Lincoln Electric IDEALARC DC-655 - Manual (Page 43)

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Section F-1 Section F-1
IDEALARC DC-655
Troubleshooting & Repair Section .................................................................................Section F
How to Use Troubleshooting Guide ......................................................................................F-2
PC Board Troubleshooting Procedures .................................................................................F-3
Troubleshooting Guide .................................................................................................F-4–F-12
Test Procedures
Internal Trigger Circuit Test ...........................................................................................F-13
Firing Board Test ...........................................................................................................F-17
Main Transformer (T1) Voltage Test...............................................................................F-22
Control Transformer (T2) Voltage Test...........................................................................F-27
Control Board Transformer (T3) Test .............................................................................F-30
Input Contactor Test......................................................................................................F-32
Static SCR Test .............................................................................................................F-35
Active SCR Test.............................................................................................................F-38
Thermal Fan/Snubber Board LED Chart .......................................................................F-41
Control Board LED Chart ..............................................................................................F-42
Oscilloscope Waveforms
Normal Open Circuit Voltage Waveform-Constant Current Mode................................F-43
Normal Open Circuit Voltage Waveform-Constant Voltage MIG Maximum Output .....F-44
Normal Open Circuit Voltage Waveform-Constant Voltage MIG Minimum Output ......F-45
Typical Output Voltage Waveform-Constant Voltage MIG ............................................F-46
Typical SCR Gate Voltage Waveform-Constant Voltage MIG .......................................F-47
Abnormal Open Circuit Voltage Waveform-Constant Voltage MIG ..............................F-48
Replacement Procedures
Input Contactor (CR1) Cleaning/Replacement .............................................................F-49
SCR Rectifier Bridge Removal and Replacement ........................................................F-51
Main Transformer and Choke Removal and Replacement ...........................................F-54
Retest After Repair ..............................................................................................................F-57
TABLE OF CONTENTS
TROUBLESHOOTING & REPAIR SECTION