Lincoln Electric PRECISION TIG 275 IM702-A Operator's Manual page 36

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Observe all Safety Guidelines detailed throughout this manual
PROBLEMS
(SYMPTOMS)
Stick electrode "blast off" when arc
is struck
Stick electrode "sticks" in the weld
puddle
Poor starting in DC polarity
Arc "flutters" in DC polarity, o.k. in
AC polarity
Arc "flutters" in both DC & AC polari-
ties
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.
TROUBLESHOOTING
POSSIBLE
CAUSE
STICK WELDING PROBLEMS
1. Current may be set too high for
electrode size
2. (Machine with Advanced Control
PC board only) Hot Start level set
too high
1. Current may be set too low for
electrode size
2. (Machine with Advanced Control
PC board only) Arc Force level set
too low
TIG WELDING PROBLEMS
1. Input line may be too low
2. Bad connection at P11 of Control
PC board
3. Bad Background rectifier, back-
ground resistor R7, or background
diode D2
1. Tungsten not "sharp"
2. Bad free wheeling diode D1 or its
connection
1. Tungsten electrode may be too
large in diameter for the current
setting
2. Gas shielding may be insufficient.
3. Contaminated gas or leaks in the
gas line, torch, or connections
4. Helium blend is used as a shield-
ing gas
CAUTION
PRECISION TIG 275
RECOMMENDED
COURSE OF ACTION
If all recommended possible areas
of misadjustment have
checked and the problem persists,
Contact your local
Authorized Field Service Facility.
If all recommended possible areas
of misadjustment have
checked and the problem persists,
Contact your local
Authorized Field Service Facility.
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Lincoln
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Lincoln