Fluke ScopeMeter 123 User manual

®
Fluke 123/124/125
Industrial ScopeMeter
Service Manual
4822 872 05398
March 2007
© 2007 Fluke Corporation, All rights reserved.
All product names are trademarks of their respective companies.

Limited Warranty & 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 three years for the Analyzer and one year for its accessories. The warranty
period 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 to 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 CONSEQUENTIAL
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.
Fluke Corporation, P.O. Box 9090, Everett, WA 98206-9090 USA, or
Fluke Industrial B.V., P.O. Box 90, 7600 AB, Almelo, The Netherlands.

i
Table of Contents
Chapter Title Page
Limited Warranty & Limitation of Liability........................................................ii
Introduction and Safety Instructions................................................................1-1
1.1 Introduction to Service Manual .....................................................................1-3
1.2 Safety.............................................................................................................1-3
1.2.1 Introduction.................................................................................................1-3
1.2.2 Safety Precautions.......................................................................................1-3
1.2.3 Caution and Warning Statements................................................................1-3
1.2.4 Symbols used in this Manual and on Instrument........................................1-4
1.2.5 Impaired Safety...........................................................................................1-4
1.2.6 General Safety Information.........................................................................1-4
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.........................................................................2-9
2.4 Cursor Readout (Fluke 124, 125)...................................................................2-10
2.5 Harmonics Measurements (Fluke 125)..........................................................2-10
2.6 Field Bus Measurements (Fluke 125)............................................................2-11
2.7 Miscellaneous ................................................................................................2-11
2.8 Environmental................................................................................................2-12
2.9 Service and Maintenance...............................................................................2-13
2.10 Safety...........................................................................................................2-13
2.11 EMC Immunity............................................................................................2-15

Fluke 123/124/125
Service Manual
ii
Performance Verification...................................................................................3-1
3.1 Introduction....................................................................................................3-3
3.2 Equipment Required For Verification ...........................................................3-3
3.3 How To Verify...............................................................................................3-4
3.4 Display and Backlight Test............................................................................3-4
3.5 Input A and Input B Tests..............................................................................3-5
3.5.1 Input A and B Base Line Jump Test...........................................................3-6
3.5.2 Input A Trigger Sensitivity Test.................................................................3-8
3.5.3 Input A Frequency Response Upper Transition Point Test ........................3-9
3.5.4 Input A Frequency Measurement Accuracy Test .......................................3-9
3.5.5 Input B Frequency Measurement Accuracy Test........................................3-10
3.5.6 Input B Frequency Response Upper Transition Point Test.........................3-11
3.5.7 Input B Trigger Sensitivity Test .................................................................3-12
3.5.8 Input A and B Trigger Level and Trigger Slope Test.................................3-13
3.5.9 Input A and B DC Voltage Accuracy Test .................................................3-16
3.5.10 Input A and B AC Voltage Accuracy Test ...............................................3-18
3.5.11 Input A and B AC Input Coupling Test....................................................3-19
3.5.12 Input A and B Volts Peak Measurements Test.........................................3-20
3.5.13 Input A and B Phase Measurements Test .................................................3-21
3.5.14 Harmonics (Fluke 125).............................................................................3-21
3.5.15 Input A and B High Voltage AC/DC Accuracy Test................................3-22
3.5.16 Resistance Measurements Test .................................................................3-24
3.5.17 Continuity Function Test ..........................................................................3-25
3.5.18 Diode Test Function Test..........................................................................3-26
3.5.19 Capacitance Measurements Test...............................................................3-26
3.5.20 Video Trigger Test....................................................................................3-27
Calibration Adjustment......................................................................................4-1
4.1 General...........................................................................................................4-3
4.1.1 Introduction.................................................................................................4-3
4.1.2 Calibration number and date.......................................................................4-3
4.1.3 General Instructions....................................................................................4-3
4.2 Equipment Required For Calibration.............................................................4-4
4.3 Starting Calibration Adjustment....................................................................4-4
4.4 Contrast Calibration Adjustment ...................................................................4-6
4.5 Warming Up & Pre-Calibration.....................................................................4-7
4.6 Final Calibration............................................................................................4-7
4.6.1 HF Gain Input A&B ...................................................................................4-7
4.6.2 Delta T Gain, Trigger Delay Time & Pulse Adjust Input A.......................4-9
4.6.3 Pulse Adjust Input B...................................................................................4-10
4.6.4 Gain DMM (Gain Volt)..............................................................................4-10
4.6.5 Volt Zero.....................................................................................................4-12
4.6.6 Zero Ohm....................................................................................................4-12
4.6.7 Gain Ohm....................................................................................................4-13
4.6.8 Capacitance Gain Low and High................................................................4-14
4.6.9 Capacitance Clamp & Zero.........................................................................4-14
4.6.10 Capacitance Gain......................................................................................4-15
4.7 Save Calibration Data and Exit......................................................................4-15

Contents (continued)
iii
Disassembling the Test Tool ............................................................................5-1
5.1. Introduction...................................................................................................5-3
5.2. Disassembling Procedures............................................................................5-3
5.1.1 Required Tools............................................................................................5-3
5.2.2 Removing the Battery Pack ........................................................................5-3
5.2.3 Removing the Bail......................................................................................5-3
5.2.4 Opening the Test Tool ................................................................................5-3
5.2.5 Removing the Main PCA Unit....................................................................5-5
5.2.6 Removing the Display Assembly................................................................5-6
5.2.7 Removing the Keypad and Keypad Foil.....................................................5-6
5.3 Disassembling the Main PCA Unit................................................................5-6
5.4 Reassembling the Main PCA Unit.................................................................5-8
5.5 Reassembling the Test Tool...........................................................................5-8
List of Replaceable Parts ..................................................................................6-1
6.1 Introduction....................................................................................................6-3
6.2 How to Obtain Parts.......................................................................................6-3
6.3 Service Centers ..............................................................................................6-3
6.4 Final Assembly Parts .....................................................................................6-4
6.5 Main PCA Unit Parts.....................................................................................6-6
6.6 Service Tools .................................................................................................6-7
6.7 Accessory Replacement Parts........................................................................6-7

v
List of Tables
Table Title Page
2-1.No Visible Trace Disturbance .....................................................................2-15
2-2.Trace Disturbance < 10% ............................................................................2-15
2-3.Multimeter Disturbance < 1%......................................................................2-15
3-1.Input A,B Frequency Measurement Accuracy Test..................................3-10
3-2.Volts DC Measurement Verification Points ...............................................3-17
3-3.Volts AC Measurement Verification Points ...............................................3-19
3-4.Input A and B AC Input Coupling Verification Points...............................3-20
3-5.Volts Peak Measurement Verification Points............................................3-21
3-6.Phase Measurement Verification Points....................................................3-21
3-7.V DC and V AC High Voltage Verification Tests........................................3-24
3-8.Resistance Measurement Verification Points ...........................................3-25
3-9.Capacitance Measurement Verification Points.........................................3-27
4-1.HF Gain Calibration Points Fast.................................................................4-8
4-2.HF Gain Calibration Points Slow................................................................4-9

Fluke 123/124/125
Service Manual
vi
4-3.Volt Gain Calibration Points <300V............................................................4-11
4-4.Ohm Gain Calibration Points......................................................................4-13
6-1.Final Assembly Parts...................................................................................6-4
6-2.Main PCA Unit ..............................................................................................6-6
6-3.Standard Accessories .................................................................................6-7
6-4.Optional Accessories ..................................................................................6-8

vii
List of Figures
Figure Title Page
2-2.Max. Input Voltage v.s. Frequency for VP40 10:1 Voltage Probe............2-14
3-1.Display Pixel Test Pattern...........................................................................3-5
3-2.Menu item selection.....................................................................................3-6
3-3.Test Tool Input A to 5500A Scope Output 50Ω.........................................3-8
3-4.Test Tool Input B to 5500A Scope Output 50Ω.........................................3-10
3-5.Test Tool Input A-B to 5500A Normal Output............................................3-13
3-6.Bargraph Harmonics Ampere.....................................................................3-22
3-7.Bargraph Harmonics Volt............................................................................3-22
3-8.Test Tool Input A-B to 5500A Normal Output for >300V ..........................3-23
3-9.Test Tool Input A to 5500A Normal Output 4-Wire....................................3-24
3-10.Test Tool Input A to TV Signal Generator................................................3-28
3-11.Test Tool Screen for PAL/SECAM line 622..............................................3-29
3-12.Test Tool Screen for NTSC line 525 .........................................................3-29
3-13.Test Tool Screen for PAL/SECAM line 310..............................................3-30

Fluke 123/124/125
Service Manual
viii
3-14.Test Tool Screen for NTSC line 262 .........................................................3-30
3-15.Test Tool Input A to TV Signal Generator Inverted.................................3-30
3-16.Test Tool Screen for PAL/SECAM line 310 Negative Video...................3-31
3-17.Test Tool Screen for NTSC line 262 Negative Video...............................3-31
4-1.Version & Calibration Screen .....................................................................4-3
4-2.Display Test Pattern ....................................................................................4-6
4-3.HF Gain Calibration Input Connections.....................................................4-7
4-4.5500A Scope Output to Input A..................................................................4-9
4-5.5500A Scope Output to Input B..................................................................4-10
4-6. Volt Gain Calibration Input Connections <300V ......................................4-11
4-7.Volt Gain Calibration Input Connections 500V..........................................4-12
4-8.Four-wire Ohms calibration connections..................................................4-13
4-9.Capacitance Gain Calibration Input Connections.....................................4-14
5-1.Fluke 123 Main Assembly ...........................................................................5-4
5-2.Flex Cable Connectors................................................................................5-5
5-3.Main PCA Unit Assembly ............................................................................5-7
5-4.Mounting the display shielding bracket ....................................................5-9
6-1.Fluke 123 Final Assembly ...........................................................................6-5
6-2.Main PCA Unit ..............................................................................................6-6