Lincoln Electric INVERTEC SVM129-B Service Manual page 68

F-30
CAPACITOR BALANCE TEST (continued)
TEST PROCEDURE
1. Turn off the Invertec STT and disconnect
main AC input power to the machine.
2. Using the 5/16" nut driver, remove the
case wraparound cover.
WARNING
ELECTRIC SHOCK can kill.
3. Carefully apply the correct input power to
the machine.
TROUBLESHOOTING & REPAIR
FIGURE F.10 – SWITCH BOARD TEST POINTS
9 9
L8441 L8441
• With input power ON,
there are high voltages
inside the machine. Do
not reach into the
machine or touch any
internal part.
INVERTEC STT
12 12
SWITCH SWITCH
NOTE: This test should only be conducted
when the machine reconnect switch and
jumper are set for high voltage (above
380VAC) and the proper line voltage is applied.
4. Test for VDC across terminals #9 and #12 of
one switch board and repeat the test for the
other switch board. See Table F.4 in this
procedure for expected voltage readings.
See Figure F.10.
A. If less than 25VDC difference is mea-
sured between each switch board, the
capacitive balance is OK.
cates that capacitors C1, C2, and resis-
tors R1 and R9 are functioning proper-
ly. Proceed to Step #5.
B. If more than 25VDC difference is mea-
sured between each switch board, test
each of the following components:
Capacitors C1, C2 and resistors R1
and R9. See the Invertec STT Wiring
Diagram.
F-30
This indi-