Ricoh M281 Series Service Manual page 848

FCU
12. Change the orientation of the battery jumper switch [A] on the new FCU board [B].

If the battery jumper switch is not in the correct position, SC820 will occur.
13. Install the new FCU board to the fax unit.
1. Attach the two brackets [A] to the new FCU board [B].
D255/D256 FAX OPTION 14 SM