Sharp R-450H Service Manual Download

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R-450H

COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE

WARNING:

Avoid possible exposure to microwave energy. Please follow the instructions below before
operating the oven.

1. Disconnect the oven from the 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 or 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 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.

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

WARNING FOR WIRING

To prevent an electric shock, take the following
manners.

1. Before wiring,

1) Disconnect the 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
voltage capacitor, High voltage rectifier assembly
and High voltage fuse.

2) Hot parts:

Oven lamp, Magnetron, High voltage transformer

and Oven cavity.

3) Sharp edge:

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

4) Movable parts (to prevent a fault)

Fan blade, Fan motor, Switch, Switch lever,
Open button.

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 make sure that the wire leads
should not come off even if the wire leads is pulled.

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

correctly, referring to the Pictorial Diagram.

To remove the outer case, proceed as follows.
1. Disconnect oven from power supply.
2. Open the oven door and wedge it open.
3. Remove the four (4) screws from rear and along the

side edge of case.

4. Slide the entire case back about 1 inch (3 cm) to free

it from retaining clips on the cavity face plate.

5. Lift the entire case from the oven.

OUTER CASE REMOVAL

6. Discharge the H.V. capacitor before carrying out any

further work.

7. Do not operate the oven with the outer case removed.
N.B.; Step 1,2 and 6 form the basis of the 3D checks.
CAUTION: DISCHARGE HIGH VOLTAGE CAPACITOR

BEFORE TOUCHING ANY OVEN COMPO-
NENTS OR WIRING.

1. CARRY OUT 3D CHECKS.
2. Disconnect wire leads from power transformer,

magnetron and capacitor terminals.

3. Remove four (4) screws holding transformer to bottom

plate.

4. Remove transformer from bottom plate.

Re-install

1. Rest transformer on the bottom plate with its primary

POWER TRANSFORMER REMOVAL

terminals toward front side.

2. Secure the transformer with four (4) screws to bottom plate.
3. Re-connect wire leads (primary and high voltage) to

power transformer and filament leads of transformer to
magnetron and high voltage capacitor. Refer to
"PICTORIAL DIAGRAM".