Sharp R308jsf Service Manual

							R-308JK
R-308JS
R-308JW
R-309JW
19
41 P70 OUTOven 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 and RY2 control circuit.
42 P71 OUT Terminal not used.
43 P72 OUT
Magnetron high-voltage circuit driving signal.
To turn on and off the cook relay (RY2).  The
signals holds “L” level during microwave cook-
ing and “H” level while not cooking. In other
cooking modes (variable cooking) the signal
turns to “H” level and “L” level in repetition
according to the power level.
44 AVDD INA/D converter power source voltage.
The power source voltage to drive the A/D converter in the LSI. Connected to GND.
45-48AIN5-AIN2 IN
Terminal to change cooking input 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 cooking constant.
49 AIN1 IN This is the terminal to detect the voltage of the signal coming from the touch key.
50 AIN0 INSignal similar to AIN1.
51 AVSS IN
A/D converter power source voltage.
The power source voltage to drive the A/D converter in the LSI.
52 P11 IN
To input signal which communicates the door open/close information to LSI.
Door close “H” level signal (0V).  Door open “L” level signal (-5V).
53 P10 OUT Terminal not used.
54 P33 OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53 terminal
while one of G1 line keys on key matrix is touched.
55 P32 OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53 terminal
while one of G2 line keys on key matrix is touched.
56 P31 OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53 terminal
while one of G3 line keys on key matrix is touched.
57 INTP0 IN
Signal synchronized with commercial power source frequency.
This is the basic timing for time processing of LSI.
58 P26 OUTKey strobe signal.
Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53 terminal
while one of G4 line keys on key matrix is touched.
59 P25 OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53 terminal
while one of G5 line keys on key matrix is touched.
60 P24 OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53 terminal
while one of G6 line keys on key matrix is touched.
61 P23 OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53 terminal
while one of G7 line keys on key matrix is touched.
62 P22 OUT
Key strobe signal.
Signal applied to touch-key section. A pulse signal is input to P50, P51, P52 and P53 terminal
while one of G8 line keys on key matrix is touched.
Pin No. Signal I/O Description
16.7 msec.
During cookingH : GND
L : -5V
Maximum
output
70% of maximum
outputH : GND
L : -5V
H : GND
L : -5V
ON
ON OFF
OFF OFF
24 sec.
8 sec.
16.7 msec.H : GND
L : -5V 
						

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20 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 in
aluminium foil. Also wrap all PW boards containing them in
aluminium foil.
2)When soldering, ground the technician as shown in the
figure and use grounded soldering iron and work table.
TOUCH CONTROL PANEL SERVICING
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. 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.
B. On some models, the power supply cord between the touch
control panel and the oven proper is long enough that they
may be separated from each other. For those models, 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 activates 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
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 activates 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
(It is recommended to use a soldering iron with a 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.
2) Connect the connectors 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.
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. 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.
(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.
Therefore, before checking the performance of the touch
control panel,
1)Disconnect the power supply cord, and then remove
outer case.
2) Open the door and block it open.
3) Discharge high voltage capacitor.
4)Disconnect the leads to the primary of the power
transformer.
5)Ensure that these leads remain isolated from other
components and oven chassis by using insulation tape.
6)After that procedure, re-connect the power supply cord.
After checking the performance of the touch control panel,
1) Disconnect the power supply cord.
2) Open the door and block it open.
3)Re-connect the leads to the primary of the power
transformer.
4) Re-install the outer case (cabinet).
5) Re-connect the power supply cord after the outer case
is installed.
6) Run the oven and check all functions.
approx. 1M ohm
Pin No. Signal I/O Description
63 BZO90 OUTSignal to sound buzzer (2.0 kHz).
A: key touch sound.
B: Completion sound.
64 P20 OUT Terminal not used.
A
B
0.1 sec.
2.0 sec.H : GND
L : -5V
H : GND
L : -5V 
						

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21
PRECAUTIONS FOR USING LEAD-FREE SOLDER
1. Employing lead-free solder
The Main PWB of this model employs lead-free solder. This is indicated by the LF symbol printed on the PWB and in the
service manual. The suffix letter indicates the alloy type of the solder.
Example:
Indicates lead-free solder of tin, silver and copper.
2. Using lead-free wire solder
When repairing a PWB with the LF symbol, only lead-free solder should be used. (Using normal tin/lead alloy solder may
result in cold soldered joints and damage to printed patterns.)
As the melting point of lead-free solder is approximately 40˚C higher than tin/lead alloy solder, it is recommend that a dedicated
bit is used, and that the iron temperature is adjusted accordingly.
3. Soldering
As the melting point of lead-free solder (Sn-Ag-Cu) is higher and has poorer wettability, (flow), to prevent damage to the land
of the PWB, extreme care should be taken not to leave the bit in contact with the PWB for an extended period of time. Remove
the bit as soon as a good flow is achieved. The high content of tin in lead free solder will cause premature corrosion of the
bit. To reduce wear on the bit, reduce the temperature or turn off the iron when it is not required.
Leaving different types of solder on the bit will cause contamination of the different alloys, which will alter their characteristics,
making good soldering more difficult. It will be necessary to clean and replace bits more often when using  lead-free solder.
To reduce bit wear, care should be taken to clean the bit thoroughly after each use.
Sn-Ag-Cu
Microwave ovens contain circuitry capable of producing very high voltage and current, contact with following parts may result
in severe, possibly fatal, electric shock.
(Example)
High Voltage Capacitor, Power Transformer, Magnetron, High Voltage Rectifier Assembly,  High Voltage Harness etc..
WARNING:Avoid possible exposure to microwave energy. Please follow the instructions below before
operating the oven.
WARNING AGAINST HIGH VOLTAGE: COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE
1. Disconnect the power supply cord.
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 leads 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 operat-
ing 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 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. 
						

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22 1. Disconnect the power supply cord and then remove outer
case.
2. Open the oven door and block it open.
3. Discharge high voltage capacitor.
4.Disconnect wire leads (primary) from power transformer
and the filament leads and high voltage wire from the
magnetron and capacitor terminals.
5.Remove four (4) screws (two (2) screws from the upper side
and two (2) screws from bottom side) holding transformer to
bottom plate.
6. Remove transformer from bottom plate.
HIGH VOLTAGE RECTIFIER AND HIGH VOLTAGE CAPACITOR REMOVAL
Special screw
Screw Driver
(Type: TORX T20 H or 
GTXH20-100)
To remove the outer case, proceed as follows.
1. Disconnect the power supply cord.
2. Open the oven door and block it open.
3.Remove the two (2) screws from the lower portion of the rear
cabinet using a T20H Torx type or GTXH20-100 screw
driver.
4. Remove the remaining three (3) screws from rear and one
(1) screw along the right side of outer case.
5. Slide the entire outer case back out about 1 inch (3 cm) to
free it from retaining clips on the cavity face plate.
6. Lift entire outer case from the unit.
CAUTION: 1.DISCONNECT OVEN FROM POWER SUP
PLY BEFORE REMOVING OUTER CASE.
2. DISCHARGE THE HIGH VOLTAGE CAPACI-
TOR BEFORE TOUCHING ANY OVEN COM-
PONENTS OR WIRING.
OUTER CASE REMOVAL
To prevent an electric shock, take the following precau-
tions.
1. Before wiring,
1) Disconnect the power supply cord.
2) Open the door block it 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 voltage
capacitor and High voltage rectifier assembly.
2) Hot parts:
Oven lamp, Magnetron, Power transformer and Oven
cavity.
WARNING FOR WIRING
3) Sharp edge:
Bottom plate, Oven cavity, Waveguide flange and
other metallic plate.
4) Movable parts (to prevent a fault)
Fan blade, Fan motor, Turntable motor, Switch, Switch
lever, Open button.
3. Do not catch the wire leads in the outer case cabinet.
4.Insert the positive lock connector until its pin is locked and
make sure that the wire leads do not  come off even if the
wire leads are pulled.
5.To prevent an error function, connect the wire leads
correctly, referring to the Pictorial Diagram.
Please refer to ‘OVEN PARTS, CABINET PARTS, CONTROL PANEL PARTS, DOOR PARTS’, when carrying out any of the
following removal procedures:
NOTE:When replacing the outer case, the 2 special
Torx screws must be reinstalled in the same
locations.
POWER TRANSFORMER REMOVAL
Reinstallation
1.Rest transformer on the bottom plate with its primary
terminals toward the oven face plate.
2.
Secure transformer with four (4) screws (two (2) screws from
the upper side and two (2) screws from bottom side) 
to
bottom plate.
3. Reconnect wire leads (primary) to power transformer and
filament leads and high voltage wire of transformer to
magnetron and high voltage capacitor. Refer to PICTORIAL
DIAGRAM on page 28.
4.Reinstall outer case and check that oven is operating
properly.
1. Disconnect the power supply cord and then remove outer
case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Disconnect the high voltage wire of the power transformerfrom the high voltage capacitor.
5.Disconnect the high voltage wire of high voltage rectifier
assembly from the magnetron.
6.Disconnect the filament lead (short one) of the power
transformer from the high voltage capacitor. 
						

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23 1. Disconnect the power supply cord, and then remove outer
case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Push the lever of positive lock
® connector.
5. Pull down on the positive lock® connector.
CAUTION:WHEN CONNECTING THE POSITIVE LOCK
®
CONNECTORS TO THE TERMINALS, CON-
NECT THE POSITIVE LOCK® SO THAT THE
LEVER FACES YOU
Figure C-1.  Positive lock
® connector
POSITIVE LOCK®  CONNECTOR (NO-CASE TYPE) REMOVALMAGNETRON REMOVAL
Removal
1. Disconnect the power supply cord and then remove outer
case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Disconnect all wire leads from magnetron.
5. Remove the one (1) screw holding the chassis support to
the magnetron.
6.Release the chassis support from the hole of the oven cavity
front flange.
7. Remove the two (2) screws holding air duct to magnetron
and oven cavity top plate.
8. Remove the air duct from oven.
9. Carefully remove the four (4) screws holding magnetron to
waveguide flange.
10.Remove magnetron with care so that magnetron antenna is
not hit by any metal object around  antenna.11. Now, the magnetron is free.
Reinstallation
1. Reinstall the magnetron to waveguide flange with the four
(4) screws.
2.Reinstall the air duct to the oven cavity top plate and the
magnetron with two (2) screws.
3.Insert the end of the chassis support into the hole of the
oven cavity front flange.
4.Hold the other end of the chassis support to the magnetron
with the one (1) screw.
5.Reconnect the wire leads to the magnetron. Refer to
PICTORIAL DIAGRAM.
6. Reinstall outer case and check that the oven is operating
properly.
CAUTION:WHEN REPLACING MAGNETRON, BE SURE
THE R.F. GASKET IS IN PLACE AND MOUNT-
ING SCREWS ARE TIGHTENED SECURELY. 7.Remove the one (1) screw holding capacitor holder to
bottom plate.
8.Remove  one (1) screw holding high voltage rectifier
assembly to capacitor holder.
9. Disconnect rectifier terminal from capacitor.
High voltage rectifier assembly is now free.10. Remove capacitor holder. Capacitor is now free.
CAUTION:WHEN REPLACING HIGH VOLTAGE RECTI-
FIER AND HIGH VOLTAGE CAPACITOR,
GROUND SIDE TERMINAL OF THE HIGH VOLT-
AGE RECTIFIER MUST BE SECURED FIRMLY
WITH A GROUNDING SCREW.
Terminal
Push
Pull down1
2
Lever Positive lock®
connector
1.Disconnect the power supply cord and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Disconnect the wire leads from control unit.
CONTROL PANEL ASSEMBLY REMOVAL
5.Remove the one (1) screw holding the control panel
assembly to the oven flange.
6. Slide the control panel assembly upward and remove it.
7. Now, individual components can be removed.
Removal
1. Disconnect the power supply cord and then remove outer
case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4.Remove the control panel assembly, referring to chapter of
CONTROL PANEL ASSEMBLY REMOVAL.
5.Remove the three (3) screws holding the control unit to the
control panel frame. And remove the control unit.
6.Remove the LCD holder and the  rubber connector from the
control panel frame.
GRAPHIC SHEET AND MEMBRANE SWITCH REPLACEMENT
7. Tear away the graphic sheet from the control panel frame.
8.Tear away the membrane switch from the control panel
frame.
Installation
1.Remove remaining adhesive on the control panel frame
surfaces with a soft cloth soaked in alcohol.
2. Tear the backing paper from the new membrane switch.
3. Insert the ribbon cable of the membrane switch into the slit
of the control panel frame.
4.Adjust the upper edge and right edge of the membrane 
						

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24 switch to the small depression on the surface of the control
panel frame.
5. Attach the membrane switch to the control panel frame by
rubbing with a soft cloth not to scratch.
6. Tear the backing paper from the new graphic sheet.
7. Adjust the upper edge and left edge of the graphic sheet to
the large depression on the surface of the control panel
frame.
8.Attach the graphic sheet to the control panel frame by
rubbing with a soft cloth not to scratch.
9. Make sure that the liquid crystal display and the LED sheet
are installed in position.
10. Tear the small backing paper from the ribbon cable of the
membrane switch.
11.Attach the ribbon cable to the control panel frame rear side.
12. Place the edge of the membrane switch’s ribbon cable on
the lower portion of the liquid crystal display.
13. Reinstall the LCD holder to the control panel frame.
14.Insert the rubber connector into the long slit of the LCD
holder.
15.Reinstall the control unit to the control panel frame with the
three (3) screws.
NOTE:
Do not contact the contact surface of the ribbon cable
(edge) and the rubber connector directly with your fingers.
This is to avoid oxidized. If display digits are missing or
scrambled, remove control unit and clean contact surface
with alcohol. After cleaning, do not attach the rubber
connector until alcohol dries up. Do not use alcohol or
solution to clean the rubber connector. Make sure that
there is no trash or foreign substance on contact surface
of the rubber connector.
Display window
Small backing 
paper
Graphic sheet
Membrame switchPanel sub assembly Control panel
frameControl unit
Large 
depression Small 
depression
Liquid
crystal display LED sheet
LCD holderScrews
Rubber connector
Figure C-2a.  Graphic Sheet and Membrane Switch
Replacement
Slit
Ribbon cable of membrane switch
Control panel frame
Figure C-2b. Rebbon Cable of Membrane Switch
1. Disconnect the power supply cord.
2. Remove turntable and turntable support from oven cavity.
3. Lay the oven on its backside. Remove the turntable motor
cover by snipping off the material in four corners.
4.Where the corners have been snipped off bend corner
areas flat. No sharp edges must be evident after removal of
the turntable motor cover.
TURNTABLE MOTOR REMOVAL
5. Disconnect wire leads from turntable motor.
(See Positive lock connector removal)
6.Remove one (1) screw holding turntable motor to oven
cavity.
7. Now the turntable motor is free.
8. After replacement use the one (1) screw to fit the turntable
motor cover.
REMOVAL
1. Disconnect the power supply cord and then remove outer
case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Disconnect the wire leads from the fan motor.
5.Remove the two (2) screws holding the fan motor to the
oven cavity back plate.
6.Remove the fan blade from the fan motor shaft according to
the following procedure.
7. Hold the edge of the rotor of the fan motor by using a pair
of groove joint pliers.
CAUTION:
*Make sure that no metal pieces enter the gap between
COOLING FAN MOTOR REMOVAL
the rotor and the stator of the fan motor because the
rotor is easily shaven by pliers and metal pieces may be
produced.
*Do not touch the pliers to the coil of the fan motor
because the coil may be cut or injured.
*Do not disfigure the bracket by touching with the pliers.
8.Remove the fan blade from the shaft of the fan motor by
pulling and rotating the fan blade with your hand.
9.  Now, the fan blade will be free.
CAUTION:
*Do not reuse the removed fan blade because the hole
(for shaft) may be larger than normal.
10. Now, the fan motor is free. 
						

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25 Side View Rear View INSTALLATION
1. Install the fan blade to the fan motor shaft according to the
following procedure.
2. Hold the center of the bracket which supports the shaft of
the fan motor on the flat table.
3.Apply the screw lock tight into the hole (for shaft) of the fan
blade.
4.Install the fan blade to the shaft of fan motor by pushing the
fan blade with a small, light weight, ball peen hammer or
rubber mallet.5. Install the fan motor to the oven cavity back plate with the
two (2) screws.
CAUTION:
*Do not hit the fan blade strongly when installed because
the bracket may be disfigured.
*Make sure that the fan blade rotates smooth after
installation.
*Make sure that the axis of the shaft is not slanted.
6.Connect the wire leads to the fan motor, referring to the
pictorial diagram.
1.
Disconnect the power supply cord and remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Disconnect wire leads from the switches.
5.
Remove two (2) screws holding latch hook to oven flange.
6. Remove latch hook assembly from oven flange.
7. Push outward on the two (2) retaining tabs holding switch
in place.
8. Switch is now free.
At this time switch lever will be free, do not lose it.
DOOR SENSING SWITCH/SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH REMOVAL
Reinstallation
1. Reinstall each switch in its place. The secondary interlock/
monitor switches are in the lower position and the door
sensing switch is in the upper position.
2. Reconnect wire leads to each switch.
Refer to pictorial diagram.
3. Secure latch hook (with two (2) mounting screws) to oven
flange.
4.Make sure that the monitor switch is operating properly and
check continuity of the monitor circuit.    Refer to chapter
Test Procedure and Adjustment procedure.
Gap
Rotor Bracket StatorGroove joint pliers
Coil
Shaft
Axis
Stator
Rotor
These are the positions 
that should be pinched 
with pliers.
Shaft
Table
Center of
bracket
1. Disconnect the power supply cord, and then remove outer
case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
If the door sensing switch, secondary interlock switch and
monitor switch do not operate properly due to a misadjustment,
the following adjustment should be made.
4. Loosen the two (2) screws holding latch hook to the oven
cavity front flange.
5. With door closed, adjust latch hook by moving it back and
forth, and up and down. In and out play of the door allowed
by the upper and lower position of the latch hook should be
less than 0.5mm. The vertical position of the latch hook
should be adjusted so that the door sensing switch and
secondary interlock switch are activated with the door
closed. The horizontal position of the latch hook should be
adjusted so that the plunger of the monitor switch is
pressed with the door closed.
6. Secure the screws with washers firmly.
7. Check the operation of all switches. If each switch has not
activated with the door closed, loosen screw and adjust the
latch hook position.
DOOR SENSING SWITCH/SECONDARY INTERLOCK SWITCH AND MONITOR SWITCH ADJUSTMENT
After adjustment, check the following.
1.In and out play of door remains less than 0.5mm when in the
latched position. First check upper position of latch hook,
pushing and pulling upper portion of door toward the oven
face. Then check lower portion of the latch hook, pushing
and pulling lower portion of the door toward the oven face.
Both results (play in the door) should be less than 0.5mm.
Latch 
HeadsDoor
Switch Lever
Latch Hook
Door Sensing
Switch
Monitor Switch
Secondary
Interlock Switch
Figure C-3. Latch Switch Adjustments 
						

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26 4.
Reinstall outer case and check for microwave leakage
around door with an approved microwave survey meter.
(Refer to Microwave Measurement Procedure.)
2.
The door sensing switch and secondary interlock switch
interrupt the circuit before the door can be open.
3. Monitor switch contacts close when door is opened.
REMOVAL
1. Disconnect the power supply cord.
2. Open the door slightly.
3. Insert a putty knife (thickness of about 0.5mm) into the gap between the choke cover and door frame as shown in
Figure C-4 to free engaging parts.
4. Pry the choke cover by inserting a putty knife as shown
Figure C-4.
5. Release choke cover  from door panel.
6. Now choke cover is free.
NOTE: When carrying out any repair to the door, do not
bend or warp the slit choke (tabs on the  door
panel assembly) to prevent microwave leakage.
7.Release two (2) pins of door panel from two (2) holes of
upper and lower oven hinges by lifting up.
8.  Now, door panel with door frame is free from oven cavity.
Figure C-4. Door Disassembly
9. Release door panel from ten (10) tabs of door frame.
10. Now, door panel with sealer film is free.
11. Tear sealer film from door panel.
12. Now, door panel is free.
13. Slide latch head upward and remove it from door frame with
releasing latch spring from door frame and latch head.
14. Now, latch head and latch spring are free.
15. Remove door screen from door frame.
16. Now, door screen is free.
REINSTALLATION
1. Reinstall door screen to door frame .
2. Reinstall the latch spring to the latch head. Reinstall the
latch spring to the door frame. Reinstall latch head to door
frame.
3. Reinstall door panel to door frame by fitting ten (10) tabs of door frame to ten (10) holes of door panel.
4. Put sealer film on door panel. Refer to “Sealer Film” about how to handle new one.
5. Catch two (2) pins of door panel on two (2) hole of upper and
lower oven hinges.
6. Reinstall choke cover  to door panel by pushing.
Note: After any service to the door;
(A) Make sure that door sensing switch and secondary
interlock switch are operating properly. (Refer to
chapter “Test Procedures”.).
(B) An approved microwave survey meter should be used
to assure compliance with proper microwave radiation
emission limitation standards.
DOOR REPLACEMENT
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.
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.)
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.
Figure C-5. Door Replacement
SEALER FILM
Installation
1. Put the adhesive tape on the backing film of the sealer filmas shown in Fig. C-6.
2. Tear the backing film by pulling the adhesive tape.
3. Put the pasted side of the sealer film on the door panel
Choke Cover
Door Frame
Putty Knife
Pin
Pin
Upper 
Oven Hinge Upper Oven 
Hinge
Lower Oven Hinge Lower 
Oven Hinge
Slit choke of
door panel
Choke Cover
Sealer filmBacking film
Adhesive tape
Figure C-6. Sealer film 
						

							R-308JK
R-308JS
R-308JW
R-309JW
27
6
45
12
3
6
45
12
3 A
B
C
D
E
F
G
HA
B
C
D
E
F
G
H
Figure S-1. Pictorial Diagram
HIGH VOLTAGE
CAPACITOR
H.V. RECTIFIERPOWER SUPPLY 
CORD 120V 60Hz
HIGH VOLTAGE COMPONENTS
MAGNETRON
COM.MONITOR
SWITCH
COM.N.O.
N.C.
DOOR
SENSING
SWITCH
SECONDARY
INTERLOCK
SWITCH
TURNTABLE
MOTOR
POWER 
TRANSFORMER
COM.NO
NOTE:
The neutral (WHT) wire must be 
connected to the terminal with N 
mark on the power supply cord.
GRY
W
H
T
WHT
GRYRED
GRYGRY
R
E
DP
N
K B
L
K
R
E
D
GRN
GRYGRY
GRN
BLKGRY
WHTGRY
RED
RED
BLK
PNKGRY
C/T FUSE
FAN MOTOR TEMPERATURE
FUSE  (OVEN)
BLK
WHT2
1
WHT
WHT
WHT
WHTRED
RY1
PRIMARY
INTERLOCK 
RELAYCN-B
CN-B
T1 1
2
N.O.  COM.
RY2N.O. COM.CONTROL UNIT
H
N 
NOTE:
The grounding conductor of 
the power supply cord has 
been grounded by power 
supply cord fixing screw.
The screw must allways  be 
kept tight. 
GRY
OVEN LAMP
PNKRED
REDPNK 
						

							R-308JK
R-308JS
R-308JW
R-309JW
28
Figure S-2. Control Unit Circuit
6
45
12
3
6
45
12
3 A
B
C
D
E
F
G
HA
B
C
D
E
F
G
H
SEG14
AIN1
AIN0
SEG0
P20VLC2
VLC1
VLC0
CAPL
CAPH
P70
AI N 5
P03
COM0
IC-1
AI N 2 AI N 3 AI N 4 SEG13 SEG12 SEG11 SEG10SEG9 SEG8 SEG7
P11
P10
P33
P32
P31
INTP0
P26
P25 AVSS
P24
P23
P22
BZO90
1 4832
49
6416
33
B2COMNONO
RY1
RY2
D20 D21
Q21
DTD143ES
C21
10uF/35V+
-
D22
D40Q22 SP1
C1
1000uF/25V+
-
C12
0.1uF/50V
0.1uF/25V
+
-C8
220uF/10V
ZD1
HZ4B3
C10
0.1uF/25V
R5
Q1
R6
15KC4
0.01uF/25V
Q10
R10
15K
C11
0.01uF/25V1K C2
Q20
DTA143EKA
C20
0. 1uF
25V
R41
15K
R40
4.7K
OVEN LAMP
TURNTABLE MOTOR
FAN MOTOR
MICRO
DOOR
SWNSING
SWITCH
VRS1
10G471K
T1D3
D4D1
D2D1--D4 1N4002
X4
SEG1 SEG3
SEG2 SEG4 SEG5 SEG6 SEG7 SEG8 SEG9 SEG10 SEG11 SEG12
COM3
COM2
COM1
B1
DOORRST-5VINTBZCOMM
C40
GND
R1
560   1/2W
CN-B
AC(H)AC(N)AC120V
60HZ
G6
G7
G8
G3
(J1)
DTA123JS
G10G11G12
G4
G5
G9
VR
R30
3.3K
0. 01uF
25V
COM1 COM2 COM3 SEG1 SEG2 SEG3 SEG4
SEG5
SEG6
P71
P72
AVDD
P01
P00
RESET
X2
X1
VSS
VDD
XT2
XT1
IC
P53
P52
P51
P50 P02
BL
17
G2
G1
SEG13 SEG14
R60
R61
R7 R8 R9
C3
R62
R630. 1uF
25V
4.7K 4.7K 4.7K
COM
R60-R63
270K x4
POWER UNIT
R80
11KF
C80
22pF/50V
(J12)4.7K
(J11)4.7K
(J10)
(J13)
(J15)10K (J14)2.2K
(J17)4.7K(J16)10K
R3
R44.7K4.7KQ30
R2
82, 1/4W
Q2
LD1 LD2 LD3
WHAWHA
C61
C62
C63 330pF/50V x 4C60-C63C60
PA151DR
LIQUID CRYSTAL DISPLAY
COOK DEF. START CHECK
LSI UNIT
DTA143EKA DTA143EKA
2SA1037AK
d
a
b
c
KTA1267Y
MINUTE
PLUS
DEFROST SOFTEN POWER
LEVELREHEAT WARM
COOK
MELT
POPCORNTIMER
CLOCK
9
3
65 2
8
0
1
4
7
START
STOP
CLEAR