1TABLE of Contents Troubleshooting and Repair F-1

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F-1TABLE OF CONTENTS - TROUBLESHOOTING AND REPAIR F-1

Troubleshooting and Repair

F-1

How to Use Troubleshooting Guide	F-2
PC Board Troubleshooting Procedures and Replacement	F-3
Troubleshooting Guide	F-4
Test Procedures
High Frequency Circuit Disable Procedure	F-15
T1 Transformer Test	F-17
Static SCR Test	F-21
Active SCR Test	F-25
Oscilloscope Waveforms
Normal Open Circuit Voltage Waveform-AC TIG Mode	F-29
Normal Open Circuit Voltage Waveform-DC TIG Mode	F-30
Normal Open Circuit Voltage Waveform-AC Stick Mode	F-31
Normal Open Circuit Voltage Waveform-DC Stick Mode	F-32
Typical Output Voltage Waveform-Machine Loaded AC TIG Mode	F-33
Typical Output Voltage Waveform-Machine Loaded DC TIG Mode	F-34
Typical Output Voltage Waveform-Machine Loaded AC Stick Mode	F-35
Typical Output Voltage Waveform-Machine Loaded DC Stick Mode	F-36
Abnormal Open Circuit Voltage-DC TIG Mode One SCR not Functioning	F-37
Replacement Procedures
SCR Bridge Assembly Removal and Replacement	F-39
Polarity Switch Removal and Replacement	F-45
High Voltage Transformer Removal and Replacement	F-49
Main Transformer and Output Choke Removal and Replacement	F-53
Retest after Repair	F-55