Lincoln Electric INVERTEC POWER WAVE 450 SVM112-B Service Manual page 130

F-70
FIELD EFFECT TRANSISTOR/SWITCH BOARD TEST (continued)
TABLE F.4 – SWITCH BOARD 3 RESISTANCE TEST TABLE (Continued)
Apply
Positive
Test
Probe to
Terminal
12C
3T
12C
405
9C
406
NOTE: K ohm = ohm reading multiplied by 1000.
NOTE: Always make sure that all four Switch Boards are changed at the same time. Never
mix an old style (different part number) Switch Board with a new style (new part
number).
TROUBLESHOOTING & REPAIR
Apply
Negative
Test
Probe to Test
Terminal Result
3T Less than
100 ohms
Greater
than 1K
ohm
12C Greater
than 1K
ohm
Less than
100 ohms
405 Greater
than 1K
ohm
Less than
100 ohms
12C Less than
100 ohms
Greater
than 1K
ohm
406 Less than
100 ohms
Greater
than 1K
ohm
9C Greater
than 1K
ohm
Less than
100 ohms
POWER WAVE 450
Repair
Conclusion Action
OK None
Open Replace 4
Switch
Boards
OK None
Shorted Replace 4
Switch
Boards
OK None
Shorted Replace 4
Switch
Boards
OK None
Open Replace 4
Switch
Boards
OK None
Open Replace 4
Switch
Boards
OK None
Shorted Replace 4
Switch
boards
F-70
Next
Procedure
Continue
Snubber
Resistor
Test
Continue
Snubber
Resistor
Test
Continue
Snubber
Resistor
Test
Continue
Snubber
Resistor
Test
Continue
Snubber
Resistor
Test
Continue
Snubber
Resistor
Test