Lincoln Electric SQUARE WAVE TIG 355 Service Manual page 57

F-5
Observe Safety Guidelines detailed in the beginning of this manual.
PROBLEMS
(SYMPTOMS)
The input contactor activates when
"start" button is pushed but will NOT
stay closed. Machine shuts off
when "start" button is released.
The machine shuts off and the con-
trol fuse (F1) repeatedly fails.
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 1-888-935-3877.
TROUBLESHOOTING AND REPAIR
POSSIBLE AREAS OF
MISADJUSTMENT(S)
OUTPUT PROBLEMS
1. Check the input voltage at the
machine.
match the rating plate and the
reconnect panel.
2. Blown or missing control circuit
fuse (F1).
1. Check the input voltage at the
machine.
match the rating plate and the
reconnect panel.
2. Make sure the fuse is the correct
rating (1/2 amp).
3. The input voltage may be too
high (more than 10% over rated).
CAUTION
SQUARE WAVE TIG 355
1. Perform the Input Contactor
Input voltage must Test.
2. Perform the Control
Transformer Test.
3. Perform the Feed – Thru PC
Board Test.
4. Perform the Control PC Board
Test.
5. The power board may be faulty.
Replace.
1. Perform the Control
Input voltage must Transformer Test.
2. Perform the Power Board Test.
3. The control board may be faulty.
Replace.
RECOMMENDED
COURSE OF ACTION
F-5