Lincoln Electric SQUARE WAVE TIG 355 Service Manual page 81

F-29
Check Points
IJ4 to 2J4
4J4 to 6J4
4J4 to 5J4
10J4 to 12J4
3J2(+) to 5J2
4J2(-) to 5J2
IJ2(+) to 2J2
NOTE: LED 3 should be ON when gate signal is applied to SCR 1.
LED 4 should be ON when gate signal is applied to SCR 4.
TROUBLESHOOTING AND REPAIR
POWER BOARD TEST (continued)
POWER BOARD VOLTAGE TEST CHART
Signals Being
Checked
AC supply voltage
from T5 transformer
AC supply voltage
from T5 transformer
AC supply voltage
from T5 transformer
AC supply voltage
from T5 transformer
Regulated +15VDC
Regulated -15VDC
Unregulated DC
SQUARE WAVE TIG 355
Expected Special Conditions
Reading
10VAC
32VAC
16VAC
36VAC
+15VDC
-15VDC
+14VDC
F-29
for Test
None
None
None
None
LED 1 ON
LED 2 ON
None