Lincoln Electric SVM138-A Service Manual page 84

F-20
TROUBLESHOOTING GUIDE
PROBLEMS
(SYMPTOMS)
SET volts and actual volts readings
match within a few tenths of a volt
while welding. However, both read-
ings are inaccurate.
The actual volts reading does NOT
match the SET volts reading within
a few tenths of a volt while welding.
One reading may be erratic. The
LN-9 GMA does NOT shut off.
NOTE: The Pulse Power Filter kit
may slow down the shutdown fea-
ture.
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)
METER FUNCTION PROBLEMS
1. Put the Lincoln power source in
the "Machine Control" mode.
Check to see if the power
source can be set for the arc
voltage required for the process.
If not, the power source may be
faulty.
2. The control cable may be faulty.
Check or replace.
1. Make sure
"BYPASS"
jumpered together on the LN-9
GMA voltage PC board.
2. Check the voltage sensing
leads for continuity (zero ohms).
Lead #21 should have continu-
ity to the work piece, and #67
should have continuity to the
brass conductor block. See the
Wiring Diagram.
3. Put the Lincoln power source in
the "Machine Control" mode.
Check to see if the power sup-
ply can be set for the arc volt-
age required for the process. If
not, the power supply may be
faulty.
CAUTION
LN-9 GMA Wire Feeder
detailed in the beginning of this manual.
RECOMMENDED
COURSE OF ACTION
1. Check the voltage sensing
leads for continuity (zero ohms).
Lead #21 should have continu-
ity to the work piece, and #67
should have continuity to the
brass conductor block. See the
Wiring Diagram.
2. Perform the Meter Circuit
Accuracy Test.
3. The voltage PC board may be
faulty. Replace.
the shutdown 1. If the actual reading is the prob-
pins are NOT lem, check the actual volts
switch and associated leads.
2. If the SET reading is the prob-
lem, check the set volts switch
and the associated leads.
3. Check the Volts-Speed selector
switch and associated leads.
4. The voltage PC board may be
faulty. Replace.
F-20
Observe Safety Guidelines