Lincoln Electric POWER MIG SVM165-A Service Manual page 63

F-17
CHOPPER BOARD CAPACITOR DISCHARGE PROCEDURE (continued)
FIGURE F.1 – CHOPPER BOARD CAPACITOR TERMINAL DISCHARGE
_
C11
_
C10
PROCEDURE
WARNING
ELECTRIC SHOCK can kill.
High voltage is present when input power is applied to
the machine.
Refer to Figure F.1.
1. Remove main input power supply to the machine.
2. Lift the hinged right side case cover.
3. Using the 3/8" nut driver, remove the bottom right
case cover.
4. Locate the Chopper Board with capacitors mount-
ed on the center of the machine base, right side.
See Figure F.1.
TROUBLESHOOTING & REPAIR
300 CHOPPER
B1
B1
+
B2
B2
+
B3
B3
J99
POWER MIG 350MP
B4
B4
C2
B5
B5
+
C12
B6
B6
5. Using the resistor and jumper leads, CAREFULLY
discharge the capacitor terminals. There are 5
capacitors. NEVER USE A SHORTING STRAP
FOR THIS PURPOSE.
TERMINALS WITH YOUR BARE HANDS.
To discharge the capacitors, hold the jumper leads to
the following terminals for a minimum of 10 seconds
each. See Figure F.1 and the Wiring Diagram.
Capacitors
C10 and C11
C5
C8 and C9
6. Using the volt/ohmmeter, check the voltage across
terminals B1 and B2 and B1 and B5 and B4 and
B5. Each reading should now be zero volts.
F-17
+
C8
_
+
C9
_
DO NOT TOUCH THE
Terminals
B1 and B2
B1 and B5
B4 and B5