Mbu - Ricoh B291 Service Manual

BOARDS
DRAM
• The 16 MB of DRAM is shared as follows.
SAF memory
Working memory : 4MB
Page memory
• The SAF memory is backed up by a rechargeable battery.
Memory back-up
• A Rechargeable battery backs up the SAF memory (DRAM) for 1 hour.

4.2.2 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 256 KB 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.
B779
CÓPIA NÃO CONTROLADA
: 4MB
: 8MB
Description
112
CÓPIA NÃO CONTROLADA
SM