Sharp R1870 Service Manual

R-1870
R-1871
S91M173R1870E
OVER THE RANGE
MICROWAVE OVEN
MODELS
R-1870/R-1871
This is a supplemental Service Manual for Models R-1870/R1871.
This model is quite similar to Base Model R-1850 (S/M# S6804R1850X//).
Use this supplemental manual together with the Base Model Service Manuals for complete operation and service information
Model R-1870
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...

R-1870
R-1871
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 and...

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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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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-1871
SERVICE MANUAL
MICROWAVE OVEN
R-1870/R1871
FOREWORD
This Manual has been prepared to provide Sharp Electronics Corp.
Service Personnel with Operation and Service Information for the SHARP
MICROWAVE OVEN, R-1870 and R-1871.
The models R-1870 and R-1871 are quite similar to base model R-1850
(Ref.# 
S6804R1850X//)
It is recommended that service personnel carefully study the entire text
of this manual and the base models manual so that they will be qualified
to render satisfactory customer...

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R-1871
ITEMDESCRIPTION
Power Requirements120 Volts / 13.2 Amperes (Microwave), 13.2  Amperes (Convection)
60 Hertz
Single phase, 3 wire grounded
Power Output 850 watts (IEC-705 TEST PROCEDURE)
Operating frequency of 2450MHz
Convection Power Output 1400 watts
Case Dimensions Width 29-15/16
Height 16-11/32
Depth  15- 9/32
Cooking Cavity Dimensions Width 17-1/8
Height 8-1/16
1.1 Cubic Feet Depth  13-13/16
Hood lamp 2 bulbs, 30W x 2,  Incandescent light bulbs
Hood fan Horizontal discharge 230 C.F.M....

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R-1871
NOTE:
Some one-touch cooking features
as MINUTE PLUS are disabled af-
ter one minute when the oven is not
used. These features are automati-
cally enabled when the door is
opened and closed or the STOP/
CLEAR pad is pressed.
MIX CONV
DEFROST
SENSOR
ON OFF COOK LBS OZ KG HELP
TURNTABLE
CONTROL PANEL
3-Pronged PlugGrounded
Receptacle Box
Grounding Pin
3-Pronged Receptacle
Electrical Requirements
The oven is equipped with a 3-prong grounding plug. DO NOT UNDER ANY CIRCUMSTANCES CUT OR REMOVE...

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R-1871
OPERATION
DESCRIPTION OF OPERATING SEQUENCE
The following is a description of component functions
during oven operation.
OFF CONDITION
Closing the door activates the door sensing switch and
secondary 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 SHARP, SIMPLY, THE, BEST,
PRESS, CLEAR, and PRESS, CLOCK.
To set any program or set the clock, you...

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R-1871
Figure O-1. Oven Schematic - Off Condition
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED.
2. CLOCK APPEARS ON DISPLAY.
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED.
2. COOKING TIME PROGRAMMED.
3. START PAD TOUCHED.
Figure O-2. Oven Schematic - Microwave Cooking Condition
MAGNETRON 
TEMPERATURE FUSERED
PNK
BLK GRY
GRY
GRY
BRN
BRN
PNK
GRY
DAMPER 
MOTOR
FAN 
MOTOR
TURNTABLE
MOTOR
CONVECTION
MOTOR GRY
BLU
GRY
GRY
GRN WHT
WHT
WHT
WHT
WHT
WHTRED
PNK WHTRED
ORG
BLK
BLK
BLK
BLK
BLK  BLK...

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SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED.
2. CONVECTION PAD TOUCHED.
3. DESIRED TEMP. TOUCHED.
4. START PAD TOUCHED.
Figure O-3. Oven Schematic - Convection Cooking Condition (CONVEC, PREHEAT, BROIL, SLOW COOK)
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED.
2. MIX COOKING PAD TOUCHED.
3. DESIRED TEMP. TOUCHED.
4. COOKING TIME PROGRAMMED.
5. START PAD TOUCHED.
Figure O-4. Oven Schematic - Automatic Mix cooking ConditionNOTE: RY2 and RY3 will alternately close during cook cycle...