Troubleshooting & repair, Warning – Lincoln Electric INVERTEC POWER WAVE 450 SVM112-B User Manual

Page 120

F-60

FIELD EFFECT TRANSISTOR/SWITCH BOARD TEST

FIGURE F.19 – F.E.T. SWITCH BOARD LOCATION

TROUBLESHOOTING & REPAIR

TEST PROCEDURE

1. Remove main input supply power to the

machine.

2. With the 3/8" nut driver, remove the 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.

Before continuing with the
test procedure, perform the
following capacitor dis-
charge procedure to avoid
electric shock.

6. Obtain a high resistance and high wattage

resistor (25 - 1000 ohms and 25 watts min-
imum). This resistor is not supplied with the
machine. Secure this resistor to a piece of
insulating material such as a glastic board.
See Figure F.22. NEVER USE A SHORTING
STRAP FOR THIS PROCEDURE.

POWER WAVE 450

WARNING

1. FET OR IGBT SWITCH BOARD ASSEMBLY