Chapter 11. Component Replacement And Adjustment Procedure Before Operating; Outer Case Removal; High Voltage Components Removal - Sharp R-939(BK) Service Manual

CHAPTER 11.
R939(W)
COMPONENT REPLACEMENT AND ADJUSTMENT PROCE-
DURE
[1] BEFORE OPERATING
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)
High Voltage Capacitor, High Voltage Transformer, Magnetron, High Voltage Rectifier Assembly, High Voltage fuse, High Voltage Harness etc..
Avoid possible exposure to microwave energy. Please follow the instructions below before operating
WARNING:
the oven.
1) Disconnect the power supply cord.
2) 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 is damaged.
4) The door is bent or warped.
To prevent an electric shock, take the following manners.
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
and High voltage rectifier assembly.
2) Hot parts:
Grill heating element, Convection heating element, Oven lamp,
Magnetron, High voltage transformer and Oven cavity.
Please refer to 'OVEN PARTS, CABINET PARTS, CONTROL PANEL PARTS, DOOR PARTS', when carrying out any of the following removal proce-
dures:

[2] OUTER CASE REMOVAL

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 one (1) screw holding the air duct to the oven cavity
rear plate.
4. Remove the air duct.
5. Remove the nine (9) screws from rear and along the side edge of
case.

[3] HIGH VOLTAGE COMPONENTS REMOVAL

(HIGH VOLTAGE CAPACITOR AND HIGH VOLTAGE RECTIFIER ASSEMBLY)
To remove the components, proceed as follows.
1. CARRY OUT 3D CHECKS.
Service Manual
WARNING AGAINST HIGH VOLTAGE:
5) There are defective parts in the door interlock system.
6) There are defective parts in the microwave generating and trans-
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.
WARNING FOR WIRING
3. Do not catch the wire leads in the outer case cabinet.
4. Insert the positive lock connector certainly until its pin is locked.
5. To prevent an error function, connect the wire leads correctly, refer-
6. Slide the entire case back about 3 cm to free it from retaining clips
7. Lift the entire case from the oven.
8. Discharge the H.V. capacitor before carrying out any further work.
9. Do not operate the oven with the outer case removed.
NOTE: Step 1, 2 and 8 form the basis of the 3D checks.
CAUTION: DISCHARGE HIGH VOLTAGE CAPACITOR BEFORE
2. Disconnect the filament lead of the high voltage transformer and
3. Disconnect the high voltage wire from the magnetron.
11 – 1
mission assembly.
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, Turntable motor, Convection
motor, convection fan and cooling fan.
And make sure that the wire leads should not come off even if the
wire leads is pulled.
ring to the Pictorial Diagram.
on the cavity face plate.
TOUCHING ANY OVEN COMPONENT OR WIRING.
the high voltage wire of the high voltage transformer from the high
voltage capacitor.
R939(W)