SHARP R510BK, R-510BW Service Manual
R-51
OBK
R-51OBW
SHARR
SERVICE MANUAL
S48MlllFWOBE
MICROWAVE
R-51 OK/R-51 OBW
In
the interest of user-safety the oven is to be restored
to
its original condition and only the parts
those specified should be used.
WARNING TO SERVICE PERSONNEL:
ovens contain circuitry capable of producing
very high voltage and current.
following parts may result in a severe, possibly
fatal electrical shock.(High Voltage Capacitor,
High Voltage Power Transformer, Magnetron,
High Voltage Rectifier Assembly, High Voltage
Harness etc..)
OVEN
MODELS
identical to
Microwave
Contact with the
TABLE OF CONTENTS
SECTION
PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICE TO
AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY.
BeforeServicing
Warning to Service Personnel
Forewordandwaming
Specifications..........................................................................:::: : 4
General
Key Unit Layout
Operation
Servicing and Troubleshooting Guide
Test Procedures..
TouchControlOutline
Component Replacement and Adjustment Procedure
Microwave Measurement Procedure
Wiring/Schematic Diagram
Parts .._................_....................._....__..............................:: : 38
PackingandAccessories..
Information
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Inside Front Cover
Inside Front Cover
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. 22
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34
SHARP ELECTRONICS CORPORATION
1
2
3
5
6
8
Service Headquarters: Sharp Plaza, Mahwah, New Jersey, 07430-2135
R-51OBK
MIOBW
Do not operate or allow the oven to be operated with the door open.
(4
Make the following safety checks on all ovens to be serviced before activating the magnetron
09
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 powerfor any service test or inspection within the microwave gen-
(cl
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
03
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
(4
should be performed on each oven prior to releasing the oven to the owner.
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 Q
l-800-237-4277.
(RDPiiOlU
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.
,___.__....
(l-w81 Wl U)
SERVICE MANUAL
SHARE
RBIOBK
R-51 OBW
Microwave Ovens
R-51 OBKIR-51 OBW
Foreword
This manual has been prepared to provide Sharp
Electronics Corporation personnel with complete
operation and service information for Sharp microwave
oven models R-51 OEM/R-SlOBW.
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.
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.
Specifications
I
General Information
Key Unit Layout
Operation
Troubleshooting /
1 Test Procedurei
Touch Control Panel
Component Replacement
Microwave Measurement
All of the parts marked
ages more than 250V.
Removal of the outer case cabinet gives access to voltage above 250V.
All of the parts marked “A” on parts list may cause undue
microwave exposure, by themselves, or when they are
damaged, loosened or removed.
“*” on parts list are used at volt-
Sharp Electronics Corporation
Sharp Plaza
Mahwah, New Jersey 07430-2135
Wiring I Schematic Diagram
Parts
1
R-51OBK
R-5lOBW
WARNING TO SERVICE PERSONNEL
Microwave ovens contain circuitry capable of
producing 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
Transformer, Magnetron, High Voltage Rectifier
Assembly, High Voltage Harness etc..
Read the Service Manual carefully and follow all
instructions.
Don’t Touch !
Danger High Voltage
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.
WARNING:RISK OF ELECTRICAL SHOCK. DISCHARGE
THE HIGH VOLTAGE CAPACITOR BEFORE SERVICING.
The high-voltage capacitor remains charged about 60 se-
conds after the oven has been switched off. Wait for 60 se-
conds 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. In some cases it may be nec-
essary 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 cabinet.
2.
Open the door and block it open.
Discharge the high voltage capacitor.
3.
4.
Disconnect the leads to the primary of the power
transformer.
Ensure that the leads remain isolated from other
5.
components and oven chassis by using insulation
tape.
6.
After the above procedure, reconnect the power supply cord.
When the testing is completed
Disconnect the power supply cord and then remove
1.
outer case cabinet.
2.
Open the door and block it open.
Discharge the high voltage capacitor.
3.
Reconnect the leads to the primary of the power
4.
transformer.
Re-install the outer case cabinet.
5.
Reconnect the power supply cord after the outer
6.
case cabinet is installed.
7
Start the oven and check all functions.
, .
After repairing
1. Reconnect all leads removed from components dur-
ing testing.
2. Re-install the outer case (cabinet).
3. Reconnect the power supply cord after the outer
case is installed.
4. Reconnect the power supply cord after the outer
case is installed.
5. Run the oven and check all functions.
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. If the water remains cold, carry out Before
Servicing procedure and re-examine the connection 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 the microwave leakage test should be carried out.
SPECIFICATIONS
R-51 OBK
R-51 OBW
Item
Power Requirements
Power Output
Case Dimensions
Cooking Cavity
1.8 Cu.Ft.
Control Complement
Description
120 Volts
14.0 Amperes
1650 Watts
60 Hertz
Single phase, 3 wire grounded
1100 watts (I EC-705 Test Procedure)
Operating frequency of 2450 MHz
Width 23.94”
Height 13.27” (including feet)
Depth 19”
Width 17”
Height 9.96”
Depth 17.8”
Tray Size 16” Diameter
Touch Control System
Clock (1:OO - 1259)
Timer (0 - 99 min. 99 sec.)
Microwave Power for variable cooking
Repetition Rate;
P-HI
(HIGH) . . . . . . . . .
P-90
. . . . . . . . . . . . . . . . .
P-80
. . . . . . . . . . . . . . . . .
P-70 (MED HIGH) . . . .
P-60
. . . . . . . . . . . . . . . . .
P-50 (MED) . . . . . . . . . .
P-40
. . . . . . . . . . . . . . . . .
P-30 (MED LOW) . . . . .
P-20
. . . . . . . . . . . . . . . . .
P-10
. . . . . . . . . . . . . . . . .
P-O . . . . . . . . . . . . . . . . . . .
Full power throughout the cooking time
approx. 90% of full power
approx. 80% of full power
approx. 70% of full power
approx. 60% of full power
approx. 50% of full power
approx. 40% of full power
approx. 30% of full power
approx. 20% of full power
approx. 10% of full power
No power throughout the cooking time
Oven Cavity Light
Safety Standard
FEATURES
Instant Action
Compu Defrost(3)
Minute Plus
Timer/Clock
Popcorn
Variable Power (10)
4 Stage Cooking
Yes
UL Listed
FCC Authorized
DHHS Rules, CFR, Title 21, Chapter 1, Subchapter J
3
R-510BK
R-5100W
GENERAL
Grounding Instructions
This oven must be fully grounded at all times. This
appliance must be connected to a 120 volt, 60 Hz, AC
only, 15 Ampere or more fused electrical supply. It is recommended that a separate circuit serving only this
appliance be provided. When installing this appliance,
observe all applicable codes and ordinances.
WARNING: Improper use of the grounding plug can
result in a risk of electric shock.
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 polarized and grounded threepronged wall receptacle or use a grounding adaptor. If
an extension cord must be used, it should be a 3-wire,
15 ampere minimum cord.
INFORMATION
Gromded
Grounding Pin
3 Pmnged Recepfacie
Do not under any circumstances cut or remove the
round grounding prong from this plug.
Grourded
- .._
necepfacm Lx*
Tab for
Grounding Screw
Oven
Diagram
1.
Digital display
2. Auto-Touch control panel
3. Door open button
4.
Door latches
5. Removable turntable support
6.
Removable turntable
7.
Oven lamp
8.
Oven door with see through window
9.
Waveguide cover
10.
Power Cord
4
Key Unit Layout
a. Indicators.
b. Lighted digital display.
c. SNACKS/COOKING/REHEATING pad.
Touch to cook or reheat popluar items using a pm-set
time constant.
d. COMPU DEFROST pad.
Touch to defrost certain foods.
e. Number selection pads.
f. TIMER/CLOCK pad.
Touch to set clock and minute timer function.
g. START/MINUTE PLUS pad.
Touch to start oven or Touch to cook for 1 minute at
100% power or to increase cooking time.
h. STOP/CLEAR pad.
Touch to erase during programming.
Touch once to stop operation of oven during cooking.
Touch twice to cancel cooking program.
i. POWER LEVEL pad.
Touch to select microwave power setting.
a
-0
R-510BK
R-51 OBW
I I
, 1
b
-0
INSTANT ACTION
To adjust quantity-touch pad again
2 ’ 3
h
cl-
5
4
5 6 -
R-5100K
R-SIOBW
Description of Operating Sequence
The following is a description of component functions
during oven operation:
OPERATION
interlock relay and is mechanically associated with
the door so that it functions as follows:
Off Condition
Closing the door activates the door sensing switch and
secondary interlock switch. In this condition, the monitor switch contacts are opened. When the oven is
plugged in, 120 volts AC is supplied to the control unit
(see schematic diagram). The display flashes 88:88. To
set any program or set the clock, first touch the STOP/
CLEAR pad. The display clears and “ : ” appears and the
control unit counts every minute.
Cooking Condition
Program desired cooking time and Variable Cooking
Control by touching the NUMBER pads and the Power
Level pad of the Variable Cooking Control. When
START is touched, the following operations occur:
1.
The relay contacts are closed and components con-
nected to the relays (Fly-1 and RY-2) are turned on.
(For details, see table below.)
Oven Lamp/Turntable Motor/Fan Motor
11
2.
120 volts AC is supplied to the primary winding of the
power transformer and is converted to approximately 3.4 volts AC on the filament winding and approximately 2400 volts AC on the high voltage winding.
The filament winding voltage heats the magnetron
3.
filament and the high voltage is sent to a voltage dou-
bler circuit.
4.
The microwave energy produced by the magnetron
is channeled through the waveguide into the cavity
feed-box and into the cavity where the food is
cooked.
5.
Upon completion of the cooking cycle, the power
transformer, oven lamp and cooling fan are turned off
and the generation of microwave energy is terminated.
6.
When the door is opened during a cook cycle, the
monitor switch, door sensing switch, secondary interlock switch and primary interlock relay are activated with the following results. The turntable motor,
cooling fan motor and the high voltage components
are de-energized. The oven lamp remains on and
the digital readout displays the time still remaining in
the cook cycle when the door was opened.
7.
The monitor switch is electrically monitoring the operation of the secondary interlock switch and primary
When the door opens from a closed position, the
(a).
secondary interlock switch and primary interlock
relay open their contacts, then the monitor switch
contacts close.
When the door is closed from the open position,
04.
the monitor switch contacts first open and the
contacts of the secondary interlock switch close.
secondary interlock switch and the primary inter-
If the
lock relay contacts are closed when the door is opened,
the monitor switch contacts form a short circuit through
the monitor fuse, secondary interlock switch and primary interlock relay causing the monitor fuse to blow.
. . _.
Power Level P-O to P-90 Cooking
When Variable Cooking Power is programmed, 120
volts AC is supplied to the power transformer intermittently through the contacts of relay RY-2 which is operated by the control unit within a 32 second time base. Mi-
crowave power operation is as follows:
Vari-Mode
P - HI (HIGH)
(100% power)
P - 90
(approx. 90% power)
P - 80
(approx. 80% power)
P - 70 (MED, HIGH)
(approx. 70% power)
P - 40
(approx. 40% power)
P - 30 (MED, LOW)
(approx. 30 % power)
P - 20
(approx. 20% power)
I-
P-10
(approx. 10% power)
I1
L$power)
The ON/OFF time ratio does not correspond with the
percentage of microwave power, because approximately 2 seconds are needed for heating the magnetron filament.
On Time
32 sec.
30 sec.
26 sec.
24 sec. 8 sec.
16 sec. 16 sec.
12 sec.
8 sec.
6 sec.
0 sec.
Off Time
0 sec.
2 sec.
6 sec.
20 sec.
24 sec.
26 sec.
32 sec.
DESCRIPTION AND FUNCTION OF COMPONENTS
R-SlOBK
R-51OBW
Cooling Fan Motor
The cooling fan motor drives a blade which draws exter-
nal cool air. This cool air is directed through the air
vanes surrounding the magnetron to cool the magnetron. This air is channeled through the oven cavity to remove steam and vapors given off from the heating
foods. It is then exhausted through exhaust vents in the
oven cavity.
Oven Temperature Fuse
The oven temperature fuse located on the top of the
oven cavity is designed to prevent damage to the unit if
the foods in the oven catch fire due to over heating produced by improper setting of cook time or failure of con-
trol unit.
Under normal operation, the oven temperature fuse re-
mains closed. However, when abnormally high temperatures are reached within the oven cavity, the fuse will
open at 152%, causing the oven to shut down.
Note: This is a fuse and it does not reset.
Magnetron Temperature Fuse
The magnetron temperature fuse located on top of the
magnetron duct is designed to prevent damage to the
magnetron if an over heated condition develops in the
tube due to cooling fan failure, obstructed air ducts, dirty
or blocked air intake, etc.
Under normal operation, the magnetron temperature
fuse remains closed. However, when abnormally high
temperatures are reached within the magnetron the
fuse will open at 121 “C, causing the oven to shut down.
Note: This is a fuse and it does not reset.
Monitor Switch
The monitor switch is activated (the contacts opened) by
the latch head on the door while the door is closed. The
switch is intended to render the oven inoperative by
means of blowing the monitor fuse when the contacts of
the primary interlock relay and secondary interlock
switch fail to open when the door is opened.
Monitor Switch Functions
1.
When the door is opened, the monitor switch contacts close (to the ON condition) due to their being
normally closed. At this time the primary interlock
relay and secondary interlock switch are in the OFF
condition (contacts open) due to their being normally
open contacts.
When the door is closed, the monitor switch contacts
2.
are first opened and then the door sensing switch
and the secondary interlock switch contacts close.
Note: When opening the door, each of these
switches operate inversely.
If the door is opened and the primary interlock relay
3.
and secondary interlock switch contacts fail to open,
the monitor fuse blows simultaneously with closing
of the monitor switch contacts.
and secondary interlock switch for proper operatron.
(Refer to section ‘Test Procedures”.)
Door Open Mechanism
The door is opened by pushing the open button on the
control panel.
When the open button is pushed, the open button
pushes up the switch lever, and then the switch lever
pushes up the latch heads.
The latch heads are moved upward and released from
the latch hook. Now the door will open.
Door Sensing / Secondary Interlock
Switches
The secondary interlock switch is mounted in the lower
position of the latch hook and the door sensing switch in
the primary interlock system is mounted in the upper
position of the latch hook. They are activated by the
latch heads on the door. When the door is opened, the
switches interrupt the circuit to all components, except
the oven lamp. A cook cycle cannot take place until the
door is firmly closed thereby activating both interlock
switches. The primary interlock system consists of the
door sensing switch and the primary interlock relay located on the control panel circuit board.
NOTE: MONITOR FUSE AND MONITOR SWITCH
ARE REPLACED AS AN ASSEMBLY.
7
RQlOBK
R-51oBW
SERVICING
When troubleshooting the microwave oven, it is helpful to follow the sequence of operation in performing the checks.
Many of the possible causes of trouble will require that a specific test be performed. These tests are given a procedure
letter which will be found in the “Test Procedure” section.
Before replacing a blown monitor fuse, test the door sensing switch, primary interlock relay, secondary interlock switch and monitor switch for proper operation. (Referto rest Procedure” sec-
tion.)
Whenever troubleshooting is performed, the power supply must be disconnected. In some cases it may be necessary to connect the power supply after the outer case cabinet has been removed. In this event,
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.
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 insulated tape.
6. After the above procedure, install the outer case cabinet and 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 the high voltage capacitor.
4. Reconnect the leads to the primary of the power transformer.
5. Re-install the outer case (cabinet).
6. Reconnect the power supply cord after the outer case is installed.
7. Run the oven and check all functions.
Troubleshooting Guide
Off Condition
Problem Possible Cause
Home fuse blows when power cord is Shorted power cord or wire harness Check or replace
plugged into the wall receptacle.
Monitor fuse blows when power is ap- Shorted power cord or wire harness Check or replace
plied.
Secondary interlock or monitor
switch
Display does not illuminate when Shorted or open wiring
power cord is plugged in.
Monitor switch or monitor fuse
Oven temperature fuse
Control unit
Display does not operate properly Primary interlock relay or door sens- Procedure E
when STOP/CLEAR button is ing switch
touched.
Control unit
Key unit unit
Oven lamp does not light with door Shorted or open wiring
opened.
Monitor fuse
Oven temperature fuse
Oven lame or socket
Control unit
Relay (RYI)
Procedure E
Check or replace
Procedure E
Procedure F
Procedure G
Procedure G
Procedure K
Check or replace
Procedure E
Procedure F
Check or replace
I
1 Procedure G
1
/ Procedure H
Test Procedure
1
8
Problem
Oven lamp does not light at all.
Oven lamp lights, but fan motor and
turntable motor do not operate.
Oven does not go into cook cycle
when START button is touched.
cooked at all at the end of cook
cycle.)
Troubleshooting Guide
Cook Condition
Possible Cause
Shorted or open wiring
Oven lamp or socket
Control unit
Shorted or open wiring
Cooling fan motor
Turntable motor
Shorted or open wiring
Primary interlock system
Monitor fuse
Magnetron
or oven temperature
Test Procedure
Check or replace
Check or replace
Procedure G
Check or replace
Check or replace
Check or replace
Check or replace
Procedure E
Procedure E
Procedure F
R-SIOBK
MIOBW
P-50 (MED.) mode. (Operates
property on Cooking Power P-HI
(HIGH) mode.)
Oven goes into COMPU DEFROST Magnetron
but food is not defrosted well
Wrong operation
Low voltage
Dirty oven check
Compu Defrost
Procedure A
Check
Check
Check
Procedure J
9
R-51 OBK
R-5lOBw
TEST PROCEDURES
Procedure Letter
A.
Magnetron Assembly Test
1. Disconnect the power supply cord, and then remove outercase cabinet.
2. Open the door and block it open.
3. Discharge the high voltage capacitor.
4. To test for an open filament, isolate the magnetron from the high voltage circuit. A continuity check
across the magnetron filament leads should indicate less than 1 SL.
5. To test for a shorted magnetron, connect the ohmmeter leads between the magnetron filament
leads and chassis ground. This test should indicate an infinite resistance. If there is little or no
resistance, the magnetron is grounded (shorted) and must be replaced.
6. Reconnect all leads removed from components during testing.
7. Re-install the outercase cabinet.
8. Reconnect the power supply cord after installing the outer case cabinet.
9. Run the oven and check all functions.
MICROWAVE OUTPUT POWER
The following test procedure should be carried out with the microwave oven in a fully assembeled
condition (outer case fitted).
HIGH VOLTAGES ARE PRESENT DURING THE COOK CYCLE, SO EXTREME CAUTION
SHOULD BE OBSERVED
Power output of the magnetron can be measured by performing a water temperature rise test. This
test should only be used if above tests do not indicate a faulty magnetron and there is no defect in
the following components or wiring: high voltage rectifier, high voltage capacitor and power transformer. This test will require a 16 oz. (453~~) measuring cup and an accurate mercury thermometer
or thermocouple type temperature tester. For accurate results, the following procedure must be followed:
1.
Fill the measuring cup with 16 oz. (453~~) of tap water and measure the temperature of the water
with a thermometer or thermocouple temperature tester.
through the water until the temperature stabilizes. Record the temperature of the water.
2.
Place the cup of water in the oven. Operate oven on HIGH selecting 62 seconds cook time. Allow
the water to heat.
3.
Remove the cup from the oven and again measure the temperature, making sure to stir the ther-
mometer or thermocouple through the water until the maximum temperature is recorded.
4.
Subtract the cold water temperature from the hot water temperature. The normal result should
be 38” to 78°F (21’ to 42.6%) rise in temperature. If the water temperatures are accurately measured and are tested for the required time period the test results will indicate if the magnetron tube
has low power output (low rise in water temperature) which would extend cooking time or high
power output (high rise in water temperature) which would reduce cook time.
time can be adjusted to compensate for power output, the magnetron tube assembly should be
replaced only if the water temperature rise test indicates a power output well beyond the normal
limits. The test is only accurate if the power supply line voltage is 120 volts and the oven cavity
is clean.
Component Test
Stir the thermometer or thermocouple
Because cooking
B.
Power Transformer
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.
4. Disconnect the primary input terminals and measure the resistance of the transformer with an ohm-
meter. Check for continuity of the coils with an ohmmeter. On the R X 1 scale, the resistance of
the primary coil should be less than 1R and the resistance of the high voltage coil should be approx-
imately 100Q; the resistance of the filament coil should be less than IQ.
5. Reconnect all leads removed from components during testing.
6. Re-install the outercase cabinet.
7. Reconnect the power supply cord after installing the outer case cabinet.
8. Run the oven and check all functions.
Note: High voltages are present at the high voltage terminal, so do not attempt to measure the fila-
ment and high voltage.
10
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