Sharp AR-651 Service Handbook page 219

[C58] Communication error between the IPC board and finisher
Is a specified finisher used?
NO
YES
Is the harness between the IPC board and finisher control board open-circuited?
YES
NO
Is the conductor pattern on the IPC board is short- or open-circuited?
YES
NO
Replace the finisher control board.
[C59] Communication error between the main CPU and laser CPU
(1) Check if the harness between the LGC board and PLG board is not disconnected or open-circuited.
(2) Check if the conductor pannern around IC13, IC25, IC57, J327 and J342 on the LGC board is not
short- or open-circuited.
(3) Check if the conductor pattern around IC4, IC19 and J202 on the PLG board is not short- or open-
circuited.
(4) Replace the LGC board.
(5) Replace the PLG board.
Replace to the specified finisher.
Replace the harness.
Replace the IPC board.
5 - 69 AR-651/810 TROUBLE SHOOTING