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R2

70WM

3 – 1

R269WM

Service Manual

 

Power Requirements

230 - 240 Volts 
50 Hertz
Single phase, 3 wire earthed

Power Consumption

                   1200W 

Power Output

800 watts nominal of RF microwave energy (measured by method of IEC 60705)
Operating frequency 2450 MHz

Case Dimensions

Width  4

52 mm

Height 2

62 mm including foot

Depth  3

42 mm

Cooking Cavity Dimensions

Width  31

5mm     NOTE: Internal capacity is calculated by measuring maximum width, depth and height.

Height 21

0 mm                Actual capacity for holding food is less.

Depth  3

29mm

Turntable diameter

2

45mm

Control Complement

Touch Control System
Timer (0 - 99 minutes 90 seconds)
No Clock 
Microwave Power for Variable Cooking
    Repetition Rate;
   HIGH .........................................................Full power 

and  90% of FULL Power throughout the cooking time

   MEDIUM HIGH ................................................................. approx.

80 % and 70% of FULL Power

   MEDIUM  ......................................................................... approx. 

60% and 50% of FULL Power

   MEDIUM LOW  ................................................................. approx. 

40% and 30% of FULL Power

   LOW ................................................................................ approx. 

20% and 10% of FULL Power

WEIGHT COOK & DEFROST key
AUTO COOK key

 

TIME keys
WEIGHT keys
LESS/MORE TIME keys
KITCHEN TIMER key
POWER LEVEL key
STOP/CLEAR key
START/AUTO MINUTE key

 

 

 Set Weight (Approx.)

12 kg

R2

70WM

4 – 1

R269WM

Service Manual

 

1. Ventilation openings

2. Oven lamp

3. Door hinges

4. Door safety latches

5. See through door

6. Door seals sealing surfaces

7. Coupling

8. Control panel

9. Waveguide cover

10. Power supply cord

11. Turntable

12. Roller stay

13. Outer case cabinet

14. Door opening button

1.Liquid 

LED Display

2. TIME keys

3. 

WEIGHT COOK & DEFROST keys

4. LESS/MORE TIME keys

5. POWER LEVEL key
6. START/AUTO MINUTE key

7. STOP/CLEAR key
8. KITCHEN TIMER key
9.WEIGHT keys

1

0.AUTO COOK key

NOTE: Some one-touch cooking features such as “AUTO MINUTE” are disabled after three

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3

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4

4

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2

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R2

70WM

5 – 1

R269WM

Service Manual

 

Closing the door activates all door interlock switches (1st. latch switch,
2nd. interlock relay control switch).

IMPORTANT

When the oven door is closed, the monitor switch contacts (COM-NC)
must be open.

When the microwave oven is plugged in a wall outlet, rated voltage is
supplied to the noise filter and the control unit.

                                            Figure O-1 on page 13-1 

1. The display will show flashing “

  :  ”.

NOTE: Plsease note that this model does NOT have a clock function. 

.

.

Enter a desired cooking time with the touching TIME keys and start the
oven with touching START key.

Function sequence 

                           Figure O-2 on page 13-1

1. Rated voltage is supplied to the primary winding of the high voltage

transformer. The voltage is converted to about 3.3 volts A.C. output
on the filament winding and high voltage of approximately 2000
volts A.C. on the secondary winding.

2. The filament winding voltage (3.3 volts) heats the magnetron fila-

ment and the high voltage (2000 volts) is sent to the voltage dou-
bling circuit, where it is doubled to negative voltage of
approximately 4000 volts D.C..

3. The 2450 MHz microwave energy produced in the magnetron gen-

erates a wave length of 12.24 cm. This energy is channelled
through the waveguide (transport channel) into the oven cavity,
where the food is placed to be cooked.

4. When the cooking time is up, a signal tone is heard and the relays

(RY1+RY2) go back to their home position. The circuits to the oven
lamp, high voltage transformer, fan motor and turntable motor are
cut off.

5. When the door is opened during a cook cycle, the switches come to

the following condition

The circuits to the high voltage transformer, fan motor, turntable motor
and oven lamp are cut off when the 1st. latch switch and 2nd. interlock
relay control switch are made open. 

6. MONITOR SWITCH CIRCUIT

The monitor switch is mechanically controlled by oven door, and
monitors the operation of the 1st. latch switch, the relay (RY1) and
the 2nd. interlock relay (RY2).

1) When the oven door is opened during or after the cycle of a

cooking program, the 1st. latch switch and 2nd. interlock relay
control switch must open their contacts first. After that the con-
tacts (COM-NC) of the monitor switch can be closed.

2) When the oven door is closed, the contacts (COM-NC) of the

monitor switch must be opened. After that the contacts of the
1st. latch switch and 2nd. interlock relay control switch are
closed.

3) When the oven door is opened and the contacts of the 1st. latch

switch, the relay (RY1) and the 2nd. interlock relay (RY2)
remain closed. The fuse (T6.3A) will blow, because the monitor
switch is closed and a short circuit is caused.

When the microwave oven is preset for variable cooking power, rated
voltage is supplied to the high voltage transformer intermittently within
a 32-second time base through the relay contact which is coupled with
the current-limiting relay. The following levels of microwave power are
given.

SETTING;

NOTE: The ON/OFF time ratio does not exactly correspond to the

percentage of microwave power, because approx. 3 seconds
are needed for heating up the magnetron filament.

After 100% power cooking mode is carried out for more than 20 min-
utes, the power out-put is automatically reduced to 70%. Even if the
cooking time is shorter than for 20 minutes, the power output is
reduced to 70% after total cooking time over 20 minutes when the
oven is started in 100% power cooking mode again within 1 minute
and 35 seconds.

CONNECTED COMPONENTS

RELAY

Oven lamp, Fan motor, Turntable motor 

RY1

High voltage transformer 

RY2

          CONDITION

SWITCH CONTACT 

DURING 

COOKING

DOOR OPEN 

(NO COOKING)

1st. latch switch 

COM-NO 

Closed 

Open

2nd. interlock relay   
control switch   

COM-NO Closed 

Open

Monitor switch       

COM-NC 

Open   

Closed

100P (HIGH)

32 sec. ON

70P (MEDIUM

HIGH)

Approx. 70%

100%

24 sec. ON

8 sec. OFF

14 sec. OFF

20 sec. OFF

26 sec. OFF

50P (MEDIUM)

Approx. 50%

18 sec. ON

30P (MEDIUM

LOW)

Approx. 30%

12 sec. ON

10P (LOW)

Approx. 10%

6 sec. ON

R2

70WM

6 – 1

R269WM

Service Manual

 

The door can be opened by pushing the open button on the control
panel. When the open button is pushed, the switch lever is moved
upward, operating the latch heads. The latch heads are moved upward
and released from the latch hook. Now, the door can be opened.

                            Figure D-1. Door Open Mechanism

1. When the oven door is closed, the contacts (COM-NO) must be

closed.

2. When the oven door is opened, the contacts (COM-NO) must be

opened.

1. When the oven door is closed, the contacts (COM-NC) must be

opened.

2. When the oven door is opened, the contacts (COM-NC) must be

closed.

3. If the oven door is opened and the contacts (COM-NO) of the 1st

latch switch, the relay (RY1) and the 2nd. interlock relay (RY2) fail
to open, the fuse (

10A) blows simultaneously with closing the

contacts (COM-NC) of the monitor switch.

CAUTION: BEFORE REPLACING A FUSE (

10A) TEST THE 1ST.

LATCH SWITCH, RELAY (RY1) AND 2ND. INTERLOCK
RELAY (RY2) AND MONITOR SWITCH FOR PROPER
OPERATION. (REFER TO CHAPTER “TEST PROCE-
DURE”.)

1. The fuse (

10A) blows when the contacts (COM-NO) of the 1 st.

latch switch, the relay (RY1) and the 2nd. interlock relay (RY2)
remain closed with the oven door open and when the monitor
switch   closes.

2. If the wire harness or electrical components are short-circuited, the

fuse (

10A) blows to prevent an electric shock of fire hazard.

The high voltage fuse blows when the high voltage rectifier or the mag-
netron is shorted.

The temperature fuse located on the top of the oven cavity is designed
to prevent damage to the oven if the foods in the oven catch fire due to
over heating produced by improper setting of cook time or failure of
control unit. Under normal operation, the temperature fuse remains
closed. However, when abnormally high temperatures are reached
within the oven cavity, the temperature fuse will open at 1

20

°C, caus-

ing the oven to shut down. The defective temperature fuse must be
replaced with a new one.

The turntable motor drives the turntable roller assembly to rotate the
turntable.

The fan motor drives a blade which draws external cool air. This cool
air is directed through the air vanes surrounding the magnetron and
cools the magnetron. This air is channelled through the oven cavity to
remove steam and vapours given off from the heating foods. It is then
exhausted through the exhausting air vents at the oven cavity.

The noise filter prevents the radio frequency interference that might
flow back in the power circuit.

2nd. Interlock

Relay Control

Switch

1st. Latch Switch

Latch

Heads

Door

Switch Lever

Latch Hook

Monitor Switch