Lincoln Electric PRECISION TIG 185 SVM169-A Service Manual page 51

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TROUBLESHOOTING GUIDE
PROBLEMS
(SYMPTOMS)
When AC TIG welding, the arc is
erratic and there is a loss of "clean-
ing" 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 test/repairs safely, con-
tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call
1-888-935-3877.
TROUBLESHOOTING & REPAIR
POSSIBLE AREAS OF
MISADJUSTMENT(S)
TIG WELDING 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 185
Observe Safety Guidelines
detailed in the beginning of this manual.
RECOMMENDED
COURSE OF ACTION
1. Check components R3 and C4 in
the high voltage transformer pri-
mary circuit.
2. Perform the SCR Bridge Test.
1. This may be a welding procedure
problem.
Contact The Lincoln Electric Service
Department 1-888-935-3877.
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