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202M - 5

MICROWAVE OUTPUT POWER (IEC-705)

The power output of this oven is rated using the method specified by IEC-705.  Full details of how to carry out this
procedure can be found in the Sharp Technical Training notes which is available from Sharp Parts Centre
(part number SERV-LITMW01).

Using this procedure,for an 800W oven, the heating time to raise 1000g of water by 10

°

C is approximately 55 seconds.

The IEC-705 procedure must be carried out using laboratory-type procedures and equipment.  These requirements
make the procedure unsuitable for routing performance checks.  An indication of the power being produced by the oven
can however be obtained using the procedure given below.

Alternative simplified method:
1. Place 2 litres of cold water (between 12

°

C and 20

°

C) in a suitable container.

2. Stir the water and measure the temperature in 

°

C.  Note temperature as T1.

3. Place the container in the microwave and heat the water for 2 minutes on full power.
4. When the 2 minutes is completed, remove the container and stir the water.  Note the water temperature as T2.
5. Calculate the output power using the following formula:

R.F. Power Output = (T2 - T1) x 70.

MICROWAVE LEAKAGE TEST

This oven should be tested for microwave leakage on completion of any repair or adjustment, following the procedure
described in the Sharp Technical Training notes (part number SERV-LITMW01).  The maximum leakage permitted in
BS EN 60335-2-25 is 50W/m

2 

(equivalent to 5mW/cm

2

), however it is not normal to detect any significant leakage,

therefore, any leakage which is detected should be investigated.

It is essential that only leakage detectors with current calibration traceable to the National Physical Laboratories are used.

Suitable leakage detectors :

CELTEC A100
APOLLO X1

1.

CARRY OUT 3D CHECKS.

2.

Disconnect the leads from all switches.

3.

Remove the one (1) screw holding the latch hook to the
oven cavity.

4.

Remove the latch hook.

5.

Push the retaining tab slightly and remove the switch.

Latch hook

Tab

SW3: Stop switch 

SW2: Monitor switch 

SW1:  Monitored latch switch 

Tab

Tab

202M - 6

10

5

4

12

8

7

9

11

3

2

1

Choke Cover

Door Frame

Putty Knife

6

Door film

Finger tab

Backing film

Pin

Pin

Lower
Oven
Hinge

Lower Oven
Hinge

Upper
Oven
Hinge

Upper Oven
Hinge

Door Panel

Choke Cover

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.

I

1. Tear away the backing film.
3. Put the pasted side of the inner sealer film on the door

panel.

1. Disconnect the power supply cord.
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.

4. Release choke cover  from door panel.
5. Now choke cover is free.

6. Release two (2) pins of door panel from two (2) holes

of upper and lower oven hinges by lifting up.

7.

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

frame with releasing latch spring from door frame and
latch head.

13. Now, latch head and latch spring are free.
14.

15.

16.

17.

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

spring to the door frame. Re-install latch head to the
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.

202M - 7

MICROWAVE MEASUREMENT

After any repair, the microwave oven must be checked for microwave leakage to ensure continued safe operation. BS EN
60335-2-25 specifies that the maximum permitted leakage with a load of 275 ml is 50 W/m

2 

(equivalent to 5 mW/cm

2) 

at

a distance of 5 cm from the oven.

The following items are required to carry out this test:-
1.  A low form of 600 ml beaker made from an electrically non-conductive material, such as glass or plastic, with an inside

diameter of approximately 8.5 cm. This must contain 275 

±

 15 ml of water, at an initial temperature of 20 

±

 2˚C.

2. A leakage detector which has been calibrated within the preceding 12 months to a standard whose accuracy  can be

traced to National Physical Laboratory Standards.

Recommended instruments are:

Apollo “XI”
Celtec “A100”

Before commencing the test, check that the leakage detector is functioning and adjusted according to the manufacturer’s
instructions, and any spacers are fitted to ensure that measurement is taken 5cm from the surface of the oven.

1. Place the beaker containing the water load in the oven cavity at the centre of the turntable. The placing of this standard

load in the oven is important, not only to protect the oven, but also to ensure that any leakage it is not disguised by too
large a load absorbing energy.

2. Close the oven door, and with the power level set to FULL, turn the oven ON with the timer set for a few minutes

operation. Should the water begin to boil before the test has been completed, it should be replaced.

3. As shown in the diagram below, move the probe slowly (not faster than 2.5 cm/sec.);-
a) around the edge of the door following the gap
b) across the face of the door
c) across any vents in the oven’s sides, rear or top

Dotted line indicates the path by the leakage detector.

Whilst the maximum leakage permitted in BS60335 2-25 is 50 /W/m 

2

(equivalent to 5 W/cm

2

),it is not normal to detect any

significant leakage, and therefore any detected leakage should be investigated.

202M - 8

Ensure the following:

1. Wires must not touch:

a) High voltage parts.
    (Magnetron, high voltage transformer,high voltage capacitor and high voltage rectifier assembly)
b) Parts that become hot.
    (Heating elements, oven lamp,oven cavity magnetron and high voltage transformer)
c) Sharp edges.
    (Bottom plates, oven cavity, waveguide flange, chassis support and other metallic parts)
d) Movable parts.
    (Fan blade, any motor, switch, switch lever and open button)

2. Positive lock connectors are fitted correctly.
3. Wires are connected correctly as per pictoral diagram.
4. No wire leads are trapped by the outer wrap.

Before carrying out any work; carry out 3D checks.
1.

isconnect the supply.

2.

oor opened, and wedged open.

3.

ischarge the high voltage capacitor.