R-22JT
20
TOUCH CONTROL PANEL ASSEMBLY
OUTLINE OF TOUCH CONTROL PANEL
The touch control section consists of the following units as
shown in the touch control panel circuit.
(1) Control Unit
(2) Key Unit
The principal functions of these units and the signals com-
municated among them are explained below.
1. Control Unit
Signal of key touch and oven function control are all processed
by one microcomputer.
1) Power Supply Circuit
This circuit changes output voltage at the secondary side of the
low voltage (T1) transformer to voltages required at each part
by full wave rectifying circuit, constant voltage circuit, etc..
2) ACL Circuit
This is an Auto-clear Circuit, i.e., a reset circuit, which enables
IC1 to be activated from initial state.
3) Power Synchronizing Signal Generating Circuit
This is a circuit for generating power synchronizing signal by
virtue of the secondary side output of transformer T1.
This signal is used as a basic frequency for time processing.
4) Clock Circuit
This is a circuit for controlling clock frequency required for
operating IC1.
5) IC1 (Main Processor)
This is a one-chip microcomputer, responsible for controlling
the entire control unit.
6) IC2 (Memory Processor)
This is a memory IC, responsible for memory function.
7) IC3
This is a IC for driving light emitting diode.
8) Display Circuit
This is a circuit for driving light emitting diode by IC1 output.
9) Key Input Circuit
This is a circuit for transmitting key input information to IC1.
10) Sound-body Driving Circuit
This is a circuit for driving sound body by IC1 output.
11) Relay Driving Circuit
This is a circuit for driving output relay by IC1 output.
12) Door Sensing Switch Circuit
This is a circuit for driving IC1 to detect door opening/closing.
13) Exhaust Air Temperature Detecting Circuit
This is a circuit for transmitting output change of thermistor
(Oven thermistor (1)) to IC1.
14) Magnetron Temperature Circuit
(Detect no load)
This is a circuit for transmitting output change of thermistor
(Magnetron thermistor) to IC1.
15) High Voltage Monitoring Circuit.
This circuit detects problems in the magnetron / high voltage
circuit by sensing a variation in the current flowing through the
primary winding of the high voltage transformer. During heating,
the primary current of the high voltage transformers also flows
through the primary winding of the current transformer CT1.
This causes a current to be induced in the secondary winding
of CT1 and results in an AC voltage which is determined by
R100. This AC voltage is then half wave rectified by D100 and
smoothed (filtered) by C100. This AC voltage is the input to the
AN3 port of IC1, which determines if there is a magnetron / high
voltage problem.
Figure T-1. High Voltage Monitoring Circuit
2. Key Unit
The key unit is composed of a matrix circuit in which when a key
it touched, one of signals P30--P34 generated by the LSI, is
passed through the key and returned to the LSI as one of
signals P24--P27.
This model has 20 Memory pads.
When the oven is shipped, Memory pad 1 to 10 are set as
follows: fig.1.
Memory No.
Cook Time
Output Power
1
10 sec.
100%
2
20 sec.
100%
3
30 sec.
100%
4
45 sec.
100%
5
1 min.
100%
6
1 min. 15 sec.
100%
7
1 min. 30 sec.
100%
8
2 min.
100%
9
2 min. 30 sec.
100%
0
3 min.
100%
(fig. 1)
This model has a double quantity pad. When the oven is
shipped, Magnification "1.8" is preset in the double quantity
pad. This model has an express defrost pad. When the oven is
shipped, express defrost is set as follows: fig.2.
1 STAGE
2 STAGE
3 STAGE
FORMULA
P = 0.2T + 20
P = 0.13T + 30
P = 0.67T - 50
POWER
40 %
30 %
20 %
T : Total cooling time
(fig. 2)
When 1/2 total cooking time is passed, the signal will
sound and "CHECK" indicator will flash.
TB1
TB2
CT1
D100
R102
R100
C100
47µ
/10v
0.01µ
/16v
R101
100k
820F
C101
4.7k
To AN3 of IC1
