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5. TROUBLE
SHOOTING
5-1. Function description of each PCB
1. M-1 PCB(Main PCB)
This PCB contains CPU and all of the control circuit.
The following functions are included.
1) LSI so called FAX ENGINE(TC35 168F)
0 8-bit CPU
@ MODEM
-Modulation and Demodulation
-Tone signal generation and detection
-DTMF signal generation
-Pre-recorded voice prompt generation
-Hold on melody generation
@ CODEC
-Coding and decoding of image signals
@ Image signal processor
-Driving of CIS(Contact Image Sensor)
-Convert analog signal to digital signal(two or multi value)
-Reduction of image(if reading width is B4)
0 DMA(Direct Memo~ Access)controller
-It is used when transferring the data from image signal processor to
line memory, fkom line memory to MODEM, thermal head and
CODEC.
@ Real time clock
@ Stepping motor control
@
I/o
ports
-Mechanism
-Operation
panel
-LCD control
2)
DSP (Digital Signal Processor) TC8845 lF-02
This is a C-MOS LSI for voice recording and playing which is used APL-MLQ
(Adaptive Predictive Coding with Maximum Likelihood Quantization)
method.
A system of voice recording and playing is set up by connecting a peripheral circuit
which consists of external memory, ~-law CODEC and audio circuit.
For voice recording: 4-Mbit A-RAM(externally)
+ 4M-bit D-RAM(intemally),
Total 8M-bit.
It can be recorded approx. 14-minutes and 33 seconds in total
3) Gate Arrey(pPD65622)
0 Thermal head Control Circuit
@
I/o
ports
-NCU/TEL control
4) 1MBit EP-ROM
-This EPROM contains the program to control CPU
—13–
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Table of Contents
Troubleshooting
