Sharp UX-A1000 Service Manual Download

Page: 56 / 128

UX-A1000U

CHAPTER 5. CIRCUIT DESCRIPTION

[1] Circuit description

1. General description

The compact design of the control PWB is obtained by using CONEXANT
fax engine in the main control section and high density printing of sur-
face mounting parts. Each PWB is independent according to its function
as shown in Fig. 1.

2. PWB configuration

Fig. 1

1) Control PWB

The control PWB controls peripheral PWBs, mechanical parts, trans-
mission, and performs overall control of the unit.
This machine employs a 1-chip modem (SCE214V) which is installed
on the control PWB.

2) TEL/LIU PWB

This PWB controls connection of the telephone line to the unit.

3) Power supply PWB

This PWB provides voltages of +5V and +30V to the other PWBs.

4) Panel PWB

The panel PWB allows input of the operation keys.

5) LCD PWB

This PWB controls the LCD display.

6) Printer PWB

This PWB controls printer machine.

7) Ink PWB

This PWB controls Ink cartridge.

3. Operational description

Operational descriptions are given below:

•

Transmission operation

When a document is loaded in stand-by mode, the state of the docu-
ment sensor is sensed via the 1 chip fax engine (SCE214V). With
depression of the START key in the off-hook state, transmission takes
place. Then, the procedure is sent out from the modem and the mo-
tor is rotated to move the document down to the scan line. In the
scan processor, the signal scanned by the CIS is sent to the internal
image processor and the AD converter to convert the analog signal
into binary data. This binary data is transferred from the scan proc-
essor to the image buffer within the RAM and encoded and stored in
the transmit buffer of the RAM. The data is then converted from par-
allel to serial form by the modem where the serial data is modulated
and sent onto the line.

•

Receive operation

There are two ways of starting reception, manual and automatic.
Depression of the START key in the off-hook mode in the case of
manual receive mode, or CI signal detection by the LIU in the auto-
matic receive mode.

First, the SCE214V controls the procedure signals from the modem
to be ready to receive data. When the program goes into phase C,
the serial data from the modem is converted to parallel form in the
modem interface of the 1 chip fax engine (SCE214V) which 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 SCE214V which is then converted from parallel to serial
form to be sent to the Hurricane on the printer PWB. Hurricane con-
trol the printing system.

•

Copy operation

To make a copy on this facsimile, the COPY key is pressed when the
machine is in stand-by with a document on the document table and
the telephone set is in the on-hook state. First, depression of the
COPY key advances the document to the scan line. Similar to the
transmitting operation, the image signal from the CIS is converted to
a binary signal in the DMA mode via the 1 chip fax engine (SCE214V)
which is then sent to the image buffer of the RAM. Next, the data is
transferred to the recording processor to send the image data to
Hurricane and then to the INK cartridge which is printed line by line.
The copying takes place as the operation is repeated.

5 – 1

LCD

PWB

CONTROL

PWB

TEL/LIU

PWB

PRINTER

PWB

INK

PWB

POWER