Lincoln Electric SVM188-A Service Manual page 48

F-8
Observe Safety Guidelines detailed in the beginning of this manual.
PROBLEMS
(SYMPTOMS)
Poor arc starting when the DC600 is
in the CV Sub-Arc or CV Innershield
Modes.
Poor arc characteristics in all
processes.
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 1-888-935-3877.
TROUBLESHOOTING AND REPAIR
POSSIBLE AREAS OF
MISADJUSTMENT(S)
OUTPUT PROBLEMS
1. Make sure the proper welding
procedures are being used.
(wire feed speed, arc voltage
and wire size)
2. Check weld cables for loose or
faulty connections.
1. Check for the correct input volt-
ages on the three phase input
lines at the DC600.
2. Make sure the proper welding
procedures are being used (wire
feed speed, arc voltage and wire
size).
3. Check the welding cables for
loose or faulty connections.
CAUTION
DC-600
RECOMMENDED
COURSE OF ACTION
1. Check the connections from the
shunt to the Control Board
(leads 210 and 215). When weld
current is present there should
be a millivolt signal at the board
(6.25mv/100 amps).
2. Perform the Firing Board Test.
3. Perform the SCR
Bridge Test.
4. The Control Board may be
faulty.
1. Check the Mode Switch (SW4)
and the associated wiring for
loose or faulty connections. See
the Wiring Diagram.
2. Check the voltage at the shunt
(leads 210 and 215). When weld
current is present there should
be a millivolt signal at the board
(6.25mv/100 amps). If not cor-
rect, the shunt may be defective
3. Perform the Firing Board Test.
4. Perform the SCR
Bridge test.
5. The Control Board may be
faulty.
F-8
Output
Output