Lincoln Electric LN-25X Operator's Manual page 35

LN-25X™
PROBLEM
Inconsistent wire feeding or
wire not feeding but drive
rolls turning.
Wire feed speed
consistently operates at the
wrong value. The speed
changes when the wire feed
speed knob is adjusted.
The wire feed speed stuck
at 200-300 in/min and there
is no change when the wire
feed speed knob is
adjusted.
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.
POSSIBLE CAUSE
6. Improper gun liner, tip, drive
rolls and/or inner wire guide.
7. Incorrect tension arm
pressure on the drive rolls.
8. The spindle brake is too tight.
9. Worn drive roll.
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.
The Run-In switch is "ON"
Improper procedures or
techniques.
RECOMMENDED COURSE OF ACTION
6. Verify the proper parts are installed.
7. Adjust the tension arm per the Instruction Manual. Most electrodes
feed well at a tension arm setting of "3".
8. Verify the spool of wire moves with minimal effort.
9. Replace the drive rolls if worn or filled with dirt.
1. Properly connect the normal speed/extra torque jumper.
2. Install the proper pinion gear in the wire drive.
3. Replace the motor/gearbox assembly.
1. Verify all of the tachometer leads are properly connected.
2. Replace the motor and tachometer assembly.
1. Replace the contact tip.
2. Verify all work and electrode connections are tight and that the
cables are in good condition. Clean/replace as necessary.
3. Adjust polarity to the recommended procedure. Verify DIP switch #7
setting matches the electrode polarity.
4. Adjust the gas nozzle and shorten the stickout to ½ to ¾ inches.
5. Check gas flow and mixture. Remove or block sources of drafts.
Use the set-up Push-button to turn Run-in OFF.
See "Gas Metal Arc Welding Guide" (GS-100)