Lincoln Electric TIG 275 - Manual (Page 39)

E-7 TROUBLESHOOTING E-7
PRECISION TIG 275
Observe all Safety Guidelines detailed throughout this manual
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact your Local
Lincoln Authorized Field Service Facility for technical troubleshooting assistance before you proceed.
CAUTION
TIG PROBLEMS
PROBLEMS
(SYMPTOMS)
POSSIBLE
CAUSE
RECOMMENDED
COURSE OF ACTION
Arc "pulsates" in AC polarity, DC
polarity is o.k.
Black area along weld bead
Output quits momentarily; gas flow
and hi-freq are also interrupted
1.Micro switch S2A on polarity switch
does not open in AC polarity
1. Oily or organic contamination from
work piece
2. Tungsten electrode may be conta-
minated
3. Leaks in gas line, torch, or con-
nections
1. May be caused by hi-freq interfer-
ence. Check that machine is
grounded properly. Surrounding
machines that generate hi-freq
also should be properly grounded.
2. Ground connection of Protection
PC board may has become loose
3. Ground connection of
Bypass/Stabilizer PC board may
has become loose. If all recommended possible areas
of misadjustment have been
checked and the problem persists,
Contact your local Lincoln
Authorized Field Service Facility.