SHARP R1850A, R-1851A, R-1852A Service Manual
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SUPPLEMENTAL
SERVICE MANUAL
R-l
R-1851A
R-l852A
S98M121 R1850A
850A
This is a
This model is
Use this supplemental
supplemental
quite
Service Manual for
similar to the
manual
togetherwith the Base Model Service Manualsforcomplete operation and service
R-1851A
Model
Models R-l 850A/R-1851A/R-1852A.
Model R-l 850 (S/M# S6804R185OXDJ
Base
TABLE OF CONTENTS
OVER
THE
RANGE
MICROWAVE OVENS
R-l 850A/R-1851 A/R-l 85249
to be
user-safety the oven
interest
In the
original condition
its
to
of
and only the parts identical to
those specified should be used.
is
information.
restored
SECTION
PRECAUTIONS TO BE OBSERVED BEFORE AND DURING
SERVICE
AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY.
Before Servicing
Forewordand
Warning to Service Personnel
Microwave Measurement Procedure
Wiring/SchematicDiagram
.............................................................
Warning
............................................................
......................................................
...........................................................
...................................................................
Parts ......................................................................................
PackingandAccessories
....................................................................
TO
SHARP ELECTRONICS CORPORATION
Service Headquarters: Sharp Plaza, Mahwah, New Jersey, 07430-2135
...........
PAGE
Inside Front Cover
Inside Front Cover
1
2
3
4
6
13
R-1850A
R-185lA
R-l 852A
Do not operate or allow the oven to be operated with the door open.
(a)
Make the following safety checks on all ovens to be serviced before activating the magnetron
04
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.
Before turning on microwave power for any service test or inspection within the microwave gen-
(d
erating compartments, check the magnetron, waveguide or transmission line, and cavity for
proper alignment, integrity, and connections.
Any defective or misadjusted components in the interlock, monitor, door seal, and microwave
(4
generation and transmission systems shall be repaired, replaced, or adjusted by procedures
described in this manual before the oven is released to the owner.
A microwave leakage check to verify compliance with the Federal performance standard
03
should be performed on each oven prior to release to the owner.
Before servicing an operative unit, perform a microwave emission check as per the Microwave
Measurement Procedure outlined in the base model service manual. If microwave emissions level
is in excess of the specified limit, contact
SHARP ELECTRONICS CORPORATION immediately Q l-800-237-4277.
(RD21101U
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 DHHS 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.
I
(RD81001 U)
SERVICE MANUAL
SHARC,
Over The Range
Microwave Ovens
R-l 850A/R-1851 A/R-l 852A
Foreword
This manual has been prepared to provide Sharp
Electronics Corporation personnel with complete
operation and service information for Sharp microwave
oven models R-l 850A/R-1851 AIR-1 852A
It is recommended that service personnel carefully
study the entire text of this manual so they will be
qualified to render satisfactory customer service.
Check interlock switches and the door seal carefully.
Special attention must be given to avoid electrical shock
and microwave radiation hazards.
This supplemental service manual contains update information only. Please refer to base model
service manual (R-1850) for complete service information.
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 are no other visible signs of damage to the
oven.
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 and High
voltage Harness.
If provided, Vent Hood, Fan Assembly and Cooling
Fan motor.
All of the parts marked
ages more than 250V.
Removal of the outer case cabinet gives access to
voltage above 25OV.
All of the parts marked “A” on parts list may cause undue microwave exposure, by themselves, or when
they are damaged, loosened or removed.
“*I’ on parts list are used at volt-
Sharp Electronics Corporation
Sharp Plaza
Mahwah, New Jersey 07430-2135
I
WARNING TO SERVICE PERSONNEL
Microwave ovens contain circuitry capable of
producing very high voltage and current. Con-
tact with following parts may result in a
possibly fatal, electrical
(EXAMPLE)
High Voltage Capacitor,
Transformer, Magnetron,
Assembly, High Voltage Harness etc..
Read
the Service
instructions.
Manual carefully and
shock.
High Voltage Power
High Voltage Rectifier
severe,
follow all
Before Servicing
1, Disconnect the power supply cord and then remove
outer
case cabinet.
2. Open the door and block it open.
3. Discharge the high voltage capacitor.
WAl?NING:RISK OF ELECTRICAL 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 powersupply must be disconnected. In some cases it may be necessary to connect the power supply after the outer case
has been removed, in this event:
Disconnect the power supply cord and then remove
1.
outer case cabinet.
Open the door and block it open.
2.
Discharge the high voltage capacitor.
3.
Disconnect the leads to the primary of the power
4.
transformer.
Ensure that the leads remain isolated from other
5.
components and oven chassis by using insulation
tape.
After the above procedure, reconnect the power sup-
6.
ply cord.
Don’t
Touch
!
Danger High Voltage
When the testing is completed
Disconnect the power supply cord and then remove
1.
outer case cabinet.
Open the door and block it open.
2.
Discharge the high voltage capacitor.
3.
4.
Reconnect the leads to the primary of the power
transformer.
Re-install the outer case
5.
Reconnect the power supply cord after the outer
6.
case cabinet is installed.
Start the oven and check all functions.
7.
cabinet.
After repairing
Reconnect all Lads removed from components dur-
1.
ing testing.
Re-install the outer case (cabinet).
2.
Reconnect the power supply cord after the outer
3.
case is
Reconnect the power supply cord after the outer
4.
case is installed.
Run the oven and check all functions.
5.
Microwave ovens should not be operated 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 to see if the water is hot.
Servicing
the component being tested.
When all service work is completed and the oven is fully
assembled, the microwave power output should be
checked and the microwave leakage test should be carried out.
installed.
If the water remains cold, carry out
procedure and re-examine the connection to
Before
2
R-l
85OA
;:;gs
MICROWAVE
After
adjustment
switches are completed individually or collectively, a INTERLOCK SWITCH
AGE TEST must be performed
with
DHHS
wave Ovens.
of the door, interlock and monitor
TEST and
(CDRH) Performance Standards for Micro-
MICROWAVE LEAK-
to
assure
MEASUREMENT
compliance
Interlock Switch Test
Make
sure that the door
terlock switch
by checking
Refer to the “Test Procedure” of the
secondary
and
with
interlock
an
sensing
monitor
switch are operating properly
ohmmeter.
switch and monitor switch.
switch, secondary in-
door sensing switch,
Microwave Leakage Test
Requirements
1. Microwave leakage limit (Power density limit).
The power density of microwave radiation emitted by
a microwave
point 5cm or more from the external surface of the
oven, measured prior to acquisition-by the purchaser,
and thereafter (through the useful life of the oven)
5mW/cm* at any point 5cm or more from
surface of the oven.
2. Safety interlock switches.
Primary interlock relay and door sensing switch will
prevent microwave radiation emissions in excess of
the requirement as above mentioned, secondary
interlock switch shall prevent microwave radiation
emission in excess of 5 mW/cm* at any point 5cm
or more from the external surface of the oven.
Preparation
Before beginning the actual measurement of leakage,
proceed
1. Make sure that the actual instrument is operating nor-
Note:
as follows:
mally as specified in its instruction booklet.
Survey instruments that comply with the requirement for instrumentatoin 21 CFR1030.1 O(c)(3)(i),
as prescribed by the performance standard for
microwave ovens must be used for testing.
oven shall not exceed 1 mW/cm* at any
the external
For Testing
PROCEDURE
2.
Place the
3. Place
tially at 20 z!z
ity.
The water container
oz.) beaker with an inside
8.5 cm (3 %
ductive material such as glass or plastic.
The placing of this standard load in the oven is important
any leakage is measured accurately.
4.
Set
5.
Close
several
survey is completed,
ter.
Leakage Test
Closed-door leakage test (microwave measurement).
1. Grasp the probe of the survey instrument
perpendicular to the gap between the door and the
body of the oven.
2. Move the probe slowly, not faster than lin./sec
(2.5cm/sec.) along the gap, watching for the maximum indication of 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
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
4. Measure carefully at the point of the highest leakage
and make sure that the highest leakage is
than 4 mW/cm* to allow for measurement uncertainty,
and that the secondary interlock switch does turn the
oven OFF before any
Note:
oven tray
the load of 275 &
5OC
in.)
not only to protect the oven, but
the cooking control on
the door and
minutes.
by the closed latch assembly.
After servicing, record data on service invoice
and microwave leakage report.
in
the oven cavity.
15ml(9.8
(68OF) in the center of the oven cav-
shall be a low form of
and made of an electrically noncon-
put the oven
If the water
replace it with 275ml of cool
door movement.
oz.) of tap water ini-
diameter
Full power
begins to
of approximately
also to insure
into
a cook
breached
600
ml
(20
that
cooking mode.
cycle
for
boil before the
wa-
and hold it
(eg., around
no greater
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