Touch Control Panel Assembly - Sharp R-1750 Service Manual

The touch control section consists of the following units.
(1) Key Unit
(2) Control Unit (The Control Unit consists of Power Unit
and LSI Unit).
The principal functions of these units and the signals com-
municated among them are explained below.
Key Unit
The key unit is composed of a matrix, signals generated in
the LSI are sent to the key unit through P93, P94, P95 and
P40.
When a key pad is touched, a signal is completed through
the key unit and passed back to the LSI through PB1, PB2,
PB3, PB4 and PB5 to perform the function that was re-
quested.
Control Unit
Control unit consists of LSI, IC, ACL circuit, inverter unit
control circuit, indicator circuit, power source circuit, relay
circuit, buzzer circuit, synchronizing signal circuit, key unit
circuit, touch screen circuit, absolute humidity sensor circuit
and back light circuit.
1) IC1 (LSI)
This is a microcomputer, responsible for controlling the
entire control unit.
2) IC2
This is a read only memory IC, responsible for giving IC1
the all programmes.
3) IC3
This is an amplifier IC. This IC controls the contrast of
LCD and amplify the sensor signal.
4) IC4
This is a memory IC. This memorizes the contrast of
LCD.
5) IC5
This IC drives the LCD.
6) ACL
This circuit generates a signal which resets the LSI (IC1)
to the initial state when power is supplied.
7) Indicator Circuit
This circuit consists of 100 x 160 dots using a Liquid
Crystal Display. The Liquid Crystal Display (LCD) is
drived by IC5.
8) Power Source Circuit
This circuit generates voltages necessary in the control
unit from the AC line voltage.

TOUCH CONTROL PANEL ASSEMBLY

OUTLINE OF TOUCH CONTROL PANEL
In addition, the synchronizing signal is available in order
to compose a basic standard time in the clock circuit.
Symbol Voltage
VC +5V
9) Relay Circuit
A circuit to drive the fan motor, stirrer motor, turntable
motor, hood motor and light the oven lamp.
10) Buzzer Circuit
The buzzer is responsive to signals from the LSI to emit
audible sounds (key touch sound and completion sound).
11) Synchronizing Signal Circuit
The power source synchronizing signal is available in
order to compose a basic standard time in the clock
circuit.
It accompanies a very small error because it works on
commercial frequency.
12) Stop Switch
A switch to "tell" the LSI if the door is open or closed.
13) Back Light Circuit
A circuit to drive the back light (Light emitting diodes
LED1 and LED2).
14) Absolute Humidity Sensor Circuit
This circuit detects moisture of the cooking food to allow
its automatic cooking.
15) Touch Screen
The touch screen is composed of a matrix, signal
generated in the LSI are sent to the key unit through
P41, P42, P43 and P44. When a key is touched, a signal
is completed through the touch screen and passed
back to the LSI through PB1, PB2, PB3, PB4 and PB5
to perform the function that was requested.
16) Inverter Unit Control Circuit
This is the circuit to control the inverter unit.
27
R-1750
R-1751
R-1752
R-1754
Application
LSI(IC1)