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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 in -
fluenced 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 alu -
minium foil.

2) When soldering, ground the technician as shown in the fig -

ure and use grounded soldering iron and work table.

approx. 1M ohm

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 MI -

CROWAVE OVEN IS STILL LIVE DURING SERVIC -
ING 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.

 Discharge high voltage capacitor.

(3) Disconnect the leads to the primary of the power transformer.

(4) Ensure that these leads remain isolated from other com -

ponents and oven chassis by using insulation tape.

After that procedure, re-connect the power supply cord.

(1) After checking the performance of the touch control 

panel,

(2) Disconnect the power supply cord.

 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.

 

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 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.

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 be-
ing 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).

Tools required to service the touch control panel assembly.

1) Soldering iron: 60W

(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, re-

move the aluminium foil applied for preventing static elec -
tricity.

2) Connect the connector of the key unit to the control unit be -

ing 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.

R-291(K)M

9 - 2

R-291(K)M

10 – 1

R218L(W)

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)

WARNING:

1) Disconnect the power supply cord.

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;

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 trans-

mission 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.

1. Before wiring, 

1) Disconnect the power supply cord.

2) Open the door and 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,

y.

2) Hot parts:

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

3) Sharp edge:

plate.

4) Movable parts (to prevent a fault)

Fan blade, Fan motor, Turntable motor and Switch.

3. Do not catch the wire leads in the outer case cabinet.

4. Insert the positive lock connector  certainly until its pin is locked and

are pulled.

5. To prevent an error function, connect the wire leads correctly, refer-

ring to the Pictorial Diagram. 

Please refer to ‘OVEN PARTS, CABINET PARTS, CONTROL PANEL PARTS, DOOR PARTS’, when carrying out any of the following removal proce-
dures:

To remove the outer case, procedure as follows.

1. Disconnect the oven from power supply.

2. Open the oven door and wedge it open.

3. Remove the two (2) screws from right side of the outer case cabi-

net.

om rear and along the side edge of

case.

5. Slide the entire case back about 3cm to free it from retaining clips

on the cavity face plate.

6. Lift the entire case from the oven.

7. Discharge the H.V. capacitor before carrying 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: DISCONNECT OVEN FROM POWER SUPPLY BEFORE

REMOVING OUTER CASE.

 

                                                                                                

                                                      

                                                      

CARRY OUT  3D  CHECKS.

Disconnect the wire leads (main wire harness and H.V. fuse) 
from high voltage transformer.

from the magnetron.

Disconnect the filament lead of the high voltage transformer 
from high voltage capacitor.

1.

2.

3.

4.

Remove the two (2) screws holding the transformer to bottom 
plate from below.

Remove the two (2) screws holding the transformer to bottom 
plate from above. 

Remove the transformer. 

5.

6.

7.

Disconnect the H.V. fuse from the high voltage capacitor.

should be free.

CAUTION: WHEN REPLACING HIGH VOLTAGE RECTIFIER 

ASSEMBLY, ENSURE THAT THE CATHODE 
(EARTH) CONNECTION IS SECURELY FIXED TO 
THE CAPACITOR HOLDER WITH AN EARTHING 
SCREW.

CAUTION: DO NOT REPLACE ONLY HIGH VOLTAGE RECTIFIER. 

WHEN REPLACING IT, REPLACE HIGH VOLTAGE  
RECTIFIER ASSEMBLY.

8.

9.

To remove the components, proceed as follows.

CARRY OUT  3D  CHECKS.

Disconnect the H.V. fuse from the high voltage transformer.

Disconnect the H.V. wire of the H.V. rectifier assembly from 
the magnetron.

Disconnect the filament lead of the high voltage transformer 
from the H.V. capacitor.

Remove one (1) screw holding capacitor holder to the oven 
cavity back plate.

Remove one (1) screw holding earth side terminal of high 
voltage rectifier assembly, and remove capacitor holder.

Disconnect all the leads and terminals of high voltage rectifier 
assembly from high voltage capacitor.

1.

2.

3.

4.

5.

6.

7.

CARRY OUT  3D  CHECKS.

Disconnect the wire leads from the magnetron.

Remove the two (2) screws holding the air duct to the oven 
cavity.

Release the air duct from the oven cavity.

Carefully remove the four (4) screws holding the magnetron 
to the waveguide flange.

Lift up magnetron with care so that the magnetron antenna 
is not hit by any metal object around antenna.

Now, the magnetron is free.

1.

2.

3.

4.

5.

6.

7.

four (4) screws.

Reinstall the air duct to the oven cavity with the two (2) 
screws.

Reconnect the wire leads to the magnetron. Refer to "PICTORIAL 
DIAGRAM".

Reinstall the outer case and check that the oven is operating 
properly.

CAUTION: WHEN REPLACING THE MAGNETRON, BE SURE 

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

1.

2.

3.

4.

CARRY OUT 3D  CHECKS.

Push the lever of positive lock

®

 connector.

Pull down on the positive lock

®

 connector.

CAUTION: WHEN CONNECTING THE POSITIVE LOCK

®

 

CONNECTORS TO THE TERMINALS, CONNECT 
THE POSITIVE LOCK

®

 SO THAT THE LEVER FACES YOU.

1.

2.

3.

Disconnect the power supply cord.

Remove turntable and turntable support from oven cavity.

1.

2.

Lay the oven on it's backside. Remove the turntable motor 

3.

Terminal

Push

Pull down

1

2

Lever

Positive lock

®

connector

R-291(K)M

10 - 2

Gap

Rotor

Bracket

Stator

Groove joint pliers

Coil

Shaft

Axis

Stator

Rotor

These are the positions

that should be pinched

with pliers.

Shaft

Table

Center of

bracket

turntable motor cover.

Disconnect wire leads from turntable motor. (See "Positive 
lock connector removal")

Remove one (1) screw holding turntable motor to oven cavity.

Remove the TTM packing from the turntable motor.

Now, the turntable motor is free.

2. REINSTALL

Re-install the TTM packing to the turntable motor.

Re-install the turntable motor with the TTM packing with the 
single (1) screw to the oven cavity bottom plate.

4.

5.

6.

7.

8.

1.

2.

Re-connect the wire leads to the turntable motor.

Insert the tab of the turntable motor cover into the hole of 
the bottom plate.

Re-install the turntable motor cover to the bottom plate with 
one (1) screw.

TTM packing

Turntable motor

3.

4.

5.

CARRY OUT  3D  CHECKS.

Disconnect the wire leads from the fan motor.

Remove the two (2) screws holding the fan motor to the 
oven cavity back plate.

Remove the fan blade from the fan motor shaft according to 
the following procedure. 

Hold the edge of the rotor of the fan motor by using a pair of 
groove joint pliers.

CAUTION: MAKE SURE THAT ANY PIECES DO NOT ENTER 

THE GAP BETWEEN THE ROTOR AND THE STA -
TOR OF THE FAN MOTOR. BECAUSE THE RO -
TOR IS EASY TO BE 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 TOUCH -
ING WITH THE PLIERS.

Remove the fan blade from the shaft of the fan motor by 
pulling and rotating the fan blade with your hand.

Now, the fan blade will be free.

1.

2.

3.

4.

5.

6.

7.

CAUTION: DO NOT RE-USE THE REMOVED FAN BLADE BECAUSE 

THE HOLE (FOR SHAFT) MAY BE LARGER THAN NORMAL.

Now, the fan motor is free.

Install the fan blade to the fan motor shaft according to the 
following procedure.

Hold the centre of the bracket which supports the shaft of 
the fan motor on the flat table.

Apply the screw lock tight into the hole (for shaft) of the fan 
blade.

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.

CAUTION: DO NOT HIT THE FAN BLADE STRONGLY WHEN 

INSTALLED BECAUSE THE BRACKET MAY BE 
TRANSFORMED.

MAKE SURE THAT THE FAN BLADE ROTATES 
SMOOTH AFTER INSTALLED.

MAKE SURE THAT THE AXIS OF THE SHAFT IS 
NOT SLANTED.

Install the fan motor assembly to the oven cavity back plate 
with two (2) screws. 

Connect the wire leads to the magnetron and fan motor, re -
ferring to the pictorial diagram.

8.

1.

2.

3.

4.

5.

6.

CARRY OUT  3D  CHECKS.

Remove the single (1) screw holding the green/yellow wire 
to the oven cavity back plate.

Disconnect the leads of the power supply cord from the 
noise filter, referring to the Figure C-3(a).

1.

2.

3.

Release the moulding cord stopper of the power supply cord 
from the square hole of the oven cavity back plate, referring 
to the Figure C-3 (b).

Now, the power supply cord is free. 

4.

5.

R-291(K)M

10 - 3