R-642M. R642M - Sharp Home Appliance Service Manual (repair manual). Page 8

8

R-642M -

1-7

SEG13 -

OUT

SEG19

Connected to LCD.
The relation between signals are as follows:

LSI signal (Pin No.)

LCD

LSI signal (Pin No.)

LCD

SEG 13 (1) .................................. S7

SEG 19 (7) ......................... S1

SEG 14 (2) .................................. S6

SEG 8 (59) ....................... S12

SEG 15 (3) .................................. S5

SEG 9 (60) ....................... S11

SEG 16 (4) .................................. S4

SEG 10 (61) ..................... S10

SEG 17 (5) .................................. S3

SEG 11 (62) ....................... S9

SEG 18 (6) .................................. S2

SEG 12 (63) ....................... S8

8

NC

Not connection terminal.

9

NC

Connected to COM2 (LSI Pin No, 49).

10

NC

Connected to COM1 (LSI Pin No, 48).

11

NC

Connected to COM0 (LSI Pin No, 47).

12-13

NC

No connection terminal.

14-16

VC1-VC3

IN/OUT

Terminal not used.

OUTLINE OF TOUCH CONTROL PANEL

The touch control section consists of the following cir-
cuits as shown in the touch control panel circuit.

The principal functions of these circuits and their related
signals are explained below.

Tact Switch
Signals generated in the LSI are sent to the tact switches
through SEG0, SEG1, SEG2, and SEG3.
When a tact switch is touched, a signal is completed
through the tact switch and passed back to the LSI
through P20 and P23 to perform the function that was
requested.

Control Unit
Control unit consists of LSI, ACL circuit, indicator circuit,
power source circuit, relay circuit, buzzer circuit, syn-
chronizing signal circuit and back light circuit.

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

This circuit generates a signal which resets the LSI to
the initial state when power is supplied.

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

This circuit generates voltage necessary in the con-
trol unit from the AC line voltage.

Symbol

Voltage

Application

VC

- 5V

LSI(IC1)

To drive the magnetron, grill heater, fan motor, turn-
table motor and  light the oven lamp.

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

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

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

LSI(IZA918DR)
The I/O signal of the LSI(IZA918DR) are detailed in the following table.