Electrolux EI30SM55JW Service manual

Technical Service Manual
Over The Range Microwave Oven
Models
EI30SM55JB
EI30SM55JS
EI30SM55JW
Publication #5995563474
P/N 316439605
April 2010
Basic Information
Safe Servicing Practices
Avoid personal injury and/or property damage by observing important Safe Servicing Practices.
Following are some limited examples of safe practices:
1. DO NOT attempt a product repair if you have any doubts as to your ability to complete the repair in a safe and
satisfactory manner.
2. Always Use The Correct Replacement Parts as indicated in the parts documentation. Substitutions may defeat
compliance with Safety Standards Set For Home Appliances. Do not exceed maximum recommended wattage on
light bulb replacements. Doing so could blow fuses and/or damage transformers.
3. Before servicing or moving an appliance:
• Remove power cord from the electrical outlet, trip circuit breaker to the OFF position, or remove fuse.
4. Never interfere with the proper operation of any safety device.
5. Use ONLY REPLACEMENT PARTS CATALOGED FOR THIS APPLIANCE. Substitutions may defeat compliance
with Safety Standards Set For Home Appliances.
6. GROUNDING: The standard color coding for safety ground wires is GREEN, or GREEN with YELLOW STRIPES.
Ground leads are not to be used as current carrying conductors. It is EXTREMELY important that the service
technician reestablish all safety grounds prior to completion of service. Failure to do so will create a hazard.
7. Prior to returning the product to service, ensure that:
• All electrical connections are correct and secure.
• All electrical leads are properly dressed and secured away from sharp edges, high-temperature components,
and moving parts.
• All non-insulated electrical terminals, connectors, heaters, etc. are adequately spaced away from all metal
parts and panels.
• All safety grounds (both internal and external) are correctly and securely connected.
• All panels are properly and securely reassembled.
© 2010 Electrolux Home Products, Inc.
1-1
Basic Information
This Manual has been prepared to provide Electrolux Service Personnel with Operation and
Service Information for Electrolux Microwave Oven EI30SM55JB, EI30SM55JS and EI30SM55JW.
Table of Contents
Section 1 Basic Information
Section 3 Troubleshooting and Error Codes
Safe Servicing Practices.......................................... 1-1
Table of Contents .................................................... 1-2
Warnings and Safety Information ............................ 1-3
Precautions To Be Observed Before And During
Servicing To Avoid Possible Exposure To
Excessive Microwave Energy .................................. 1-4
Before Servicing ...................................................... 1-4
Danger High Voltage ............................................... 1-4
Before Servicing ...................................................... 1-5
When Testing Is Completed .................................... 1-5
Microwave Measurement Procedure USA .............. 1-6
Microwave Measurement Procedure Canada ......... 1-7
Product Specification ............................................... 1-8
Grounding Instructions ............................................ 1-9
Discharging Capacitor ............................................. 1-9
Oven Diagram ......................................................... 1-10
Special Instructions for the Turntable Support
and Turntable Glass Tray ........................................ 1-11
Warnings and Cautions ...........................................
Troubleshooting Guide Chart ..................................
Test Procedures ......................................................
Section 2 Operation
Operating Sequence Description.............................
Off Condition............................................................
Cooking Condition ...................................................
Variable Cooking .....................................................
Power Output Reduction .........................................
Cook Top Lamp .......................................................
Ventilation Methods .................................................
Sensor Cooking Condition .......................................
Cooking Sequence ..................................................
Component Descriptions .........................................
Door Open Mechanism ........................................
Door Sensing Switch, Secondary Interlock
Switch ...................................................................
Monitor Switch ......................................................
Thermal Cut-Out (Cavity) .....................................
Turntable Motor ....................................................
Cooling Fan Motor ................................................
Hood Fan Motor ...................................................
Thermostat (60°C On) ..........................................
Thermostat (70°C Off) ..........................................
Antenna Motor ......................................................
Hood Lamp ...........................................................
Touch Control Panel Assembly ...............................
Humidity Sensor Circuit ...........................................
2-1
2-1
2-1
2-3
2-3
2-3
2-3
2-4
2-4
2-5
2-5
2-5
2-5
2-6
2-6
2-6
2-6
2-6
2-6
2-6
2-6
2-7
2-8
3-1
3-2
3-3
Section 4 Component Teardown and Testing
Warnings and Cautions ...........................................
Removal Of Oven From Wall...................................
Hood Louver Removal .............................................
Outer Case Removal ...............................................
Power Transformer Removal...................................
Positive Lock® Connector (No-Case
Type) Removal ........................................................
Hood Fan Motor, Hood Duct, Oven Lamp Socket
And AH Sensor Removal.........................................
Magnetron Removal ................................................
High Voltage Rectifier And High
Voltage Capacitor Removal .....................................
Hood Fan Thermostat (60ºC ON and
70ºC OFF) Removal ................................................
Cooling Fan Motor Removal ....................................
Turntable Motor Removal ........................................
Antenna Motor Removal ..........................................
Oven Lamp Removal ...............................................
Stirrer Cover And Stirrer Fan Installation.................
Servicing For Touch Control Panel..........................
Panel Sub Assembly And Control Unit Removal .....
Door Sensing Switch / Secondary Interlock Switch
And Monitor Switch Removal ..................................
Door Sensing Switch / Secondary Interlock Switch
And Monitor Switch Adjustment...............................
Door Replacement...................................................
Door Disassembly ...................................................
Cook Top Lamp Socket Removal ............................
4-1
4-2
4-2
4-2
4-3
4-3
4-4
4-5
4-5
4-6
4-6
4-7
4-8
4-8
4-8
4-8
4-10
4-10
4-11
4-12
4-13
4-13
Section 5 Wire Diagrams
Circuit Components .................................................
Glass Touch Key Unit Diagram ...............................
Control Unit Circuit ..................................................
Oven Wiring Schematic Off Condition .....................
5-1
5-2
5-3
5-4
Section 6 Parts List
Parts List..................................................................
Parts List..................................................................
Oven And Cabinet Parts Exploded View .................
Door Assembly and Control Unit .............................
Packing And Accessories ........................................
1-2
6-1
6-2
6-3
6-4
6-5
Basic Information
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:
INVERTER UNIT, THAT INCLUDES HIGH VOLTAGE CAPACITOR, HIGH VOLTAGE POWER TRANSFORMER,
HIGH VOLTAGE RECTIFIER, HEAT SINK, ETC., AND MAGNETRON, HIGH VOLTAGE HARNESS ETC.;
IF PROVIDED, FAN ASSEMBLY, COOLING FAN MOTOR.
ALL THE PARTS MARKED “*” ON PARTS LIST ARE USED AT VOLTAGES MORE THAN 250V.
REMOVAL OF THE OUTER WRAPPER GIVES ACCESS TO VOLTAGE ABOVE 250V.
ALL THE PARTS MARKED “Ä” ON PARTS LIST MAY CAUSE UNDUE MICROWAVE EXPOSURE, BY
THEMSELVES, OR WHEN THEY ARE DAMAGED, LOOSENED OR REMOVED.
THIS SERVICE MANUAL IS INTENDED FOR USE BY PERSONS HAVING ELECTRICAL AND MECHANICAL
TRAINING AND A LEVEL OF KNOWLEDGE OF THESE SUBJECTS GENERALLY CONSIDERED
ACCEPTABLE IN THE APPLIANCE REPAIR TRADE. ELECTROLUX HOME PRODUCTS CANNOT BE
RESPONSIBLE, NOR ASSUME ANY LIABILITY, FOR INJURY OR DAMAGE OF ANY KIND ARISING FROM
THE USE OF THIS MANUAL.
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.
SERVICEMEN SHOULD REMOVE THEIR WATCHES WHENEVER WORKING CLOSE TO OR REPLACING THE
MAGNETRON.
All repairs should be done in accordance with the procedures described in this manual. This product
complies with Federal Performance Standard 21 CFR Subchapter J(DHHS).
Never defeat any of the B+ voltage interlocks. Do not apply AC power to the unit (or any of its assemblies)
unless all solid-state heat sinks are correctly installed.
Some semiconductor (“solid state”) devices are easily damaged by static electricity. Such components
are called Electrostatically Sensitive Devices (ESDs). Examples include integrated circuits and field-effect
transistors.
Immediately before handling any semiconductor components or assemblies, drain the electrostatic
charge from your body by touching a known earth ground.
1-3
Basic Information
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 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 ELECTROLUX HOME PRODUCTS, INC.
immediately.
If the unit operates with the door open, service person should:
1) Tell the user not to operate the oven.
2) Contact Electrolux HOME PRODUCTS, INC. and Food and Drug Administration’s Center for Devices and
Radiological Health immediately.
Service personnel should inform ELECTROLUX HOME PRODUCTS, INC. 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.
Danger High Voltage
Do not energize a microwave oven with the outer case cabinet removed, because a microwave oven generates high
voltage in the circuit.
If you intend to operate the oven employing the high frequency switching power converter circuit, you should take
special precautions to avoid an electrical shock hazard.
The high voltage transformer, high voltage capacitor and high voltage diode have energized high voltage potential
of approximately 8KV.
The aluminium heat sink is connected to the switching power transistor collector pole, and has an energized high
voltage potential of approximately 650V peak.
DO NOT ACCESS THE HIGH VOLTAGE TRANSFORMER, HIGH VOLTAGE CAPACITOR, HIGH VOLTAGE
DIODE AND HEAT SINK WHEN THE POWER SUPPLY IS CONNECTED TO AN ELECTRICAL OUTLET.
1-4
Basic Information
MICROWAVE OVENS CONTAIN CIRCUITRY CAPABLE OF PRODUCING
VERY HIGH VOLTAGE AND CURRENT. CONTACT WITH THE
FOLLOWING PARTS MAY RESULT IN A SEVERE, POSSIBLY FATAL,
ELECTRICAL SHOCK.
INVERTER UNIT, THAT INCLUDES HIGH VOLTAGE CAPACITOR,
HIGH VOLTAGE POWER TRANSFORMER, HIGH VOLTAGE RECTIFIER,
HEAT SINK ETC., AND MAGNETRON, HIGH VOLTAGE HARNESS ETC..
READ THE SERVICE MANUAL CAREFULLY AND FOLLOW ALL
INSTRUCTIONS.
Don't Touch !
Danger High Voltage
Before Servicing
When 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.
1.
To discharge the high voltage capacitor, 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. In some cases it may be
necessary to connect the power supply after the outer
case has been removed, in this event:
1. Disconnect the oven power supply cord and then
remove the outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. Disconnect leads to the primary of the inverter unit.
5. Ensure that these leads remain isolated from other
components and oven chassis by using insulation
tape.
6. After that procedure, reconnect the power supply
cord.
2.
3.
Disconnect the power supply cord, and then remove
outer case.
Open the door and block it open.
Discharge high voltage capacitor.
To discharge the high voltage capacitor, 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.
4.
5.
6.
7.
Reconnect leads to the primary of the inverter unit.
Reinstall the outer case (cabinet).
Reconnect the power supply cord after the outer
case is installed.
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 then 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.
1-5
Basic Information
Microwave Measurement Procedure (USA)
A. Requirements:
1) Microwave leakage limit (Power density limit): The power density of microwave radiation emitted by a
microwave oven should not exceed 1 mW/cm2 at any point 5 cm 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 5 cm or more from the external surface of the oven.
2) Safety interlock switches: Primary interlock 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/cm2 at any point 5 cm 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°±5C (68±9°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
4 mW/cm2, and that the primary interlock switch and secondary interlock switch do turn the oven OFF before
any door movement.
NOTE: After servicing, record data on service invoice and microwave leakage report.
1-6
Basic Information
Microwave Measurement Procedure (Canada)
After adjustment of the door switches are completed individually or collectively, switch test and microwave leakage
test must be performed with survey instrument and test result must be confirmed to meet the requirement of the
performance standard for microwave ovens as under mentioned.
A. Requirements:
Every microwave oven shall function in such a manner that when the oven is fully assembled and operating with
its service controls and user controls adjusted to yield the maximum output, the leakage radiation, at all points at
least 5 cm. from the external surface of the oven, does not exceed:
1) 1.0 mW/cm2 with the test load of 275 ± 15 ml of water at an initial temperature 20 ±5°C.
2) 5.0 mW/cm2 when the outer enclosure is removed with a test load of 275 ± 15 ml of water at an initial
temperature 20±5°C.
3) 5.0 mW/cm2 without a test load.
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.
Survey instruments that comply with the requirement for instrumentation as prescribed by CSA and NHW
performance standard for microwave ovens must be used for testing recommended instruments are, NARDA
8100 and NARDA 8200.
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°±5C (68±9°F) in the center of oven cavity.
The water container shall be a low form of a 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 with enclosure installed:
1) Grasp probe of survey instrument and hold it perpendicular to gap between door and the body of the oven.
2) Move the probe slowly, not faster than 2.5 cm/sec. along the gap, watching for maximum indication on 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 door, pull 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 4 mW/cm2, and that the primary interlock switch and secondary interlock switch do turn the oven
OFF before any door movement.
D. Leakage test without enclosure:
1) Remove the enclosure (cabinet).
2) Grasp the probe of the survey instrument and hold it perpendicular to all mechanical and electric parts of the
oven that is accessible to the user of the oven including, but not limited to, the waveguide, cavity seams,
magnetron gap between the door and the body of the oven.
3) Move probe slowly, not faster than 2.5 cm/sec. along the gap, watching for the maximum indication on meter.
4) Measure carefully at the point of highest leakage and make sure that the highest leakage is under 5 mW/cm2.
CAUTION: Special attention should be given to avoid electrical shock because HIGH VOLTAGE is generated
during this test.
E. No Load test
1) Operate the oven without a load and measure the leakage by the same method as the above test procedure
“ Leakage test with enclosure installed”
2) Make sure that the highest leakage should not exceed 5 mW/cm2.
NOTE: After servicing, record data on service invoice and microwave leakage report.
1-7
Basic Information
Product Specification
Item
Description
Power Requirements
(USA)120 Volts / 14.3 Amperes
60 Hertz
Single phase, 3 wire grounded
Power Output
1000 watts (IEC 705 Test Procedure)
Operating frequency of 2450MHz
Outside Case Dimensions
Width 29-15/16”
Height 16-1/16”
Depth 18-15/32”
Cooking Cavity Dimensions
2.0 Cubic Feet
Width 22-1/2”
Tray Size 15-7/8
Height 10-1/16”
Depth 14-31/32”
Lighting- Hood Lamp
40W x 1 Krypton light bulb
Lighting- Oven Cavity Light
40W x 1 Krypton light bulb
Weight
Approximately 58 lbs.
Control Complement
Touch Control System
Clock ( 1:00 - 12:59 )
Timer (0 - 99 min. 99 seconds)
Microwave Power for Variable Cooking
Repetition Rate;
P-HI Full power throughout the cooking time
P-90 approx. 90% of Full Power
P-80 approx. 80% of Full Power
P-70 approx. 70% of Full Power
P-60 approx. 60% of Full Power
P-50 approx. 50% of Full Power
P-40 approx. 40% of Full Power
P-30 approx. 30% of Full Power
P-20 approx. 20% of Full Power
P-10 approx. 10% of Full Power
P-0 No power throughout the cooking time
Timer on-off pad, Set clock pad, User Pref pad, Sensor Cook pad
Sensor Reheat pad, Popcorn pad, Baked Potato pad, Fresh veggies pad
Frozen veggies pad, Auto cook pad, Auto defrost pad, Auto reheat pad
Snacks pad, Keep warm pad, Melt, soften pad, Power level pad
Turn table on-off pad, Number pads, (Quick start pads),
START/add 30sec pad, STOP/Clear pad, Light pad, Fan pad
Safety Standard
UL Listed FCC Authorized
DHHS Rules, CFR, Title 21, Chapter 1, Subchapter J
1-8
Basic Information
Grounding Instructions
Discharging Capacitor
This oven is equipped with a three prong grounding plug.
It must be plugged into a wall receptacle that is properly
installed and grounded in accordance with the National
Electrical Code, local codes and ordinances. In the event
of an electrical short circuit, grounding reduces the risk of
electric shock by providing an escape wire for the electric
current.
1.
IMPROPER USE OF THE GROUNDING PLUG CAN
RESULT IN A RISK OF ELECTRIC SHOCK.
Electrical Requirements
The oven is equipped with a 3-prong grounding plug.
DO NOT UNDER ANY CIRCUMSTANCES CUT OR
REMOVE THE GROUNDING PIN FROM THE PLUG.
The power supply cord and plug must be connected to a
separate 120 Volt AC, 60 Hz, 15 Amp. or more dedicated
line, using a grounded receptacle. The receptacle should
be located inside the cabinet directly above the
Microwave Oven/Hood system mounting location.
3-Pronged Plug
High Voltage Warning!
Do not attempt to measure any of the high voltages,
this includes the filament voltage of the magnetron.
High voltage is present during any cook cycle.
Before touching any components or wiring, always
unplug the oven and discharge the high voltage
capacitor (See Figure 1-3).
2. The high-voltage capacitor remains charged about
60 seconds after disconnection. Short the negative
terminal of the high-voltage capacitor to the oven
chassis. (Use an insulated screwdriver.)
3. High voltage is maintained within specified limits
by close-tolerance, safety-related components
and adjustments. If the high voltage exceeds the
specified limits, check each of the special
components.
Grounded
Receptacle Box
High Voltage
Capacitor
Grounding Pin
3-Pronged Receptacle
Figure 1-1. Electrical Connection
Figure 1-3. Capacitor Discharging
NOTE: The illustration above gives a generalized
location of the high voltage capacitor. Refer to the
exploded view of the oven and cabinet for exact
location.
Figure 1-2. Electrical Connection In Cabinet
1-9
Basic Information
Oven Diagram
Components
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Microwave oven door with see-through window.
Door hinges.
Waveguide cover: DO NOT REMOVE.
Turntable motor shaft.
Microwave oven light. It will light when microwave
oven is operating or door is open.
Rack holders.
Safety door latches. The microwave oven will not
operate unless the door is securely closed.
Handle.
Light pad. Touch the light pad once for high, twice for
medium, three times for low and four times to turn off
the light.
Fan pad. Touch the fan pad once for high speed,
twice for medium speed, three times for low speed
and four times to turn off the fun.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
Auto-Touch control panel.
Time display: Digital display, 99 minutes, 99 seconds
Ventilation openings.
Removable turntable. The turntable will rotate
clockwise or counterclockwise. Only remove for
cleaning.
Removable turntable support. First, carefully place
the turntable support in the motor shaft in the center
of the microwave oven floor. Then, place the turntable
on the turntable support securely.
Rack for 2-level cooking/ reheating.
Light cover.
Grease filters.
Menu label.
Rating label (model and serial number).
Figure 1-4. Oven Overview
1-10
Basic Information
Special Instructions for the
Turntable Support and Turntable
Glass Tray
Turntable Support
Make sure to remove the tape at the turntable
support before operation. Because the tape is
attached when the product is shipped from the
factory.
Oven Bottom Plate Hole
Figure 1-5a.
Remove this tape before operation
Figure 1-5b.
Figure 1-5. Turntable Support Installation
Turntable Support
Read carefully before installing the turntable glass tray
and turtable support for proper operation. Improper
installation will cause dragging noise and erratic turntable
glass rotation.
1. Place the turntable support to the turntable motor
shaft (Inside oven bottom plate hole). And make
sure the center of turntable support is inserted to
turntable motor shaft.
2. The turntable glass tray should be set so all three
rollers of the turntable support contact to the flat
surface of the turntable glass tray.
Figure 1-5c.
CORRECT
Flat Surface of Turntable Glass Tray
WRONG
Flat Surface of Turntable Glass Tray
Back
View
Roller of Turntable Support
Flat Surface of Turntable Glass Tray
Out of Flat Surface
Flat Surface of Turntable Glass Tray
Side
View
Roller of Turntable Support
1-11
Out of Flat Surface
Basic Information
Notes
1-12
Operation
Operating Sequence Description
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. (See Figure 2-1).
6. When the door is opened during a cook cycle, monitor switch, door sensing switch, secondary interlock
switch, and primary interlock relay are activated with
the following results. The circuits to the antenna
motor, the cooling fan motor, the turntable motor, and
the high voltage components are de-energized, and
the digital read-out 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 door
sensing switch is mechanically associated with the
door so that it will function in the following sequence.
1. The display will show “ENJOY YOUR OVEN, PRESS
CLEAR AND TOUCH CLOCK”.
To set any program or set the clock, you must first
touch the STOP/CLEAR pad. The display will clear,
and “ : “ appears.
(1) When the door opens from a closed position, the
primary interlock relay, door sensing switch and
secondary interlock switch open their contacts,
and then the monitor switch contacts close.
(2) When the door is closed from the open position,
the monitor switch contacts open first. Then the
contacts of the secondary interlock switch and
door sensing switch close, and contacts of the
relay (RY1) open.
COOKING CONDITION
Program desired cooking time by touching the NUMBER
pads. Program the power level by touching the POWER
LEVEL pad and then a Number pad.
When the START pad is touched, the following operations
occur:
1. The contacts of relays are closed and components
connected to the relays are turned on as follows.
(For details, refer to Figure 2-2)
If the secondary interlock switch and primary interlock
relay (RY2) fail with the contacts closed when the door is
opened, the closing of the monitor switch contacts will
form a short circuit through the monitor fuse, secondary
interlock switch, relay (RY1) and primary interlock relay
(RY2), causing the monitor fuse to blow.
RELAY CONNECTED COMPONENTS
RY-1
Oven Lamp / Fan Motor / Fan Motor
RY-2
Power Transformer
RY-7
Turntable Motor
2. 120 volts AC is supplied to the primary winding of
the power transformer and is converted to about
3.3 volts AC output on the filament winding, and
approximately 2000 volts AC on the high voltage
winding.
3. The filament winding voltage heats the magnetron
filament and the H.V. winding voltage is sent to a
voltage doubler circuit.
4. The microwave energy produced by the magnetron
is channeled through the waveguide into the cavity
feedbox, and then into the cavity where the food
is placed to be cooked.
5. Upon completion of the cooking time, the power
transformer, oven lamp, etc. are turned off, and the
generation of microwave energy is stopped. The
oven will revert to the OFF condition.
2-1
Operation
Figure 2-1. Microwave Oven Off Condition
Figure 2-2. Oven Schematic-Microwave Oven Cooking Condition
2-2
Operation
Variable Cooking
Ventilation Methods
When Variable Cooking Power is programmed, the 120
volts A.C. 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. Microwave power operation is as follows:
1. VERTICAL VENTING
Vari-Mode
ON TIME
OFF TIME
Power 10 (High) (100% Power)
Power 9 (P-90) (Approx. 90%)
Power 8 (P-80) (Approx. 80%)
Power 7 (P-70) (Approx. 70%)
Power 6 (P-60) (Approx. 60%)
Power 5 (P-50) (Approx. 50%)
Power 4 (P-40) (Approx. 40%)
Power 3 (P-30) (Approx. 30%)
Power 2 (P-20) (Approx. 20%)
Power 1 (P-10) (Approx. 10%)
Power 0 (P-0) (0% power)
32 sec.
30 sec.
26 sec.
24 sec.
22 sec.
18 sec.
16 sec.
12 sec.
8 sec.
6 sec.
0 sec.
0 sec.
2 sec.
6 sec.
8 sec.
10 sec.
14 sec.
16 sec.
20 sec.
24 sec.
26 sec.
32 sec.
For this venting method, hot air rising from the conventional range below is drawn in by the hood fan motor
through the grease filters at the right and left sides of the
base cover, up through the right and left sides of the oven
cavity, then discharged vertically at rear center top of the
oven, into the customer’s vent system.
2. HORIZONTAL VENTING
The air handling is the same as VERTICAL VENTING
except that the final air discharge is directed horizontally
out from the top rear of the oven into the customer’s vent
system.
The ON/OFF time ratio does not correspond with the
percentage of microwave power, because approx. 2
seconds are needed for heating of the magnetron
filament.
Power Output Reduction
If the oven is set for over 40 minutes at 80%, 90% or
100% power level, after the first 40 minutes the power
level will automatically adjust itself to 70% power to avoid
overcooking.
3. RE-CIRCULATION (INSIDE VENTING)
Cook Top Lamp
The brightness of the cook top lamp is controlled by the
relays RY7, RY8 and RY9 as shown in the following table.
The air handling is the same as VERTICAL VENTING
except that the final air discharge is directed horizontally
through the upper front of the oven into the kitchen.
2-3
Operation
Sensor Cooking Condition
Cooking Sequence
Using the SENSOR COOK function, the foods are
cooked without figuring time, power level or quantity.
When the oven senses enough steam from the food, it
relays the information to its microprocessor which will
calculate the remaining cooking time and power level
needed for best results.
1. Operate the oven in sensor cooking mode by
referring to the operation manual.
When food is cooked, water vapor is developed. The
sensor “senses” the vapor and its resistance increases
gradually. When resistance reaches the value set
according to the menu, supplementary cooking is started.
The time of supplementary cooking is determined by
experiment with each food category and inputted into the
LSI.
An example of how the sensor works:
(BAKED POTATOES)
1. Potatoes at room temperature. Vapor is emitted
very slowly.
The oven should not be operated on Sensor Cooking
immediately after plugging in the unit. Wait two minutes
before cooking on Sensor Cooking.
2. The coil of shut-off relays (RY1 and RY3) are energized, the oven lamp, turntable motor and cooling fan
motor are turned on, but the power transformer is not
turned on.
3. After about 32 seconds, the relay (RY2) is energized.
The power transformer is turned on, microwave
energy is produced and first stage is started. The 32
seconds is the cooling time required to remove any
vapor from the oven cavity and sensor.
During this first stage, do not open the door or touch
Clear Off pad.
2. Heat Potatoes. Moisture and humidity is emitted
rapidly. You can smell the aroma as it cooks.
MIC
RO
WA
VE
3. Sensor detects moisture and humidity and
calculates cooking time and variable power.
4. When the sensor detects the vapor emitted from
the food, the display switches over to the remaining
cooking time and the timer counts down to zero.
At this time, the door may be opened to stir food, turn
it or season, etc.
5. When the timer reaches zero, an audible signal
sounds. The shut-off relay (RY1 and RY3) and relay
(RY2) are generalized and the power transformer,
oven lamp, etc. are turned off.
6. Opening the door or touching the STOP CLEAR pad,
the time of day will reappear on the display and the
oven will revert to an OFF condition.
2-4
Operation
MONITOR SWITCH
Component Descriptions
DOOR OPEN MECHANISM
The door is opened by pulling the door handle down and
forward, referring to Figure 2-6. When the door handle is
pulled down, the latch heads are moved upward. When
the door handle is pulled forward, the latch heads are
released from the latch hooks right and left. Now, the
door will open.
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 (RY2) and secondary interlock
switch fail to open when the door is opened.
Functions:
1. When the door is opened, the monitor switch contact
close (to the ON condition) due to their being
normally closed. At this time, the primary interlock
relay (RY2), and secondary interlock switch are in
the OFF condition (contacts open) due to their being
normally open contact switches. The contacts of
relay (RY1) are in the ON condition (contacts close).
2. As the door goes to a closed position, the monitor
switch contacts are first opened and then the door
sensing switch and the secondary interlock switch
contacts close. (On opening the door, each of these
switches operate inversely.)
3. If the door is opened, and the primary interlock relay
(RY2) and secondary interlock switch contacts fail
to open, the monitor fuse blows simultaneously with
closing of the monitor switch contacts.
Figure 2-6.
DOOR SENSING SWITCH, SECONDARY INTERLOCK
SWITCH
The secondary interlock switch is mounted in the lower
position of the latch hook. The door sensing switch in
the primary interlock system is mounted in the upper
position of the latch hook. The switches are activated by
the latch heads on the door. When the door is opened,
the switches interrupt the circuit to all components. 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 primary interlock relay located on the control
circuit board.
Before replacing a blown monitor fuse test the
door sensing switch, primary interlock relay (RY2),
relay (RY1), secondary interlock switch and monitor
switch for proper operation.
Monitor fuse and switch are replaced as an assembly.
THERMAL CUT-OUT (CAVITY)
This thermal cut-out is located on the top of the oven
cavity. It is designed to prevent damage to the oven unit
if the food in the oven catches fire due to overheating
produced by improper setting of cooking time or failure of
control unit. Under normal operation, the thermal cut-out
remains closed. However, the thermal cut-out will open at
293°F (145°C) causing the oven to shut down.
2-5
Operation
TURNTABLE MOTOR
THERMOSTAT (70°C OFF)
The turntable motor rotates the turntable located on
the bottom of the oven cavity, so that the foods on the
turntable cook evenly during cooking. Turntable will turn
in either direction. The turntable motor can be turned off
by touching TURNTABLE ON/OFF pad.
This thermostat is located on the right base plate. It is
designed to automatically cut off power to the hood fan
low speed terminal whenever the hot air rising from the
conventional range below causes the temperature at the
thermostat to rise to 158°F (70°C) or higher, thus
removing this hot air from around microwave oven.
When the temperature around the thermostat drops to
131°F (55°C) or lower, the thermostat supplies power to
the hood fan low speed terminal.
COOLING FAN MOTOR
The cooling fan motor drives a blade which draws
external cool air. This cool air is directed through the
air vanes surrounding the magnetron and cools the
magnetron. This air is channelled through the oven
cavity to remove steam and vapors given off from the
heating foods. It is then exhausted through the exhausting air vents at the oven cavity.
ANTENNA MOTOR
The antenna motor drives the stirrer antenna to stir the
microwave radiation from the waveguide.
HOOD FAN MOTOR
HOOD LAMP
The hood fan motor is a three-speed, single-phase,
double pole induction type, requiring a hood fan capacitor. It is located outside the upper rear part of the oven
cavity, is to remove, from around the oven, hot air rising
from the conventional electric or gas range over which it
is installed. This air is then expelled either vertically or
horizontally through the customer supplied duct system,
or discharged back into the kitchen. The automatically
operation is medium speed. The manual operation is a
three speed (Low/ Mid/ High).
The hood lamps are mounted at the hood lamp angle on
the base cover. Touch the Light pad once for high, twice
for medium, three times for low and four times to turn off
the light.
THERMOSTAT (60°C ON)
This thermostat is located on the right base plate. It is
designed to automatically turn on the hood fan motor
whenever the hot air rising from the conventional range
below causes the temperature at the thermostat to rise
to 140°F (60°C) or higher, thus removing this hot air from
around microwave oven. When the temperature around
the thermostat drops to 113°F (45°C) or lower, the
thermostat shuts off the hood fan motor.
2-6
Operation
Touch Control Panel Assembly
OUTLINE OF TOUCH CONTROL PANEL
The touch control section consists of the following units.
(1) Glass touch key
(2) Control Unit
The principal functions of these units and the signals
communicated among them are explained below.
Glass Touch Key Unit
The glass touch key unit is composed of a matrix, signals
generated in the LSI are sent to the glass touch key unit.
When a key pad is touched, a signal is completed
through the glass touch key unit and passed back to the
LSI to perform the function that was requested.
1. IC3
This is the IC to judge the selected key.
6. Relay Circuit:
A circuit to drive the magnetron, fan motor, stirrer
motor, hood motor and light the oven lamp and cook
top lamp.
7. Buzzer Circuit:
The buzzer is responsive to signals from the LSI to
emit audible sounds (key touch sound and
completion sound).
8. Synchronizing Signal Circuit:
The power source synchronizing signal is available in
order to compose a basic standard time in the clock
circuit. It accompanies a very small error because it
works on commercial frequency.
9. Door Sensing Switch:
A switch to “tell” the LSI if the door is open or closed.
10. Humidity Sensor Circuit:
This circuit detects moisture of the cooking food to
allow its automatic cooking.
Control Unit
Control unit consists of LSI, IC, reset circuit, indicator
circuit, power source circuit, relay circuit, buzzer circuit,
synchronizing signal circuit, glass touch key unit circuit
and humidity sensor circuit.
1. IC1 (LSI):
This is a microcomputer, responsible for controlling
the entire control unit.
2. IC2:
This is the IC to amplify the signal from the humidity
sensor.
3. Reset Circuit:
This circuit generates a signal which resets the LSI
(IC1) to the initial state when power is supplied.
4. Indicator Circuit:
Indicator element is Fluorescent Display. Basically, a
Fluorescent Display is triode having a cathode, a grid
and an anode. Usually, the cathode of a Fluorescent
Display is directly heated and the filament serves
as cathode. The Fluorescent Display has 8-digits,
16-segments are used for displaying figures.
5. Power Source Circuit:
This circuit generates voltages necessary in the
control unit from the AC line voltage. In addition, the
synchronizing signal is available in order to compose
a basic standard time in the clock circuit.
Symbol
VC
Voltage
Application
+5V
LSI(IC1)
2-7
Operation
Humidity Sensor Circuit
(1) Structure of Humidity Sensor:
The humidity sensor includes two thermistors as
shown in the illustration. One thermistor is housed
in the closed vessel filled with dry air while another
in the open vessel. Each sensor is provided with the
protective cover made of metal mesh to be protected
from the external airflow.
(2) Operational Principle of Humidity Sensor:
The figure below shows the basic structure of an
absolute humidity sensor. A bridge circuit is formed
by two thermistors and two resistors (R91 and R96).
The output of the bridge circuit is to be amplified by
the operational amplifier.
Each thermistor is supplied with a current to keep
it heated at about 150˚C (302˚F), the resultant heat
is dissipated in the air and if the two thermistors are
placed in different humidity conditions they show
different degrees of heat conductivity leading to a
potential difference between them causing an output
voltage from the bridge circuit, the intensity of which
is increased as the absolute humidity of the air
increases. Since the output is very minute, it is
amplified by the operational amplifier.
(3) Detector Circuit of Humidity Sensor Circuit:
This detector circuit is used to detect the output
voltage of the absolute humidity circuit to allow the
LSI to control sensor cooking of the unit. When the
unit is set in the sensor cooking mode, 16 seconds
clearing cycle occurs then the detector circuit starts
to function and the LSI observes the initial voltage
available at its AN1 terminal.
With this voltage given, the switches SW1 to SW5 in
the LSI are turned on in such a way as to change the
resistance values in parallel with R98 ~ R102.
Changing the resistance values results in that there
is the same potential at both F-3 terminal of the absolute humidity sensor and AIN6 terminal of the LSI.
The voltage of AIN6 terminal will indicate about -2.5V.
This initial balancing is set up about 16 seconds after
the unit is put in the Sensor Cooking mode. As the
sensor cooking proceeds, the food is heated to
generate moisture by which the resistance balance of
the bridge circuit is deviated to increase the voltage
available at AIN5 terminal of the LSI.
Then the LSI observes that voltage at AIN5 terminal
and compares it with its initial value, and when the
comparison rate reaches the preset value (fixed for
each menu to be cooked), the LSI causes the unit to
stop sensor cooking; thereafter, the unit goes in the
next operation automatically.
When the LSI starts to detect the initial voltage at
AIN5 terminal 16 seconds after the unit has been put
in the Sensor Cooking mode, if it is not possible to
balance the bridge circuit due to disconnection of the
absolute humidity sensor, ERROR will appear on the
display and the cooking is stopped.
(4) Humidity sensor circuit:
2-8
Troubleshooting and Testing
Troubleshooting Guide
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.
If the oven becomes inoperative because of a blown monitor fuse, check the monitor switch, relay (RY1)
primary interlock relay (RY2), door sensing switch and secondary interlock switch before replacing the
monitor fuse. If the monitor fuse is replaced, the monitor switch must also be replaced.
Use part FFS-BA042WRKZ as an assembly.
WHENEVER TROUBLESHOOTING IS PERFORMED WITH THE POWER SUPPLY CORD DISCONNECTED. IT
MAY IN, SOME CASES, BE NECESSARY TO CONNECT THE POWER SUPPLY CORD 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. TO DISCHARGE HIGH VOLTAGE CAPACITOR, 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.
4. REMOVE THE BACK PLATE FROM THE OVEN.
5. DISCONNECT THE LEADS TO THE PRIMARY OF THE POWER TRANSFORMER.
6. ENSURE THAT LEADS REMAIN ISOLATED FROM OTHER COMPONENTS AND OVEN CHASSIS BY
USING INSULATION TAPE.
7. 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. TO DISCHARGE HIGH VOLTAGE CAPACITOR, 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.
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.
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 then 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.
3-1
Troubleshooting and Testing
3-2
Troubleshooting and Testing
Test Procedures
Procedure
Letter
A
Component Test
MAGNETRON ASSEMBLY TEST
HIGH VOLTAGES ARE PRESENT DURING THE COOK CYCLE, SO EXTREME CAUTION
SHOULD BE OBSERVED.
DISCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE TOUCHING ANY OVEN
COMPONENTS OR WIRING.
1.
2.
3.
4.
5.
6.
7.
8.
9.
Disconnect the power supply cord and then remove outer case.
Open the oven door and block it open.
Discharge the high voltage capacitor. (See Warnings and Instructions on page 3-1)
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 ohm.
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 and must be replaced.
Reconnect all leads removed from components during testing.
Reinstall the outer case (cabinet).
Reconnect the power supply cord after the outer case is installed.
Run the oven and check all functions.
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: silicon rectifier, high voltage capacitor and power transformer.
This test will require a 16 ounce (453 cc.) measuring cup and an accurate mercury thermometer or
thermocouple type temperature tester. For accurate results, the following procedure must be
followed carefully:
1. Fill the measuring cup with 16 oz. (453 cc.) of tap water and measure the temperature of the
water with a thermometer or thermocouple temperature tester. Stir the thermometer or thermocouple through the water until the temperature stabilizes. Record the temperature of the water.
2. Place the cup of water in the oven. Operate oven at POWER 10(HIGH) selecting more than 60
seconds cook time. Allow the water to heat for 60 seconds, measuring with a stop watch, second
hand of a watch or the digital read-out countdown.
3. Remove the cup from the oven and again measure the temperature, making sure to stir the
thermometer 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 29.2 to 54.2ºF(16.2 to 30.1ºC) rise in temperature. If the water temperatures are accurately
measured and 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 cooking time. Because
cooking 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.
3-3
Troubleshooting and Testing
Procedure
Letter
B
Component Test
POWER TRANSFORMER TEST
DO NOT TOUCH THE COMPONENTS OF THE POWER TRANSFORMER WHILE POWER
TRANSFORMER IS ENERGIZED. IT IS DANGEROUS BECAUSE THIS HAS HIGH VOLTAGE
COMPONENTS. (HIGH VOLTAGES ARE PRESENT AT THE HIGH VOLTAGE TERMINAL, SO
DO NOT ATTEMPT TO MEASURE THE FILAMENT AND HIGH VOLTAGE.)
1.
2.
3.
4.
5.
6.
7.
8.
C
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
Disconnect the primary input terminals and measure the resistance of the transformer with an
ohmmeter. 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 1 ohm and the resistance of the high voltage coil
should be approximately 85 ohms (RTRN-A774WRZZ)/ approximately 103.5 ohms (RTRNA777WRZZ); the resistance of the filament coil should be less than 1 ohm.
Reconnect all leads removed from components during testing.
Reinstall the outer case (cabinet).
Reconnect the power supply cord after the outer case is installed.
Run the oven and check all functions.
HIGH VOLTAGE RECTIFIER TEST
1.
2.
3.
4.
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
Isolate the rectifier from the circuit. Using the highest ohm scale of the meter, read the
resistance across the terminals and observe, reverse the leads to the rectifier terminals and
observe meter reading. If a short is indicated in both directions, or if an infinite resistance is
read in both directions, the rectifier is probably defective and should be replaced.
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
NOTE: Be sure to use an ohmmeter that will supply a forward bias voltage of more than 6.3 volts.
D
HIGH VOLTAGE CAPACITOR TEST
1.
2.
3.
4.
5.
6.
7.
8.
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
If the capacitor is open, no high voltage will be available to the magnetron. Disconnect input
leads and check for short or open between the terminals using an ohmmeter.
Checking with a high ohm scale, if the high voltage capacitor is normal, the meter will indicate
continuity for a short time and should indicate an open circuit once the capacitor is charged. If
the above is not the case, check the capacitor with an ohmmeter to see if it is shorted between
either of the terminals and case. If it is shorted, replace the capacitor.
Reconnect all leads removed from components during testing.
Reinstall the outer case (cabinet).
Reconnect the power supply cord after the outer case is installed.
Run the oven and check all functions.
3-4
Troubleshooting and Testing
Procedure
Letter
E
Component Test
CAVITY THERMAL CUT-OUT TEST
1.
2.
3.
4.
5.
6.
7.
8.
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
A continuity check across the thermal cut-out terminals should indicate a closed circuit unless
the temperature of the thermal cut-out reaches approximately 293°F(145°C). An open thermal
cut-out indicates overheating of the oven, exchange the oven thermal cut-out and check inside
of oven cavity and for improper setting of cooking time or operation of control unit. Check for
restricted air flow through the vent holes of the oven cavity, especially the cooling fan and air
guide.
Reconnect all leads removed from components during testing.
Reinstall the outer case (cabinet).
Reconnect the power supply cord after the outer case is installed.
Run the oven and check all functions.
MAGNETRON TEMPERATURE FUSE TEST
1.
2.
3.
4.
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
A continuity check across the C/T fuse terminals should indicate a closed circuit unless the
temperature of the cavity temperature fuse reaches approximately 302°F(150°C). An open
cavity temperature fuse indicates overheating of the oven, exchange the cavity temperature
fuse and check inside of oven cavity and for improper setting of cooking time or operation of
control unit. Check for restricted air flow through the vent holes of the oven cavity, especially
the cooling fan and air guide.
If the temperature fuse indicates an open circuit at room temperature, replace temperature
fuse.
5.
6.
7.
8.
Reconnect all leads removed from components during testing.
Reinstall the outer case (cabinet).
Reconnect the power supply cord after the outer case is installed.
Run the oven and check all functions.
3-5
Troubleshooting and Testing
Procedure
Letter
F
Component Test
SECONDARY INTERLOCK SWITCH TEST
1.
2.
3.
4.
5.
6.
7.
8.
G
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
Isolate the switch and connect the ohmmeter to the common (COM.) and normally open
(NO) terminal of the switch. The meter should indicate an open circuit with the door open
and a closed circuit with the door closed. If improper operation is indicated, replace the
secondary interlock switch.
Reconnect all leads removed from components during testing.
Reinstall the outer case (cabinet).
Reconnect the power supply cord after the outer case is installed.
Run the oven and check all functions.
PRIMARY INTERLOCK SYSTEM TEST
DOOR SENSING SWITCH
1.
2.
3.
4.
5.
6.
7.
8.
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
Isolate the switch and connect the ohmmeter to the common (COM.) and normally open
(NO) terminal of the switch. The meter should indicate an open circuit with the door open
and a closed circuit with the door closed. If improper operation is indicated, replace the
door sensing switch.
Reconnect all leads removed from components during testing.
Reinstall the outer case (cabinet).
Reconnect the power supply cord after the outer case is installed.
Run the oven and check all functions.
NOTE: If the door sensing switch contacts fail in the open position and the door is closed, the
cooling fan, turntable and oven light will be activated by RY1.
PRIMARY INTERLOCK RELAY (RY2)
1.
2.
3.
4.
5.
6.
7.
8.
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
Disconnect two (2) wire leads from the male tab terminals of the Primary Interlock Relay.
Check the state of the relay contacts using a ohmmeter. The relay contacts should be
open. If the relay contacts are closed, replace the circuit board entirely or the relay itself.
Reconnect all leads removed from components during testing.
Reinstall the outer case (cabinet).
Reconnect the power supply cord after the outer case is installed.
Run the oven and check all functions.
3-6
Troubleshooting and Testing
Procedure
Letter
H
Component Test
MONITOR SWITCH TEST
1.
2.
3.
4.
5.
6.
7.
8.
I
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
Before performing this test, make sure that the secondary interlock switch and primary interlock
relay are operating properly, according to the Switch Test Procedure. Disconnect the wire lead
from monitor switch (COM) terminal. Check monitor switch operation by using the ohmmeter
as follows. When the door is open, the meter should indicate a closed circuit. When the
monitor switch actuator is pushed by a screwdriver through the lower latch hole on the front
plate of the oven cavity with the door opened (in this condition the plunger of the monitor switch
is pushed in), the meter should
indicate an open circuit. If improper
operation is indicated, the switch
may be defective. After testing the
monitor switch, reconnect the wire
lead to the monitor switch (COM)
terminal and check the continuity of
the monitor circuit.
Reconnect all leads removed from
components during testing.
Reinstall the outer case (cabinet).
Reconnect the power supply cord after the outer case is installed.
Run the oven and check all functions.
BLOWN MONITOR FUSE TEST
1.
2.
3.
4.
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
If the monitor fuse is blown when the door is opened, check the secondary interlock switch,
primary interlock relay (RY2), relay (RY1) and monitor switch according to the “Test
Procedure” for those switches before replacing the blown monitor fuse.
Before replacing a blown monitor fuse, test the secondary interlock switch, primary
interlock relay, door sensing switch and monitor switch for proper operation.
5.
6.
7.
8.
If the monitor fuse is blown by improper switch operation, the monitor fuse and monitor switch
must be replaced with “monitor fuse and monitor switch assembly” even if the monitor switch
operates normally. The monitor fuse and monitor switch assembly is comprised of a 20
ampere fuse and switch.
Reconnect all leads removed from components during testing.
Reinstall the outer case (cabinet).
Reconnect the power supply cord after the outer case is installed.
Run the oven and check all functions.
3-7
Troubleshooting and Testing
Procedure
Letter
J
Component Test
HOOD THERMOSTAT TEST
Thermostat (60°C ON)
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
4. A continuity check across the thermal cut-out terminals should indicate an open circuit
unless temperature of thermal cut-out reaches approximately 140°F (60°C) or more. At that
temperature, the contacts will close. The thermal cut-out opens automatically at approximately
113°F (45°C).
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
Thermostat (70°C OFF)
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
4. A continuity check across the thermal cut-out terminals should indicate an closed circuit unless
the temperature of the thermal cut-out reaches approximately 158°F (70°C) or more. At that
temperature, the contacts will open. The thermal cut-out closes automatically at approximately
131°F (55°C).
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
K
BLOWN MONITOR FUSE TEST
1.
2.
3.
4.
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
If motor does not turn, touch FAN HI/MID/LO pad once (set hood fan motor power “HIGH”) and
check voltage between pins “1” and “2” (Blue and Black wires) of the 6 pin connector. If 120
Volts appear and the hood capacitor is good, replace the hood fan assembly. If 120 Volts does
not appear, check the motor circuit. The resistance values of motor terminals are as follows:
5.
6.
7.
8.
Reconnect all leads removed from components during testing.
Reinstall the outer case (cabinet).
Reconnect the power supply cord after the outer case is installed.
Run the oven and check all functions.
3-8
Troubleshooting and Testing
Procedure
Letter
L
Component Test
TOUCH CONTROL PANEL ASSEMBLY TEST
The touch control panel consists of circuits including semiconductors such as LSI, ICs, etc. Therefore, unlike conventional microwave ovens, proper maintenance cannot be performed with only
a voltmeter and ohmmeter. In this service manual, the touch control panel assembly is divided
into two units, Control Unit and Glass Touch Key Unit, and troubleshooting by unit replacement is
described according to the symptoms indicated.
Before testing,
1. Disconnect the power supply cord, and then disassemble as per “Hood Louver Removal”,
“Removal Of Oven From Wall” And “Outer Case Removal”.
2. Open the door and block it open.
3. Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
4. Disconnect the leads to the primary of the power transformer.
5. Ensure that these leads remain isolated from other components and oven chassis by using
insulation tape.
6. After that procedure, re-connect the power supply cord.
Glass Touch Key Unit
1. Check glass touch key unit connection before replacement.
2. Reconnect all leads removed from components during testing.
3. Reconnect the power supply cord after the covers are installed.
4. Run the oven and check all functions.
The following symptoms indicate a defective glass touch key unit.
a) When touching the pads, a certain pad produces no signal at all.
b) When touching a number pad, two figures or more are displayed.
c) When touching the pads, sometimes a pad produces no signal.
If the keyboard unit is defective.
1.
2.
3.
4.
5.
6.
7.
Disconnect the power supply cord and then remove outer case.
Open the door and block it open.
Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
Replace the door frame assembly.
Reconnect all leads removed from components during testing.
Reconnect the power supply cord.
Run the oven and check all functions.
Control Unit
The following symptoms indicate a defective control unit. Before replacing the control unit, perform
the glass touch key unit test (Procedure M) to determine if control unit is faulty.
1. In connection with indicators:
a) At a certain digit, all or some segments do not light up.
b) At a certain digit, brightness is low.
c) Only one indicator does not light.
d) The corresponding segments of all digits do not light up; or they continue to light up.
e) Wrong figure appears.
f) A certain group of indicators do not light up.
g) The figure of all digits flicker.
continued on next page
3-9
Troubleshooting and Testing
Procedure
Letter
Component Test
2. Other possible problems caused by defective control unit.
a) Buzzer does not sound or continues to sound.
b) Clock does not operate properly.
c) Cooking is not possible.
d) Fan motor, antenna motor, oven lamp or electrical parts do not turn on or do not turn off.
e) Digital display on the control unit does not show anything.
When 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. (See Warnings and Instructions on page 3-1)
4. Reconnect all leads removed from components during testing.
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.
M
GLASS TOUCH KEY UNIT TEST
Before testing:
1. Disconnect the power supply cord, and then remove the outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
4. Disconnect the leads to the primary of the power transformer.
5. Ensure that these leads remain isolated from other components and oven chassis by using
insulation tape.
6. After that procedure, re-connect the power supply cord.
Testing:
7. Disconnect the power supply cord, and then reconnect power supply cord. Display should show
the words: “ENJOY YOUR OVEN TOUCH CLEAR AND TOUCH CLOCK.” in the display.
8. Wait 3 sec. and press the following keys within 20 seconds: “Power Level” then “Set Clock”
then “Start / add 30 sec” then “Stop Clear”. Test mode should start checking each digit.
9. After each digit is confirmed, press every key on Glass touch key unit.
NOTE: At this time, oven lamp, hood lamp, fan motor, hood fan or some electric parts may operate
by pressing keys. But please ignore operations of the electric parts.
10. After every key is pressed, open door and verify the following display:
OK
11. If any other code is displayed, one or more Key pads are bad and the Glass touch key unit will
be defective. Remove the old glass touch key unit and install the new one (as the normal glass
touch key unit).
12. Reconnect the wire harness to the glass touch key unit.
After testing:
13. Disconnect the power supply cord and then remove outer case.
14. Open the door and block it open.
15. Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
16. Reconnect all leads removed from components during testing.
17. Reconnect the power supply cord.
18. Run the oven and check all functions.
3-10
Troubleshooting and Testing
Procedure
Letter
N
Component Test
RELAY TEST
1.
2.
3.
4.
5.
Disconnect power supply cord, and remove outer case.
Open the door and block it open.
Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
Disconnect the leads to the primary of the power transformer.
Ensure that these leads remain isolated from other components and oven chassis by using
insulation tape.
6. After that procedure, re-connect the power supply cord.
7. Remove the outer case and check voltage between Pin No. 1 of the 3 pin connector (A) and the
oven side terminal of the relay RY1 on the control unit with an A.C. voltmeter. The meter should
indicate 120 volts, if not check oven circuit.
Shut-off, Cook and Heater Relays Test
These relays are operated by D.C. voltage
Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking operation.
DC. voltage indicated ................ Defective relay.
DC. voltage not indicated .......... Check diode which is connected to the relay coil. If diode is good,
control unit is defective.
8.
9.
10.
11.
12.
13.
14.
15.
If any abnormal condition is defected, replace the control unit.
Disconnect the power supply cord and then remove outer case.
Open the door and block it open.
Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
Reconnect all leads removed from components during testing.
Re-install the outer case (cabinet).
Reconnect the power supply cord after the outer case is installed.
Run the oven and check all functions.
3-11
Troubleshooting and Testing
Procedure
Letter
O
Component Test
PROCEDURES TO BE TAKEN WHEN THE FUSE ON THE PRINTED WIRING BOARD (PWB) IS
OPEN
To protect the electronic circuits, this model is provided with a fuse added to the primary on the
PWB.
1. Fuse check and repairs.
a) Disconnect the power supply cord.
b) Remove the covers.
c) Open the door and block it open.
d) Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
e) If the Fuse is blown, replace power unit.
f) Make a visual inspection of the varistor. Check for burned damage. If the varistor has been
burned, replace the power unit.
g) Examine the touch control transformer with a tester for the presence of layer short-circuit
(check the primary coil resistance which is approximately 110W±10%). If any abnormal
condition is detected, replace the touch control transformer.
h) Reconnect all leads removed from components during testing.
i) Re-install the covers.
j) Reconnect the power supply cord after the covers are installed.
k) Run the oven and check all functions.
2. Follow the troubleshooting guide given below, if indicator does not light up after above check and
repairs are finished.
a) Disconnect the power supply cord.
b) Remove the covers.
c) Open the door and block it open.
d) Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
e) Disconnect the leads to the primary of the power transformer.
f) Ensure that these leads remain isolated from other components and oven chassis by using
insulation tape.
g) After that procedure, re-connect the power supply cord.
h) Follow the troubleshooting guide given below for repair.
i)
j)
k)
l)
m)
n)
o)
Disconnect the power supply cord, and then remove the covers.
Open the door and block it open.
Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
Reconnect all leads removed from components during testing.
Re-install the covers.
Reconnect the power supply cord after the covers are installed.
Run the oven and check all functions.
3-12
Troubleshooting and Testing
Procedure
Letter
P
Component Test
HUMIDITY SENSOR TEST
Checking The Initial Sensor Cooking Condition
THE OVEN SHOULD BE FULLY ASSEMBLED BEFORE FOLLOWING PROCEDURE.
1. The oven should be plugged in at least two minutes before sensor cooking.
2. Room temperature should not exceed 35°C.
3. The unit should not be installed in any area where heat and steam are generated. The unit
should not be installed, for example, next to a conventional surface unit. Refer to the
“Installation Instructions”.
4. Exhaust vents are provided on the back of the unit for proper cooling and air flow in the cavity.
To permit adequate ventilation, be sure to install so as not to block these vents. There should
be some space for air circulation.
5. Be sure the exterior of the cooking container and the interior of the oven are dry. Wipe off any
moisture with a dry cloth or paper towel.
6. The Sensor works with food at normal storage temperature. For example, chicken pieces would
be at refrigerator temperature and canned soup at room temperature.
7. Avoid using aerosol sprays or cleaning solvents near the oven while using Sensor settings. The
sensor will detect the vapor given of by the spray and turn off before food is properly cooked.
8. After the oven is started on sensor cooking condition, if the sensor has not detected the vapor
of the food, ERROR will appear and the oven will shut off.
Water Load Cooking Test
THE OVEN SHOULD BE FULLY ASSEMBLED BEFORE FOLLOWING PROCEDURE.
Make sure the oven has been plugged in at least two minutes before checking sensor cook
operation. The cabinet should be installed and screws tightened.
1.
2.
3.
4.
Fill approximately 200 milliliters of tap water in a 1000 milliliter measuring cup.
Place the container on the center of tray in the oven cavity.
Close the door.
Touch the SET/CLOCK pad once, the POWER LEVEL pad twice and the START pad once.
And touch the number pads 1 once and the number pad 2 once. Now, the oven is in the sensor
cooking condition, and “AH10” and “COOK” will appear in the display.
5. The oven will operate for the first 32 seconds, without generating microwave energy.
NOTE: ERROR will appear if the door is opened or STOP/CLEAR pad is touched during first stage
of sensor cooking.
6. After approximately 32 seconds, microwave energy is produced. If ERROR is displayed or the
oven does not turn off, replace the humidity sensor or check the control unit, refer to explanation
on next page.
continued on next page
3-13
Troubleshooting and Testing
Procedure
Letter
P
Component Test
TESTING METHOD FOR HUMIDITY SENSOR AND/OR CONTROL UNIT
To determine if the sensor is defective, the simplest method is to replace it with a new replacement
sensor.
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
4. Remove the humidity sensor.
5. Install the new humidity sensor.
6. Reconnect all leads removed from components during testing.
7. Re-install the outer case (cabinet).
8. Reconnect the power supply cord after the outer case is installed.
9. Reconnect the oven to the power supply and check the sensor cook operation as follows:
a) Fill approximately 200 milliliters of tap water in a 1000 milliliter measuring cup.
b) Place the container on the center of tray in the oven cavity.
c) Close the door.
d) Touch the SET/CLOCK pad once, the POWER LEVEL pad twice and the START pad once.
And touch the number pads 1 once and the number pad 2 once.
e) The control panel is in automatic Sensor operation.
f) The oven turns off automatically, and the time for detecting moisture will be displayed.
If new sensor dose not operate properly, the problem is with the control unit, and refer to explanation
below.
CHECKING CONTROL UNIT
1.
2.
3.
4.
5.
6.
7.
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
Disconnect the sensor connector that is mounted to control panel.
Then connect the dummy resistor circuit (see fig.) to the sensor connector of control panel.
Disconnect the leads to the primary of the power transformer.
Ensure that these leads remain isolated from other components and oven chassis by using
insulation tape.
8. After that procedure, re-connect the power supply cord.
9. Check the sensor cook operation proceed as follows:
a) Close the door. Touch the SET/CLOCK pad once, the POWER LEVEL pad twice and the
START pad once. And touch the number pads 1 once and the number pad 2 once.
b) The control panel is in the sensor cooking operation.
c) After approximately 41 seconds, push plunger of select switch for more than 3 seconds. This
condition is same as judgement by humidity sensor.
d) After approximately 3 seconds, the display shows “X X. X X “ which is the time for detecting
moisture.
If the above is not the case, the control unit is probably defective.
If the above is proper, the humidity sensor is probably defective.
continued on next page
3-14
Troubleshooting and Testing
Procedure
Letter
P
Component Test
10.
11.
12.
13.
14.
15.
16.
17.
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
Disconnect the dummy resistor circuit from the sensor connector of control panel.
Carry out necessary repair.
Reconnect all leads removed from components during testing and repairing.
Re-install the outer case (cabinet).
Reconnect the power supply cord after the outer case is installed. Run the oven and check all
functions.
18. Carry out “Water load cooking test” again and ensure that the oven works properly.
Sensor Dummy Resistor Circuit
Q
NOISE FILTER TEST
1.
2.
3.
4.
5.
Disconnect the power supply cord, and then remove outer case.
Open the door and block it open.
Discharge high voltage capacitor. (See Warnings and Instructions on page 3-1)
Disconnect the leads to the primary of the power transformer.
Using an ohmmeter, check between the terminals as described in the following table.
If incorrect readings are obtained, replace the noise filter.
6. Reconnect all leads removed from components during testing.
7. Reinstall the outer case (cabinet).
8. Reconnect the power supply cord after the outer case is installed.
9. Run the oven and check all functions.
3-15
Troubleshooting and Testing
Notes
3-16
Component Teardown and Testing
TO PREVENT AN ELECTRIC SHOCK, TAKE THE FOLLOWING PRECAUTIONS:
1. BEFORE WIRING:
1) Disconnect the power supply.
2) Open the door and block the door open.
3) Discharge the high voltage capacitor and wait for 60 seconds.
2. DO NOT LET WIRE LEADS TOUCH TO THE FOLLOWING PARTS:
1) High voltage parts:
Magnetron, High Voltage Transformer, High Voltage Capacitor And High Voltage Rectifier Assembly.
2) Hot parts:
Oven Lamp, Magnetron, High Voltage Transformer And Oven Cavity.
3) Sharp edge:
Bottom Plate, Oven Cavity, Waveguide Flange, Chassis Support And Other Metallic Plates.
4) Movable parts (to prevent a fault)
Fan Blade, Fan Motor, Switch, Switch Lever, Open Button.
3. Do not catch the wire leads in the outer case cabinet.
4. Insert the positive lock connector completely until its pin is locked. Make sure that the wire leads should
not come off even if the wire leads are pulled.
5. To prevent an error function, connect the wire leads correctly, referring to the Pictorial Diagram.
AVOID POSSIBLE EXPOSURE TO MICROWAVE ENERGY. PLEASE FOLLOW INSTRUCTIONS BELOW
BEFORE OPERATING THE OVEN.
1. Disconnect the power supply cord.
2. Make sure that a definite” click” can be heard when the microwave oven door is unlatched. (Hold the
door in a closed position with one hand, then push the door open button with the other, this causes
the latch leads to rise, it is then possible to hear a “click’ as the door switches operate.)
3. Visually check the door and cavity face plate for damage (dents, cracks, signs of arcing etc.).
Carry out any remedial work that is necessary before operating the oven.
DO NOT OPERATE THE OVEN IF ANY OF THE FOLLOWING CONDITIONS EXIST:
1. Door does not close firmly.
2. Door hinge, support or latch hook is damaged.
3. The door gasket or seal is damaged.
4. The door is bent or warped.
5. There are defective parts in the door interlock system.
6. There are defective parts in the microwave generating and transmission assembly.
7. There is visible damage to the oven.
DO NOT OPERATE THE OVEN:
1. Without the RF gasket (Magnetron).
2. If the wave guide or oven cavity are not intact.
3. If the door is not closed.
4. If the outer case (cabinet) is not fitted.
Disconnect oven from power supply before removing outer case.
Discharge high voltage capacitor before touching any oven components or wiring after removing outer
case.
4-1
Component Teardown and Testing
The following adjustments or component replacement can be performed without removing the oven
from the wall:
1. Hood lamps, sockets and grease filter.
2. Oven lamp, base cover and lamp glass assembly.
3. Turntable motor.
4. Hood louver.
5. Control panel assembly or components
6. Stirrer cover and stirrer antenna.
Figure 4-1. Outer Case Removal
Removal Of Oven From Wall
Outer Case Removal
Two persons recommended to remove the oven.
To remove the outer case, proceed as follows:
1. Disconnect the power supply cord, and uncoil the
power supply cord.
2. Remove the turntable tray and support from the oven
cavity.
3. While supporting the front of the oven, unfasten the
two (2) screws holding the oven to the unit mounting
plate.
4. While supporting the oven, remove the two (2)
screws holding the oven (outer case cabinet) to the
top cabinet.
5. Remove the oven from the unit mounting plate and
pull the power cord out of the wall cabinet.
6. The oven is now free and can be placed on the work
surface selected for servicing the oven.
7. Installation is the reverse of this procedure.
Hood Louver Removal
1. Disconnect the power supply cord.
2. Open the oven door and block it open.
3. Remove the one (1) screw holding the outer case
cabinet to the oven cavity front face plate (the
position is front/ center on the outer case cabinet).
4. Remove the two (2) screws holding the hood louver
to the oven cavity.
5. Remove the hood louver from the over by pushing
the right and left tabs of the hood louver.
6. Now, the hood louver is free.
To remove the outer case, proceed as follows;
1. Disconnect the power supply cord.
2. Open the oven door and block it open.
1. Disconnect oven from power supply before
removing outer case.
2. Discharge the high voltage capacitor before
touching any oven components or wiring.
3. Remove the one (1) screw holding the outer case
cabinet to the oven cavity front face plate (the
position is front/ center on the outer case cabinet).
4. Remove eight (8) screws holding the rear stay to the
hood fan motor or the oven, and remove it.
5. Remove the four (4) screws holding the base cover to
the outer case cabinet.
6. Remove the six (6) screws from the rear of the outer
case cabinet.
7. Slide the outer case cabinet back about 1 inch (3 cm)
to free it from retaining clips on the cavity face plate.
8. Disconnect the three (3) pin connector of the power
supply cord from the wiring harness and remove the
power supply cord together with the outer case.
9. Discharge high voltage capacitor.
To discharge the high voltage capacitor, 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.
4-2
Component Teardown and Testing
Removal
Positive Lock® Connector (No-Case
Type) Removal
1. Disconnect the power supply cord and then remove
outer case.
2. Open the oven door and block it open.
3. Discharge high voltage capacitor.
1. Disconnect the power supply cord, and then remove
outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
To discharge the high voltage capacitor, 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.
To discharge the high voltage capacitor, 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.
Power Transformer Removal
4. Disconnect filament leads of transformer from the
magnetron and capacitor.
5. Disconnect high voltage leads of capacitor from the
transformer.
6. Remove one (1) screw holding the capacitor holder to
fan duct and remove the capacitor.
7. Disconnect wire leads from transformer.
8. Remove three (3) screws holding the deflector to the
cavity face plate and remove the deflector.
9. Remove three (3) screws holding the base cover to
the cavity face plate and one (1) screw holding the
base cover to the cavity back plate, and remove the
base cover.
10. Remove two (2) screws holding the transformer to
right base plate.
4. Push the lever of positive lock® connector.
5. Pull down on the positive lock® connector.
Figure 4-2. Positive Lock® Connector
Re-install
1. Install by sliding the transformer on the right base
plate with its primary terminals toward the fan duct.
2. Secure the transformer with two (2) screws to right
base plate.
3. Re-connect wire leads (primary and high voltage) to
the transformer and filament leads of transformer to
magnetron and high voltage capacitor. Refer to
“Pictorial Diagram”.
4. Re-install the capacitor.
5. Re-install the base cover and the deflector.
6. Re-install the outer case and check that oven is
operating properly.
Make sure the wire leads never touch the fan blade.
4-3
Component Teardown and Testing
Hood Fan Motor, Hood Duct, Oven
Lamp Socket And AH Sensor
Removal
1. Disconnect the power supply cord and remove the
oven from wall and remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
To discharge the high voltage capacitor, 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.
4. Remove the hood louver.
5. Remove two (2) screws holding the chassis support
right to the rear and face of the oven cavity flanges.
6. Remove two (2) screws holding the chassis support
left to rear flange and face of the oven cavity flanges.
7. Remove both chassis supports.
8. Remove the wire tie holding the hood fan harness to
the hood duct by cutting it.
9. Disconnect the 6-pin connector of the hood fan motor
from the main wire harness located at the right edge
of the hood duct. Remove one (1) screw holding the
hood intake duct to right base plate. Remove one (1)
screw holding the hood duct to the hood intake duct
right. Remove the hood intake duct right. Release
the snap band from the cavity top plate.
10. Disconnect the two (2) grounding wires from the
chassis support left.
11. Now, the hood fan motor is free.
12. Remove the one (1) screw holding the noise filter
assembly to the fan duct.
13. Disconnect the connector CN-F and CN-D from the
control unit.
14. Remove one (1) screw holding the hood duct to the
oven cavity top plate.
15. Remove the one (1) screw holding the hood duct to
the fan duct.
16. Release the 6-pin connector and the 3-pin connector
of the main harness A from the hood duct.
17. Disconnect the control harness A from the control
harness B.
18. Disconnect the connector of control harness A from
the cavity face plate.
19. Remove the hood duct from the oven cavity by lifting
it up.
20. Release the snap band of control harness A from the
hood duct.
21. Release the harness of the sensor assembly and the
control harness A from four (4) wire holders of the
hood duct.
22. Remove two (2) screws holding the sensor assembly
to the hood duct.
23. Now, the sensor assembly is free.
24. Lift the oven lamp cover up and remove the oven
lamp cover from hood duct.
25. Remove the oven lamp (Refer to the procedure of
“Oven Lamp Removal”).
26. Remove the lamp heat cover from hood duct.
27. Disconnect the wire leads from the oven lamp socket.
28. Rotate the oven lamp socket to remove from hood
duct.
29. Now, the oven lamp socket is free.
When the hood fan motor is reinstalled, hold the
hood fan motor harness at the right edge of the
hood duct with one wire tie.
4-4
Figure 4-3. Hood Fan Motor Components
Component Teardown and Testing
Magnetron Removal
High Voltage Rectifier And High
Voltage Capacitor Removal
1. Disconnect the power supply cord and then remove
outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
1. Disconnect the power supply cord and then remove
outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
To discharge the high voltage capacitor, 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.
4. Remove two (2) screws holding the chassis support
right to the rear and face of the oven cavity flanges.
5. Remove the one (1) screw holding the noise filter
assembly to the fan duct.
6. Disconnect the wire leads from the fan motor.
7. Disconnect the high voltage wire leads of the high
voltage rectifier assembly from the magnetron.
8. Disconnect the filament lead of the transformer from
the magnetron.
9. Remove the one (1) screw holding the hood duct to
the fan duct and remove the one (1) screw holding
the oven cavity top plate to the fan duct.
10. Remove the one (1) screw holding the right base
plate to the fan duct and remove the fan duct
assembly.
11. Remove the power transformer from the right base
plate, referring to “Power Transformer Removal“.
12. Carefully remove four (4) mounting screws holding
the magnetron to waveguide. When removing the
screws hold the magnetron to prevent it from falling.
13. Remove the magnetron from the unit with care so the
magnetron tube should not be hit by any metal object
around the tube.
To discharge the high voltage capacitor, 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.
4. Disconnect the high voltage wire leads with high
voltage rectifier from the magnetron.
5. Disconnect filament lead of the transformer from high
voltage capacitor.
6. Disconnect high voltage wire from capacitor.
7. Remove one (1) screw holding capacitor holder and
high voltage rectifier to the fan duct.
8. Disconnect the high voltage rectifier assembly from
the high voltage capacitor and remove one (1) screw
holding the voltage rectifier assembly to the capacitor
holder.
9. Now, the high voltage rectifier assembly is free.
10. Remove capacitor from the holder.
11. Now, the high voltage capacitor is free.
When replacing high voltage rectifier and high
voltage capacitor, ground side terminal of the high
voltage rectifier must be secured firmly with a
grounding screw.
When replacing the magnetron, be sure the R.F.
Anode Gasket is in place and mounting screws are
tightened securely.
4-5
Component Teardown and Testing
Hood Fan Thermostat (60ºC ON and
70ºC OFF) Removal
1. Disconnect the power supply cord and then remove
outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
To discharge the high voltage capacitor, 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.
4. Disconnect the wire leads from the hood fan
thermostat (60°C ON or 70°C OFF).
5. Remove one (1) screw holding the thermostat (60°C
ON or 70°C OFF) to the right base plate.
6. Remove the hood fan thermostat (60°C ON or 70°C
OFF) from the right base plate.
7. Now, the hood fan thermostat (60°C ON or 70°C
OFF) is free.
Cooling Fan Motor Removal
1. Disconnect the power supply cord and then remove
outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
To discharge the high voltage capacitor, 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.
4. Remove two (2) screws holding the chassis support
right to the rear and face of the oven cavity flange.
5. Remove the one (1) screw holding the noise filter
assembly to the fan duct.
6. Disconnect the wire leads from the fan motor.
7. Disconnect the high voltage wire leads of the high
voltage rectifier assembly from the magnetron.
8. Disconnect filament lead of transformer from
magnetron.
9. Remove the one (1) screw holding the hood duct to
the fan duct and remove the one (1) screw holding
the oven cavity top plate to the fan duct.
10. Remove the one (1) screw holding the right base
plate to fan duct and remove the fan duct assembly.
11. Remove the fan blade from the fan motor shaft
according the following procedure.
12. Hold the edge of the rotor of the fan motor by using a
pair of groove joint pliers.
*
Make sure that no metal pieces enter the gap
between the rotor and the stator of the fan motor
because the rotor is easily shaven by pliers and
metal pieces may be produced.
Do not touch the pliers to the coil of the fan
motor because the coil may be cut or injured.
Do not disfigure bracket by touching with pliers.
*
Figure 4-4. Thermostat Removal
*
13. Remove the fan blade from the shaft of the fan motor
by pulling and rotating the fan blade with your hand.
14. Now, the fan blade will be free.
Do not reuse the removed fan blade because the
hole (for shaft) may be larger than normal.
4-6
Component Teardown and Testing
15. Remove the two (2) screws holding the fan motor
to the fan duct.
16. Now, the fan motor is free.
INSTALLATION
1. Install the fan motor to the fan duct with the two (2)
screws.
2. Install the fan blade to the fan motor shaft according
to the following procedure.
3. Hold the center of the bracket which supports the
shaft of the fan motor on the flat table.
4. Apply the screw locktight into the hole (for shaft) of
the fan blade.
5. Install the fan blade to the shaft of fan motor by
pushing the fan blade with a small, light weight, ball
peen hammer or rubber mallet.
*
*
*
Do not hit the fan blade strongly when installed
because the bracket may be disfigured.
Make sure that the fan blade rotates smooth after
installation.
Make sure that the axis of the shaft is not
slanted.
6. Install the fan duct to the oven cavity, base plate right
and hood duct with the three (3) screws.
7. Connect the high voltage wire leads with high voltage
rectifier from the magnetron, referring to the pictorial
diagram.
8. Connect filament lead of the transformer from high
voltage capacitor, referring to the pictorial diagram.
9. Connect high voltage wire from capacitor, referring to
the pictorial diagram.
10. Connect the wire leads to the fan motor, referring to
the pictorial diagram.
11. Re-install the outer case.
Figure 4-5. Fan Assembly Removal
Turntable Motor Removal
1. Disconnect the power supply cord and then remove
outer case.
2. Open the door and block it open.
3. Remove the three (3) screws holding the deflector to
the cavity face plate.
4. Remove the four (4) screws holding the base cover to
the oven cavity.
5. Remove the base cover from the oven cavity by
pulling down and moving to the left slightly.
6. Disconnect the wire leads from the turntable motor.
7. Remove one (1) screw holding turntable motor to the
oven cavity.
8. Now the turntable motor is free.
4-7
Component Teardown and Testing
Antenna Motor Removal
Stirrer Cover And Stirrer Fan
Installation
1. Disconnect the power supply cord and then remove
outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
To discharge the high voltage capacitor, 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.
4. Remove the hood duct from the oven cavity, referring
to the procedure of “Hood Fan Motor, Hood Duct And
Oven Lamp Socket Removal”.
5. Disconnect the wire leads from the antenna motor.
6. Remove the one (1) screw holding the antenna motor
to the waveguide of the oven cavity.
7. Remove the antenna motor from the waveguide.
8. Now, the antenna motor is free.
9. When installing the antenna motor, the shaft of
antenna motor must be inserted to the stirrer antenna
shaft. Refer to the procedure of “Stirrer Cover And
Stirrer Fan Installation”.
Oven Lamp Removal
1. Disconnect the power supply cord.
2. Remove the hood louver from the oven. (Refer to
procedure of “Hood Louver Removal”)
3. Lift the oven lamp cover up.
4. Now, the oven lamp and the socket are found.
5. Screw the oven lamp off from the lamp socket.
6. Now, the oven lamp is free.
1. Put the stirrer antenna on the wave guide to match
the stirrer antenna shaft to the center of the stirrer
hole.
2. Insert the shaft of stirrer antenna to the shaft of
antenna motor.
3. Rotate the antenna holder to lock at the cavity top
plate.
4. Insert the cutout of stirrer cover to the tabs on the
ceiling.
5. Install the stirrer cover to the oven cavity, and secure
it by one canoe clip.
Figure 4-6. Oven Lamp Socket
Servicing For Touch Control Panel
Precautions for Handling Electronic Components
This unit uses CMOS LSI in the integral part of the
circuits. When handling these parts, the following
precautions should be strictly followed. CMOS LSI
have extremely high impedance at its input and output
terminals. For this reason, it is easily influenced by the
surrounding high voltage power source, static electricity
charge in clothes, etc. and sometimes it is not fully
protected by the built-in protection circuit.
In order to protect CMOS LSI.
1. When storing and transporting, thoroughly wrap them
in aluminium foil. Also wrap all PW boards containing
them in aluminium foil.
2. When soldering, ground the technician as shown in
the figure and use grounded soldering iron and work
table.
4-8
Component Teardown and Testing
Servicing of Touch Control Panel
The following are descriptions of the procedures to permit
servicing of the touch control panel of the microwave
oven and the precautions you must take when doing
so. To perform the servicing, power to the touch control
panel is available either from the power line of the oven
itself or from an external power source.
1. Servicing the touch control panel with power
supply of the oven:
The high voltage transformer of the microwave
oven is still live during servicing and presents a
hazard.
b) On some models, the power supply cord between
the touch control panel and the oven proper is long
enough that they may be separated from each other.
For those models, it is possible to check and repair
the controls of the touch control panel while keeping
it apart from the oven proper; in this case you must
short both ends of the door sensing switch (on PWB)
of the touch control panel with a jumper, which
activates an operational state that is equivalent to
the oven door being closed. As for the sensor-related
controls of the touch control panel, checking them is
possible if dummy resistor(s) with resistance equal to
that of the controls are used.
2. Servicing the touch control panel with power
supply from an external power source:
Disconnect the touch control panel completely from
the oven proper, and short both ends of the door
sensing switch (on PWB) of the touch control panel,
which brings about an operational state that is
equivalent to the oven door being closed. Connect
an externa power source to the power input terminal
of the touch control panel, then it is possible to check
and repair the controls of the touch control panel; it is
also possible to check the sensor-related controls
of the touch control panel by using the dummy
resistor(s).
Therefore, before checking the performance of the touch
control panel:
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 these leads remain isolated from other
components and oven chassis by using insulation
tape.
6. After that procedure, re-connect the power supply
cord.
Servicing Tools
After checking performance of touch control panel:
1. Disconnect the power supply cord.
2. Open the door and block it open.
3. Re-connect the leads to the primary of the power
transformer.
4. Re-install the outer case (cabinet).
5. Re-connect the power supply cord after the outer
case is installed.
6. Run the oven and check all functions.
a) On some models, the power supply cord between
the touch control panel and the oven itself is so short
that the two can’t be separated. For those models,
check and repair all the controls (sensor-related ones
included) of the touch control panel while keeping it
connected to the oven.
Tools required to service the touch control panel
assembly.
1. Soldering iron: 60W (It is recommended to use a
soldering iron with a grounding terminal.)
2. Oscilloscope: Single beam, frequency range: DC 10MHz type or more advanced model.
3. Others: Hand tools
Other Precautions
1. Before turning on the power source of the control
unit, remove the aluminium foil applied for preventing
static electricity.
2. Connect the connectors of the key unit to the control
unit being sure that the lead wires are not twisted.
3. After aluminium foil is removed, be careful that
abnormal voltage due to static electricity etc. is not
applied to the input or output terminals.
4. Attach connectors, electrolytic capacitors, etc. to
PWB, making sure that all connections are tight.
5. Be sure to use specified components where high
precision is required.
4-9
Component Teardown and Testing
Panel Sub Assembly And Control Unit Door Sensing Switch / Secondary
Interlock Switch And Monitor Switch
Removal
Removal
1. Disconnect the power supply cord.
2. Open the door and block it open.
3. Remove the hood louver from the oven.
4. Remove one (1) screw holding the panel sub assembly to the oven cavity front face plate.
5. Release the panel sub assembly from the oven cavity
front face plate by lifting it up.
6. Disconnect the wire leads from the relays RY1 and
RY2.
7. Disconnect the connectors CN-A, CN-B, CN-C, CNE, CN-F and CN-G from the control unit.
8. Remove the panel sub assembly from the oven.
9. Now, the panel sub assembly is free.
10. Remove two (2) screws holding the control unit to the
panel sub assembly.
11. By releasing the tabs from the control unit, remove
the control unit from the panel sub. assembly.
12. Now, the control unit is free.
1. Disconnect the power cord and remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
To discharge the high voltage capacitor, 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.
4. Remove the control panel assembly, referring to the
procedure of “Control Panel Assembly, Control Unit
And Key Unit Removal”.
5. Remove the two (2) screws holding the latch hook to
the oven cavity front flange.
6. Remove latch hook from the oven cavity front flange.
7. Disconnect the wire leads of each switch.
8. Remove each switch from the latch hook by pushing
the one (1) stopper tub holding each switch.
9. Now, each switch is free..
Re-install
1. Re-install each switch in its place. The secondary
interlock switch is in the lower position, door sensing
switch is in the upper position and the monitor switch
is in the middle position.
2. Re-connect wire leads to each switch. Refer to
pictorial diagram.
3. Secure latch hook with two (2) mounting screws to
oven flange.
4. Make sure that the monitor switch is operating
properly and check continuity of the monitor circuit.
4-10
Component Teardown and Testing
After adjustment, check the following:
Door Sensing Switch / Secondary
Interlock Switch And Monitor Switch
Adjustment
1. In and out play of door remains less than 0.5mm
when in the latched position. First check upper
position of latch hook, pushing and pulling upper
portion of door toward the oven face. Then check
lower portion of the latch hook, pushing and pulling
upper portion of door toward the oven face. Both
results (play in the door) should be less than 0.5mm.
2. The door sensing switch, primary switch and third
door switch interrupt the circuit before the door can
be opened.
3. Monitor switch contacts close when door is opened.
4. Re-install outer case and check for microwave
leakage around door with an approved microwave
survey meter.
1. Disconnect power cord and remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
To discharge the high voltage capacitor, 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.
4. Remove the right panel assembly, referring to the
procedure of “Right Panel Assembly And Power Unit
Removal”.
If the door sensing switch, secondary interlock switch
and monitor switch do not operate properly due to a
misadjustment, the following adjustment should be
made.
5. Loosen the two (2) screws holding latch hook to the
oven cavity front flange.
6. With door closed, adjust latch hook by moving it back
and forth, and up and down. In and out play of the
door allowed by the upper and lower position of the
latch hook should be less than 0.5mm. The vertical
position of the latch hook should be adjusted so that
the door sensing switch, secondary interlock switch
are activated with the door closed. The horizontal
position of the latch hook should be adjusted so that
the monitor switch is activated with the door closed.
7. Secure the screws with washers firmly.
8. Check all of the switches operation. If any switch
has not activated with the door closed, loosen screw
and adjust the latch hook position.
4-11
Figure 4-7. Latch Switch Adjustments
Component Teardown and Testing
Door Replacement
Removal
1. from wal and remove outer case. (Refer to procedure
of “Removal of Oven from Wall” and “Outer case
Removal”)
2. Open the door and block it open.
3. Discharge high voltage capacitor.
After any service to the door:
(A) Make sure that door sensing switch, primary
switch and secondary switch are operating
properly.
(B) An approved microwave survey meter should be
used to assure compliance with proper microwave radiation emission limitation standards.
After any service, make sure of the following:
To discharge the high voltage capacitor, 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.
4. Remove the hood louver from the oven. (Refer to the
procedure of “Hood Louver Removal”.)
5. Insert a putty knife (thickness of about 0.5mm) into
the gap A between the door stopper and the choke
cover as shown in Figure 4-9 to free engaging parts.
6. Lift up the door stopper.
7. Now, the door stopper is free from the door assembly.
8. Lift up the door assembly to release the upper and
lower door hinge pins from the upper and lower oven
hinges.
9. Now, the door assembly is free.
NOTE: When the individual parts are replaced, refer to
“Door Disassembly”.
Re-Install
1. On re-installing door, insert the lower oven hinge to
lower door hinge pin.
2. Insert the upper oven hinge to the upper door hinge
pin.
3. Shut the door (close the contacts of interlock
switches).
4. Make sure upper and lower oven hinges are inserted
into the upper an lower door hinge pins.
5. Make sure the door is parallel with oven face lines
(left and upper side lines) and door latch heads pass
through latch holes correctly.
6. Re-install the door stopper to the door assembly.
7. Re-install the hood louver to the oven cavity front
face plate.
1. Door latch heads smoothly catch latch hook through
latch holes and that latch head goes through center
of latch hole.
2. Deviation of door alignment from horizontal line of
cavity face plate is to be less than 1.0mm.
3. Door is positioned with its face pressed toward cavity
face plate.
4. Check for microwave leakage around door with an
approved microwave survey meter.
(Refer to Microwave Measurement Procedure.)
The door on a microwave oven is designed to act
as an electronic seal preventing the leakage of
microwave energy from oven cavity during cook
cycle. This function does not require that door be
air-tight, moisture (condensation)-tight or lighttight. Therefore, occasional appearance of moisture, light or sensing of gentle warm air movement
around oven door is not abnormal and do not of
themselves indicate a leakage of microwave energy
from oven cavity.
Figure 4-8. Choke Cover
4-12
Component Teardown and Testing
DOOR FRAME
Door Disassembly
1. Disconnect the power supply cord and remove the
oven from wall and remove outer case. (Refer to
procedure of “Removal of Oven from Wall” and “Outer
case Removal”)
2. Open the door and block it open.
3. Discharge high voltage capacitor.
13. Remove eight (8) screws holding the door panel to
the door frame assembly.
14. Release the door frame assembly from the door
panel.
It is easier to release the engaging parts of the
upper or lower door hinge pin side at first.
To discharge the high voltage capacitor, 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.
15. Now, door frame assembly is free.
4. Remove the hood louver from the oven cavity. (Refer
to the procedure of “Hood Louver Removal”.)
5. Remove door assembly, refer to “Door Replacement”.
Replacement of door components are as follows:
6. Place door assembly on a soft cloth with latches
facing up.
As the engaging part of choke cover and door
frame are provided at 16 places, do not force any
particular part.
Figure 4-9. Choke Cover
CHOKE COVER
Cook Top Lamp Socket Removal
7. Insert a putty knife (thickness of about 0.5mm) into
the gap A between the choke cover and door stopper
and between the choke cover and the door frame as
shown Figure 4-9 to free engaging parts.
8. Pry the choke cover by inserting a putty knife in order
shown in Figure 4-9.
9. Now choke cover is free from door panel and door
frame.
1. Disconnect the power supply cord.
2 Remove the three (3) screws holding the deflector to
the base cover.
3. Remove the one (1) screw holding the base cover to
the oven cavity back plate.
4. Remove the four (4) screws holding the base cover to
the outer case cabinet.
5. Remove the three (3) screws holding the base cover
to the oven cavity base plate.
6. Pull down and slide to left the base cover. Then
remove the base cover from the cavity back plate.
7. Remove the one (1) screw holding the lamp mounting
angle.
8. Remove the lamp mounting angle from the oven
cavity face plate.
9. Disconnect the wire leads from the lamp socket.
10. Remove the two (2) screws holding the lamp socket
from the lamp mounting angle.
11. Now, the lamp socket is free.
LATCH SPRING, LATCH HEAD AND DOOR PANEL
10. Release the latch spring from the tab of the latch
head and tab of the door panel.
11. Release the latch head from the door panel.
12. Now, the latch spring, latch head and door panel are
free.
4-13
Component Teardown and Testing
Notes
4-14
Wiring Diagrams
Circuit Components
5-1
Wiring Diagrams
Glass Touch Key Unit Diagram
5-2
Wiring Diagrams
Control Unit Circuit
5-3
Wiring Diagrams
Oven Wiring Schematic Off Condition
5-4
Parts List
6-1
Parts List
6-2
Parts List
Oven And Cabinet Parts
107
107
36
107
107
88
106
107
25
107
106
107
107
27
57
16
75
54
9
10
107
14
47
107
107
108
107
110
37
107
107
50
34
59
107
92
96
22
19
11
34
48
110
107 A
113
108
4
12
108
116
89
17
15
107
52
21
50
112
52
38
90
108
89
107
46
109
99
49
107
28
78
41
55
61
2
58
62
40
117
91
55
7
34
77
117
107
6
113
81
60
A
8 111 18
5
44
24
9
8
81
107
45
107
95
26
29
76-4
42
93
53
105
105
76-4
76-1
105
76-2
76
76-3
76-4
76-5
23-2
23-1
76-6
105
6-3
108
80
3
107
108
19
20
107
39
108
114
43
51
94
1
13
93
23
59
Parts List
Door Assembly and Control Unit
56
71
100
72
64
68
65
69
101
30
35
101
74
89
70
102
107
31
73
88
102
67
6-4
Parts List
Packing And Accessories
PACKING SUPPORT
UNIT MOUNTING ANGLE
29
DOOR PROTECTOR
TOP PAD
PROTECTION SHEET
WRAP COVER
38
TURNTABLE TRAY
CABINET COVER
TRAY PAD
82
CUSHION
76
ACCESSORY ASSEMBLY
87
WALL TEMPLATE
84
INSTALLATION INSTRUCTION
86
TOP TEMPLATE
DOOR PAD
95
118 INFORMATION
85
RACK
OPERATION MANUAL
RACK PAD
93
GREASE FILTER(x2)
36 DAMPER ASSEMBLY
BOTTOM PAD
ACCESSORY HOLDER
Non-replaceable items
PACKING CASE
6-5
Parts List
Notes
6-6