Sharp R-343 (serv.man3) Service Manual ▷ View online
R343M - 8
5) Buzzer Circuit
The buzzer is responsive to signals from the LSI to emit
audible sounds (key touch sound and completion
sound).
audible sounds (key 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
A switch to "tell" the LSI if the door is open or closed.
8) Encoder
The encoder converts the signal generated by LSI into
the pulse signal, and the pulse signal is returned to the
LSI.
the pulse signal, and the pulse signal is returned to the
LSI.
9) Back Light Circuit
A circuit to drive the back light (Light emitting diodes
LED1-LED3)
LED1-LED3)
TOUCH CONTROL PANEL ASSEMBLY
OUTLINE OF TOUCH CONTROL PANEL
The touch control section consists of the following circuits as
shown in the touch control panel circuit.
shown in the touch control panel circuit.
The principal functions of these circuits and their related
signals are explained below.
signals are explained below.
Tact Switch
Signals generated in the LSI are sent to the tact switches
through R60, R61,R62 and R63.
When a tact switch is touched, a signal is completed through
the tact switch and passed back to the LSI through R81 to
perform the function that was requested.
through R60, R61,R62 and R63.
When a tact switch is touched, a signal is completed through
the tact switch and passed back to the LSI through R81 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.
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.
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)
4) Relay Circuit
To drive the magnetron, fan motor, turntable motor and
light the oven lamp.
light the oven lamp.
R343M - 9
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
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) .............................. S12(4)
SEG 0 (1) .............................. S12(4)
SEG 6 (7)
S6(10)
SEG 1 (2) .............................. S11(5)
SEG 1 (2) .............................. S11(5)
SEG 7 (8)
S5(11)
SEG 2 (3) .............................. S10(6)
SEG 2 (3) .............................. S10(6)
SEG 8 (9)
S4(12)
SEG 3 (4) ................................ S9(7)
SEG 3 (4) ................................ S9(7)
SEG 9 (10)
S3(13)
SEG 4 (5) ................................ S8(8)
SEG 4 (5) ................................ S8(8)
SEG 10 (11)
S2(14)
SEG 5 (6) ................................ S7(9)
SEG 5 (6) ................................ S7(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.
DESCRIPTION OF LSI
LSI(IZA919DR)
The I/O signal of the LSI(IZA919DR) are detailed in the following table.
Pin No.
Signal
I/O
Description
R343M - 10
Pin No.
Signal
I/O
Description
20.0 msec
H : +5V
L : 0V
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.
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
R343M - 11
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
panel while keeping it connected to the oven.
(sensor-related ones included) of the touch control
panel while keeping it connected to the oven.
E
C B
Transistor
2SA1267Y
KRA101M
KRC101M
KRC105M
2SA1267Y
KRA101M
KRC101M
KRC105M
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
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.
TOUCH CONTROL PANEL ASSEMBLY
SERVICING
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