Lincoln Electric POWER-ARC 4000 SVM103-A Service Manual page 41

TROUBLE SHOOTING & REPAIR SECTION
Troubleshooting & Repair Section.................................................................................Section F
Safety Precautions.................................................................................................................F-1
How to Use Troubleshooting Guide ......................................................................................F-1
Troubleshooting Guide...................................................................................................F1 - F-9
Test Procedures
Rotor Voltage Test ........................................................................................................F-10
Rotor Resistance Test...................................................................................................F-12
Engine Throttle Adjustment Test...................................................................................F-15
Oscilloscope Waveforms
Normal Open Circuit Weld Voltage Waveform .............................................................F-18
Normal Open Circuit Weld Voltage Waveform (115 VAC Supply) ................................F-19
Typical Weld Output Waveform - Machine Loaded .....................................................F-20
Replacement Procedures
Brush Removal and Replacement ................................................................................F-21
Rheostat Removal and Replacement ..........................................................................F-23
Capacitor and Diode Bridge Removal and Replacement.............................................F-25
Stator/Rotor Removal and Replacement (Kit S20925) .................................................F-27
Retest After Repair ..............................................................................................................F-32
TABLE OF CONTENTS
Section F
POWER-ARC 4000