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CHAPTER 5.
UX-B800A
CIRCUIT DESCRIPTION
[1] Circuit description
1. General description
The compact design of the control PWB is obtained by using CONEX-
ANT fax engine in the main control section and high density printing of
surface mounting parts. Each PWB is independent according to its
function as shown in Fig. 1.
2. PWB configuration
MOTOR
ENCODER
CIS
LCD
CONTROL
UNIT
PWB
PANEL
PWB
2.1. Control PWB
The Control PWB controls peripheral PWBs, mechanical parts, trans-
mission, and performs overall control of the unit. This machine
employs 1 chip fax engine (CX93310) which is installed on the Control
PWB.
2.2. LIU PWB
This PWB controls connection of a telephone line to the unit.
2.3. Power supply PWB
This PWB provides voltages of +5V and +30V to the other PWBs.
2.4. Panel PWB
The panel PWB allows input of the operation keys.
2.5. LCD UNIT
This unit controls the LCD display.
PRINTER
UNIT
LIU PWB
POWER
SUPPLY
PWB
AC CORD
Fig.1
Service Manual
3. Operational description
Operational descriptions are given below:
•
Transmission operation
When a document is loaded in stand-by mode, the state of the doc-
ument sensor is sensed via the 1 chip fax engine (CX93310). With
depression of the START key in the off-hook state, transmission
takes place. Then, the procedure is sent out from the modem
(CX20452) and the motor 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 CX20556 to convert the analog signal into binary
data. This binary data is transferred from the scan processor to the
image buffer within the RAM and encoded and stored in the trans-
mit buffer of the RAM. The data is then converted from parallel to
serial form by the modem (CX20452) where the serial data is mod-
ulated 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 CX93310 controls the procedure sig-
nals from the modem to be ready to receive data. When the
program goes into phase C, the serial data from the modem is con-
verted to parallel form in the modem interface of the 1 chip fax
engine (CX93310) which is stored in the receive buffer of the RAM.
The data in the receive buffer is decoded software-wise to repro-
duce it as binary image data in the image buffer. The data is sent to
Printer unit by serial data. CX93310 controls 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 con-
verted to a binary signal in the DMA mode via the CX20556 which
is then sent to the image buffer of the RAM. Next, the data is trans-
ferred to CX93310 and modify the data to send to Printer unit
CX93310 controls Feed Motor and Carrier Motor.
5 – 1
UX-B800A
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