Sharp R-242M Service Manual ▷ View online
R-242M - 9
Pin No.
Signal
I/O
Description
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
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(4)
SEG 0 (1) ............................ S6(4)
SEG 6 (7) ..................... S12(10)
SEG 1 (2) ............................ S7(5)
SEG 7 (8) ....................... S5(11)
SEG 2 (3) ............................ S8(6)
SEG 8 (9) ....................... S4(12)
SEG 3 (4) ............................ S9(7)
SEG 9 (10) ..................... S3(13)
SEG 4 (5) .......................... S10(8)
SEG 10 (11) ................... S2(14)
SEG 5 (6) .......................... S11(9)
SEG 11 (12) ................... S1(15)
13
R60
OUT
Tact switch strobe signal.
Signal applied to tact switch section. A pulse signal is input to R81 terminal while
the tact switch SW4 or the tact switch SW5 is touched.
the tact switch SW4 or the tact switch SW5 is touched.
14
R61
OUT
Tact switch strobe signal.
Signal applied to tact switch section. A pulse signal is input to R81 terminal while
the tact switch SW3 or the tact switch SW7 is touched.
the tact switch SW3 or the tact switch SW7 is touched.
15
R62
OUT
Tact switch strobe signal.
Signal applied to tact switch section. A pulse signal is input to R81 terminal while
the tact switch SW2 or the tact switch SW6 is touched.
the tact switch SW2 or the tact switch SW6 is touched.
16
R63
OUT
Tact switch strobe signal.
Signal applied to tact switch section. A pulse signal is input to R81 terminal while
the tact switch SW1 is touched.
the tact switch SW1 is touched.
17
AIN0
IN
To input signal which communicates the door open/close information to
LSI.
LSI.
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.
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.
22
R70
OUT
Magnetron high-voltage circuit driving signal.
To turn on and off the cook relay (RY2).
The signals holds "L" level during micro-
wave cooking and "H" level while not
cooking. In other cooking modes (vari-
able cooking) the signal turns to "H"
level and "L" level in repetition accord-
ing to the power level.
The signals holds "L" level during micro-
wave cooking and "H" level while not
cooking. In other cooking modes (vari-
able cooking) the signal turns to "H"
level and "L" level in repetition accord-
ing to the power level.
23
R71
OUT
Signal to sound buzzer (2.0 kHz).
A: key 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 deliv-
ered to the RY1 driving circuit.
The square waveform voltage is deliv-
ered to the RY1 driving circuit.
25
R73
IN
Signal coming from tact switch.
When either of tact switches SW5-SW7 is touched, a corresponding signal out
of R60,R61 and R62 will be input into R73. When no key is touched, the signal
is held at "H" level.
of R60,R61 and R62 will be input into R73. When no key is touched, the signal
is held at "H" level.
DESCRIPTION OF LSI
LSI(IZA787DR)
The I/O signal of the LSI(IZA787DR) are detailed in the following table.
10
R-242M -
DESCRIPTION OF LSI
LSI(IZA787DR)
The I/O signal of the LSI(IZA787DR) are detailed in the following table.
Pin No.
Signal
I/O
Description
26
INT2
IN
Signal synchronized with commercial power source frequency.
This is the basic timing for time processing of LSI.
27
R81
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 R81. When no key is touched, the
signal is held at "H" level.
of R60, R61, R62 and R63 will be input into R81. When no key is touched, the
signal is held at "H" level.
28
INT1
OUT
Terminal not used.
29
R83
OUT
Terminal not used.
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.
with respect to XOUT terminal.
34
XOUT
OUT
Internal clock oscillation frequency control output.
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.
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.
38
COM1
OUT
Common data signal: COM1.
Connected to LCD (Pin No. 1)
39
COM2
OUT
Common data signal: COM2.
Connected to LCD (Pin No. 2)
40
COM3
OUT
Common data signal: COM1.
Connected to LCD (Pin No. 3)
41
COM4
OUT
Terminal not used.
42
VDD
IN
Power source voltage input terminal.
Connected to VC.
20.0 msec
H : +5V
L : 0V
R-242M - 11
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
E
C B
Transistor
2SA1267Y
KRA101M
KRC101M
KRC105M
2SA1267Y
KRA101M
KRC101M
KRC105M
(sensor-related ones included) of the touch
control panel while keeping it connected to the
oven.
control 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).
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
assembly.
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.
static 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.
applied to the 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.
12
R-242M -
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE
1. CARRY OUT 3D CHECKS.
2. Make sure that a definite "click" can be heard when the
2. Make sure that a definite "click" can be heard when the
microwave oven door is unlatched. (Hold the door in a
closed position with one hand, then push the door open
button with the other, this causes the latch heads to rise,
it should then possible to hear a "click" as the door
switches operate.)
closed position with one hand, then push the door open
button with the other, this causes the latch heads to rise,
it should then possible to hear a "click" as the door
switches operate.)
3. Visually check the door and cavity face plate for damage
(dents, cracks, signs of arcing etc.).
Carry out any remedial work that is necessary before
operating the oven.
Do not operate the oven if any of the following conditions
exist;
1. Door does not close firmly.
operating the oven.
Do not operate the oven if any of the following conditions
exist;
1. Door does not close firmly.
2. Door hinge, support or latch hook is damaged.
3. The door seal is damaged.
4. The door is bent or warped.
5. There are defective parts in the door interlock system.
6. There are defective parts in the microwave generating
3. The door seal is damaged.
4. The door is bent or warped.
5. There are defective parts in the door interlock system.
6. There are defective parts in the microwave generating
and transmission assembly.
7. There is visible damage to the oven.
Do not operate the oven:
1. Without the RF gasket (Magnetron).
2. If the wave guide or oven cavity are not intact.
3. If the door is not closed.
4. If the outer case (cabinet) is not fitted.
2. If the wave guide or oven cavity are not intact.
3. If the door is not closed.
4. If the outer case (cabinet) is not fitted.
WARNING: Avoid possible exposure to microwave energy. Please follow the instructions below before
operating the oven.
Removal
1. CARRY OUT 3D CHECKS.
2. Remove the single (1) screw holding the green/yellow
2. Remove the single (1) screw holding the green/yellow
wire to the cavity.
3. Disconnect the leads of the power supply cord from the
noise filter, referring to the Figure C-3 (a).
4. Release the power supply cord from the rear cabinet.
5. Now, the power supply cord is free.
5. Now, the power supply cord is free.
Re-install
1. Insert the moulding cord stopper of power supply cord
into the square hole of the rear cabinet, referring to the
Figure C-3 (b). Installation of Power supply cord.
Figure C-3 (b). Installation of Power supply cord.
2. Install the earth wire lead of power supply cord to the
cavity with one (1) screw and nut and tighten the screw.
3. Connect the brown and blue wire leads of power supply
cord to the noise filter correctly, referring to the Pictorial
Diagram.
Diagram.
Figure C-3 (b) Replacement of Power Supply Cord
Figure C-3 (a) Replacement of Power Supply Cord
POWER SUPPLY CORD REPLACEMENT
OVEN CAVITY
BACK PLATE
BACK PLATE
SQUARE HOLE
MOULDING
CORD
STOPPER
CORD
STOPPER
POWER SUPPLY
CORD
CORD
GROMMET
MOULDING
MOULDING
OVEN CAVITY
BACK PLATE
BACK PLATE
BROWN WIRE
POWER
SUPPLY CORD
SUPPLY CORD
CHASSIS SUPPORT
BLUE WIRE
NOISE FILTER
N
L
F1
RED
WHT
EARTH WIRE
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