Troubleshooting Guide - Lincoln Electric LN-25 Service Manual

F-5
Troubleshooting Guide –
components. See Wiring Diagrams for troubleshooting of specific circuits.
PROBLEMS
(SYMPTOMS)
The wire feeds for a short period of
time but then stops feeding. When
the gun trigger is released and
then retriggered, the wire resumes
feeding but soon stops again.
The wire stops or stubs while
welding.
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely,
contact the Lincoln Electric Service Department for technical troubleshooting assistance before you proceed.
Call 216-383-2531 or 1-800-833-9353.
TROUBLESHOOTING AND REPAIR
See Wiring Diagrams for location of specified
POSSIBLE AREAS OF
MISADJUSTMENT(S)
FEEDING PROBLEMS (Continued)
1. The drive motor may be
overloaded. Check the wire
feeding path for mechanical
restrictions.
2. While welding make certain the
power source arc voltage is
staying above 15 VDC. The
feeder will not function properly
on less than 15 VDC.
1. If the LN-25 is connected to a
constant current power source,
the arc
"dipping" below the 15 VDC
threshold that is essential for
proper LN-25 operation.
2. Try connecting the LN-25 to a
constant voltage power source
or a flatter slope output.
3. Make sure the wire feed mode
switch (S3) is in the correct
position for the power source
being used, and proper speed
setting
procedure.
4. Check
restrictions in the wire feed
path.
CAUTION
RECOMMENDED
COURSE OF ACTION
1. Check the motor armature
2. If 5 amps or less is indicated
3. If more than 5 amps is
4. The motor or gearbox may be
1. Monitor the motor armature
voltage may be
2. If the motor armature voltage is
is used for the
for mechanical
LN-25
Observe Safety Guidelines
detailed in the beginning of this manual.
current through either of the
armature leads (539 or 541). A
typical value is 4 amps DC.
and the armature voltage is
being disabled by the control
board, then the control board
may be faulty. Replace.
indicated, then the motor is
drawing too much armature
current. Check and or replace
the motor brushes.
faulty. Replace.
voltage (leads 539 to 541).
Normal range is 2 to 23 VDC.
If the armature voltage is
proper, then check or replace
the motor brushes.
not correct, then the control
board may be faulty. Replace.
F-5