Lincoln Electric LN-8 SVM132-A Service Manual page 57

F-7
Observe all Safety Guidelines detailed throughout this manual
PROBLEMS
(SYMPTOMS)
The wire feed speed cannot be
controlled. The motor runs and
feeds wire but the speed cannot
be changed regardless of control
setting.
The wire feed "coasts" when the
gun trigger is released.
The wire feeds normally and welds
but the solenoid is not operating.
When the gun trigger is activated
the wire "backs up" instead of feed-
ing forward.
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 1-800-833-9353.
TROUBLESHOOTING AND REPAIR
POSSIBLE AREAS OF
MISADJUSTMENT(S)
FUNCTION PROBLEMS (Continued)
1. If the LN-8 is being used for sub-
merged arc welding with the vari-
able voltage board switch in the
VV position, change it to the CV
position. If proper motor speed
control returns, the variable volt-
age board may be faulty.
1. Make sure the gun trigger is not
"sticking".
1. Check or replace the solenoid.
1. Check wire feed direction switch
for proper direction and operation.
CAUTION
RECOMMENDED
COURSE OF ACTION
1. Check for loose connections
between the speed control, the
control board, and the variable
voltage board. See wiring
diagram.
2. Check the speed control rheostat
for proper operation. Normal
resistance is 5000 ohms.
3. Perform the Drive Motor Test.
4. The control board may be faulty.
1. Perform the 1CR Relay Test.
1. With the gun trigger activated,
check for the presence of
115VAC at terminals 32A and 7.
If the proper voltage is present,
the solenoid may be faulty. If the
correct voltage (115VAC) is NOT
present, the relay board may be
faulty.
1. The 1CR relay may be faulty.
Check or replace.
LN-8
F-7