Lincoln Electric SVM141-A service manual Table of Contents Troubleshooting & Repair Section

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Section F-1 Section F-1

TABLE OF CONTENTS

- TROUBLESHOOTING & REPAIR SECTION -

Troubleshooting & Repair Section	Section F
How to Use Troubleshooting Guide	F-2
PC Board Troubleshooting Procedures	F-3
Troubleshooting Guide	F-4
Test Procedures
High Frequency Circuit Disable Procedure	F-18
T1 Main Transformer Test	F-20
Gas (Water) Solenoid Test	F-24
Static SCR Test	F-26
Active SCR Test	F-29

Oscilloscope Waveforms
Normal Open Circuit Voltage Waveform—AC TIG Mode	F-33
Normal Open Circuit Voltage Waveform—DC TIG Mode	F-34
Normal Open Circuit Voltage Waveform—AC Stick Mode	F-35
Normal Open Circuit Voltage Waveform—DC Stick Mode	F-36
Typical Output Voltage Waveform—MachineLoaded—AC TIG Mode	F-37
Typical Output Voltage Waveform—MachineLoaded—DC TIG Mode	F-38
Typical Output Voltage Waveform—MachineLoaded—AC Stick Mode	F-39
Typical Output Voltage Waveform—MachineLoaded—DC Stick Mode	F-40
Abnormal Open Circuit Voltage—DC TIG Mode—One Output SCR Not Functioning	F-41

Replacement Procedures
High Voltage Transformer Removal and Replacement	F-42
SCR Bridge Assembly Removal and Replacement	F-45
Polarity Switch Removal and Replacement	F-49
Main Transformer and Output Choke Assembly Removal and Replacement	F-54
Retest After Repair	F-59

SQUARE WAVE TIG 275