Samsung CLX-8640 series Service Manual page 358

4. Troubleshooting
e) Replace the finisher stack full sensor(S10).
f) Replace the Finisher main control board(JC81–07242A).
3) Is the Stacker Motor (M8) working?
a) Check if the connector(SJ10 8360) of stacker motor is disconnected.
b) Check if the connector(SJ10 8360) J14 on the finisher main board(JC81–07242A) is disconnected.
c) Check for continuity in the wire harness and whether the harness is damaged(SJ10 8360), replace it if required.
d) Replace the stack motor(M8).
4) Replace the Finisher main control board(JC81–07242A).
4-199 Copyright© 1995-2013 SAMSUNG. All rights reserved.