Lincoln Electric Idealarc DC600 9773MSP Service Manual page 68

TROUBLESHOOTING & REPAIR
14. Test for approximately 5.8 VDC
between leads #231 and # 215 on
the Firing Board in VV (CC) mode.
a. Keep the meter probes insert-
ed into the Plug lead cavities
for leads #231 and #215.
b. Keep the jumper connected at
terminals #2 and #4 at the ter-
minal strip.
c. Set the WELDING MODE
SWITCH (SW4) to the VV (CC)
position.
d. Rotate the OUTPUT CON-
TROL POTENTIOMETER
clockwise and counter-clock-
wise. The DC voltage between
leads #231 and #215 should be
constant at approximately 5.8
VDC. This voltage should not
vary when the pot is turned.
e. Remove probes inserted into
the Molex Plug lead cavities of
lead #231 and #215.
FIRING BOARD TEST
15. Test Output Pilot Control Relay
(CR4) for proper operation by
removing and replacing repeatedly
the jumper wire from terminal # 2.
This should cause the relay con-
tacts to open and close. The con-
tacts can be seen closing and
opening through the clear plastic
relay case or can be heard opening
and closing.
a. If the Output Control Relay
16. Remove the jumper from terminals
#2 and #4 on the terminal strip.
17. Replace the Firing Board if the
above voltage and control relay
tests were passed.
faulty.
(CR4) does not close when
energized, check for loose or
faulty wiring.
It may be
IDEALARC DC-600
F-27