Sharp R-254M (serv.man5) Service Manual ▷ View online
R-254M - 17
Pin No.
Signal
I/O
Description
27
RESET
IN
Auto clear terminal.
Signal is input to reset the LSI to the initial state when power is applied.
Temporarily set "L" level the moment power is applied, 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 applied.
Temporarily set "L" level the moment power is applied, at this time the LSI is reset.
Thereafter set at "H" level.
28-29
P71-P70
OUT
Terminal not used.
30
XIN
IN
Internal clock oscillation frequency input setting.
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.
31
XOUT
OUT
Internal clock oscillation frequency control output.
Output to control oscillation input of XIN.
Output to control oscillation input of XIN.
32
VSS
IN
Power source voltage: -5.0V.
VC voltage of power source circuit input.
VC voltage of power source circuit input.
33
P27
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G1 line keys on key matrix is touched.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G1 line keys on key matrix is touched.
34
P26
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G2 line keys on key matrix is touched.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G2 line keys on key matrix is touched.
35
P25
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G3 line keys on key matrix is touched.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G3 line keys on key matrix is touched.
36
P24
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G4 line keys on key matrix is touched.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G4 line keys on key matrix is touched.
37
P23
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G5 line keys on key matrix is touched.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G5 line keys on key matrix is touched.
38
P22
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G6 line keys on key matrix is touched.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G6 line keys on key matrix is touched.
39
P21
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G7 line keys on key matrix is touched.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G7 line keys on key matrix is touched.
40
P20
OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G8 line keys on key matrix is touched.
Signal applied to touch-key section. A pulse signal is input to P43, P44, P45 and
P46 terminal while one of G8 line keys on key matrix is touched.
41-56
P17-P00
OUT
Terminal not used.
57-60
P37-P34
OUT
Terminal not used.
61-72
SEG11-SEG0
OUT
Segment data signal.
Connected to LCD.
The relation between signals are as follows:
LSI signal (Pin No.) LCD segment
Connected to LCD.
The relation between signals are as follows:
LSI signal (Pin No.) LCD segment
LSI signal (Pin No.) LCD segment
SEG 11 (61) ............................ S12
SEG 5 (67) .............................. S6
SEG 10 (62) ............................ S11
SEG 4 (68) .............................. S5
SEG 9 (63) ............................ S10
SEG 3 (69) .............................. S4
SEG 8 (64) ............................ S9
SEG 2 (70) .............................. S3
SEG 7 (65) ............................ S8
SEG 1 (71) .............................. S2
SEG 6 (66) ............................ S7
SEG 0 (72) .............................. S1
73/74
VCC/VREF
IN
Connected to GND.
75
AVSS
IN
Connected to VC.
76
COM3
OUT
Terminal not used.
77
COM2
OUT
Common data signal.
Connected to LCD signal C3.
Connected to LCD signal C3.
LSI(IXA083DR)
The I/O signal of the LSI(IXA083DR) are detailed in the following table.
The I/O signal of the LSI(IXA083DR) are detailed in the following table.
DESCRIPTION OF LSI
R-254M - 18
Pin No.
Signal
I/O
Description
79
COM0
OUT
Common data signal.
Connected to LCD signal C1.
Connected to LCD signal C1.
80
VL3
IN
Power source voltage input terminal.
Standard voltage for LCD.
Standard voltage for LCD.
LSI(IXA083DR)
The I/O signal of the LSI(IXA083DR) are detailed in the following table.
The I/O signal of the LSI(IXA083DR) are detailed in the following table.
78
COM1
OUT
Common data signal.
Connected to LCD signal C2.
Connected to LCD signal C2.
DESCRIPTION OF LSI
R-254M - 19
SERVICING
approx. 1M ohm
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. 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.
B. On some models, the power supply cord be-
tween the touch control panel and the oven is
long enough that they may be separated from
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; 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.
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,
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 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).
3. 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
4. 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.
R-254M - 20
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 or 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 or 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:
6. Discharge the H.V. capacitor before carrying out any
further work.
7. Do not operate the oven with the outer case removed.
NOTE; Step 1, 2 and 6 form the basis of the 3D checks.
NOTE; Step 1, 2 and 6 form the basis of the 3D checks.
CAUTION: DISCHARGE HIGH VOLTAGE CAPACI-
TOR BEFORE TOUCHING ANY OVEN
COMPONENT OR WIRING.
COMPONENT OR WIRING.
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 screws from rear and along the side edge
1. Disconnect oven from power supply.
2. Open the oven door and wedge it open.
3. Remove the screws from rear and along the side edge
of case.
4. Slide the entire case back about 3 cm to free it from
retaining clips on the cavity face plate.
5. Lift the entire case from the oven.
5. Now, the high voltage rectifier and the capacitor should
be free.
CAUTION: WHEN REPLACING HIGH VOLTAGE REC-
TIFIER, ENSURE THAT THE CATHODE
(EARTH) CONNECTION IS SECURELY
FIXED TO THE CAPACITOR HOLDER AND
BASE PLATE WITH AN EARTHING
SCREW.
(EARTH) CONNECTION IS SECURELY
FIXED TO THE CAPACITOR HOLDER AND
BASE PLATE WITH AN EARTHING
SCREW.
HIGH VOLTAGE COMPONENTS REMOVAL
(HIGH VOLTAGE CAPACITOR AND HIGH VOLTAGE RECTIFIER)
To remove the components, proceed as follows.
1. CARRY OUT 3D CHECKS.
2. Disconnect all the leads and the terminal of high
1. CARRY OUT 3D CHECKS.
2. Disconnect all the leads and the terminal of high
voltage rectifier from the high voltage capacitor.
3. Remove one (1) screw holding earth side terminal of
the high voltage rectifier and remove the capacitor
holder from the base plate.
holder from the base plate.
4. Remove the capacitor from the capacitor holder.
RE-WIRING
Ensure the following:
1. Wires must not touch:
a) High voltage parts.
(Magnetron, high voltage transformer, high voltage capacitor and high voltage rectifier assembly)
b) Parts that become hot.
(Heating elements, oven lamp, oven cavity magnetron and high voltage transformer)
c) Sharp edges.
(Bottom plates, oven cavity, waveguide flange, chassis support and other metallic parts)
d) Movable parts.
(Fan blade, any motor, switch, switch lever and open button)
(Magnetron, high voltage transformer, high voltage capacitor and high voltage rectifier assembly)
b) Parts that become hot.
(Heating elements, oven lamp, oven cavity magnetron and high voltage transformer)
c) Sharp edges.
(Bottom plates, oven cavity, waveguide flange, chassis support and other metallic parts)
d) Movable parts.
(Fan blade, any motor, switch, switch lever and open button)
2. Positive lock connectors are fitted correctly.
3. Wires are connected correctly as per pictoral diagram.
4. No wire leads are trapped by the outer wrap.
3. Wires are connected correctly as per pictoral diagram.
4. No wire leads are trapped by the outer wrap.
WARNING: WIRING/RE-WIRING
Before carrying out any work; carry out 3D checks.
1. Disconnect the supply.
2. Door opened, and wedged open.
3. Discharge the high voltage capacitor.
Before carrying out any work; carry out 3D checks.
1. Disconnect the supply.
2. Door opened, and wedged open.
3. Discharge the high voltage capacitor.
WARNING FOR WIRING
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