Lincoln Electric PRO-CUT 55 Service Manual page 39

Section F-1
TROUBLESHOOTING & REPAIR SECTION
Troubleshooting & Repair Section .................................................................................Section F
How to Use Troubleshooting Guide ......................................................................................F-2
PC Board Troubleshooting Procedures and Replacement ...................................................F-3
Troubleshooting Guide...........................................................................................................F-4
Test Procedures
Input Filter Capacitor Discharge Procedure..................................................................F-10
Input Rectifier Test ........................................................................................................F-12
Primary Power Board Resistance Test and Capacitor Voltage Test .............................F-15
Output Power Board Resistance Test...........................................................................F-20
Torch Continuity and Solenoid Test ..............................................................................F-23
Air/Gas Solenoid Test....................................................................................................F-25
T2 Auxiliary Transformer Test ........................................................................................F-27
Trigger Circuit Test ........................................................................................................F-30
Low Voltage Circuit Test................................................................................................F-35
Replacement Procedures
Control Board Removal and Replacement ...................................................................F-40
Display Board Removal and Replacement ...................................................................F-43
Output Power Board Removal and Replacement.........................................................F-46
Primary Power Board and Filter Capacitor Removal and Replacement ......................F-50
Input Rectifier Bridge Removal and Replacement........................................................F-54
Retest after Repair ........................................................................................................F-57
TABLE OF CONTENTS
PRO-CUT 55
Section F-1