R-216(G)
R-216(IN)
R-216(W)
R - 2 1 6 ( Y )
15
Control Unit
Control unit consists of LSI, power source circuit, synchro-
nizing signal circuit, reset circuit, buzzer circuit, encoder
circuit and indicator circuit.
1) LSI
This LSI controls the encoder signal, tact switch strobe
signal, relay driving signal for oven function, buzzer
signal and LED signal.
2) Power Source Circuit
This circuit generates voltage necessary in the control
unit.
Symbol
Voltage
Application
VC
-5.0V
LSI(IC-1)
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) Reset Circuit
A circuit to generate a signals which resets the LSI to
the initial state when power is supplied.
CONTROL PANEL ASSEMBLY
OUTLINE OF CONTROL PANEL
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) 2nd. Interlock Relay Control 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 and
light the oven lamp.
8) Encoder
The encoder generates the pulse signal, and the pulse
signal is sent to the LSI.
9) Indicator Circuit
Indicator elements are the Light-emitting diodes (LD1-
LD24 and LD30-LD34).
This circuit consists of 4-digits and 8 segments.
10) Tact Switch
Signal generated in the LSI is sent to the tact switch.
When a tact switch is touched, a signal is completed
through the tact switch and passed back to the LSI
through to perform the function that was requested.
DESCRIPTION OF LSI
LSI
The I/O signal of the LSI are detailed in the following table.
Pin No.
Signal
I/O
Description
1
D3
OUT
Segment data signal.
Signal is input to the cathodes of the light-emitting diodes (LD8, LD16 and LD24).
2
D4
OUT
Signal to sound buzzer.
A: Tact switch touch sound.
B: Completion sound.
3
D5
OUT
Oven lamp, turntable motor and fan motor driving signal(Square
Waveform : 50Hz).
To turn on and off shut-off relay (RY1).
The square waveform voltage is delivered
to the relay (RY1) driving circuit and
relay(RY2) control circuit.
4
D6
OUT
Magnetron high-voltage circuit driving signal.
To turn on and off the cook relay (RY2).
In 100% power operation, the signals
hold “L” level during microwave cooking
and “H” level while not cooking. In other
cooking modes (70%, 50%, 30%, 10%)
the signal turns to “H” level and “L” level
in repetition according to the power level.
A
B
H: GND
L: -5V
0.1 sec
2.0 sec
20 msec
During cooking
H
L
ON/OFF time ratio in Mi-
cro cooking
(a. 32second time base)
MICRO
ON
OFF
COOK
100%
32sec.
0sec.
70%
24sec.
8sec.
50%
18sec.
14sec.
30%
12sec.
20sec.
10%
6sec.
26sec.
