Sharp R-244M (serv.man4) Service Manual ▷ View online
R-244M - 9
TOUCH CONTROL PANEL ASSEMBLY
OUTLINE OF TOUCH CONTROL PANEL
4) Relay Circuit
To drive the magnetron, fan motor, turntable motor and
light the oven lamp.
light the oven lamp.
5) Buzzer Circuit
The buzzer is responsive to signals from the LSI to emit
audible sounds (tact switch touch sound and completion
sound).
audible sounds (tact switch touch sound and completion
sound).
6) 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.
order to compose a basic standard time in the clock circuit.
It accompanies a very small error because it works on
commercial frequency.
7) Door Sensing Switch (Stop Switch)
A switch to "tell" the LSI if the door is open or closed.
8) Back Light Circuit
A circuit to drive the back light (Light emitting diodes
LED1-LED3)
LED1-LED3)
The touch control section consists of the following units.
(1) Switch Unit
(2) Control Unit
(2) Control Unit
The principal functions of these units and the signals
communicated among them are explained below.
communicated among them are explained below.
Switch Unit
The switch unit is composed of a matrix, signals generated
in the LSI are sent to the switch unit through R60, R61, R62
and R63.
When a switch button is touched, a signal is completed
through the switch unit and passed back to the LSI through
R81 and R83 to perform the function that was requested.
The switch unit is composed of a matrix, signals generated
in the LSI are sent to the switch unit through R60, R61, R62
and R63.
When a switch button is touched, a signal is completed
through the switch unit and passed back to the LSI through
R81 and R83 to perform the function that was requested.
Control Unit
Control unit consists of LSI, ACL circuit, indicator circuit,
power source circuit, relay circuit, buzzer circuit, synchroniz-
ing signal circuit and back light circuit.
Control unit consists of LSI, ACL circuit, indicator circuit,
power source circuit, relay circuit, buzzer circuit, synchroniz-
ing signal circuit and back light circuit.
1) ACL
This circuit generates a signal which resets the LSI to the
initial state when power is supplied.
initial state when power is supplied.
2) Indicator Circuit
This circuit consists of 4-digits, 12-segments and 3-
common electrodes using a Liquid Crystal Display.
common electrodes using a Liquid Crystal Display.
3) Power Source Circuit
This circuit generates voltage necessary in the control unit
from the AC line voltage.
from the AC line voltage.
Symbol
Voltage
Application
VC
+5V
LSI(IC1)
10
R-244M -
HIGH
H : +5V
L : 0V
H : +5V
L : 0V
MEDIUM
HIGH
ON
ON
OFF
OFF
OFF
24 sec.
8 sec.
A
B
0.1 sec.
2 sec.
H : +5V
L: 0V
H : +5V
L: 0V
20.0 msec
During cooking
H : +5V
L : 0V
20.0 msec
H : +5V
L : 0V
1-12
SEG0 -
OUT
Segment data signal.
SEG11
Connected to LCD.
The relation between signals are as follows:
The relation between signals are as follows:
LSI signal (Pin No.)
LCD (Pin No.)
LSI signal (Pin No.) LCD (Pin No.)
SEG 0 (1) ................................ S6
SEG 6 (7) ........................... S12
SEG 1 (2) ................................ S7
SEG 7 (8) ............................. S5
SEG 2 (3) ................................ S8
SEG 8 (9) ............................. S4
SEG 3 (4) ................................ S9
SEG 9 (10) ........................... S3
SEG 4 (5) .............................. S10
SEG 10 (11) ......................... S2
SEG 5 (6) .............................. S11
SEG 11 (12) ......................... S1
13
R60
OUT
Tact switch strobe signal.
Signal applied to tact switch section. A pulse signal is input to R81 or R83 terminal
while the tact switch SW1 or SW8 is touched.
Signal applied to tact switch section. A pulse signal is input to R81 or R83 terminal
while the tact switch SW1 or SW8 is touched.
14
R61
OUT
Tact switch strobe signal.
Signal applied to tact switch section. A pulse signal is input to R81or R83 terminal
while the tact switch SW2 or SW5 is touched.
Signal applied to tact switch section. A pulse signal is input to R81or R83 terminal
while the tact switch SW2 or SW5 is touched.
15
R62
OUT
Tact switch strobe signal.
Signal applied to tact switch section. A pulse signal is input to R81 or R83 terminal
while the tact switch SW3 or SW6 is touched.
Signal applied to tact switch section. A pulse signal is input to R81 or R83 terminal
while the tact switch SW3 or SW6 is touched.
16
R63
OUT
Tact switch strobe signal.
Signal applied to tact switch section. A pulse signal is input to R81 or R83 terminal
while the tact switch SW4 or SW7 is touched.
Signal applied to tact switch section. A pulse signal is input to R81 or R83 terminal
while the tact switch SW4 or SW7 is touched.
17
AIN0
IN
To input signal which communicates the door open/close information to LSI.
Door close "L" level signal (0V). Door open "H" level (+5V)
Door close "L" level signal (0V). Door open "H" level (+5V)
18-20
AIN1-AIN3
IN
Terminal to change functions according to the Model.
By using the A/D converter contained in the LSI, DC voltage in accordance with the
Model in operation is applied to set up its function.
By using the A/D converter contained in the LSI, DC voltage in accordance with the
Model in operation is applied to set up its function.
21
VSS
IN
Power source voltage: 0V.
VSS voltage of power source circuit input.
VSS voltage of power source circuit input.
22
R70
OUT
Magnetron high-voltage circuit driving signal.
To turn on and off the cook relay
(RY2). The signals holds "L" level
during microwave cooking and "H"
level while not cooking. In other cook-
ing modes (variable cooking) the sig-
nal turns to "H" level and "L" level in
repetition according to the power level.
(RY2). The signals holds "L" level
during microwave cooking and "H"
level while not cooking. In other cook-
ing modes (variable cooking) the sig-
nal turns to "H" level and "L" level in
repetition according to the power level.
23
R71
OUT
Signal to sound buzzer (2.0 kHz).
A: Tact switch touch sound.
B: Completion sound.
24
R72
OUT
Oven lamp, fan motor and turntable motor driving signal.
To turn on and off shut off relay (RY1). The
square waveform voltage is delivered to
the RY1 driving circuit.
square waveform voltage is delivered to
the RY1 driving circuit.
25
R73
IN
Terminal not used.
26
INT2
IN
Signal synchronized with commercial power source frequency.
This is the basic timing for time processing of LSI.
DESCRIPTION OF LSI
LSI(IXA085DR)
The I/O signal of the LSI(IXA085DR) are detailed in the following table.
The I/O signal of the LSI(IXA085DR) are detailed in the following table.
Pin No.
Signal
I/O
Description
R-244M - 11
Pin No.
Signal
I/O
Description
27
R81
IN
Signal coming from tact switch.
When either of tact switches SW5-SW8 is touched, a corresponding signal out of
R60, R61, R62 and R63 will be input into R81. When no tact switch is touched, the
signal is held at "H" level.
When either of tact switches SW5-SW8 is touched, a corresponding signal out of
R60, R61, R62 and R63 will be input into R81. When no tact switch is touched, the
signal is held at "H" level.
28
INT1
IN
Terminal not used.
29
R83
IN
Signal coming from tact switch.
When either of tact switches SW1-SW4 is touched, a corresponding signal out of
R60, R61, R62 and R63 will be input into R83. When no tact switch is touched, the
signal is held at "H" level.
When either of tact switches SW1-SW4 is touched, a corresponding signal out of
R60, R61, R62 and R63 will be input into R83. When no tact switch is touched, the
signal is held at "H" level.
30-32
R90-R92
OUT
Terminal not used.
33
XIN
IN
Internal clock oscillation frequency setting input.
The internal clock frequency is set by inserting the capacitor and resistor circuit with
respect to XOUT terminal.
The internal clock frequency is set by inserting the capacitor and resistor circuit with
respect to XOUT terminal.
34
XOUT
OUT
Internal clock oscillation frequency control output.
Output to control oscillation input of XIN.
Output to control oscillation input of XIN.
35
RESET
IN
Auto clear terminal.
Signal is input to reset the LSI to the initial state when power is supplied.
Temporarily set "L" level the moment power is supplied, at this time the LSI is reset.
Thereafter set at "H" level.
Signal is input to reset the LSI to the initial state when power is supplied.
Temporarily set "L" level the moment power is supplied, at this time the LSI is reset.
Thereafter set at "H" level.
36
HOLD
IN/OUT
Connected to VDD.
37
VLC
IN
Signal synchronized with commercial power source frequency.
Signal similar to VSS.
Signal similar to VSS.
38
COM1
OUT
Common data signal.
Connected to LCD(C1).
Connected to LCD(C1).
39
COM2
OUT
Common data signal.
Connected to LCD(C2).
Connected to LCD(C2).
40
COM3
OUT
Common data signal.
Connected to LCD (C3).
Connected to LCD (C3).
41
COM4
OUT
Terminal not used.
42
VDD
IN
Power source voltage input terminal.
Connected to VC.
Connected to VC.
DESCRIPTION OF LSI
LSI(IXA085DR)
The I/O signal of the LSI(IXA085DR) are detailed in the following table
The I/O signal of the LSI(IXA085DR) are detailed in the following table
12
R-244M -
TOUCH CONTROL PANEL ASSEMBLY
SERVICING
1. Precautions for Handling Electronic Components
This unit uses CMOS LSI in the integral part of the circuits.
When handling these parts, the following precautions
should be strictly followed. CMOS LSI have extremely
high impedance at its input and output terminals. For this
reason, it is easily influenced by the surrounding high
voltage power source, static electricity charge in clothes,
etc., and sometimes it is not fully protected by the built-in
protection circuit.
In order to protect CMOS LSI.
1) When storing and transporting, thoroughly wrap them
When handling these parts, the following precautions
should be strictly followed. CMOS LSI have extremely
high impedance at its input and output terminals. For this
reason, it is easily influenced by the surrounding high
voltage power source, static electricity charge in clothes,
etc., and sometimes it is not fully protected by the built-in
protection circuit.
In order to protect CMOS LSI.
1) When storing and transporting, thoroughly wrap them
in aluminium foil. Also wrap PW boards containing
them in aluminium foil.
them in aluminium foil.
2) When soldering, ground the technician as shown in
the figure and use grounded soldering iron and work
table.
table.
approx. 1M ohm
2. Shapes of Electronic Components
3. Servicing of Touch Control Panel
We describe the procedures to permit servicing of the
touch control panel of the microwave oven and the
precautions you must take when doing so.
To perform the servicing, power to the touch control panel
is available either from the power line of the oven itself or
from an external power source.
touch control panel of the microwave oven and the
precautions you must take when doing so.
To perform the servicing, power to the touch control panel
is available either from the power line of the oven itself or
from an external power source.
(1) Servicing the touch control panel with power
supply of the oven :
CAUTION:
THE HIGH VOLTAGE TRANSFORMER OF THE
MICROWAVE OVEN IS STILL LIVE DURING SERV-
ICING AND PRESENTS A HAZARD .
THE HIGH VOLTAGE TRANSFORMER OF THE
MICROWAVE OVEN IS STILL LIVE DURING SERV-
ICING AND PRESENTS A HAZARD .
Therefore, when checking the performance of the
touch control panel, put the outer cabinet on the oven
to avoid touching the high voltage transformer, or
unplug the primary terminal (connector) of the high
voltage transformer to turn it off; the end of such
connector must be insulated with an insulating tape.
After servicing, be sure to replace the leads to their
original locations.
touch control panel, put the outer cabinet on the oven
to avoid touching the high voltage transformer, or
unplug the primary terminal (connector) of the high
voltage transformer to turn it off; the end of such
connector must be insulated with an insulating tape.
After servicing, be sure to replace the leads to their
original locations.
A. On some models, the power supply cord between
the touch control panel and the oven itself is so
short that the two can't be separated.
short that the two can't be separated.
For those models, check and repair all the controls
(sensor-related ones included) of the touch control
(sensor-related ones included) of the touch control
E
C B
Transistor
2SA1267Y
KRA101M
KRC101M
KRC105M
2SA1267Y
KRA101M
KRC101M
KRC105M
panel while keeping it connected to the oven.
B. On some models, the power supply cord between
the touch control panel and the oven proper is so
long enough that they may be separated from each
other. For those models, therefore, it is possible to
check and repair the controls of the touch control
panel while keeping it apart from the oven proper;
in this case you must short both ends of the door
sensing switch (on PWB) of the touch control panel
with a jumper, which brings about an operational
state that is equivalent to the oven door being
closed. As for the sensor-related controls of the
touch control panel, checking them is possible if
the dummy resistor(s) with resistance equal to that
of the controls are used.
long enough that they may be separated from each
other. For those models, therefore, it is possible to
check and repair the controls of the touch control
panel while keeping it apart from the oven proper;
in this case you must short both ends of the door
sensing switch (on PWB) of the touch control panel
with a jumper, which brings about an operational
state that is equivalent to the oven door being
closed. As for the sensor-related controls of the
touch control panel, checking them is possible if
the dummy resistor(s) with resistance equal to that
of the controls are used.
(2) Servicing the touch control panel with power
supply from an external power source:
Disconnect the touch control panel completely from
the oven proper, and short both ends of the door
sensing switch (on PWB) of the touch control panel,
which brings about an operational state that is
equivalent to the oven door being closed. Connect an
external power source to the power input terminal of
the touch control panel, then it is possible to check and
repair the controls of the touch control panel; it is also
possible to check the sensor-related controls of the
touch control panel by using the dummy resistor(s).
Disconnect the touch control panel completely from
the oven proper, and short both ends of the door
sensing switch (on PWB) of the touch control panel,
which brings about an operational state that is
equivalent to the oven door being closed. Connect an
external power source to the power input terminal of
the touch control panel, then it is possible to check and
repair the controls of the touch control panel; it is also
possible to check the sensor-related controls of the
touch control panel by using the dummy resistor(s).
4. Servicing Tools
Tools required to service the touch control panel assembly.
1) Soldering iron: 30W
1) Soldering iron: 30W
(It is recommended to use a soldering iron with a
grounding terminal.)
grounding terminal.)
2) Oscilloscope: Single beam, frequency range: DC -
10MHz type or more advanced model.
3) Others: Hand tools
5. Other Precautions
1) Before turning on the power source of the control unit,
remove the aluminium foil applied for preventing static
electricity.
electricity.
2) Connect the connector of the key unit to the control unit
being sure that the lead wires are not twisted.
3) After aluminium foil is removed, be careful that abnormal
voltage due to static electricity etc. is not applied to the
input or output terminals.
input or output terminals.
4) Attach connectors, electrolytic capacitors, etc. to PWB,
making sure that all connections are tight.
5) Be sure to use specified components where high
precision is required.
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