Touch Control Panel Assembly - Sharp R-22AM Service Manual

R-22AM
R-23AM
R - 2 3 A T
TOUCH CONTROL PANEL ASSEMBLY FOR R-23AT
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
communicated 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 trans-
former T1.
This signal is used for a basic frequency to time
processing and so on.
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) Display Circuit
This is a circuit for driving display tubes by IC1 output.
8) Key Input Circuit
This is a circuit for transmitting key input information to
IC1.
9) Sound-body Driving Circuit
This is a circuit for driving sound body by IC1 output.
10) Relay Driving Circuit
This is a circuit for driving output relay by IC1 output.
11) Stop Switch Circuit
This is a circuit for driving IC1 to detect door opening/
closing.
12) Exhaust Air Temperature Detecting Circuit
This is a circuit for transmitting output change of
thermistor (Oven thermistor (1)) to IC1.
13) 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 transformers CT1 and CT2.
This causes a current to be induced in the
secondary windings of CT1/CT2 and results in an
OUTLINE OF TOUCH CONTROL PANEL
14) Magnetron Temperature Circuit.
15) Oven Cavity Temperature Detecting Circuit.
2. Key Unit
POWER
DEFROSTING TIME 0.2T+20sec. 0.13T+30sec. 0.67T-50sec.
NOTE :
"CHECK" indicator will flash at half of defrosting time.
20
AC voltage which is determined by R61/R62.
This AC voltage is then half wave rectified by D61/
D62 and smoothed (filtered) by C61/C62.
This AC voltage is the input to the IN3 and IN5 ports of
IC1, which determines if there is a magnetron / high
voltage problem.
HIGH VOLTAGE TRANSFORMER
CT1 or CT2
RY3 or RY4
R65 or
R61 or
R66
R62
D61 or R63 or
D62 R64
Figure T-1. High Voltage Monitoring Circuit For R-23AT
(Detect Noload or Fan Lock)
This is a circuit for transmitting output change of
thermistor (Magnetron thermistor) to IC1.
This is a circuit for transmitting output change of
thermistor (Oven thermistor (2)) to IC1.
The key unit is composed of a matrix circuit in which
when a key it touched, one of signals P11, P12, P15,
P16 and P17 generated by the LSI, is passed through
the key and returned to the LSI as one of signals R0-
-R3. 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
1 5 sec.
2 10 sec.
3 20 sec.
4 30 sec.
5 40 sec.
6 50 sec.
7 1 min.
8 1 min.15 sec.
9 1 min.30 sec.
10 2 mins.
(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 defrost pad. When the
oven is shipped, defrost is set as follows: fig.2.
1STAGE
50%
(fig. 2)
HIGH VOLTAGE CIRCUIT
MAIN BODY SIDE
T/C SIDE
C61 or C62
IC1
IN3 or
D63 or
IN5 PORT
D64
Vc
Output Power
100%
100%
100%
100%
100%
100%
100%
100%
100%
100%
2STAGE 3STAGE
30% 20%