Sharp R21JCA - Commercial Microwave Oven User manual

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R-21JCA
TABLE OF CONTENTS Page
PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO
AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY...................INSIDE FRONT COVER
BEFORE SERVICING ......................................................................................................INSIDE FRONT COVER
WARNING TO SERVICE PERSONNEL................................................................................................................1
MICROWAVE MEASUREMENT PROCEDURE ...................................................................................................2
FOREWORD AND WARNING...............................................................................................................................3
PRODUCT SPECIFICATIONS ..............................................................................................................................4
OPERATION..........................................................................................................................................................4
SCHEMATIC DIAGRAM ........................................................................................................................................5
TEST PROCEDURE..............................................................................................................................................5
CONTROL PANEL ASSEMBLY ............................................................................................................................8
COMPONENT REPLACEMENT AND ADJUSTMENT PROCEDURE................................................................11
CONTROL PANEL CIRCUIT ...............................................................................................................................14
PRINTED WIRING BOARD .................................................................................................................................15
PARTS LIST ........................................................................................................................................................16
PACKING AND ACCESSORIES .........................................................................................................................20
S8213R21HCPA/
LIGHT DUTY
COMMERCIAL
MICROWAVE OVEN
MODEL R-21JCA
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 the following parts may result in a
severe, possibly fatal, electrical shock. (High Voltage Capaci-
tor, High Voltage Power Transformer, Magnetron, High Volt-
age Rectifier Assembly, High Voltage Harness etc..)
SHARP CORPORATION This document has been published to be used for after
sales service only.
The contents are subject to change without notice.
SUPPLEMENTAL SERVICE MANUAL
This is a supplemental Service Manual for Model R-21JCA. This model is quite similar to base
model R-21HC. Use this supplemental manual together with the Base Model Service Manual
(Reference No. is S7813R21HCP//) for complete operation, service information, etc..
1000W/ R-21JCA
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TIME GUIDE FOR ONE SERVING
15- 30sec.
Bagel, Roll
Muffin, Pastry
Pie Slice
30- 60sec.
Hot Dog
Pizza Slice
Small Sandwich
1- 2 min.
Beverage, Soup
LargeSandwich
Popcorn, 1.5 oz.
2- 3 min.
Casserole, Stew
Chili, Chowder
Popcorn, 3.5 oz.
With the door closed,turn the timer to
the desired time. Oven will begin
operating immediately.
To shut oven off manually,return timer
to "0".
INSTRUCTIONS
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R-21JCA
PRECAUTIONSTO BE OBSERVED BEFORE AND
DURING SERVICINGTO AVOID POSSIBLE
EXPOSURETO 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
latches, (5) evidence of dropping or abuse.
(c) Before turning on microwave power for any service test or inspection within the microwave generating
compartments, check the magnetron, wave guide or transmission line, and cavity for proper alignment,
integrity, and connections.
(d) Any defective or misadjusted components in the interlock, monitor, door seal, and microwave
generation and transmission systems shall be repaired, replaced, or adjusted by procedures described
in this manual before the oven is released to the owner.
(e) A microwave leakage check to verify compliance with the Federal Performance Standard should be
performed on each oven prior to release to the owner.
BEFORE SERVICING
Before servicing an operative unit, perform a microwave emission check as per the Microwave
Measurement Procedure outlined in this service manual.
If microwave emissions level is in excess of the specified limit, contact SHARP ELECTRONICS
CORPORATION immediately @1-800-237-4277.
If the unit operates with the door open, service person should 1) tell the user not to operate the oven
and 2) contact SHARP ELECTRONICS CORPORATION and The Food and Drug Administration's
Center for Devices and Radiological Health immediately.
Service personnel should inform SHARP ELECTRONICS CORPORATION of any certified unit found
with emissions in excess of 4mW/cm2. The owner of the unit should be instructed not to use the unit
until the oven has been brought into compliance.

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R-21JCA
WARNINGTO 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)
HighVoltageCapacitor,HighVoltagePowerTrans-
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 case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
WARNING:RISK OF ELECTRIC SHOCK.
DISCHARGE THE HIGH-VOLTAGE
CAPACITOR BEFORE SERVICING.
The high-voltage capacitor remains charged about 60
seconds after the oven has been switched off. Wait for 60
seconds and then short-circuit the connection of the high-
voltage capacitor (that is the connecting lead of the high-
voltage rectifier) against the chassis with the use of an
insulated screwdriver.
Whenever troubleshooting is performed the power supply
must be disconnected. It may in, some cases, be necessary
to connect the power supply after the outer case has been
removed, in this event,
1. Disconnect the power supply cord, and then remove
outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Disconnect the leads to the primary of the power
transformer.
5. Ensure that the leads remain isolated from other
components and oven chassis by using insulation tape.
6. After that procedure, reconnect the power supply cord.
When the testing is completed,
1. Disconnect the power supply cord, and then remove
outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Reconnect the leads to the primary of the power
transformer.
5. Reinstall the outer case (cabinet).
6. Reconnect the power supply cord after the outer case is
installed.
7. Run the oven and check all functions.
After repairing
1. Reconnect all leads removed from components during
testing.
2. Reinstall the outer case (cabinet).
3. Reconnect the power supply cord after the outer case is
installed.
4. Run the oven and 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 Before Servicing procedure 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.
Don't Touch !
Danger High Voltage

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R-21JCA
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/cm2at 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/cm2at any point 5cm or more from the external
surface of the oven.
2) Safety interlock switches: Primary interlock relay and door sensing switch shall prevent microwave radiation emission
in excess of the requirement as above mentioned, secondary interlock switch shall prevent microwave radiation emission
in excess of 5 mW/cm2at any point 5cm or more from the external surface of the oven.
B. Preparation for testing:
Before beginning the actual measurement of leakage, proceed as follows:
1) Make sure that the actual instrument is operating normally as specified in its instruction booklet.
Important:
Survey instruments that comply with the requirement for instrumentation as prescribed by the performance standard for
microwave ovens, 21 CFR 1030.10(c)(3)(i), must be used for testing.
2) Place the oven tray in the oven cavity.
3) Place the load of 275±15 ml (9.8 oz) of tap water initially at 20±5˚C (68˚F) in the center of the oven cavity.
The water container shall be a low form of 600 ml (20 oz) beaker with an inside diameter of approx. 8.5 cm (3-1/2 in.)
and made of an electrically nonconductive material such as glass or plastic.
The placing of this standard load in the oven is important not only to protect the oven, but also to insure that any leakage
is measured accurately.
4) Set the cooking control on Full Power Cooking Mode.
5) Close the door and select a cook cycle of several minutes. If the water begins to boil before the survey is completed,
replace it with 275 ml of cool water.
C. Leakage test:
Closed-door leakage test (microwave measurement)
1) Grasp the probe of the survey instrument and hold it perpendicular to the gap between the door and the body of the oven.
2) Move the probe slowly, not faster than 1 in./sec. (2.5 cm/sec.) along the gap, watching for the maximum indication on
the meter.
3) Check for leakage at the door screen, sheet metal seams and other accessible positions where the continuity of the metal
has been breached (eg., around the switches, indicator, and vents).
While testing for leakage around the door pull the door away from the front of the oven as far as is permitted by the closed
latch assembly.
4) Measure carefully at the point of highest leakage and make sure that the highest leakage is no greater than 4mW/cm2,
and that the secondary interlock switch does turn the oven OFF before any door movement.
NOTE: After servicing, record data on service invoice and microwave leakage report.

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R-21JCA
SHARP ELECTRONICS CORPORATION
SHARP PLAZA, MAHWAH,
NEW JERSEY 07430-2135
SERVICE MANUAL
LIGHT DUTY
COMMERCIAL
MICROWAVE OVEN
R-21JCA
FOREWORD
This Manual has been prepared to provide Sharp Electronics Corp. Service Personnel with Operation and Service
Information for the SHARP MICROWAVE OVEN, R-21JCA.
The model R-21JCA is quite similar to base model R-21HC (Refer No. is S7813R21HCP//).
It is recommended that service personnel carefully study the entire text of this manual and the base model's manual so
that they will be qualified to render satisfactory customer service.
Check the interlock switches and the door seal carefully. Special attention should be given to avoid electrical shock and
microwave radiation hazard.
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 no other visible damage with the oven.
Servicing and repair work must be carried out only by trained service personnel.
DANGER
Certain initial parts are intentionally not grounded and present a risk of electrical shock only during servicing.
Service personnel - Do not contact the following parts while the appliance is energized;
High Voltage Capacitor, Power Transformer, Magnetron, High Voltage Rectifier Assembly, High Voltage
Harness;
If provided, Vent Hood, Fan assembly, Cooling Fan Motor.
All the parts marked “*” on parts list are used at voltages more than 250V.
Removal of the outer wrap gives access to voltage above 250V.
All the parts marked “∆” on parts list may cause undue microwave exposure, by themselves, or when they are
damaged, loosened or removed.