Lincoln Electric 11519 Service Manual page 63

F-17
RECTIFIER DIODE BRIDGE TEST (continued)
6. Turn the Power MIG® 255XT ON/OFF POWER
SWITCH to ON.
7. Carefully make the following voltage tests:
a. Turn the machine OFF between each test.
b. Carefully connect the meter plugs to the
exposed lead connections.
c. Turn the machine ON to conduct the volt-
age test at J5 connector Control board
FROM
LEAD LEAD
208
209
8. If any of the AC voltages tested are incorrect or
missing, check the leads and connections. See
the Wiring Diagram.
TROUBLESHOOTING AND REPAIR
TO EXPECTED
VOLTAGE
206 28 VAC
206 28 VAC
Power MIG® 255XT
9. Make the following voltage test:
a. Turn the machine OFF between each test.
b. Carefully connect the meter probes to the
exposed lead connections.
c. Turn the machine ON to conduct the volt-
age test.
TO
FROM
LEAD LEAD
206
354
10. If the DC voltage tested is incorrect or missing,
and the AC voltages are correct, the rectifier
diode bridge may be faulty.
F-17
EXPECTED
VOLTAGE
36 VDC