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LN-7 GMA WIRE FEEDER
PROBLEMS
(SYMPTOMS)
When the gun trigger is pulled
there is no wire feed, but gas
flows and arc voltage is present.
POSSIBLE AREAS OF
MISADJUSTMENT(S)
1. Check to see if the motor drive
rolls are turning when the gun
trigger is pulled. If the drive rolls
are turning then check for
clogged gun liner or a
mechanical restriction in the
wire feeding path.
2. If the drive rolls do not turn
when the gun trigger is pulled
then contact your Local Lincoln
Authorized Field Service Shop.
RECOMMENDED
COURSE OF ACTION
1. With the trigger activated check
for the presence of drive motor
armature voltage. 5 to 95 VDC at
leads #539 to #541.
Note: The armature voltage will be
dependent on the wire speed setting.
2. If the correct armature voltage IS
present at leads #539 and #541
and the drive motor is NOT
turning, then the drive motor may
be defective. Also check the
brushes in the drive motor;
replace if less than 1/4 in. in
length.
3. If the correct armature voltage is
NOT present at leads #539 and
#541 then the CR1 control relay
may be defective. Replace per
Control Relay Replacement
procedure.
4. If the armature voltage is not
restored then the control PC
board may be defective. Replace
per Control PC Board
Replacement procedure.
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.
FUNCTIONAL PROBLEMS (Continued)
CAUTION
TROUBLESHOOTING AND REPAIR F-5
Observe Safety Guidelines
detailed in the beginning of this manual.
Troubleshooting Guide – See Wiring Diagrams for location of specified
components. See Wiring Diagrams for troubleshooting of specific circuits.