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E-3
TROUBLESHOOTING & REPAIR
E-3
LN-7 & LN-7 GMA
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 Authorized
Field Service Facility.
CAUTION
PROBLEMS
PROBLEMS
(SYMPTOMS)
POSSIBLE
CAUSE
RECOMMENDED
COURSE OF ACTION
Weld porosity, narrow and ropey
bead, or electrode stubbing into
plate when welding.
LN-7 circuit breaker trips while weld-
ing.
LN-7 or power source electrical
problems such as:
• Power source fuse blowing.
• LN-7 circuit breaker tripping.
• No control of wire feed motor.
• Wire feed motor not running.
• Auxiliary equipment connected
to 32A and 7 not working.
• Power source contactor not
working but LN-7 feeds wire.
1. Contaminated weld joint or
improper procedures.
2. Lack of shielding gas.
1. See problem 1.
2. High ambient temperature (caus-
ing circuit breaker to trip).
3. Electrical problems in power
source or LN-7
1. Loose connections or broken lead.
2. Grounding lead protector tripped.
3. Electrical component has failed.
4. Contactor circuit fuse on motor
control P.C. board blown.
1. Clean welded joint. Check that
controls are set correctly for pro-
cedure.
2. Obtain proper gas flow.
1. Correct problems.
2. Provide better ventilation for LN-7.
Make sure ventilation louvers and
clean and un-obstructed.
3. See problem 5.
1. Turn power source and LN-7 off
and check leads and connections.
2. Push reset button.
3. Replace blown fuses or reset cir-
cuit breaker and try to weld. If
trouble reoccurs, contact your
local authorized field service shop.
4. Correct problem and replace fuse
(2A-250V)