R-64 (serv.man2). Part 1 Text (1-14) - Sharp Home Appliance Service Manual (repair manual). Page 9

R-64STM -9

OUTLINE OF TOUCH CONTROL PANEL

OUTLINE OF TOUCH CONTROL PANEL

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.

A circuit to generate a signals which resets the LSI to
the initial state when power is supplied.

The buzzer is responsive to signals from the LSI to emit
audible sounds (tact switch touch sound and comple-
tion sound).

A switch to "tell" the LSI if the door is open or closed.

To drive the magnetron, fan motor, turntable motor,
grill heating element and light the oven lamp.

This circuit consists of 4-digits, 12-segments and 3-
common electrodes using a Liquid Crystal Display.

The encoder converts the signal generated by LSI into
the pulse signal, and the pulse signal is returned to the
LSI.

A circuit to drive the back light (Light emitting diodes
LED1-LED4)

The touch control section consists of the following units.

(1) Switch Unit
(2) Control Unit

The principal functions of these units and the signals
communicated among them are explained below.

Switch Unit
The switch unit is composed of a matrix, signals
generated in the LSI are sent to the switch unit through
R60 and R61.
When a switch button is touched, a signal is completed
through the switch 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, relay
circuit, back light circuit, synchronizing signal circuit, ACL
circuit, buzzer circuit and indicator circuit.

This LSI controls the tact switch strobe signal, relay
driving signal for oven function and indicator signal.

This circuit generates voltage necessary in the control
unite.

Symbol

Voltage

Application

VC

+5V

LSI(IC1)