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

Page 121

F-61

FIELD EFFECT TRANSISTOR/SWITCH BOARD TEST

(continued)

FIGURE F.20 - RESISTOR LOCATIONS

TROUBLESHOOTING & REPAIR

7. Locate the two sets of two resistors on the

left side of the machine and three sets of
two resistors on the right side of the
machine. See Figure F.20. Do not touch
the resistors or any other internal machine
component. Using a DC voltmeter, check
for any DC voltage that may be present
across the terminals of each resistor and
from each resistor to case ground (20 mea-
surements in all). If a voltage is present, be
careful not to touch these resistors.

ELECTRIC SHOCK
can kill.

Proceed with caution. Be
careful not to touch any

internal machine components during the dis-
charge procedure.

8. Locate terminals #9 and #12 on the switch

boards. They can be identified by the
“Discharge” labels, which are located on
each of the four switch boards. See Figure
F.21.

POWER WAVE 450