Sharp R-353 (serv.man3) Service Manual ▷ View online
R353M - 13
SERVICING
TOUCH CONTROL PANEL ASSEMBLY
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
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
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 in aluminium foil. Also wrap PW boards
containing them in aluminium foil.
containing them in aluminium foil.
2) When soldering, ground the technician as shown
in the figure and use grounded soldering iron
and work table.
and 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
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.
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.
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.
itself 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
between the touch control panel and the oven
proper is so long enough that they may be
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.
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).
3. 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
4. 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.
R353M - 14
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 is 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 is 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.
COMPONENT REPLACEMENT AND ADJUSTMENT
WARNING: Avoid possible exposure to microwave energy. Please follow the instructions below before
operating the oven.
2. Door hinge, support or latch hook is damaged.
3. The door gasket or 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 gasket or 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.
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, DOOR PARTS’, when carrying out any of the following removal
procedures:
procedures:
MONITORED LATCH SWITCH, MONITOR SWITCH AND STOP SWITCH REMOVAL
MONITOR SWITCH (SW2)
STOP SWITCH (SW3)
MONITORED
LATCH SWITCH (SW1)
LATCH SWITCH (SW1)
TAB
TAB
TAB
1. CARRY OUT 3D CHECKS.
2. Remove the control panel assembly referring to
2. Remove the control panel assembly referring to
"CONTROL PANEL ASSEMBLY REMOVAL".
3. Disconnect the all leads from the switches.
4. Remove the two (2) screws holding the latch hook to the
4. Remove the two (2) screws holding the latch hook to the
oven cavity.
5. Remove the latch hook.
6. Push the retaining tab slightly and remove the switch.
6. Push the retaining tab slightly and remove the switch.
R353M - 15
COMPONENT REPLACEMENT AND ADJUSTMENT
REMOVAL
1. Disconnect the power supply cord.
2. Open the door slightly.
3. Remove the choke cover taking care not to break clips
2. Open the door slightly.
3. Remove the choke cover taking care not to break clips
by inserting an iron plate (thickness of about 0.5mm)
or flat type screw driver to the gap between the choke
cover and door panel as shown Figure C-4 to free the
engaged parts.
or flat type screw driver to the gap between the choke
cover and door panel as shown Figure C-4 to free the
engaged parts.
4. Release choke cover from door panel.
5. Now choke cover is free.
5. Now choke cover is free.
Figure C-4. Door Disassembly
6. Release two (2) pins of door panel from two (2) holes
of upper and lower oven hinges by lifting up.
7.
1. Remove door assy by removing screws (4).
8. Release door panel from tabs of door frame and
remove door frame by sliding the door panel downward.
9. Now, door panel with inner sealer film is free.
10. Tear inner sealer film from door panel.
11. Now, door panel is free.
12. Slide latch head upward and remove it from door
10. Tear inner sealer film from door panel.
11. Now, door panel is free.
12. Slide latch head upward and remove it from door
frame with releasing latch spring from door frame and
latch head.
latch head.
13. Now, latch head and latch spring are free.
14.
14.
Remove Glass Stopper Screw (noting position of
stopper) and slide stopper down while lifting up.
stopper) and slide stopper down while lifting up.
15.
Slide glass towards Glass Stopper position and
then down towards the lower edge of the door
frame.
frame.
16.
Lift upper edge of glass, which will now be free
from upper clips and remove from lower clips.
17.
Refitting is a reversal of the above when refitting,
ensure the glass and the glass stopper is in the
original position.
original position.
RE-INSTALL
1. Re-install the outer door glass to the door frame with
the glass stopper.
2. Hold the glass stopper with the one (1) screw.
3. Re-install latch spring to the head. Re-install latch
3. Re-install latch spring to the head. Re-install latch
spring to the door frame. Re-install latch head to the
door frame.
door frame.
4. Re-install door panel to door frame by fitting tabs of
door frame to holes of door panel.
5. Put sealer film on door panel. Refer to “Inner Sealer
Film” and figure C-6, on how to handle the new film.
6. Catch two (2) pins of door panel on two (2) hole of
upper and lower oven hinges.
7. Re-install choke cover to door panel by pushing.
Note: After any service to the door;
(A) Make sure that monitored latch switch, stop
(A) Make sure that monitored latch switch, stop
switch and monitor switch are operating properly.
(Refer to chapter “Test Procedures”.).
(Refer to chapter “Test Procedures”.).
(B) An approved microwave survey meter should be
used to assure compliance with proper
microwave radiation emission limitation
standards.
microwave radiation emission limitation
standards.
10
5
4
12
8
7
9
11
3
2
1
Choke Cover
Door Frame
Putty Knife
6
After any service, make sure of the following :
1. Door latch heads smoothly catch latch hook through
latch holes and that latch head goes through center of
latch hole.
latch hole.
2. Deviation of door alignment from horizontal line of
cavity face plate is to be less than 1.0mm.
3. Door is positioned with its face pressed toward cavity
face plate.
4. Check for microwave leakage around door with an
approved microwave survey meter. (Refer to
Microwave Measurement Procedure.)
Microwave Measurement Procedure.)
Note:
The door on a microwave oven is designed to act
as an electronic seal preventing the leakage of
microwave energy from oven cavity during cook
cycle. This function does not require that door be
air-tight, moisture (condensation)-tight or light-
tight. Therefore, occasional appearance of
moisture, light or sensing of gentle warm air
movement around oven door is not abnormal
and do not of themselves, indicate a leakage of
microwave energy from oven cavity.
as an electronic seal preventing the leakage of
microwave energy from oven cavity during cook
cycle. This function does not require that door be
air-tight, moisture (condensation)-tight or light-
tight. Therefore, occasional appearance of
moisture, light or sensing of gentle warm air
movement around oven door is not abnormal
and do not of themselves, indicate a leakage of
microwave energy from oven cavity.
Figure C-5. Door Replacement
INNER
SEALER FILM
Installation
1. Tear away the backing film.
3. Put the pasted side of the inner sealer film on the door
3. Put the pasted side of the inner sealer film on the door
panel.
Door film
Finger tab
Backing film
Figure C-6. Inner Sealer Film
PIN
PIN
LOWER
OVEN HINGE
OVEN HINGE
UPPER
OVEN HINGE
OVEN HINGE
LOWER
OVEN HINGE
OVEN HINGE
CHOKE COVER
DOOR
PANEL
PANEL
DOOR SUB
ASSEMBLY
ASSEMBLY
R353M - 16
SCHEMATIC DIAGRAM
SW3:
no
com
no
com
no
com
SW2
COM.
NO.
RY3
RY1
COM.
FM
TTM
OL
TURNTABLE
MOTOR
MOTOR
FAN
SWITCH
MONITOR
MONITORED
125C
CUT-OUT
THERMAL
125C
CUT-OUT
THERMAL
CONTROL UNIT
NO.
NOISE FILTER
UNIT
B1
B2
A3
STOP
SWITCH
LATCH
SWITCH
SWITCH
OVEN
LAMP
A1
GRY
*
INDICATES PARTS WITH POTENTIALS OVER 240V
ORG
HV
HV
BLK
13LX/20
GRY
WHT
RED
BLK
/20
WHT
/20
BLK
/20
BRN
/18
RED
WHT
BLU
WHT
RED
/20
YLW
*
WIRE
WIRE
*
GRY
*
MAGNETRON
OVEN
MAGNETRON
230-240V
EARTH
N
L
BLU
BRN
0.0033 /250V
0.0033 /250V
/17
/17
G-Y/17
FUSE
F8A
NOISE SUPPRESSION COIL
F1:
0.22 /250V
680K/0.5W
10M/0.5W
1.0 F
2100VAC
2100VAC
*
CAPACITOR
RECTIFIER
ASYMMETRIC
RECTIFIER
*
H.V.
*
POWER TRANSFORMER
50Hz
SW1
Figure 0-1 Oven Schematic
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