications............................................................................ 10-1
List of Tables
Table Title Page
2-1. No Visible Trace Disturbance ............................................................................... 2-12
2-2. Trace Disturbance < 10%...................................................................................... 2-12
2-3. Multimeter Disturbance < 1%............................................................................... 2-12
3-1. Fluke 123 Main Blocks ......................................................................................... 3-3
3-2. Fluke 123 Operating Modes.................................................................................. 3-9
3-3. Voltage Ranges And Trace Sensitivity ................................................................. 3-18
3-4. Ohms Ranges, Trace Sensitivity, and Current ...................................................... 3-18
3-5. Capacitance Ranges, Current, and Pulse Width.................................................... 3-20
3-6. D-ASIC PWM Signals........................................................................................... 3-29
4-1. Input A,B Frequency Measurement Accuracy Test .............................................. 4-9
4-2. Volts DC Measurement Verification Points ......................................................... 4-15
4-3. Volts AC Measurement Verification Points ......................................................... 4-16
4-4. Input A and B AC Input Coupling Verification Points......................................... 4-17
4-5. Volts Peak Measurement Verification Points ....................................................... 4-18
4-6. Phase Measurement Verification Points ............................................................... 4-18
4-7. V DC and V AC High Voltage Verification Tests................................................ 4-20
4-8. Resistance Measurement Verification Points........................................................ 4-21
4-9. Capacitance Measurement Verification Points ..................................................... 4-23
5-1. HF Gain Calibration Points Fast ........................................................................... 5-8
5-2. HF Gain Calibration Points Slow.......................................................................... 5-9
5-3. Volt Gain Calibration Points <300V..................................................................... 5-12
5-4. Ohm Gain Calibration Points ................................................................................ 5-14
7-1. Starting Fault Finding............................................................................................ 7-4
8-1. Final Assembly Parts............................................................................................. 8-4
8-2. Main PCA Unit...................................................................................................... 8-6
8-3. Main PCA.............................................................................................................. 8-7
9-1. Parts Location Main PCA Side 1 .......................................................................... 9-4
9-2. Parts Location Main PCA Side 2 .......................................................................... 9-5
List of Figures
Figure Title Page
3-1. Fluke 123 Block Diagram...................................................................................... 3-2
3-2. Fluke 123 Start-up Sequence, Operating Modes................................................... 3-8
3-3. Power Supply Block Diagram............................................................................... 3-9
3-4. CHAGATE Control Voltage ................................................................................. 3-12
3-5. Fly-Back Converter Current and Control Voltage ................................................ 3-12
3-6. Fly-Back Converter Block Diagram...................................................................... 3-13
3-7. Back Light Converter Voltages............................................................................. 3-15
3-8. C-ASIC Block Diagram......................................................................................... 3-15
3-9. Capacitance Measurement..................................................................................... 3-19
3-10. T-ASIC Trigger Section Block Diagram............................................................... 3-21
3-11. Random Repetitive Sampling Mode ..................................................................... 3-22
3-12. Reference Voltage Section .................................................................................... 3-24
3-13. LCD Control .......................................................................................................... 3-28
4-1. Display Pixel Test Pattern ..................................................................................... 4-4
4-2. Menu item selection .............................................................................................. 4-6
4-3. Test Tool Input A to 5500A Scope Output 50Ω ................................................... 4-7
4-4. Test Tool Input B to 5500A Scope Output 50Ω ................................................... 4-9
4-5. Test Tool Input A-B to 5500A Normal Output..................................................... 4-11
4-6. Test Tool Input A-B to 5500A Normal Output for >300V ................................... 4-19
4-7. Test Tool Input A to 5500A Normal Output 4-Wire............................................. 4-20
4-8. Test Tool Input A to TV Signal Generator ........................................................... 4-23
4-9. Test Tool Screen for PAL/SECAM line 622 ........................................................ 4-24
4-10. Test Tool Screen for NTSC line 525..................................................................... 4-24
4-11. Test Tool Screen for PAL/SECAM line 310 ........................................................ 4-25
4-12. Test Tool Screen for NTSC line 262..................................................................... 4-25
4-13. Test Tool Input A to TV Signal Generator Inverted ............................................. 4-25
4-14. Test Tool Screen for PAL/SECAM line 310 Negative Video .............................. 4-26
4-15. Test Tool Screen for NTSC line 262 Negative Video .......................................... 4-26
5-1. Version & Calibration Screen ............................................................................... 5-3
5-2. Display Test Pattern .............................................................................................. 5-6
5-3. HF Gain Calibration Input Connections................................................................ 5-7
5-4. 5500A Scope Output to Input A............................................................................ 5-9
5-5. 5500A Scope Output to Input B ............................................................................ 5-11
5-6. Volt Gain Calibration Input Connections <300V ................................................. 5-12
5-7. Volt Gain Calibration Input Connections 500V.................................................... 5-13
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5-8. Four-wire Ohms calibration connections .............................................................. 5-14
5-9. Capacitance Gain Calibration Input Connections ................................................. 5-15
5-10. 20 V Supply Cable for Calibration........................................................................ 5-16
6-1. Fluke 123 Main Assembly..................................................................................... 6-4
6-2. Flex Cable Connectors .......................................................................................... 6-5
6-3. Main PCA Unit Assembly..................................................................................... 6-7
6-4. Mounting the display shielding bracket ................................................................ 6-9
6-5. Battery pack installation........................................................................................ 6-9
7-1. Operative Test Tool without Case......................................................................... 7-3
7-2. 20V Supply Cable for Loading Software.............................................................. 7-17
8-1. Fluke 123 Final Assembly..................................................................................... 8-5
8-2. Main PCA Unit...................................................................................................... 8-6
9-1. Circuit Diagram 1, Channel A Circuit................................................................... 9-7
9-2. Circuit Diagram 2, Channel B Circuit................................................................... 9-8
9-3. Circuit Diagram 3, Trigger Circuit........................................................................ 9-9
9-4. Circuit Diagram 4, Digital Circuit......................................................................... 9-10
9-5. Circuit Diagram 4 (cont), Digital Circuit Keyboard ............................................. 9-11
9-6. Circuit Diagram 5, Power Circuit.......................................................................... 9-12
9-7. Main PCA side 1 ................................................................................................... 9-13
9-8. Main PCA side 2 ................................................................................................... 9-14
9-9. Main PCA side 1, PCB version 8 .......................................................................... 9-15
9-10. Main PCA side 2, PCB version 8 .......................................................................... 9-16
Chapter 1
Safety Instructions
Title Page
1.1 Introduction................................................................................................. 1-3
1.2 Safety Precautions....................................................................................... 1-3
1.3 Caution and Warning Statements................................................................ 1-3
1.4 Symbols....................................................................................................... 1-3
1.5 Impaired Safety........................................................................................... 1-4
1.6 General Safety Information......................................................................... 1-4
1-1
1.1 Introduction
Read these pages carefully before beginning to install and use the instrument.
The following paragraphs contain information, cautions and warnings which must be
followed to ensure safe operation and to keep the instrument in a safe condition.
Servicing described in this manual is to be done only by
qualified service personnel. To avoid electrical shock, do not
service the instrument unless you are qualified to do so.
1.2 Safety Precautions
For the correct and safe use of this instrument it is essential that both operating and
service personnel follow generally accepted safety procedures in addition to the safety
precautions specified in this manual. Specific warning and caution statements, where
they apply, will be found throughout the manual. Where necessary, the warning and
caution statements and/or symbols are marked on the instrument.
Warning
Safety Instructions
1.1 Introduction
1
1.3 Caution and Warning Statements
Caution
Used to indicate correct operating or maintenance procedures
to prevent damage to or destruction of the equipment or other
property.
Warning
Calls attention to a potential danger that requires correct
procedures or practices to prevent personal injury.
1.4 Symbols
Read the safety information in the Users
Manual
Equal potential inputs, connected
internally
Live voltage Recycling information
Earth Disposal information
DOUBLE INSULATION (Protection Class)
Static sensitive components
(black/yellow).
Conformité Européenne
1-3
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Service Manual
1.5 Impaired Safety
1.6 General Safety Information
Whenever it is likely that safety has been impaired, the instrument must be turned off
and disconnected from line power. The matter should then be referred to qualified
technicians. Safety is likely to be impaired if, for example, the instrument fails to
perform the intended measurements or shows visible damage.
Warning
Removing the instrument covers or removing parts, except
those to which access can be gained by hand, is likely to
expose live parts and accessible terminals which can be
dangerous to life.
The instrument shall be disconnected from all voltage sources before it is opened.
Capacitors inside the instrument can hold their charge even if the instrument has been
separated from all voltage sources.
Components which are important for the safety of the instrument may only be replaced
by components obtained through your local FLUKE organization. These parts are
indicated with an asterisk (*) in the List of Replaceable Parts, Chapter 8.
1-4
Chapter 2
Characteristics
Title Page
2.1 Introduction................................................................................................. 2-3
2.2 Dual Input Oscilloscope.............................................................................. 2-3
2.2.1 Vertical ................................................................................................ 2-3
2.2.2 Horizontal ............................................................................................ 2-4
2.2.3 Trigger ................................................................................................. 2-4
2.2.4 Advanced Scope Functions.................................................................. 2-5
2.3 Dual Input Meter......................................................................................... 2-5
2.3.1 Input A and Input B ............................................................................. 2-5
2.3.2 Input A ................................................................................................. 2-8
2.3.3 Advanced Meter Functions.................................................................. 2-8
2.4 Miscellaneous ............................................................................................. 2-9
2.5 Environmental............................................................................................. 2-10
2.6 Service and Maintenance ............................................................................ 2-11
2.7 Safety .......................................................................................................... 2-11
2.8 EMC Immunity ........................................................................................... 2-12
2-1
2.1 Introduction
Performance Characteristics
FLUKE guarantees the properties expressed in numerical values with the stated
tolerance. Specified non-tolerance numerical values indicate those that could be
nominally expected from the mean of a range of identical ScopeMeter test tools.
Environmental Data
The environmental data mentioned in this manual are based on the results of the
manufacturer’s verification procedures.
Safety Characteristics
The test tool has been designed and tested in accordance with Standards ANSI/ISA
S82.01-1994, EN 61010-1 (1993) (IEC 1010-1), CAN/CSA-C22.2 No.1010.1-92
(including approval), UL3111-1 (including approval) Safety Requirements for Electrical
Equipment for Measurement, Control, and Laboratory Use. Use of this equipment in a
manner not specified by the manufacturer may impair protection provided by the
equipment.
Characteristics
2.1 Introduction
2
2.2 Dual Input Oscilloscope
2.2.1 Vertical
Frequency Response
DC Coupled:
excluding probes and test leads: DC to 20 MHz (-3 dB)
with STL120 1:1 shielded test leads: DC to 12.5 MHz (-3 dB)
with PM8918 10:1 probe: DC to 20 MHz (-3 dB)
(optional accessory)
AC Coupled (LF roll off):
excluding probes and test leads <10 Hz (-3 dB)
with STL120 <10 Hz (-3dB)
with PM8918 <1 Hz (-3 dB)
Rise Time
excluding probes and test leads <17.5 ns
Input Impedance
excluding probes and test leads 1 MΩ//12 pF
with BB120 1 MΩ//20 pF
with STL120 1 MΩ//225 pF
with PM8918 10 MΩ//15 pF
DC to 20 MHz (-6 dB)
Sensitivity 5 mV to 500 V/div
Display Modes A, -A, B, -B
2-3
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Service Manual
2.2.2 Horizontal
Max. Input Voltage A and B
direct or with test leads 600 Vrms
with BB120 300 Vrms
(For detailed specifications see “2.7 Safety”)
Max. Floating Voltage
from any terminal to ground 600 Vrms, up to 400Hz
Resolution 8 bit
Vertical Accuracy ±(1% + 0.05 range/div)
Max. Vertical Move ±4 divisions
Max. Base Line Jump After changing time base or sensitivity
Normal & Single mode ±0.04 divisions (= ±1 pixel)
Scope Modes Normal, Single, Roll
Ranges
Normal:
equivalent sampling 20 ns to 500 ns/div
real time sampling 1 µs to 5 s/div
Single (real time) 1 µs to 5 s/div
Roll (real time) 1s to 60 s/div
Sampling Rate (for both channels simultaneously)
Equivalent sampling (repetitive signals) up to 1.25 GS/s
Real time sampling:
1 µs to 5 ms/div 25 MS/s
10 ms to 5 s/div 5 MS/s
Time Base Accuracy
Equivalent sampling ±(0.4% +0.04 time/div)
Real time sampling ±(0.1% +0.04 time/div)
Glitch Detection ≥40 ns @ 20 ns to 5 ms/div
≥200 ns @ 10 ms to 60 s/div
Glitch detection is always active.
Horizontal Move 10 divisions
Trigger point can be positioned anywhere
across the screen.
2-4
2.2.3 Trigger
Screen Update Free Run, On Trigger
Source A, B, EXT
EXTernal via optically isolated trigger
probe ITP120 (optional accessory)
Sensitivity A and B
@ DC to 5 MHz 0.5 divisions or 5 mV
@ 25 MHz 1.5 divisions
@ 40 MHz 4 divisions
Voltage level error ±0.5 div. max.
Slope Positive, Negative
Video on A Interlaced video signals only
Modes Lines, Line Select
Standards PAL , NTSC, PAL+, SECAM
Polarity Positive, Negative
Sensitivity 0.6 divisions sync.
2.2.4 Advanced Scope Functions
Display Modes
Normal Captures up to 40 ns glitches and displays analog-like persistence
waveform.
Smooth Suppresses noise from a waveform.
Envelope Records and displays the minimum and maximum of waveforms
over time.
Characteristics
2.3 Dual Input Meter
2
Auto Set
Continuous fully automatic adjustment of amplitude, time base, trigger levels, trigger
gap, and hold-off. Manual override by user adjustment of amplitude, time base, or
trigger level.
2.3 Dual Input Meter
The accuracy of all measurements is within ± (% of reading + number of counts) from
18 °C to 28 °C.
Add 0.1x (specific accuracy) for each °C below 18 °C or above 28 °C. For voltage
measurements with 10:1 probe, add probe uncertainty +1%.
More than one waveform period must be visible on the screen.
2.3.1 Input A and Input B
DC Voltage (VDC)
Ranges 500 mV, 5V, 50V, 500V, 1250V
Accuracy ±(0.5% +5 counts)
Turnover ±12 counts
Normal Mode Rejection (SMR) >60 dB @ 50 or 60 Hz ±1%
Common Mode Rejection (CMRR) >100 dB @ DC
>60 dB @ 50, 60, or 400 Hz
Full Scale Reading 5000 counts
Move influence ±6 counts max.
2-5
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True RMS Voltages (VAC and VAC+DC)
Ranges 500 mV, 5V, 50V, 500V, 1250V
Accuracy for 5 to 100% of range
DC coupled:
DC to 60 Hz (VAC+DC) ±(1% +10 counts)
1 Hz to 60 Hz (VAC) ±(1% +10 counts)
AC or DC coupled:
60 Hz to 20 kHz ± (2.5% +15 counts)
20 kHz to 1 MHz ±(5% +20 counts)
1 MHz to 5 MHz ±(10% +25 counts)
5 MHz to 12.5 MHz ±(30% +25 counts)
5 MHz to 20 MHz ±(30% +25 counts), excluding test leads or
probes
AC coupled with 1:1 (shielded) test leads:
60 Hz (6 Hz with 10:1 probe) -1.5%
50 Hz (5 Hz with 10:1 probe) -2%
33 Hz (3.3 Hz with 10:1 probe) -5%
10 Hz (1 Hz with 10:1 probe) -30%
DC Rejection (only VAC) >50 dB
Common Mode Rejection (CMRR) >100 dB @ DC
>60 dB @ 50, 60, or 400 Hz
Full Scale Reading 5000 counts
The reading is independent of any signal
crest factor.
Move influence ±6 counts max.
Peak
Modes Max peak, Min peak, or pk-to-pk
Ranges 500 mV, 5V, 50V, 500V, 1250V
Accuracy:
Max peak or Min peak 5% of full scale
Peak-to-Peak 10% of full scale
Full Scale Reading 500 counts
Frequency (Hz)
Ranges 1Hz, 10Hz, 100Hz, 1 kHz, 10 kHz,
100 kHz,1 MHz, 10 MHz, 40 MHz
Frequency Range for Continuous Autoset 15Hz (1Hz) to 30 MHz
2-6
Accuracy:
@1Hz to 1 MHz ±(0.5% +2 counts)
@1 MHz to 10 MHz ±(1.0% +2 counts)
@10 MHz to 40 MHz ±(2.5% +2 counts)
Full Scale Reading 10 000 counts
Duty Cycle (DUTY)
Range 2% to 98%
Frequency Range for Continuous Autoset 15Hz (1Hz) to 30 MHz
Accuracy:
@1Hz to 1 MHz ±(0.5% +2 counts)
@1 MHz to 10 MHz ±(1.0% +2 counts)
@10 MHz to 40 MHz ±(2.5% +2 counts)
Resolution 0.1%
Pulse Width (PULSE)
Frequency Range for Continuous Autoset 15Hz (1Hz) to 30 MHz
Accuracy:
@1Hz to 1 MHz ±(0.5% +2 counts)
@1 MHz to 10 MHz ±(1.0% +2 counts)
@10 MHz to 40 MHz ±(2.5% +2 counts)
Full Scale reading 1000 counts
Characteristics
2.3 Dual Input Meter
2
Amperes (AMP) with optional current probe
Ranges same as VDC, VAC, VAC+DC, or PEAK
Scale Factor 1 mV/A, 10 mV/A, 100 mV/A, and 1 V/A
Accuracy same as VDC, VAC, VAC+DC, or PEAK
(add current probe uncertainty)
Temperature (TEMP) with optional temperature probe
Range 200 °C/div (200 °F/div)
Scale Factor 1 mV/°C and 1 mV/°F
Accuracy as VDC (add temperature probe
uncertainty)
Decibel (dB)
0 dBV 1V
0 dBm (600Ω /50Ω) 1 mW, referenced to 600Ω or 50Ω
dB on VDC, VAC, or VAC+DC
Full Scale Reading 1000 counts
Crest Factor (CREST)
Range 1 to 10
Accuracy ±(5% +1 count)
Full Scale Reading 100 counts
Phase
Modes A to B, B to A
Range 0 to 359 degrees
Accuracy ±(1 degree +1 count)
Resolution 1 degree
2-7
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Service Manual
2.3.2 Input A
Ohm (ΩΩΩΩ)
Ranges 500Ω, 5 kΩ, 50 kΩ, 500 kΩ, 5 MΩ,
30 MΩ
Accuracy ±(0.6% +5 counts)
Full Scale Reading
500Ω to 5 MΩ 5000 counts
30 MΩ 3000 counts
Measurement Current 0.5 mA to 50 nA
decreases with increasing ranges
Open Circuit Voltage <4V
Continuity (CONT)
Beep 30Ω ± 5Ω in 50Ω range
Measurement Current 0.5 mA
Detection of shorts of ≥1 ms
Diode
Maximum Voltage:
@0.5 mA >2.8V
@open circuit <4V
Accuracy ±(2% +5 counts)
Measurement Current 0.5 mA
Polarity + on input A, - on COM
Capacitance (CAP)
Ranges 50 nF, 500 nF, 5 µF, 50 µF, 500 µF
Accuracy ±(2% +10 counts)
Full Scale Reading 5000 counts
Measurement Current 5 µA to 0.5 mA, increases with increasing
Measurement principle Dual slope integrating measurement with
2.3.3 Advanced Meter Functions
ranges
parasitic serial and parallel resistance
cancellation.
2-8
Zero Set Set actual value to reference
Fast/Normal/Smooth
Meter settling time Fast 1s @ 1µs to 10 ms/div
Meter settling time Normal 2s @ 1µs to 10 ms/div
Meter settling time Smooth 10s @ 1µs to 10 ms/div
Touch Hold (on A) Captures and freezes a stable measurement
TrendPlot Graphs meter readings of the Min and
Fixed Decimal Point Possible by using attenuation keys.
2.4 Miscellaneous
Display
Size 72 x 72 mm (2.83 x 2.83 in)
Characteristics
2.4 Miscellaneous
result. Beeps when stable. Touch Hold
works on the main meter reading , with
threshholds of 1 Vpp for AC signals and
100mV for DC signals.
Max values from 15 s/div (120 seconds) to
2 days/div (16 days) with time and date
stamp. Automatic vertical scaling and time
compression.
Displays the actual and Minimum,
Maximum, or average (AVG) reading.
2
Resolution 240 x 240 pixels
Waveform display:
Vertical 8 divisions of 20 pixels
Horizontal 9.6 divisions of 25 pixels
Backlight Cold Cathode Fluorescent (CCFL)
Power
External: via Power Adapter PM8907
Input Voltage 10 to 21V DC
Power 5W typical
Input Connector 5 mm jack
Internal:
Battery Power Rechargeable Ni-Cd 4.8V
Operating Time 4 hours with bright backlight
5 hours with dimmed backlight
Charging Time 4 hours with test tool off
12 hours with test tool on
12 hours with refresh cycle
Allowable ambient temperature
during charging 0 to 45 °C (32 to 113 °F)
Memory
Number of Screens 2
Number of User Setups 10
Mechanical
Size 232 x 115 x 50 mm (9.1 x 4.5 x 2 in)
Weight 1.1 kg (2.5 lbs), including battery pack.
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2.5 Environmental
Interface RS-232, optically isolated
To Printer supports Epson FX, LQ, and HP Deskjet
Laserjet
, and Postscript
Serial via PM9080 (optically isolated
RS232 adapter/cable, optional).
Parallel via PAC91 (optically isolated
print adapter cable, optional).
To PC Dump and load settings and data.
Serial via PM9080 (optically isolated
RS232 adapter/cable, optional), using
SW90W (FlukeView software for
Windows).
Environmental MIL 28800E, Type 3, Class III, Style B
Temperature
Operating 0 to 50 °C (32 to 122 °F)
Storage -20 to 60 °C (-4 to 140 °F)
,
Humidity
Operating:
@0 to 10 °C (32 to 50 °F) noncondensing
@10 to 30 °C (50 to 86 °F) 95%
@30 to 40 °C (86 to 104 °F) 75%
@40 to 50 °C (104 to 122 °F) 45%
Storage:
@-20 to 60 °C (-4 to 140 °F) noncondensing
Altitude
Operating 4.5 km (15 000 feet)
Max. Input and Floating Voltage 600
Vrms up to 2 km, linearly derating to 400
Vrms @ 4.5 km
Storage 12 km (40 000 feet)
Vibration max. 3g
Shock max. 30g
Fungus Resistance MIL28800E, Class 3, 3.7.7 & 4.5.6.1
Salt Exposure MIL28800E, Class 3, 3.7.8.2 & 4.5.6.2.2.
Structural parts meet 48 hours 5% salt
solution test.
Electromagnetic Compatibility (EMC)
2-10
Emission EN 50081-1 (1992): EN55022 and
EN60555-2
Immunity EN 50082-2(1992): IEC1000-4-2, -3, -4, -5
(see also Section 2.8, Tables 2-1 to 2-3)
Enclosure Protection IP51, ref: IEC529
2.6 Service and Maintenance
Calibration Interval 1 Year
2.7 Safety
Designed for measurements on 600 Vrms Category III Installations, Pollution Degree 2,
per:
• ANSI/ISA S82.01-1994
• EN61010-1 (1993) (IEC1010-1)
• CAN/CSA-C22.2 No.1010.1-92 (including approval)
• UL3111-1 (including approval)
Max. Input Voltage Input A and B
Direct on input or with leads 600 Vrms. For derating see Figure 2-1.
With Banana-to-BNC Adapter BB120 300V rms. For derating see Figure 2-1.
Max. Floating Voltage
from any terminal to ground 600 Vrms up to 400Hz
Characteristics
2.6 Service and Maintenance
2
Figure 2-1. Maximum Input Voltage vs Frequency
ST8112.CGM
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2.8 EMC Immunity
No visible disturbance E= 3 V/m E= 10 V/m
The Fluke 123, including standard accessories, conforms with the EEC directive 89/336
for EMC immunity, as defined by IEC1000-4-3, with the addition of tables 2-1 to 2-3.
Trace Disturbance with STL120 See Table 2-1 and Table 2-2.
Table 2-1. No Visible Trace Disturbance
Frequency range 10 kHz to 27 MHz
Frequency range 27 MHz to 1 GHz
Table 2-2. Trace Disturbance < 10%
Disturbance less than 10% of full scale E= 3 V/m E= 10 V/m
Frequency range 10 kHz to 27 MHz
Frequency range 2 MHz to 1 GHz
(-): no visible disturbance
Test tool ranges not specified in Table 2-1 and Table 2-2 may have a disturbance of more than 10% of full
scale.
50 mV/div to 500 V/div
50 mV/div to 500 V/div
10 mV/div to 20 mV/div
5 mV/div to 20 mV/div
500 mV/div to 500 V/div
50 mV/div to 500 V/div
50 mV/div to 200 mV/div
-
Multimeter disturbance See Table 2-3.
• VDC, VAC, and VAC+DC with STL 120 and short ground lead
• OHM, CONT, DIODE, and CAP with STL120 and black test lead to COM
Table 2-3. Multimeter Disturbance < 1%
Disturbance less than 1% of full scale E= 3 V/m E= 10 V/m
2-12
Frequency range 10 kHz to 27 MHz
VDC, VAC, VAC+DC
OHM, CONT, DIODE
CAP
Frequency range 27 MHz to 1 GHz
VDC, VAC, VAC+DC
OHM, CONT, DIODE
CAP
Test tool ranges not specified in Table 2-3 may have a disturbance of more than 10% of full scale.
500 mV to 1250V
500Ω to 30 MΩ
50 nF to 500 µF
500 mV to 1250V
500Ω to 30 MΩ
50 nF to 500 µF
500 mV to 1250V
500Ω to 30 MΩ
50 nF to 500 µF
500 mV to 1250V
500Ω to 30 MΩ
50 nF to 500 µF
Chapter 3
Circuit Descriptions
Title Page
3.1 Introduction................................................................................................. 3-3
3.2 Block Diagram ............................................................................................ 3-3
3.2.1 Channel A, Channel B Measurement Circuits..................................... 3-4
3.2.2 Trigger Circuit ..................................................................................... 3-4
3.2.3 Digital Circuit ...................................................................................... 3-5
3.2.4 Power Circuit....................................................................................... 3-6
3.2.5 Start-up Sequence, Operating Modes .................................................. 3-7
3.3 Detailed Circuit Descriptions...................................................................... 3-9
3.3.1 Power Circuit....................................................................................... 3-9
3.3.2 Channel A - Channel B Measurement Circuits ................................... 3-15
3.3.3 Trigger Circuit ..................................................................................... 3-20
3.3.4 Digital Circuit ...................................................................................... 3-25
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3-2
Figure 3-1. Fluke 123 Block Diagram
ST7965.EPS
3.1 Introduction
Section 3.2 describes the functional block diagram shown in Figure 3-1. It provides a
quick way to get familiar with the test tool basic build-up.
Section 3.3 describes the principle of operation of the test tool functions in detail, on the
basis of the circuit diagrams shown in Figures 9-1 to 9-5.
For all measurements, input signals are applied to the shielded input banana jackets.
Traces and readings are derived from the same input signal samples. So readings are
related to the displayed readings.
3.2 Block Diagram
In the overall block diagram Figure 3-1, the test tool is divided in five main blocks. Each
block represents a functional part, build up around an Application Specific Integrated
Circuit (ASIC). A detailed circuit diagram of each block is shown in Section 9.
See Table 3-1. for an overview of the blocks in which the test tool is broken down, the
main block function, the ASIC name, and the applicable circuit diagram.
Circuit Descriptions
3.1 Introduction
3
Table 3-1. Fluke 123 Main Blocks
Block Main Functions ASIC Circuit
Diagram
CHANNEL A Input A signal (V-Ω-F) conditioning C(hannel)-ASIC OQ0258 Figure 9-1
CHANNEL B Input B signal (V) conditioning C(hannel)-ASIC OQ0258 Figure 9-2
TRIGGER Trigger selection and conditioning
Current source for resistance, capacitance,
continuity, and diode measurements
AC/DC input coupling and Ω/F relay control
Voltage reference source
DIGITAL Analog to Digital Conversion
Acquisition of ADC samples
Micro controller (µP-ROM-RAM)
Keyboard- and LCD control
POWER Power supply, battery charger
LCD back light voltage converter
Optical interface input
T(rigger)-ASIC OQ0257 Figure 9-3
D(igital)-ASIC MOT0002 Figure 9-4
P(ower)-ASIC OQ0256 Figure 9-5
All circuits, except the LCD unit and the KEYBOARD, are located on one Printed
Circuit Board (PCB), called the MAIN PCB.
The ASIC’s are referred to as C-ASIC (Channel ASIC), T-ASIC (Trigger ASIC), P-ASIC
(Power ASIC), and D-ASIC (Digital ASIC).
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3.2.1 Channel A, Channel B Measurement Circuits
The Channel A and Channel B circuit are similar. The only difference is that Channel A
can do all measurements, whereas Channel B does not provide resistance, diode, and
capacitance measurements.
Volts, and derived measurements (e.g. current with optional probe)
The input voltage is supplied to the C-ASIC, via the LF and HF path. The C-ASIC
converts (attenuates, amplifies) the input signal to a normalized output voltage ADCA/ADC-B, which is supplied to the Analog to Digital Converters (ADC-A and ADC-B)
on the DIGITAL part. The D-ASIC acquires the digital samples to build the trace, and to
calculate readings. For the HF and LF attenuation section of the C-ASIC some external
components are required: the HF DECade ATTenuator and LF DECade ATTenuator
section.
Resistance, continuity, and diode measurements (Input A only)
The T-ASIC supplies a current via the Ω/F relays to the unknown resistance Rx,
connected to the Input A and the COM input jacket. The voltage drop across Rx is
measured as for voltage measurements.
Capacitance measurements (Input A only)
The T-ASIC supplies a current via the Ω/F relays to the unknown capacitance Cx,
connected to the Input A and the COM input jacket. Cx is charged and discharged by
this current. The C-ASIC converts the charging time and the discharging time into a
pulse width signal. This signal is supplied to the T-ASIC via the C-ASIC trigger output
TRIG-A. The T-ASIC shapes and levels the signal, and supplies the resulting pulse
width signal ALLTRIG to the D-ASIC. The D-ASIC counts the pulse width and
calculates the capacitance reading.
When the capacitance function is selected no other measurement or wave form display is
possible. There is only a numeric readout of the capacitance value.
Frequency, pulse width, and duty cycle measurements
The input voltage is measured as described above. From the ADC samples to built the
trace, also the frequency, pulse width, and duty cycle of the input signal are calculated.
Miscellaneous
Control of the C-ASIC, e.g. selecting the attenuation factor, is done by the D-ASIC via
the SDAT and SCLK serial communication lines.
An offset compensation voltage and a trace position control voltage are provided by the
D-ASIC via the APWM bus.
The C-ASIC’s also provide conditioned input voltages on the TRIG-A/TRIG-B line.
These voltages can be selected as trigger source by the T-ASIC.
3.2.2 Trigger Circuit
The T ASIC selects one of the possible trigger sources TRIG-A (Input A) or TRIG-B
(Input B). For TV triggering the selected trigger source signal is processed via the
Sync(hronization) Pulse Separator circuit (TVOUT-TVSYNC lines). Two adjustable
trigger levels are supplied by the D-ASIC via the PWM FILTERS (TRIGLEV1 and
TRIGLEV2 line). Depending on the selected trigger conditions (- source, - level, - edge,
- mode), the T-ASIC generates the final trigger signal TRIGDT, which is supplied to the
D-ASIC.
3-4
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