Lincoln Electric SVM144-B service manual Troubleshooting & Repair Section, Section F

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Section F-1	TABLE OF CONTENTS	Section F-1
	- TROUBLESHOOTING & REPAIR SECTION -

Troubleshooting & Repair Section	Section F
How to Use Troubleshooting Guide	F-2
PC Board Troubleshooting Procedures and Replacement	F-3
Troubleshooting Guide	F-4
Test Procedures
Main Transformer Test	F-11
Rectifier Diode Bridge Test	F-15
Static SCR Rectifier Assembly Test	F-19
Active SCR Rectifier Assembly Test	F-23
Wire Drive Motor and Tachometer Feedback Test	F-27
Oscilloscope Waveforms
Normal Open Circuit Voltage Waveform	F-31
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
Typical SCR Gate Voltage Waveform	F-35
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
Retest After Repair	F-57

POWER MIG 255