R-772M (serv.man2) - Sharp Home Appliance Service Manual (repair manual)

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This Manual has been prepared to provide Sharp Corp. Service
engineers with Operation and Service Information.

It is recommended that service engineers carefully study the entire text
of this manual, so they will be qualified to render satisfactory customer
service.

WARNING

MICROWAVE RADIATION

Personnel should not be exposed to the microwave energy
which may radiate from the magnetron or other microwave
generating devices if it is improperly used or connected. All input
and output microwave connections, waveguides, flanges and
gaskets must be secured. Never operate the device without a
microwave energy absorbing load attached. Never look into an
open waveguide or antenna while the device is energized.

WARNING

Never operate the oven until the following points are ensured.
(A) The door is tightly closed.
(B) The door brackets and hinges are not defective.
(C) The door packing is not damaged.
(D) The door is not deformed or warped.
(E) There is not any other visible damage with the oven.

Servicing and repair work must be carried out only by trained
service engineers.

All the parts marked “*” on parts list are used at voltages more than
250V.

Removal of the outer wrap gives access to potentials above 250V.

All the parts marked “

∆

” on parts list may cause undue microwave

exposure, by themselves, or when they are damaged, loosened or
removed.

Never operate the Grill and/ or  Bottom heater with the oven
outer cabinet removed. (Because air flow is eliminated, and the
excess heat generated on adjacent components). It can cause
permanent damage or a fire.

SERVICING

PRODUCT SPECIFICATIONS

GENERAL INFORMATION

APPEARANCE VIEW

OPERATING SEQUENCE

FUNCTION OF IMPORTANT
COMPONENTS

TROUBLESHOOTING GUIDE
AND TEST PROCEDURE

TOUCH CONTROL PANEL

COMPONENT REPLACEMENT
AND ADJUSTMENT PROCEDURE

MICROWAVE MEASUREMENT

WIRING DIAGRAM

PARTS LIST

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1) Disconnect the supply.
2) Door opened, and wedged open.
3) Discharge high voltage capacitor.

The high-voltage capacitor remains charged about 60 sec-
onds after the oven has been switched off. Wait for 60
seconds and then short-circuit the connection of the high-
voltage capacitor (that is, of the connecting lead of the high-
voltage rectifier) against the chassis with the use of an
insulated screwdriver.

Sharp recommend that wherever possible fault-finding is
carried out with the supply disconnected. It may in, some
cases, be necessary to connect the supply after the outer
case has been removed, in this event carry out 3D checks and
then disconnect the leads to the primary of the High voltage
transformer. Ensure that these leads remain isolated from
other components and the oven chassis. (Use insulation tape
if necessary.) When the testing is completed carry out 3D
checks and reconnect the leads to the primary of the High
voltage transformer.

Microwave ovens contain circuitry capable of producing very high voltage and current, contact with following parts will
result in electrocution.
High voltage capacitor, High voltage transformer, Magnetron, High voltage rectifier assembly, High voltage harness.

1) Reconnect all leads removed from components during
testing.
2) Replace the outer case (cabinet).
3) Reconnect the supply.
4) Run  the oven. Check all functions.

Microwave ovens should not be run empty. To test for the
presence of microwave energy within a cavity, place a cup of
cold water on the oven turntable, close the door and set the
power to HIGH and set the microwave timer for two (2)
minutes. When the two minutes has elapsed (timer at zero)
carefully check that the water is now hot. If the water remains
cold carry out 3D checks and re-examine the connections to
the component being tested.

When all service work is completed, and the oven is fully
assembled, the microwave power output should be checked
and a microwave leakage test should be carried out.

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Power Requirements

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

Power Consumption

Microwave cooking

1.6 kW  Approx. 7.2 A

Oven cooking

1.5 kW  Approx. 6.5 A

Top Grill mode ...................... 1.05 kW

Approx. 4.2 A

Grill cooking

Bottom Grill mode ................. 0.55 kW

Approx. 2.2 A

Top and Bottom  mode ......... 1.55 kW

Approx. 6.5 A

Micro and Top Grill ............... 2.55 kW

Approx. 11.2 A

Dual cooking

Micro and Bottom Grill ............ 2.1 kW

Approx. 9.2 A

Power Output

900 W nominal of RF microwave energy (measured by method of IEC 705)
Operating frequency 2450 MHz

Top Grill heating element Power Output

1.0 kW

Bottom heating element Power Output

0.5 kW

Case Dimensions

Width 520 mm

Height 309 mm (including foot)

Depth 436 mm

Cooking Cavity Dimensions

Width  349 mm

Height 207 mm

Depth 357 mm

Turntable diameter

325 mm

Control Complement

Touch Control System

Clock (1:00 - 12:59) / Timer (0 - 99 minutes 90 sec.)

Microwave Power for Variable Cooking

 Repetition Rate;
100 (HIGH) ....................... Full power throughout the cooking time
70 (MEDIUM HIGH) .........................  approx. 70% of FULL Power
50 (MEDIUM) ...................................  approx. 50% of FULL Power
30 (MEDIUM LOW) ..........................  approx. 30% of FULL Power
10 (LOW) .........................................  approx. 10% of FULL Power

Oven temperature control range:

   200˚C, 180˚C, 160˚C, 130˚C, 100˚C, 70˚C and 40˚C

TIME keys, BREAKFAST key, PIZZA key, INSTANT COOK keys
AUTO COOK key, AUTO DEFROST key, WEIGHT keys
LESS/MORE keys, OVEN (˚C) key, GRILL key
DUAL /GRILL key, MICROWAVE POWER LEVEL key
STOP/CLEAR key, START/AUTO MINUTE key, TIMER key
WEIGHT CONVERSION key, AUTO START/CLOCK key,

Set Weight

Approx. 20 kg

THE WIRES IN THIS MAINS LEAD ARE COLOURED IN ACCORDANCE WITH THE FOLLOWING CODE:

GREEN-AND-YELLOW

: EARTH

BLUE

: NEUTRAL

BROWN

: LIVE

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8. Grill heating element

(Bottom Grill)

9. Door seals and sealing surfaces
10.Ventilation openings
11.Outer cabinet
12.Power supply cord
13.Turntable
14.Rack

1. Control panel
2. Oven lamp
3. Grill heating element (Top Grill)
4. Door opening button
5. Waveguide cover
6. Oven cavity
7. Turntable motor shaft

BREAKFAST

PIZZA

MIXED GRILL

CRISPY CRUMB FOODS

CHICKEN PTNS

FRESH VEG.

OVEN CHIPS

BAKED POTATOES

1 Chilled Ready Meals

1 Meat Joint

1 Frozen Ready Meals

2 Poultry

3 Roast Beef / Lamb

3 Chicken Ptn, Steak, Chops

4 Roast Pork

4 Minced Meat

5 Roast Poultry

5 Bread

LBS
KG

OZ

COOK

DEFROST AUTO

%

AUTO indicator, showing auto cooking on progress.

DEFROST indicator.

TOP GRILL indicator.

BOTTOM GRILL indicator

COOK indicator showing oven in operation.

MICROWAVE indicator.

WEIGHT indicators.

LESS/MORE indicators.

DIGITAL DISPLAY.

PIZZA key. Press to cook pizza.

AUTO DEFROST key.

LESS/MORE keys. 
Press to shorten or lengthen heating time.

INSTANT COOK keys.

DUAL GRILL key.
Press to select Dual Grill.

AUTO START/CLOCK key.
Use to set the clock.

START/AUTO MINUTE key.
Press to start a programme.  Press to cook on
(HIGH) for 1 minute or increase time during
cooking in multiples of 1 minute.

% percentage microwave power level indicator.

BREAKFAST key.

TIME keys. 
Use to select cooking time.                  

STOP/CLEAR key.
Press once to stop a programme,
and/or twice to cancel a programme.

TIMER key

WEIGHT CONVERSION key

MICROWAVE POWER LEVEL key.
Press to select microwave 
power level.

WEIGHT keys.

OVEN (˚C) key.

GRILL key.
Press to select Grill.

AUTO COOK key.

R-772