Sharp R-734 (serv.man4) Service Manual ▷ View online
R-734 - 21
1-3
SEG21-
OUT
Terminal not used.
SEG23
4
COM1
OUT
Common data signal: COM1.
Connected to LCD (Pin No. 1)
Connected to LCD (Pin No. 1)
5
COM2
OUT
Common data signal: COM2.
Connected to LCD (Pin No. 2)
Connected to LCD (Pin No. 2)
6
COM3
OUT
Common data signal: COM3.
Connected to LCD (Pin No. 3)
Connected to LCD (Pin No. 3)
7
COM4
OUT
Terminal not used.
8
VLC
IN
Signal synchronized with commercial power source frequency.
Signal similar to VSS.
Signal similar to VSS.
9
VSS
IN
Power source voltage: 0V.
VSS voltage of power source circuit input.
VSS voltage of power source circuit input.
10
XIN
IN
Internal clock oscillation frequency setting input.
The internal clock frequency is set by inserting the ceramic filter oscillation circuit
with respect to XOUT terminal.
The internal clock frequency is set by inserting the ceramic filter oscillation circuit
with respect to XOUT terminal.
11
XOUT
OUT
Internal clock oscillation frequency control output.
Output to control oscillation input of XIN.
Output to control oscillation input of XIN.
12-15
K00-K03
IN
Terminal to change functions according to the Model.
DC voltage in accordance with the Model in operation is applied to set up its
function.
DC voltage in accordance with the Model in operation is applied to set up its
function.
16
TEST
IN
Connected to VC.
17
RESET
IN
Auto clear terminal.
Signal is input to reset the LSI to the initial state when power is supplied.
Temporarily set to "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 to "L" level the moment power is supplied, at this time the LSI is
reset. Thereafter set at "H" level.
18
HOLD
IN/OUT
Connected to VDD.
19
INT2
IN
Signal synchronized with commercial power source frequency.
This is the basic timing for time processing of LSI.
This is the basic timing for time processing of LSI.
20
R81
IN
Signal coming from encoder.
When the encoder is turned, the contacts of encoder make pulse signals. And
pulse signals are input into R81.
When the encoder is turned, the contacts of encoder make pulse signals. And
pulse signals are input into R81.
21
INT1
IN
Signal coming from encoder.
Signal similar to R81. Pulse signals are input into INT1.
Signal similar to R81. Pulse signals are input into INT1.
22
R83
OUT
Terminal not used.
23
R90
IN
To input signal which communicates the door open/close information to LSI.
Door open "L" level signal (0V). Door close "H" level (+5V)
Door open "L" level signal (0V). Door close "H" level (+5V)
24-25
R91-R92
OUT
Terminal not used.
26
VDD
IN
Connected to GND.
27
R40
OUT
Signal to sound buzzer (2.0 kHz).
A: tact switch touch sound.
B: Completion sound.
28
R41
OUT
Grill heating element driving signsl.
To turn on and off the grill heating element relay
(RY2). "L" level during grill cooking or dual
cooking; "H" level otherwise.
(RY2). "L" level during grill cooking or dual
cooking; "H" level otherwise.
LSI(IXA089DR)
The I/O signal of the LSI(IXA089DR) are detailed in the following table.
The I/O signal of the LSI(IXA089DR) are detailed in the following table.
Pin No.
Signal
I/O
Description
20.0 msec
H : +5V
L : 0V
A
B
0.1 sec.
2 sec.
H : +5V
L: 0V
H : +5V
L: 0V
(Grill or dual)
ON
OFF
During
cooking
L
GND
H.
DESCRIPTION OF LSI
R-734 - 22
29
R42
OUT
Magnetron high-voltage circuit driving signal.
To turn on and off the cook relay
(RY3). In 100% POWER
operation, the signals hold "L"
level during microwave cooking
and "H" level while not cooking.
In other cooking modes (70%,
50%, 30%, 10%) the signal turns
to "H" level and "L" level in
repetition according to the power
level.
To turn on and off the cook relay
(RY3). In 100% POWER
operation, the signals hold "L"
level during microwave cooking
and "H" level while not cooking.
In other cooking modes (70%,
50%, 30%, 10%) the signal turns
to "H" level and "L" level in
repetition according to the power
level.
30
R43
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.
31
R50
IN
Signal coming from tact switch.
When tact switches SW1 is touched, a signal out of R61 will be input into R50.
When no tact switch is touched, the signal is held at "H" level.
When tact switches SW1 is touched, a signal out of R61 will be input into R50.
When no tact switch is touched, the signal is held at "H" level.
32
R51
IN
Signal coming from tact switch.
When either of tact switches SW2 and SW5 is touched, a corresponding signal out
of R60 and R61 will be input into R51. When no tact switch is touched, the signal
is held at "H" level.
When either of tact switches SW2 and SW5 is touched, a corresponding signal out
of R60 and R61 will be input into R51. When no tact switch is touched, the signal
is held at "H" level.
33
R52
IN
Signal coming from tact switch.
When either of tact switches SW3 and SW6 is touched, a corresponding signal out
of R60 and R61 will be input into R52. When no tact switch is touched, the signal
is held at "H" level.
When either of tact switches SW3 and SW6 is touched, a corresponding signal out
of R60 and R61 will be input into R52. When no tact switch is touched, the signal
is held at "H" level.
34
R53
IN
Signal coming from tact switch.
When either of tact switches SW4 and SW7 is touched, a corresponding signal out
of R60 and R61 will be input into R53. When no tact switch is touched, the signal
is held at "H" level.
When either of tact switches SW4 and SW7 is touched, a corresponding signal out
of R60 and R61 will be input into R53. When no tact switch is touched, the signal
is held at "H" level.
35
R60
OUT
Tact switch strobe signal.
Signal applied to tact switch section. A pulse signal is input to R51, R52 or R53
terminal while the tact switch SW5, SW6 or SW7 is touched.
Signal applied to tact switch section. A pulse signal is input to R51, R52 or R53
terminal while the tact switch SW5, SW6 or SW7 is touched.
36
R61
OUT
Tact switch strobe signal.
Signal applied to tact switch section. A pulse signal is input to R50, R51, R52 or
R53 terminal while the tact switch SW1, SW2, SW3 or SW4 is touched.
Signal applied to tact switch section. A pulse signal is input to R50, R51, R52 or
R53 terminal while the tact switch SW1, SW2, SW3 or SW4 is touched.
37-38
R62-R63
OUT
Terminal not used.
39-42
R70-R73
OUT
Terminal not used.
43-54
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 6 (7) ........................ S6(10)
SEG 1 (2) .......................... S11(5)
SEG 7 (8) ........................ S5(11)
SEG 2 (3) .......................... S10(6)
SEG 8 (9) ........................ S4(12)
SEG 3 (4) ............................ S9(7)
SEG 9 (10) ...................... S3(13)
SEG 4 (5) ............................ S8(8)
SEG 10 (11) .................... S2(14)
SEG 5 (6) ............................ S7(9)
SEG 11 (12) .................... S1(15)
55-57
SEG12-
OUT
Terminal not used.
SEG14
58
VDD
IN
Power source voltage input terminal.
Connected to GND.
Connected to GND.
59-64
SEG15-
OUT
Terminal not used.
SEG20
Pin No.
Signal
I/O
Description
20.0 msec
During cooking
H : +5V
L : 0V
ON/OFF time ratio in
Micro cooking
(a. 48second time base)
Micro cooking
(a. 48second time base)
ON/OFF time ratio in Mi-
cro cooking
(a. 32second time base)
cro cooking
(a. 32second time base)
MICRO
ON
OFF
COOK
100%
100%
32sec.
0sec.
70%
24sec.
8sec.
50%
18sec.
14sec.
30%
12sec.
20sec.
10%
6sec.
26sec.
MICRO
ON
OFF
COOK
100%
48sec.
0sec.
70%
36sec.
12sec.
50%
26sec.
22sec.
30%
16sec.
32sec.
10%
8sec.
40sec.
LSI(IXA089DR)
The I/O signal of the LSI(IXA089DR) are detailed in the following table.
The I/O signal of the LSI(IXA089DR) are detailed in the following table.
DESCRIPTION OF LSI
R-734 - 23
1. Precautions for Handling Electronic Components
This unit uses CMOS LSI in the integral part of the
circuits. When handling these parts, the following pre-
cautions 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 electric-
ity 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
circuits. When handling these parts, the following pre-
cautions 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 electric-
ity 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 con-
taining them in aluminium foil.
taining them in aluminium foil.
2) When soldering, ground the technician as shown in
the figure and use grounded soldering iron and
work table.
work table.
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
SERVICING AND PRESENTS A HAZARD .
THE HIGH VOLTAGE TRANSFORMER OF THE
MICROWAVE OVEN IS STILL LIVE DURING
SERVICING 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 trans-
former, 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 insulat-
ing 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 trans-
former, 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 insulat-
ing tape. After servicing, be sure to replace the
leads to their original locations.
A. On some models, the power supply cord be-
tween the touch control panel and the oven itself
is so short that the two can't be separated.
is so 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.
controls (sensor-related ones included) of the
touch control panel while keeping it connected
to the oven.
SERVICING
B. On some models, the power supply cord be-
tween the touch control panel and the oven itself
is so long enough so 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; 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, check-
ing them is possible if the dummy resistor(s) with
resistance equal to that of the controls are used.
is so long enough so 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; 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, check-
ing 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 termi-
nal 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 termi-
nal 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 as-
sembly.
1) Soldering iron: 30W
sembly.
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 prevent-
ing static electricity.
ing 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.
Transistor
2SB1238
2SB1238
Transistor
DTA123ES
KRA101M
KRA223M
KRC243M
DTA123ES
KRA101M
KRA223M
KRC243M
E
C
B
E
C B
approx. 1M ohm
R-734 - 24
9. Lift the entire case from the oven.
10.Discharge the H.V. capacitor before carrying out any
10.Discharge the H.V. capacitor before carrying out any
further work.
11.Do not operate the oven with the outer case removed.
N.B.; Step 1, 2 and 10 form the basis of the 3D checks.
CAUTION: DISCHARGE HIGH VOLTAGE CAPACI-
TOR BEFORE TOUCHING ANY OVEN
COMPONENT OR WIRING.
COMPONENT OR WIRING.
CAUTION: WHEN THE OUTER CASE CABINET IS
RE-INSTALLED, INSTALL IT BEFORE THE
REAR AIR ANGLE, AIR DUCT AND BACK
PLATE ARE INSTALLED, OR THE OUTER
CASE CABINET WILL BE DEFORMED.
REAR AIR ANGLE, AIR DUCT AND BACK
PLATE ARE INSTALLED, OR THE OUTER
CASE CABINET WILL BE DEFORMED.
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE
WARNING: Avoid possible exposure to microwave energy. Please follow the instructions below
before operating the oven.
1. Disconnect oven from power supply.
2. Visually check the door and cavity face plate for dam-
2. Visually check the door and cavity face plate for dam-
age (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.
2. Door hinge, support or latch hook is damaged.
3. The door gasket or seal are damaged.
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 gasket or seal are 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
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.
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.
Please refer to ‘OVEN PARTS, CABINET PARTS, CONTROL PANEL PARTS, DOOR PARTS’, when carrying out any
of the following removal procedures:
of the following removal procedures:
WARNING FOR WIRING
To prevent an electric shock, take the following
precautions
1. Before wiring,
precautions
1. Before wiring,
1) Disconnect the power supply.
2) Open the door and wedge the door open.
3) Discharge the high voltage capacitor and wait for
2) Open the door and wedge the door open.
3) Discharge the high voltage capacitor and wait for
60 seconds.
2. Don't let the wire leads touch to the following parts;
1) High voltage parts:
Magnetron, High voltage transformer, High volt-
age capacitor and High voltage rectifier assembly.
age capacitor and High voltage rectifier assembly.
2) Hot parts:
Grill heating element, Oven lamp, Magnetron,
High voltage transformer and Oven cavity.
3) Sharp edge:
Bottom plate, Oven cavity, Waveguide flange,
Chassis support and other metallic plate.
Chassis support and other metallic plate.
4) Movable parts (to prevent a fault)
Fan blade, Fan motor, Switch and Turntable
motor.
motor.
3. Do not catch the wire leads in the outer case cabinet.
4. Insert the positive lock connector correctly until its pin
4. Insert the positive lock connector correctly until its pin
is locked. And make sure that the wire leads should
not come off even if the wire leads is pulled.
not come off even if the wire leads is pulled.
5. To prevent an error function, connect the wire leads
correctly, referring to the Pictorial Diagram Page 33.
the high voltage rectifier assembly.
4. Remove one (1) screw holding fan duct to the oven
cavity rear plate.
5. Remove one (1) screw holding capacitor holder to the
oven cavity rear plate.
6. Release the capacitor holder from the fan duct.
OUTER CASE REMOVAL
To remove the outer case proceed as follows.
1. Disconnect oven from power supply.
2. Open the oven door and wedge it open.
3. Remove the one (1) screw holding the back plate to the
1. Disconnect oven from power supply.
2. Open the oven door and wedge it open.
3. Remove the one (1) screw holding the back plate to the
oven cavity rear plate. Remove the back plate.
4. Remove the one (1) screw holding the air duct assem-
bly to the oven cavity rear plate.
5. Remove the air duct assembly
6. Remove the two (2) screws holding the rear air angle
6. Remove the two (2) screws holding the rear air angle
to the outer case cabinet.
7. Remove the six (6) screws from rear and along the side
edge of case.
8. Slide the entire case back about 3 cm to free it from
retaining clips on the cavity face plate.
HIGH VOLTAGE COMPONENTS REMOVAL
(HIGH VOLTAGE CAPACITOR AND HIGH VOLTAGE RECTIFIER ASSEMBLY)
To remove the components, proceed as follows.
1. CARRY OUT 3D CHECKS.
2. Disconnect the filament lead and high voltage wire of
1. CARRY OUT 3D CHECKS.
2. Disconnect the filament lead and high voltage wire of
the high voltage transformer and the high voltage wire
B from the high voltage capacitor.
B from the high voltage capacitor.
3. Remove one (1) screw holding earth side terminal of
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