Testing For A Shorted Motor - Xerox 2135DX - Phaser Color Laser Printer Service Manual

3. Disconnect the POWER wiring harness (red wire bundle) from the engine
controller board. Also, disconnect the power wiring harness interconnect
connecting the toner sensor board's white wire harness to the low-voltage
power supply board's dark-gray wire harness. The interconnect is located
by the rear hinge.
Run a jumper wire from the +5V pins of the first wiring harness (pins 11 -
14, red wire bundle) to the +5V pin (pin 9, dark-gray wire bundle) of the
second power wiring harness. (With the jumper wire, you are bypassing
the engine controller board, the OPTN ribbon cable and the toner sensor
board).
Turn the printer on. If the jumper connection is correct, the low-voltage
power supply will start and the power supply fans will run. This indicates
the problem lies with the engine controller board or the toner sensor board
or their wiring. If the low-voltage power supply does not turn on, it is
probably bad. (Ensure your jumper connection is correct.)

Testing for a shorted motor

1. Remove the top and rear covers.
2. Disconnect the motor harnesses and verify motor resistances (see the
following topic).
3. Refer to the topic "Wiring Diagram" on page 215 for a diagram that locates
each connector.
4.
Turn on the printer again to see if it overloads now that the motors are
disconnected from the engine driver board.
If the power supply still does not function, replace it.
36 Phaser 2135 Color Printer