Lincoln LN-7 - Manual (Page 17)

The Lincoln Electric Company
Cleveland, Ohio 44117 Maintenance Instructions
SEC J6.6 TROUBLESHOOTING
WARNING: Have a qualified electrician do the maintenance and trouble shooting work.
Turn the input power off using the disconnect switch at the fuse box before woricing
inside the machine.
Trouble Cause What to Do
1. Rough wire feeding or wire not
feeding but drive rolls turning.
a. Gun cable kinked and/or twisted.
b. Wire jammed in gun and cable.
c. Incorrect drive rolls and guide
tubes.
d. Drive rolls loose.
e. Gun cable dirty.
f. Worn drive rolls.
g. Electrode rusty and/or dirty.
h. Worn nozzle liner,
j. Partially flashed or melted
contact tip.
a. Inspect gun cable and replace if necessary.
b. Remove wire from gun and cable — feed in new
wire. Note any obstructions in gun and cable.
Replace gun and cable if necessary.
c. Check wire diameters stamped on drive rolls,
wire guides, and drive roll spacers for correct
combination for wire being used.
d. Remove, clean, install and tighten.
e. Clean per Sec. J6.2.1.
f. Replace and/or reverse split drive roll type.
g. Replace.
h. Replace.
j. Replace contact tip.
2. Variable or “hunting” arc. a. Worn and/or melted contact tip.
b. Worn or undersize work cable
or poor work connection.
c. Loose electrode connections.
a. Replace tip - remove any spatter on end of tip.
b. Inspect - repair or replace as necessary.
c. Be sure electrode lead is tight. Gun cable tight
in wire feeder contact block. Gun nozzle and
gun tip tight.
3. Weld Porosity, narrow and ropey
bead, or electrode stubbing into
plate when welding.
a. Dirty plate or improper
procedures.
See trouble shooting information in Bulletin
N676, “Innershield Semiautomatic Welding
Guide.”
4. LN-7 circuit breaker trips while
welding.
a. See Trouble 1 above.
b. High ambient temperature
(causing circuit breaker to trip.)
c. Electrical problems in power
source or LN-7.
a. Correct problems.
b. Provide better ventilation for LN-7.
c. See Trouble 5.
LN-7 or power source electrical
problems such as:
LN-7 fuse blows.
Power Source Fuse blows.
LN-7 circuit breaker trips.
No control of wire feed motor.
Wire feed motor won’t run.
Auxilliary equipment connected
to 32A and 7 won’t work.
Power source contactor won’t
work, but LN-7 feeds wire.
a. Loose connection or broken lead.
b. Electrical component has failed.
a. Turn power source and LN-7 off and check
leads and connections.
b. Replace blown fuses or reset circuit breaker
and try to weld. If trouble recurs, call Lincoln
semiautomatic distributor, local representa­
tive or authorized Field Service Shop.
October 1971
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