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TROUBLESHOOTING & REPAIR
F-17 F-17
POWER MIG 300
CHOPPER BOARD TEST (continued)
FIGURE F.3 – CHOPPER BOARD CONNECTIONS
TABLE F.1– CHOPPER BOARD RESISTANCE TEST TABLE
TEST PROCEDURE
1. Disconnect the main AC input power to the
machine.
2. Remove the case side panels with a 3/8 in. nutdriv-
er.
3. Locate plug J99. (Later machine do not have J99).
4. Make the following voltage test. From the table
below.
5. Turn the machine off between each test:
a. Carefully insert the meter probes into the back of
each Molex plug cavity.
If 20 VDC is not present check Digital Power Supply.
See the Wiring Diagram.
RESISTANCE TEST
1. Perform the Capacitor Discharge Procedure.
2. Remove input power to the machine.
3. Perform the resistance tests in Table F.1.
