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The control section consists of the following units as
shown in the control panel circuit.
(1) Jog and Switch Unit
(2) Control Unit (The Control unit consists of Power unit
and CPU unit.)
The principal functions of these units and signals commu-
nicated among them are explained below.
Jog and Switch Unit
1) Tact switch circuit
The jog and switch unit is composed of a matrix, signals
generated in the LSI are sent to the jog and switch unit
from P14, P15, P16 and P17.
When a tact switch pad is touched, a signal is completed
through the jog and switch unit and passed back to the
LSI through P70, P71, P72 and P73 to perform the
function that was requested.
2) Encoder
The encoder converts the signal generated by LSI into
the pulse signal, and the pulse signal is returned to the
LSI.
3) Potentiometer circuit
The circuit makes setting of the cooking mode by
variable resistance.
Control Unit
Control unit consists of LSI, power source circuit, synchro-
nizing signal circuit, ACL circuit, buzzer circuit, relay
circuit, temperature measurement circuit, indicator circuit
and back light circuit.
1) LSI
This LSI controls the temperature measurement sig-
nal, tact switch strobe signal, relay driving signal for
oven function and indicator signal.
2) Power Source Circuit
This circuit generates voltage necessary in the control
unit.
Symbol
Voltage
Application
VC
-5.2V
LSI(IC1)
CONTROL PANEL ASSEMBLY
OUTLINE OF CONTROL PANEL
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.
4) ACL
A circuit to generate a signal which resets the LSI to the
initial state when power is supplied.
5) Buzzer Circuit
The buzzer is responsive to signals from the LSI to emit
audible sounds (tact switch 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, grill heating element, convec-
tion heating element, convection motor, fan motor,
turntable motor, damper motor, touch control trans-
former and light the oven lamp.
8) Back Light Circuit
A circuit to drive the back light (Light emitting diodes
LD10 - LD19).
9) Indicator Circuit
This circuit consists 40-segments and 16-common
electrodes using a Liquid Crystal Display.
The Liquid Crystal Display (LCD) is drived by LCD
driver IC3.
10) 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.
11) Damper Switch
A switch to tell the LSI if the damper is open or
close.
