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15

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

them in aluminium foil. Also wrap PW boards con-
taining them in aluminium foil.

2) When soldering, ground the technician as shown in

the figure and use grounded soldering iron and
work table.

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.

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.

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. For
those models, check and repair all the controls
(sensor-related ones included) of the touch con-
trol 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
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.

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).

Tools required to service the touch control panel as-
sembly.
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

1) Before turning on the power source of the control

unit, remove the aluminium foil applied for prevent-
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.

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.

approx. 1M ohm

16

To To remove the outer case, procedure as follows.
1. Disconnect the power supply cord.
2. Open the oven door and block it open.
3. Remove the two (2) screws along the right side of the

outer case.

4. Remove the remaining five (5) screws from the rear of

the 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.

7. Discharge the H. V. capacitor before curring out any

further work.

8. Do not operate the oven with the  outer case removed.
NOTE: Step 1, 2 and 7 form the basis of the 3D checks.

CAUTION:1. DISCONNECT OVEN FROM POWER SUP-

PLY BEFORE REMOVING OUTER CASE.

2. DISCHARGE THE HIGH VOLTAGE CA-

PACITOR BEFORE TOUCHING ANY
OVEN COMPONENTS OR WIRING.

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, High Voltage Transformer, Magnetron, High Voltage Rectifier Assembly,  High Voltage
Harness, High Voltage fuse etc..

To prevent an electric shock, take the following pre-
cautions.
1. Before wiring,

1) Disconnect the oven from power supply.
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, High voltage rectifier assembly and
High voltage fuse.

2) Hot parts:

1. Disconnect the oven from power supply.
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
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 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 generat-

ing 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.

Oven lamp, Magnetron, High voltage transformer,
Oven cavity.

3) Sharp edge:

Bottom plate, Oven cavity, Waveguide flange,
Chassis support and other metallic plate.

4) Moveable parts (to prevent a fault)

Fan blade, Fan motor, Switch, Turntable motor.

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:

17

1. CARRY OUT 3D CHECKS.
2. Disconnect the wire leads from magnetron.
3. Remove the three (3) screws holding the magnetron to

the waveguide.

4. Remove the magnetron from waveguide.

5. Now, the magnetron is free.

CAUTION: WHEN REPLACING THE MAGNETRON,

BE SURE THE R.F. GASKET IS IN PLACE
AND THE MAGNETRON MOUNTING
SCREWS ARE TIGHTENED SECURELY.

To remove the components, proceed as follows.
1. CARRY OUT 3D CHECKS.
2. Remove one (1) screw holding capacitor holder to rear

cabinet.

3. Disconnect the H.V. wire of the H.V. rectifier assembly

from the magnetron.

4. Disconnect the filament lead of the high voltage trans-

former from the H.V. capacitor.

5. Remove one (1) screw holding ground side terminal of

high voltage rectifier assembly, and remove capacitor
holder.

6. Disconnect all the leads and terminals of high voltage

rectifier assembly from high voltage capacitor.

7. Now the H.V. rectifier assembly and H.V. capacitor

should be free.

CAUTION: WHEN REPLACING HIGH VOLTAGE REC-

TIFIER ASSEMBLY, ENSURE THAT THE
CATHODE (GROUND) CONNECTION IS
SECURELY FIXED TO THE CAPACITOR
HOLDER WITH A GROUNDING SCREW.

CAUTION: DO NOT REPLACE ONLY HIGH VOLT-

AGE RECTIFIER. WHEN REPLACING IT,
REPLACE HIGH VOLTAGE RECTIFIER
ASSEMBLY.

1. CARRY OUT 3D CHECKS.
2. Disconnect the wire leads (main wire harness) from

high voltage transformer.

3. Disconnect the lead from magnetron filament.
4. Disconnect the leads of the high voltage transformer

from high voltage capacitor.

5. Remove the two (2) screws holding the transformer to

bottom plate from the upper side.

6. Remove the remaining two (2) screws from the bottom.
7. Remove the transformer.
8. Now the high voltage transformer is free.

Re-install
1. Rest transformer on the bottom plate with its primary

terminals toward the oven face plate.

2. Secure transformer with four (4) screws to the bottom

plate.

3. Re-connect wire leads (primary and high voltage) and

filament leads to the high voltage transformer,
magnetron and high voltage capacitor, referring to
"Pictorial Diagram".

4. Re-install outer case and check that the oven is oper-

ating properly.

Terminal

Push

Pull down

1

2

Lever

Positive lock®

connector

1. CARRY OUT 3D CHECKS.
2. Push the lever of positive lock

®

 connector.

3. Pull down on the positive lock

®

 connector.

CAUTION: WHEN CONNECTING THE POSITIVE

LOCK

®

 CONNECTORS TO THE TERMI-

NALS, INSTALL THE POSITIVE LOCK

®

 SO

THAT THE LEVER FACES YOU

1. CARRY OUT 3D CHECKS.
2. Disconnect the leads from the control unit and the

surge relay unit.

3. Remove the one (1) screw holding the control panel to

the front plate of the oven cavity.

4. Now, the control panel assembly is free.

Removal
1. CARRY OUT 3D CHECKS.
2. Remove the control panel assembly, referring to chap-

ter of CONTROL PANEL ASSEMBLY REMOVAL.

3. Remove the three (3) screws holding the control unit to

the control panel frame. And remove the control unit.

18

1. Disconnect the oven from the power supply.
2. Remove the turntable and turntable support from the

oven cavity.

3. Turn the oven over.
4. Remove the one (1) screw holding the turntable motor

cover to the bottom plate.

5. Now, the turntable motor cover is free.
6. Disconnect the wire leads from the turntable motor.
7. Remove the single (1) screw holding the turntable

motor to the oven cavity.

8. Remove the turntable motor from the oven cavity.
9. Remove the TTM packing from the turntable motor.
10.Now, the turntable motor is free.

1. Re-install the TTM packing.
2. Re-install the turntable motor with theTTM packing

with the single (1) screw.

3. Re-connect the wire leads to the turntable motor.
4. Insert the tab of the turntable motor cover into the hole

of the bottom plate.

5. Re-install the turntable motor cover to the bottom plate

with one (1) screw.

4. Remove the rubber connector from the long slit on the

control panel frame.

5. Tear away the graphic sheet from the control panel frame.
6. 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

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. Tear the small backing paper from the ribbon cable of

the membrane switch.

10. Attach the ribbon cable to the control panel frame rear side.
11. Place the edge of the membrane switch’s ribbon cable

on the lower portion of the liquid crystal display.

12. Insert the rubber connector into the long slit on the

control panel frame.

13. Reinstall the control unit to the control panel frame with

the three (3) screws.

TTM packing

Turntable motor

REMOVAL
1. CARRY OUT 3D CHECKS.
2. Remove the magnetron from the waveguide. Refer to

chapter "MAGNETRON REMOVAL"

3. Disconnect the wire leads from the fan motor.
4. Release the wire leads from the hole of the fan duct.
5. Remove the three (3) screws holding the fan duct to the

oven cavity.

Graphic sheet

Rubber connector

Contact surface

Membrane
switch

Ribbon cable
of membrane
switch

Large 
depression

Small 
depression

Small backing 
paper

Ribbon 
cable

Liquid crystal 
display

Control panel frame 
(Rear side)

Control panel frame

Long slit

Slit