If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con-
tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call
216-383-2531 or 1-800-833-9353.

PROBLEMS
(SYMPTOMS)

POSSIBLE AREAS OF
MISADJUSTMENT(S)

RECOMMENDED
COURSE OF ACTION

OUTPUT PROBLEMS

The machine makes a very loud
buzzing noise in DC Stick or in DC
TIG modes. There is no current
draw from the machine’s output ter-
minals. (The machine is not exter-
nally loaded).

1. Inspect the output terminal insu-

lators for cracks or signs of
overheating.

1. Diode D1 may be shorted.

Check and replace if necessary.

2. Check the polarity switch (S2)

for proper function and correct
connections.

3. Perform the

SCR Bridge Test.