Lincoln Electric PRO DUAL POWER LN-25 Operator's Manual page 40

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PROBLEMS
(SYMPTOMS)
Wire feed speed consistently oper-
ates at the wrong value. The speed
changes when the wire feed speed
knob is adjusted.
The wire feed speed is fast (maxi-
mum) and there is no change when
the wire feed speed knob is adjust-
ed.
Variable or "hunting" arc.
When the trigger is pulled, the wire
feeds slowly.
Poor arc starts with sticking or
"blast-offs", weld porosity, narrow
and ropy looking bead.
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
Observe all Safety Guidelines detailed throughout this manual
POSSIBLE
Output Problems
1. The jumper lead for normal
speed/extra torque is connected
improperly.
2. The wrong gear is installed in the
wire drive.
3. The brushes on the motor are
worn.
1. The tachometer is connected
improperly.
2. The tachometer has failed.
1. Wrong size, worn and/or melted
contact tip.
2. Worn work cable or poor work
connection.
3. Wrong polarity.
4. The gas nozzle is extended
beyond the contact tip or the wire
stickout is too long.
5. Poor gas shielding on processes
requiring gas.
1. The Run-In switch is "ON"
1. Improper procedures or tech-
niques.
LN-25™ PRO DUAL POWER
CAUSE
1. Properly connect the normal
2. Install the proper pinion gear in
3. Replace
1. Verify all of the tachometer leads
2. Replace the motor and tachome-
1. Replace the contact tip.
2. Verify all work and electrode con-
3. Adjust polarity to the recommend-
4. Adjust the gas nozzle and shorten
5. Check gas flow and mixture.
1. Place the Run-In switch to the
1. See "Gas Metal Arc Welding
CAUTION
RECOMMENDED
COURSE OF ACTION
speed/extra torque jumper.
the wire drive.
the motor/gearbox
assembly.
are properly connected.
ter assembly.
nections are tight and that the
cables are in good condition.
Clean/replace as necessary.
ed procedure.
the stickout to 3/8 to 1/2 inches.
Remove or block sources of
drafts.
"OFF" position.
Guide" (GS-100)
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