Lincoln Electric LF-72 WIRE FEEDER IM847-D - Manual (Page 40)

E-3 TROUBLESHOOTING E-3
LF-72
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 Lincoln Authorized Field Service Facility for technical troubleshooting assistance before you proceed.
CAUTION
PROBLEMS
(SYMPTOMS)
POSSIBLE AREAS OF
MISADJUSTMENTS(S)
RECOMMENDED
COURSE OF ACTION
Variable or "hunting" arc.
The motor thermal LED illuminates.
When the gun trigger is pulled, the
drive rolls spin but no arc is present.
The arc burns back to the tip at the
end of the weld.
The gas continues to flow for a long
time at the end of a weld.
1. Check for proper size contact.
Make sure the contact tip is not
worn, free of spatter and not melt-
ed.
2. Clean and tighten all electrode
and work connections.
3. Verify the proper polarity is being
used for the weld procedure.
4. Make sure the proper electrode
stick-out is being maintained.
5. Check the gas flow rate and mix-
ture.
6. Verify the gun bushing is tightly to
the wire drive.
7. Verify the gun is tightly mounted
to the gun bushing.
1. Check for sharp bends in the gun
liner.
2. Examine the contact tip for wear
and proper size. Replace as nec-
essary.
3. Check the gun liner. The welding
e l e c t r o d e s h o u l d s l i d e e a s i l y
through the gun.
4. V e ri f y t h e p ro p er g u n l in e r is
installed.
5. Reduce the pressure arm setting.
6. On bench models, make sure the
brake tension is not too tight.
7. If using a wire conduit, verify the
wire slides easily through the
conduit.
1. Check all electrode and work
connections.
2. Verify the gun bushing is tightly to
the wire drive.
3. Verify the gun is tightly mounted
to the gun bushing.
4. Check the control cable and con-
nectors for cuts. Verify that no
pins are broken or bent.
1. If the timer kit is installed, reduce
the amount of burnback time.
1. If the timer kit is installed, reduce
the amount of postflow time.
If all recommended possible areas of
misadjustment have been checked
and the problem persists, Contact
your local Lincoln Authorized
Field Service Facility.