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PROBLEMS
(SYMPTOMS)
POSSIBLE AREAS OF
MISADJUSTMENTS(S)
RECOMMENDED
COURSE OF ACTION
F-9
TROUBLESHOOTING AND REPAIR
F-9
Observe all Safety Guidelines detailed throughout this manual
WELDING PROBLEMS
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 216-383-2531 or 1-800-833-9353.
CAUTION
LN-742 & LN-742H
The welding arc is variable or “hunt-
ing”.
Poor arc striking with sticking or
“blast-offs”. The weld bead may be
ropy and narrow.
1. Check the welding cables for
loose or faulty connections.
2. Make sure the wire feed speed,
voltage, polarity and shielding
gas are correct for the process
being used.
3. Check for mechanical restric-
tions in the wire feed path.
4. Make sure the welding power
source is functioning properly.
1. Make sure the wire feed speed,
voltage, polarity and shielding
gas are correct for the process
being used.
2. Make sure the welding power
source is functioning properly.
3. Make certain the gas solenoid is
operating properly and the gas
flow rate is correct for the proce-
dure.
4. The welding gun may be faulty.
Check for gas leaks or replace
gun.
1.
Contact the Lincoln Electric
Service Department, 1-216-383-
2531 or 1-800-833-9353 (WELD).
1.
Contact the Lincoln Electric
Service Department, 1-216-383-
2531 or 1-800-833-9353 (WELD).