Lincoln Electric SQUARE WAVE TIG 255 SVM100-A Service Manual page 60

F-19
CONTROL TRANSFORMER (T2) VOLTAGE TEST (continued)
G2150
SQUARE WAVE 255 CONTROL
7. Test the resistance from 8J14, on the
protection/ snubber board, to the #432
lead at the control transformer. Also
check resistance from 4J14, on the pro-
tection/snubber board, to the #433 lead
at the control transformer.
A. If zero ohms resistance is shown
B. If resistance of any value is shown,
8. Test for the correct AC voltages at Plug
8. See Figure F-4.
A. If one or more voltages are missing
SQUARE WAVE TIG 255
TROUBLESHOOTING & REPAIR
FIGURE F.4 - CONTROL BOARD AND TRANSFORMER.
test is OK. Proceed to protection/
snubber board continuity test.
check wires and connections.
or incorrect, control transformer is
faulty. Replace.
1
RED (1)
(7)
WHITE
RED (2) 2
(3)
BLACK
(9)
BLACK
3
YELLOW (10)
(4)
YELLOW
4
(11)
BLUE
BLUE (5)
5
(12)
ORANGE
(6)
ORANGE
6
PLUG P8
IMPORTANT: If the Control Transfor-
mer is replaced refer to label on the
new transformer for correct primary lead
connections. If connected wrong, the
machine will have no OCV output. If no
OCV occurs reverse the control trans-
former's primary connections and re-
check machine's OCV.
Note: If main supply voltage varies, con-
trol transformer voltages will vary
accordingly.
Secondary
Lead Colors
Red to Red
Red to White
Yellow to Yellow
Black to Black
Orange to Orange
Blue to Blue
7
8
9
10
11
12
Approximate
Plug P8 Voltages
1 to 2 36 VAC
1 to 7 18 VAC
4 to 10 16 VAC
3 to 9 24 VAC
6 to 12 16 VAC
5 to 11 16 VAC