Lincoln Electric INVERTEC SVM129-B Service Manual page 77

F-39
6. Test for 25 ohms resistance from lead termi-
nal 401 to terminal 12 on the switch board.
See Figure F.13.
a. If 25 ohms is measured, resistor R4 is OK.
b. If 30 ohms or more is measured, resistor
R4 is faulty and must be replaced.
c. If 20 ohms or less is measured, resistor
R4 is faulty and must be replaced.
Check
Lead 401 to
Terminal 12
Lead 402 to
Terminal 9
Lead 403 to
Terminal 12
Lead 404 to
Terminal 9
> = GREATER THAN
TROUBLESHOOTING & REPAIR
SNUBBER RESISTORS TEST (continued)
FIGURE F.13 - SWITCH BOARD TEST POINTS
401/403 401
L8441 L8441
TABLE F.6 – SNUBBER RESISTORS TEST
Test Result Conclusion
25 ohms OK
>30 ohms R4 open
<20 ohms R4 faulty
25 ohms OK
>30 ohms R5 open
<20 ohms R5 faulty
25 ohms OK
>30 ohms R6 open
<20 ohms R6 faulty
25 ohms OK
>30 ohms R7 open
<20 ohms R7 faulty
< = LESS THAN
INVERTEC STT
402/404 12
9
12 12
SWITCH SWITCH
7. Repeat the same procedures to test R5, R6,
and R7 according to Table F.6.
8. Reconnect leads 401/403 and 402/404 to the
switch board.
9. Install the case wraparound cover.
Next Test Step
Continue
Continue
Continue
Continue
F-39
Repair Action
Replace R4
Replace R5
Replace R6
Replace R7