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TROUBLESHOOTING & REPAIR
F-13 F-13
SQUARE WAVE TIG 275
TROUBLESHOOTING GUIDE Observe Safety Guidelines
detailed in the beginning of this manual.
CAUTION
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
TIG WELDING PROBLEMS
The high frequency “spark” is pre-
sent at the tungsten electrode, but
the operator is unable to establish
a welding arc. The machine has
normal open circuit voltage. Refer
to
Technical Specifications
in the
Installation section.
1. The torch may be faulty. Check
or replace.
2. The current control may be set
too low.
3. The tungsten electrode may be
contaminated. Replace or
sharpen.
4. The electrode may be too large
for the process.
5. If a helium blend is being used
as a shielding gas, reduce the
percentage of helium.
6. Check the welding cables for
loose or faulty connections.
1. Check spark gap adjustment.
See the
Maintenance
section.
2. This may be a welding proce-
dure problem.
Contact the Lincoln Service
Department (216) 383-2531 or
1-800-833-9353 (WELD).
When AC TIG welding, the arc is
erratic and there is a loss of “clean-
ing” of the work piece.
1. The tungsten electrode may be
small for the process. Use a
larger diameter tungsten or a
pure tungsten.
2. If a helium blend is used as a
shielding gas, reduce the per-
centage of helium.
1. Check components R5 and C6
in the high voltage transformer
primary circuit.
2. Perform the
SCR Bridge Test.