Sharp R820bk Service Manual

R-820BK
R-820BW
In the interest of user-safety the oven should be restored to its original
condition and only parts identical to those specified should be used.
WARNING TO SERVICE PERSONNEL: Microwave ovens con-
tain circuitry capable of producing very high voltage and
current, contact with following parts may result in a severe,
possibly fatal, electrical shock. (High Voltage Capacitor, High
Voltage Power Transformer, Magnetron, High Voltage Recti-
fier Assembly,  High Voltage Harness etc..)
TABLE OF...

R-820BK
R-820BW
PRECAUTIONS TO BE OBSERVED BEFORE AND
DURING SERVICING TO AVOID POSSIBLE
EXPOSURE TO EXCESSIVE MICROWAVE
ENERGY
(a) Do not operate or allow the oven to be operated with the door open.
(b) Make the following safety checks on all ovens to be serviced before activating the magnetron or other
microwave source, and make repairs as necessary: (1) interlock operation, (2) proper door closing, (3)
seal and sealing surfaces (arcing, wear, and other damage), (4) damage to or loosening of hinges...

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R-820BK
R-820BW
WARNING TO SERVICE PERSONNEL
Microwave ovens contain circuitry capable of pro-
ducing very high voltage and current, contact with
following parts 
 may result in a severe, possibly
fatal, electrical shock.
(Example)
High Voltage Capacitor, High Voltage Power Trans-
former, Magnetron, High Voltage Rectifier Assem-
bly,  High Voltage Harness etc..
Read the Service Manual carefully and follow all
instructions.
Before Servicing
1. Disconnect the power supply cord ,and  then
remove outer...

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R-820BK
R-820BW
MICROWAVE MEASUREMENT PROCEDURE
A. Requirements:
1) Microwave leakage limit (Power density limit): The power density of microwave radiation emitted by a microwave oven
should not exceed 1mW/cm
2 at any point 5cm or more from the external surface of the oven, measured prior to acquisition
by a purchaser, and thereafter (through the useful life of the oven), 5 mW/cm2 at any point 5cm or more from the external
surface of the oven.
2) Safety interlock switches Primary interlock relay and...

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R-820BK
R-820BW
SHARP ELECTRONICS CORPORATION
SHARP PLAZA, MAHWAH,
NEW JERSEY 07430-2135
SERVICE MANUAL
DOUBLE GRILL
CONVECTION
MICROWAVE OVEN
R-820BK / R-820BW
FOREWORD
This Manual has been prepared to provide Sharp Electronics Corp.
Service Personnel with Operation and Service Information for the
SHARP MICROWAVE OVEN, R-820BK, R-820BW.
It is recommended that service personnel carefully study the entire
text of this manual so that they will be qualified to render satisfactory
customer service.
Check...

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R-820BK
R-820BW
ITEM DESCRIPTION
Power Requirements 120 Volts
12.5 Amperes (Microwave)  / 13.0 Amperes (Grill/ Convection)
60 Hertz / Single phase, 3 wire grounded
Power Output 900 watts (IEC 705 Test Procedure)
Operating frequency of 2450MHz
Top Heater Power Output 1000 Watts
Top & Bottom Heater Power Output 1500 Watts
Case Dimensions Width 20-1/2 Height 12-1/8 Depth  19-3/4
Cooking Cavity Dimensions
 (0.9 Cubic Feet )Width 13-7/8 Height 7-1/2 Depth  14-1/2
Control Complement Touch Control System...

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R-820BK
R-820BW
A short power-supply cord is provided to reduce risks of becoming
entangled in or tripping  over a longer cord.
Where a two-pronged wall-receptacle is encountered, it is the personal
responsibility and obligation of the customer to contact a qualified
electrician and have it replaced with a properly grounded three-pronged
wall receptacle or have a grounding adapter properly grounded and
polarized. If the extension cord must be used, it should be a 3-wire, 15
amp. or higher rated cord....

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R-820BK
R-820BW
OPERATION
DESCRIPTION OF OPERATING SEQUENCE
The following is a description of component functions during
oven operation.
OFF CONDITION
Closing the door activates door sensing switch and second-
ary interlock switch. (In this condition, the monitor switch
contacts are opened.)
When oven is plugged in, 120 volts A.C. is supplied to the
control unit. (Figure O-1).
1. The display will show , , ,
, , , , ,
and .
To set any program or set the clock, you must first touch
the STOP/CLEAR pad....

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R-820BK
R-820BW
TOP AND BOTTOM HEATER MODE
In this mode, the food is cooked by both the top heaters and
bottom heater. Press the GRILL pad and number 1 pad
and then enter the cooking time by pressing the number
pads. When the START pad is pressed, the following
operations occur (Figure O-3a):
1. The relays(RY3, RY4, RY5 and RY6) are energized.
2. The numbers of the digital read-out start the count down
to zero.
3. Then the top heaters, bottom heater, turntable motor,
oven lamp and fan motor are...

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R-820BK
R-820BW
ROAST COOKING CONDITION
Touch the ROAST pad once. And then program desired
cooking time  by touching the number pads. The ROAST
pad is preprogrammed for 325ûF with 30% microwave
power.
NOTE: The microwave power can not be changed. To
change the temperature, touch the ROAST pad
twice. When the display says SELECT TEMP,
touch desired temperature pad.
When the START pad is pressed, the following operations
occur:
1. The numbers on the digital read-out start to count down.
2. The shut-off...