[L] Circuit Description; Control Pwb - Sharp FO-3700 Service Manual

1. General description
The compact design of the control PWB is obtained by using two gate
arrays and high density printing of surface mounting parts. Each PWB
is independent according to its function as shown in Fig. 1.
2. PWB configuration
Fig. 1 PWB configuration

1) Control PWB

The control PWB controls peripheral PWB's, mechanical parts, trans-
mission, and performs overall control of the unit.
This machine employs a l-chip modem (R96DFXL) which is installed
on the control PWB.
2) TELMU
This PWB controls connection of.5 telephone line to the unit.
3) Power supply
This provides voltages of +5V, f12V, and +24V to the control PWB
and the Inkjet Printer.
4) Panel
me panel allows input of the operation panel and LCD display.
5) Option memory board (FO-1 MD)
This unit ls the use of an extend memory.
If this unit is setted, the memory function is increased.
To AC outlet
Power supply
1 L
Control PWB
3. Operational description
Operational descriptions are given below:
Transmission
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When a document in loaded in the standby mode, the state of the
document sensor is sensed via the gate array A. If the sensor
signal was on, the motor is started to bring the document into the
standby position. With depression of the START/copy key in the
off-hook state, transmission takes place.
Upon depression of the START/copy key, the CML relay is set
active which switches the line from the telephone to the modem.
Then, the procedure is sent out from the modem and the motor is
rotated to move the document down to the scan line. In the Image
processor (M66SSS), the signal scanned by CCD is sent to the
internal AD converter to convert the analog signal into binary data.
This binary data is transferred from the Image processor to the
image buffer and encoded and stored in the transmit buffer of the
DRAM. The data is then written to the modem according to inter-
ruption by the data transmission request signal from the modem.
The modem madulates the code data and sends signals through
the TEULIU PWB.
Receive operation
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There are two ways of starting reception, manual and automatic.
Depression of the START/copy key in the off-hook mode in the
case of the manual receive mode, or Cl signal detection by the LIU
in the automatic receive mode, causes the CML relay to activate to
initiate the receive operation.
be ready to receive data. When the program goes into phase C,
the serial data from the modem is stored in the receive buffer of
the RAM. The data in the receive buffer is decoded software-wise
to reproduce it as binary image data in the image buffer. The data
is DMA transferred to the recording processor within the gate array
A (F255011) which is then converted from parallel to serial form to
be sent to the printer unit. The data is printed by the printer unit.
Copy operation
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To make a copy on this facsimile, the START/copy key is pressed
when the machine is ready with a document on the document
table and the telephone set is in the on-hook state.
First, depression of the START/copy key advances the document
to the first scan line. Similar to the transmitting operation, the
image signal from the CCD is converted to a binary signal in the
DMA mode via the Image Processor which is then sent to the
image buffer of the RAM. Next, the data is transferred to the
recording processor in the DMA mode to send the image data to
the printer unit which is printed. The copying takes place as the
operation is repeated.
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