Mbu - Gestetner B147 Service Manual

DRAM
• The 16 MB of DRAM is shared as follows.
SAF memory
Working memory : 4 MB
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.
Switches
Item
SW1 Reset switch, to reboot the FCU board

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.
SM
: 4 MB
: 8 MB
Description
Description
99
BOARDS
B603