Lincoln Electric INVERTEC POWER WAVE 450 SVM112-B Service Manual page 113

F-53
OUTPUT SHUNT/WELDING FEEDBACK TEST (continued)
1. SHUNT AMPLIFIER BOARD
TEST PROCEDURE
1. Remove main input supply power to the
machine.
2. With the 3/8" nut driver, remove the 4
screws that hold the handle to the machine.
3. Remove the rubber gasket (cover seal) from
the lift bail.
4. With the 5/16" nut driver, remove the sheet
metal screws from the case top.
5. With the 5/16" nut driver, remove the
screws holding the right and left case sides.
Remove the case sides by lifting up and
out.
6. Perform the
Procedure described earlier in this section
of the manual.
TROUBLESHOOTING & REPAIR
FIGURE F.16 - SHUNT AMPLIFIER BOARD LOCATION
Capacitor Discharge
POWER WAVE 450
WARNING
Before continuing with the
test procedure, perform the
capacitor discharge proce-
dure to avoid electric shock.
7. After you have completed the capacitor dis-
charge procedure for all four switch boards,
locate plug J50 at the shunt amplifier
board. Locate the plug and insert your
voltmeter positive (+) probe into pin 3 and
negative probe (-) into pin 1. Right-angle
probes are recommended.
8. Turn supply power to the machine ON.
F-53