Mbu - Ricoh D009 Service Manual

Memory Back-up
A Rechargeable battery backs up the SAF memory (DRAM) for 1 hour.

5.2.2 MBU

On this board, the flash ROM contains the FCU firmware, and the SRAM contains the
system data and user parameters. Even if the FCU is changed, the system data and user
parameters are kept on the MBU board.
ROM
3MB flash ROMs for system software storage
2MB (16bit x 1MB) + 1MB (16bit x 512K)
SRAM
The 256KB SRAM for system and user parameter storage is backed up by a lithium
battery.
Memory Back-up
A lithium battery backs up the system parameters and programmed items in the SRAM,
in case the base copier's main switch is turned off.
Switches
Item
SW1 Switches the SRAM backup battery on/off.
SM
Description
153
Boards
D346