Lincoln Electric IDEALARC DC-1500 Service Manual page 68

F-34
CONTROL BOARD TEST PROCEDURE (continued)
#256
# 2 1 0 9 8 7 6 5 3 4 2 1 L 3 L 4
# 2 5 5 # 2 5 6 4 1 2 1 1 1 0 9 8 1 6 5 3 # 2 2 2 7 L 1 2 G 1 5 3 0 - 1 L 2 L 5
#255
12 9
11
10
#210
9 6
8 5
7 4
IF LED 2 (Volage Feedback) does not light when
#2 and #4 are jumpered together.
1. Check for the presence of open circuit voltage
at the weld output terminals (20 to 65 VDC in
constant voltage mode, 45 to 98 VDC in con-
stant current mode).
a. If open circuit voltage IS present at the
output terminals, then check for open
circuit voltage from lead #222 (-) 12 pin
molex plug to lead #210 (+) 9 pin molex
plug on the Control Board See Figure
F.11.
b. If open circuit voltage is NOT present at
the Control Board, then check leads
#222 and #210 and associated wiring
for loose or faulty connections. See
wiring diagram. Remove main supply
power to the DC-1500.
2. Test for continuity (zero ohms) from the posi-
tive output stud to lead #210 at 9 pin molex
plug on the Control Board. See wiring diagram
and Figure F.11.
TROUBLESHOOTING AND REPAIR
FIGURE F.11 – CONTROL BOARD
#222
L1
6 3
2
8 5
7 4 1
3
2
1
IDEALARC® DC-1500
L2
L5
L3
3. Test for continuity (zero ohms) from the nega-
tive output terminal to lead #222 at 12 pin
molex plug on the Control Board. See wiring
diagram.
4. If the previous tests do not reveal the problem
then the Control Board may be faulty. Replace.
5. If open circuit voltage is NOT measured at the
weld output terminals, then check the Output
Choke and associated heavy current carrying
leads for loose or faulty connections.
• Perform the Main Transformer Test.
• Perform the Firing Board Test.
• Perform the SCR Output Bridge Test.
If the previous tests do not reveal the problem then
the Control Board may be faulty. Replace.
F-34
G1530-1
L4