Lincoln Electric 10372 Service Manual page 94

F-30
NEGATIVE (-)
TERMINAL
TEST PROCEDURE
1. Remove main input supply power to
the Power Wave 455.
NOTE: Later code machines have a 50
ohm resistor across the welding output ter-
minals. It will be necessary to remove the
case sides and Perform the Input Filter
Capacitor Discharge Procedure. Remove
and insulate one of the resistor leads (#
202A or #206A) from the appropriate weld-
ing output terminal. See the wiring diagram.
2. Remove any output load that may be
connected to the Power Wave 455.
TROUBLESHOOTING ND REP IR
OUTPUT RECTIFIER TEST ( ontinued)
FIGURE F.4 — OUTPUT RECTIFIER TEST.
OUTPUT
POWER W VE 455/POWER FEED 10
POSITIVE (+)
OUTPUT
TERMINAL
3. With the analog ohmmeter, measure
the resistance between the positive
and negative output terminals. Refer to
Figure F.4. IMPORTANT: The positive
(+) meter probe must be attached to
the positive (+) output terminal and the
negative (-) meter probe must be
attached to the negative (-) output ter-
minal.
4. If the reading is more than 200 ohms,
the output rectifier modules are not
shorted. If the reading is less than 200
ohms, one or more of the rectifier mod-
ules are shorted. Refer to the Output
Rectifier Module Replacement
Procedure.
F-30