Lincoln Electric SVM 122-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 - F-14
Test Procedures
Input Contactor Test	F-15
Control Transformer (T2) Voltage Test	F-18
Main Transformer (T1) Voltage Test	F-21
Static SCR/Diode Rectifier Bridge Test	F-26
Active SCR Test	F-29
Oscilloscope Waveforms	F-33
Normal Open Circuit Voltage Waveform-Constant Current Mode	F-33
Normal Open Circuit Voltage Waveform-Constant Voltage FCAW/GMAW	F-34
Normal Open Circuit Voltage Waveform-Constant Voltage Subarc	F-35
Typical Output Voltage Waveform-Constant Voltage FCAW/GMAW	F-36
Typical Output Voltage Waveform-Constant Voltage Subarc	F-37
Typical SCR Gate Voltage Waveform-Constant Voltage Subarc	F-38
Abnormal Open Circuit Voltage Waveform-Constant Voltage Subarc	F-39
Replacement Procedures	F-40
Input Contactor (CR1) Cleaning/Replacement	F-40
Fan Motor and Blade Removal and Replacement	F-42
SCR/Diode Rectifier Assembly Removal and Replacement	F-44
SCR Removal and Replacement	F-46
Mounting of Stud Type Diodes to Aluminum Heat Sinks	F-52
Main Transformer Removal and Replacement	F-54
Retest After Repair	F-61

IDEALARC DC-400

LINCOLN ®

ELECTRIC