POWER MIG 255
TROUBLESHOOTING & REPAIR
F-23 F-23
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ACTIVE SCR RECTIFIER ASSEMBLY TEST
Service and repair should only be performed by Lincoln Electric factory trained
personnel. Unauthorized repairs performed on this equipment may result in dan-
ger to the technician or machine operator and will invalidate your factory war-
ranty. For your safety and to avoid electrical shock, please observe all safety
notes and precautions detailed throughout this manual.
If for any reason you do not understand the test procedures or are unable to per-
form the test/repairs safely, contact the Lincoln Electric service department for
technical troubleshooting assistance before you proceed. Call 1-888-935-3877.
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TEST DESCRIPTION
The Active SCR Rectifier Assembly Test will determine if the device is able to be gated
ON and conduct current from anode to cathode.
The Static SCR Rectifier Assembly Test must be performed before proceeding with the
Active SCR Test.
MATERIALS NEEDED
3/8 in. Nutdriver
5/16 in. Nutdriver
An SCR Tester as specified in this procedure
POWER MIG 255 wiring diagrams (See Electrical Diagrams Section of this Manual)
SCR Heat Sink Assembly Drawings
A volt-ohmmeter
WARNING