Read Sharp R-750AM (serv.man5) Service Manual online
6
750A -
TOUCH CONTROL PANEL ASSEMBLY
OUTLINE OF TOUCH CONTROL PANEL
The touch control section consists of the following units as
shown in the touch control panel circuit.
shown in the touch control panel circuit.
(1) Key Unit
(2) Control Unit
(2) Control Unit
The principal functions of these units and the signals
communicated among them are explained below.
communicated among them are explained below.
Key Unit
The key unit is composed of a matrix, signals R60, R61,
R62, R63, R72 and R73 generated in the LSI are sent to
the key unit.
When a key pad is touched, a signal is completed
through the key unit and passed back to the LSI through
R50, R51, R52 and R53 to perform the function that was
requested.
The key unit is composed of a matrix, signals R60, R61,
R62, R63, R72 and R73 generated in the LSI are sent to
the key unit.
When a key pad is touched, a signal is completed
through the key unit and passed back to the LSI through
R50, R51, R52 and R53 to perform the function that was
requested.
Control Unit
Control unit consists of LSI, power source circuit, syn-
chronizing signal circuit, ACL circuit, buzzer circuit and
indicator circuit.
Control unit consists of LSI, power source circuit, syn-
chronizing signal circuit, ACL circuit, buzzer circuit and
indicator circuit.
1) LSI(IC1)
This LSI controls the key strobe signal, relay driving
signal for oven function and indicator signal.
signal for oven function and indicator signal.
2) Power Source Circuit
This circuit generates voltages necessary in the control
unit.
unit.
Symbol
Voltage
Application
VC
-5V
LSI(IC1)
3) 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.
order to compose a basic standard time in the clock
circuit. It accompanies a very small error because it
works on commercial frequency.
4) ACL Circuit
A circuit to generate a signal which resets the LSI to the
initial state when power is supplied.
initial state when power is supplied.
5) Buzzer Circuit
The buzzer is responsive to signals from the LSI to
emit audible sounds (key touch sound and comple-
tion sound).
emit audible sounds (key touch sound and comple-
tion sound).
6) Door Sensing Switch (Stop Switch)
A switch to “tell” the LSI if the door is open or closed.
7) Relay Circuit
To drive the magnetron, fan motor, turntable motor, grill
heater and light the oven lamp.
heater and light the oven lamp.
8) Indicator Circuit
This circuit consists of 4-digits, 12-segments and 3-
common electrodes using a Liquid Crystal Display.
common electrodes using a Liquid Crystal Display.
9) Back Light Circuit
A circuit to drive the back light (Light emitting diodes
LED1-LED4).
LED1-LED4).
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