Lincoln Electric SHIELD-ARC SVM128-A Service Manual page 60

F-6
Observe Safety Guidelines
detailed in the beginning of this manual.
PROBLEMS
(SYMPTOMS)
The welding output varies abnor-
mally. The auxiliary output remains
constant. The engine is operating
correctly.
If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con-
tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call
216-383-2531 or 1-800-833-9353.
TROUBLESHOOTING & REPAIR
POSSIBLE AREAS OF
MISADJUSTMENT(S)
OUTPUT PROBLEMS
1. May be a normal condition. The
machine will normally lose
some output as the components
get heated.
2. Check for loose, worn, dirty, or
poorly seated DC generator
brushes.
3. The armature commutator may
need cleaned.
4. Check for loose or faulty weld-
ing cables.
CAUTION
SA-250
TROUBLESHOOTING GUIDE
RECOMMENDED
COURSE OF ACTION
1. Check the Fine
Adjustment rheostat for resis-
tance and proper operation.
Normal resistance is 64 ohms.
Check associated wires for
loose or faulty connections.
See the Wiring Diagram.
2. Perform the Field
Winding Test.
3. Check the Current
Selector switch and contacts for
proper operation.
4. While the machine is loaded,
check the interpole and series
coils for signs of "arcing" This
condition would point to shorted
turns in the "arcing" coil.
5. The main armature may be
faulty. Check for grounds.
F-6
Current
Shunt
Range