R-8000G
25
The touch control section consists of the following units as shown
in the touch control panel circuit.
(1) Tact switch circuit on the CPU unit and the control unit (switch
unit).
(2) Control Unit (The control unit consists of Power unit and CPU
unit.)
The principal functions of these units and the signals communi-
cated among them are explained below.
Tact Switch Circuit
The tact switch circuit is composed of a matrix, signals AN0-AN7
generated in the LSI are sent to the tact switches. When a tact
switch is touched, a signal is completed through the tact switch
circuit and passed back to the LSI through PB0-PB3 to perform the
function that was requested.
Control Unit
Control unit consists of LSI, power source circuit, synchronizing
signal circuit, reset circuit, buzzer circuit, temperature measure-
ment circuit, relay watching circuit, input voltage watching circuit
and indicator circuit.
1) LSI (IC-1)
This LSI controls the temperature measurement signal, tact
switch strobe signal, relay driving signal and indicator signal.
And also LSI watches the relay operation and the primary input
voltage.
2) Power Source Circuit
This circuit generates the voltage necessary for the control unit
from the AC line voltage.
3) Synchronizing Signal Circuit
The power source synchronizing signal is available in order to
compose a basic standard time in the clock circuit. It incorporates
a very small error because it works on commercial frequency.
4) Reset Circuit
A circuit to generate a signals which resetting the LSI to the
initial state when power is applied.
TOUCH CONTROL PANEL ASSEMBLY
OUTLINE OF TOUCH CONTROL PANEL
5) Buzzer Circuit
The buzzer is responds to signals from the LSI to emit noticing
sounds (tact switch touch sound and completion sound).
6) Temperature Measurement Circuit : (OVEN THERMISTOR)
The temperature in the oven cavity is sensed by the thermistor.
The variation of resistance according to sensed temperature is
detected by the temperature measurement circuit and the
result applied to LSI. The LSI uses this information to control
the relay and display units.
7) Relay Operation Watching Circuit
This circuit watches so that the three (3) relays for the top
heating element, the side heating element and the power
transformer do not operate at the same time. This circuit
consists of the transistor Q24 - Q27 and resistors R23 - R26.
8) Input Voltage Watching Circuit
This circuit watches the primary input voltage.
9) Door Sensing Switch
A switch to inform the LSI if the door is open or closed.
10) Relay Circuit
To drive the magnetron, heating elements, fan motor, jet
motor, turntable motor and light the oven lamp.
11) Indicator Circuit
Indicator element is a Fluorescent Display.
Basically, a Fluorescent Display is triode having a cathode, a
grid and an anode. Usually, the cathode of a Fluorescent
Display is directly heated and the filament serves as cathode.
The Fluorescent Display has 10-digits, 42-segments are used
for displaying figures.
12) Memory Processor (IC-2)
This is a memory IC, responsible for memory function.
DESCRIPTION OF LSI (IC-1)
LSI(IC-1):
The I/O signals of the LSI(IC-1) are detailed in the following table.
Pin No.
Signal
I/O
Description
1
AN5
OUT
Tact switch strobe signal.
Signal applied to tact switch section (SW1, SW4, SW7, SW10).
2
AN4
OUT
Turminal not used.
3
AN3
OUT
Tact switch strobe signal.
Signal applied to tact switch section (SW14, SW18, SW22).
4
AN2
OUT
Tact switch strombe signal
Signal applied to tact switch section (SW13, SW17, SW21).
5
AN1
OUT
Tact switch strobe signal.
Signal applied to tact switch section (SW12, SW16, SW20).
6
AN0
OUT
Tact switch strobe signal.
Signal applied to tact switch section (SW11, SW15, SW19, SW23).
