R-21AT - Sharp Home Appliance Service Manual (repair manual). Page 27

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1. Disconnect the oven from the power supply.
2. Open the oven door and wedge it open.
3. Make sure that the smooth surface of the ceramic shelf

face up.

4. Make sure that the rubber packing without a fin of the

ceramic shelf faces the front of the oven.

NOTE: The three (3) rubber packings with the fins and the

one (1) rubber packing without a fin are attached
to the four (4) edges of the ceramic shelf. The one
(1) rubber packing without a fin is the front edge of
the ceramic shelf.

5. Put the front edge of the ceramic shelf into the front

edge of the oven cavity bottom plate.

6. Push down the rear edge of the ceramic shelf into the

oven cavity bottom plate.

7. Now, the ceramic shelf is installed.

Rear Edge

Push

Front Edge

Ceramic 
Shelf

Oven Cavity

WARNING

Make sure that the rubber packing is not caught be-
tween the oven door and the oven cavity front plate, to
avoid possible exposure to excessive microwave en-
ergy.

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 taken by the leakage detector.

Whilst the maximum leakage permitted in BS EN 60335-2-25 is 50 W/m

2 

(equivalent to 5 mW/cm

2

), it is not normal to detect

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

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 stand whose accuracy
can be traced to National Physical Laboratory Stand-
ards.

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.