Lincoln Electric PRECISION TIG SVM186-A Service Manual page 53

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Observe Safety Guidelines detailed in the beginning of this manual.
PROBLEMS
(SYMPTOMS)
When AC TIG welding, the arc is
erratic and there is a loss of
"cleaning" of the work piece.
The end of the tungsten electrode
melts away.
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. The tungsten electrode may be
too small for the process. Use
a larger diameter tungsten or a
pure tungsten.
2. If a helium blend is used as a
shielding gas, then reduce the
percentage of helium.
1. The welding current is too high
for the electrode type and or
size. See Table B.1 in the
Operation Section.
CAUTION
PRECISION TIG® 225
RECOMMENDED
COURSE OF ACTION
1. Check components R3 and C4
in the high voltage transformer
primary circuit.
2. Perform the SCR Bridge Test.
1. This may be a welding proce-
dure problem.
Contact The Lincoln Electric
Service Department 1-888-935-
3877.
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