Appendix C. Electrical Component Description/Data Flow - Ricoh FAX220 Service Manual

APPENDIX C. ELECTRICAL COMPONENT DESCRIPTION/DATA FLOW

1. PCBs
This section explains the functions of the PCBs and their components.
Thermal
Head
OPU
1-1. FCE (Facsimile Control Engine)
This engine board performs all control tasks, image processing, and Tx/Rx data processing. It contains the KFCP
(which contains a CPU and a video processor), DSP (which contains the modem), a ROM (1 Mbits), an SRAM (32
kbytes), and two 128 kbyte DRAMs (one for SAF, and the other for ECM in the FAX240 only). There is an OTP
(One Time Programmable) ROM in an SOP type package.
1-2. FDU (Facsimile Driver Unit)
This driver unit interfaces with the peripherals. It contains Tx, Rx and cutter motor drivers, the scanner interface,
secondary power supply (which generates ±5V from the +24V output from the PSU), a battery for FCE back-up, a
HIC for modem signal amplification and filtering, and an AVM generation circuit.
Scanner and Printer
Drive Conponents and
SBU
Sensors
CONTROL SIGNALS
Voice
Processor
KFCP
Video
Processor
DATA AND ADDRESS BUS
EOI2
PSU
FDU
HIC2
FCE
DSP AFE
SRAM DRAM
C-1
HSB
Line
LIU
Handset
Speaker
FAX240 only