Service and repair should be performed only by Lincoln Electric factory trained personnel.
Unauthorized repairs performed on this equipment could result in danger to the technician or the
machine operator and will invalidate your factory warranty. 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 perform the
tests/repairs safely, contact the Lincoln Electric Service Department for technical troubleshooting
assistance before you proceed. Call (800) 833-9353 (WELD).

TEST DESCRIPTION

The Test determines whether or not the Firing Board is receiving the correct voltages and gate
signals. The LEDs (Light Emitting Diodes) will help you determine if the Firing Board is Generating
gate signals to the main SCRs.

MATERIALS NEEDED

Volt/Ohm Meter (Multimeter)
MULTI-SOURCE Wiring Diagram and Firing Board Schematic Diagram (See Electrical Diagram
Section of Manual).

This procedure takes approximately 30 minutes to perform.