Lincoln Electric INVERTEC SVM129-B Service Manual page 84

F-46
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.
3. Perform the Input Filter Capacitor Discharge
Procedure. See the Maintenance section.
WARNING
ELECTRIC SHOCK can kill.
4. Locate the protection PC board just in front
of the input rectifier and relay mountings.
TROUBLESHOOTING & REPAIR
PROTECTION BOARD TEST (continued)
FIGURE F.17 – PROTECTION PC BOARD TEST POINTS
L7915-[ ]
PROTECTION
313
J8
311
• Before continuing with
the test procedure, per-
form the capacitor dis-
charge procedure
avoid electric shock.
INVERTEC STT
315
317
WARNING
ELECTRIC SHOCK can kill.
5. Apply the correct input power and turn the
machine ON.
6. Test for approximately 1VDC from plug J8
pin 1 (lead #311)(+) to plug J8 pin 3 (lead
#313) (-). See Figure F.17.
to
A. If approximately 1VDC is present, the
protection PC board is functioning prop-
erly.
B. If more than 5 VDC is measured, per-
form the Capacitor Balance Test.
314
J15
316
• With input power ON,
there are high voltages
inside the machine. Do
not reach into the
machine or touch any
internal part.
F-46