Lincoln Electric IDEALARC DC-600 Service Manual page 79

F-35
b. If the open circuit voltage is not present at
the Control Board, then check leads #222
and #215 for loose or faulty wiring connec-
tions. See wiring diagram.
5. Test for continuity (zero ohms) between the
negative output terminal and lead #222 at Plug
J1 on the Control Board.
a. If more than zero ohms is measured, the
lead may be faulty.
6. Test for continuity (zero ohms) between the
positive output terminal and lead #215 at Plug
J3 on the Control Board.
a. If more than zero ohms is measured, the
lead may be faulty.
NOTE: If previous tests do not reveal the problem
then the Control Board may be faulty.
Replace.
If LED 3 Does Not Glow But LED 1 Does Glow
When ON PUSH BUTTON Is Pushed
NOTE: When this condition occurs, the Fault
Protection Relay (CR2) is not receiving the
24 VDC supply voltage. Therefore, the
Input Contactor (CR1) cannot close.
Perform the following:
1. Set and hold in the ON position the ON/OFF
PUSH BUTTON.
a. If LED 4 glows or flickers,
• Check the Weld Output Terminals and
associated wiring for a "short" condition.
See wiring diagram.
• Check the Remote Control Circuit (leads
#75, #76, #77). They may be shorted to
the negative welding voltage. See wiring
diagram.
b. If the above procedures do not uncover the
problem, the Control Board may be faulty.
Replace.
TROUBLESHOOTING AND REPAIR
CONTROL BOARD TEST (continued)
IDEALARC
If LED 5 Does Not Glow and Vary in Brightness
Under the Following Conditions
Machine is operating under load (or terminals #2
and #4 are jumpered together on the terminal
strip).
The OUTPUT CONTROL POTENTIOMETER is
rotated.
The WELD MODE SWITCH is in either CV posi-
tion.
The OUTPUT CONTROL SWITCH is in the
"Output Control at DC-600" position.
1. Check the OUTPUT CONTROL POTEN-
TIOMETER and associated wiring for loose or
faulty connections.
a. If all the above conditions are met, the
Control Board may be faulty. Replace.
® DC-600
F-35