Section f - troubleshooting & repair – Lincoln Electric POWER MIG 255 SVM144-B User Manual
Page 39
POWER MIG 255
Section F-1
Section F-1
TABLE OF CONTENTS
- TROUBLESHOOTING & REPAIR SECTION -
Troubleshooting & Repair Section ........................................................................Section F
PC Board Troubleshooting Procedures and Replacement...........................................F-3
Test Procedures
Wire Drive Motor and Tachometer Feedback Test ...............................................F-27
Oscilloscope Waveforms
Typical Output Voltage Waveform - Machine Loaded..........................................F-32
Abnormal Output Voltage Waveform - Machine Loaded One Output SCR Not Functioning .............F-33
Abnormal Open Circuit Voltage Output Capacitor Bank Not Functioning...........F-34
Replacement Procedures
Control PC Board Removal and Replacement .....................................................F-37
Wire Drive Assembly Removal and Replacement ................................................F-41
SCR Output Rectifier Removal and Replacement ...............................................F-45
Capacitor Bank Removal and Replacement ........................................................F-49
Main Transformer and Output Choke Removal and Replacement ......................F-51
Fan Motor and Fan Removal and Replacement ..................................................F-55