Lincoln Electric SVM175-A TROUBLESHOOTING & REPAIR SECTION

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Section F-1 Section F-1
RANGER 305D
Troubleshooting& Repair Section ................................................................................Section F
How to Use TroubleshootingGuide .......................................................................................F-2
PC Board TroubleshootingProcedures .................................................................................F-3
Troubleshooting Guide................................................................................................F-4 - F-20
TestProcedures ...................................................................................................................F-21
Case Cover Removal and Replacement Procedure ....................................................F-21
Chopper Module Capacitor Discharge Procedure ........................................................F-23
Fuel Shutdown Solenoid Test........................................................................................F-25
Engine ThrottleAdjustment Test....................................................................................F-29
Idler Solenoid Test.........................................................................................................F-33
EngineAlternator Test...................................................................................................F-35
Brush and Slip Ring Service Procedure........................................................................F-37
Rotor Resistance and Ground Test...............................................................................F-39
Rotor Resistance and Ground Test...............................................................................F-41
Rotor Voltage Test .........................................................................................................F-43
Flashing Voltage Test....................................................................................................F-47
Stator VoltageTest .......................................................................................................F-51
Stator Short Circuit & Ground Test...............................................................................F-55
Output rectifier Bridge Test...........................................................................................F-57
Chopper Module Function Test ....................................................................................F-61
Chopper Module Resistance Test ................................................................................F-65
Weld Control Board PWM Gate Signal Test ................................................................F-69
Weld Control Feedback Test .........................................................................................F-71
Control Potentiometer and Mode Switch Resistance Test............................................F-75
Remote Receptacle Test ...............................................................................................F-79
Replacement Procedures ....................................................................................................F-83
Output Rectifier Bridge and Choke Removal and Replacement...................................F-83
Chopper Module Removal and Replacement...............................................................F-87
Engine/Stator/Rotor Removal and Replacement..........................................................F-91
Oscilloscope Waveforms......................................................................................................F-97
Normal Open Circuit VoltageWaveform (120 VAC Supply)..........................................F-97
Normal Open Circuit VoltageWaveform (Stick) ............................................................F-98
Normal Weld VoltageWaveform (Stick CC) ..................................................................F-99
Normal Open Circuit VoltageWaveform (Wire CV Tap)..............................................F-100
Normal Weld VoltageWaveform (Wire CV) ................................................................F-101
RetestAfter Repair.............................................................................................................F-102
TABLE OF CONTENTS
TROUBLESHOOTING & REPAIR SECTION