LG LSMC3089BD User manual

MICROWAVE OVEN
SERVICE MANUAL
MODEL: LSMC3086ST
LSMC3089BD
CAUTION
BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
Website http://biz.lgservice.com
P/NO : MFL06272539
May, 2015
Printed in Korea
삼흥
정판
Internal Use Only

CAUTION
WARNING TO SERVICE TECHNICIANS
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.
• Proper operation of the microwave ovens requires that the magnetron be assembled to the wave guide and cavity.
Never operate the magnetron unless it is properly installed.
• Be sure that the magnetron gasket is properly installed around the dome of the tube whenever installing the
magnetron.
• Routine service safety procedures should be exercised at all times.
• Untrained personnel should not attempt service without a thorough review of the test procedures and safety
information contained in this manual.

FOREWORD
Read this Manual carefully. Failure to adhere to or observe the information in this Manual may result in exposing
yourself to the Microwave Energy normally contained within the oven cavity.
TABLE OF CONTENTS
(Page)
SAFETY PRECAUTIONS ............................................................................................................. Inside front page
SPECIFICATIONS................................................................................................................................................ 1-1
CAUTIONS........................................................................................................................................................... 2-1
INSTALLATIONS ................................................................................................................................................. 3-1
OPERATING INSTRUCTIONS ............................................................................................................................ 4-1
CONTROL PANEL........................................................................................................................................... 4-1
CONTROL PANEL INSTRUCTIONS............................................................................................................... 4-2
OVERALL CIRCUIT DIAGRAM........................................................................................................................... 5-1
SCHEMATIC DIAGRAM.................................................................................................................................. 5-1
GENERAL INFORMATION FOR SERVICE......................................................................................................... 6-1
GENERAL PRECAUTIONS IN USE .............................................................................................................. 6-1
TRIAL OPERATION ........................................................................................................................................ 6-1
FEATURES AND SPECIFICATIONS FEATURES .......................................................................................... 6-1
SERVICE INFORMATION.................................................................................................................................... 7-1
PRECAUTIONS AND REPAIR SERVICE TIPS .............................................................................................. 7-1
MICROWAVE LEAKAGE TEST ...................................................................................................................... 7-2
POWER OUTPUT MEASUREMENT .............................................................................................................. 7-3
DISASSEMBLY INSTRUCTIONS ................................................................................................................... 7-4
INTERLOCK SYSTEM .................................................................................................................................. 7-11
INTERLOCK CONTINUITY TEST................................................................................................................. 7-13
TEST AND CHECKOUT PROCEDURES AND TROUBLESHOOTING........................................................ 7-14
A. TEST PROCEDURES ......................................................................................................................... 7-14
B. CHECKOUT PROCEDURES .............................................................................................................. 7-17
C. TROUBLESHOOTING......................................................................................................................... 7-20
EXPLODED VIEW................................................................................................................................................ 8-1

1-1
SPECIFICATIONS
Rated Power Consumption ................................ Microwave 1650W
Convection 1650W
Microwave Output............................................... Microwave 950W (IEC60705)
Adjustable 95W through 950W, 10 steps
Convection 1500W
Frequency .......................................................... 2450 MHz ±50 MHz
Power Supply .................................................... 120 V~ 60 Hz
Rated Current .................................................... Microwave 14.0A
Convection 14.0A
Magnetron Cooling ............................................ Forced Air Cooling
Rectification ....................................................... Rectification Voltage Double Half-Wave
Door Sealing ...................................................... Choke System
Safety Devices ................................................... Magnetron Thermostat: Open at 160 °C ± 5 °C
Close at 0 °C ± 5 °C
............................................................................ Oven Thermostat: Open at 145 °C ± 5 °C
Close at 0 °C ± 5 °C
............................................................................ Fuse(20A)
............................................................................ Primary Interlock Switch
............................................................................ Secondary Interlock Switch
............................................................................ Interlock Monitor Switch
Magnetron ......................................................... 2M246
Cook top Lamp .................................................. 130 V, 50 W
Cavity Lamp ....................................................... 130 V, 50 W
Timer ................................................................. Digital, up to 99 min. 99 sec. (in each cooking stage)
Tray ................................................................... Tempered Safety Glass
Overall Dimensions ........................................... 2915/16”(W)x167/16”(H)x153/8”(D)
Oven Cavity Size ............................................... 211/4”(W)x97/16”(H)x143/16”(D)
Effective Capacity of Oven Cavity ..................... 1.7 Cu.ft.
Accessories ....................................................... Use & Care Guide, Cooking Guide, Installation Manual
Exhaust Adapter, Exhaust Damper, Mounting Kit & Two Filter
Shaft, Rotating Ring, Glass Tray, Grill Rack, Metal Tray
SWITCH CHART
SWITCH MODE
PRIMARY
INTERLOCK
SWITCH
SECONDARY
INTERLOCK
SWITCH
INTERLOCK
MONITOR
SWITCH
CONDITIONS COM
NO
COM
NO
COM
NC
DOOR OPEN OPEN OPEN OPEN
DOOR CLOSED CLOSE CLOSE CLOSE
NOTE: Use the above switch chart with circuit diagram on page 5-1.

2-1
CAUTIONS
Unlike other appliances, the microwave oven is
high-voltage and high-current equipment.
Though it is free from danger in ordinary use,
extreme care should be taken during repair.
MICROWAVE RADIATION
Personnel should not be exposed to the
microwave energy which may radiate from the
magnetron or other microwave generating
device if it is improperly used or connection.
All input and output microwave connections,
waveguide, flange, and gasket must be secure
never operate the device without a microwave
energy absorbing load attached.
Never look into an open waveguide or antenna
while the device is energized.
• DO NOT operate on a 2-wire extension cord during repair
and use.
• NEVER TOUCH any oven components or wiring during
operation.
• BEFORE TOUCHING any parts of the oven, always
remove the power plug from the outlet.
• Remove your watches whenever working close to or
replacing the Magnetron.
• DO NOT touch any parts of the control panel circuit. A
resulting static electric discharge may damage this P.C.B.
• NEVER operate the oven with no load.
• NEVER injure the door seal and front plate of the oven
cavity.
• NEVER put iron tools on the magnetron.
• NEVER put anything into the latch hole and the interlock
switches area.
• Proper operation of the microwave oven requires that
the magnetron be assembled to the waveguide and
cavity. Never operate the magnetron unless it is
properly installed.
• Be sure that the magnetron gasket is properly
installed around the dome of the tube whenever
installing the magnetron.
THE OVEN IS TO BE SERVICED ONLY
BY PROPERLY QUALIFIED SERVICE
PERSONNEL.
Gasket
ANTENNA
COOLING FIN
MAGNETRON
CHASSIS GROUND FILAMENT
TERMINALS
MAGNETRON

3-1
INSTALLATIONS
BEFORE YOU BEGIN, READ THE FOLLOWING INSTRUCTIONS COMPLETELY AND CAREFULLY.
PRECAUTIONS ON INSTALLATION
A. Plug the power supply cord into a 120V AC, 60Hz,
single-phase power source with a capacity of at least
20 amperes.
B. Avoid placing the unit in a location where there is
direct heat or splashing water.
C. Install the unit on the mounting plate firmly.
D. Place the unit as far away as possible from TV,
radio, etc. to prevent interference.
GROUNDING INSTRUCTIONS
For personal safety, this appliance must be fully
grounded at all times.
In the event of an electrical short circuit, grounding
reduces the risk of electrical shock.
The plug must be plugged into an outlet that is
properly installed and grounded.
CAUTION
This unit is equipped with a 3-prong plug for your
safety. If the wall outlet is a grounded 3-hole type,
the unit will be grounded automatically.
WARNING
Improper use of the grounding plug can result in a
risk of electric shock.
Do not, under any circumstances, cut or remove the
third ground prong from the power cord plug.
Plug with Ground
Prong
Properly Polarized
and Grounded
Outlet

4-1
OPERATING INSTRUCTIONS
CONTROL PANEL
1
2
46
3
9
12
14
15
18
21
7
10
13
16
19
17
20
11
8
5

4-2
CONTROL PANEL INSTRUCTIONS
1. DISPLAY: The Display includes a clock and indicators
to tell you time of day, cooking time settings, and
cooking functions selected.
ICONS
2. SMART DIAGNOSIS: Hold the mouthpiece of a phone
up to this icon when directed to by service center
personnel, to help diagnose problems with the oven
when calling for service.
3. TAG ON: Hold a smart phone over this icon to activate
the NFC function.
COMMAND KEYS
4. SENSOR REHEAT: Touch this key to reheat
casseroles, dinner plates, pizza slices, and soups/
sauces. The oven’s sensor tells the oven how long to
cook depending on the amount of humidity coming
from the food.
5. SENSOR COOK: Touch this key to cook-baked potato,
frozen vegetable, fresh vegetable, canned vegetable,
frozen entrée, and rice. The oven’s sensor tells the
oven how long to cook depending on the amount of
humidity coming from the food.
6. SENSOR POPCORN: Touch this to pop popcorn.
The oven’s sensor tells the oven how long to cook
depending on the amount of humidity it detects from
the popcorn.
7. CUSTOM COOK: Touch this key to recall one cooking
instruction previously programmed into memory.
8. MANUAL COOK: Select the functions to operate
MICROWAVE and CONVECTION, COMBI.
9. CUSTOM SET: Touch this key to change the oven’s
default settings for sound, clock, display speed, and
defrost weight.
10. AUTO COOK: Touch this key to cook bacon, fresh
rolls and muffins, frozen rolls and muffins, beverages,
chicken pieces, and hot cereal.
- SOFTEN : butter, ice cream, cream cheese, or
frozen juice.
- MELT: butter, chocolate, cheese, or marshmallows.
11. SPEED AUTO COMBI: Touch this pad when setting
weight combination cooking.
12. AUTO DEFROST: Touch this pad to select food type
and defrost food by weight.
CONTROLS
13. CONTROL DIAL: Set cooking time, temperature,
weight and cooking categories. Lengthen or
shorten the cooking time at any point by turning the
dial(except in defrost mode). Press on the dial to start
a function or enter all entries.
14. START: Touch the key to start a function, accept
selections, or restart after opening.
15. STOP/CLEAR: Touch this key to stop the oven or to
clear all entries.
16. LIGHT ON/OFF: Touch this key to turn the cooktop/
countertop light on or off.
17. TURNTABLE ON/OFF: Touch this key to turn off the
turntable. OFF appears in the display.
NOTE: This option is not available in sensor cook and
defrost modes.
18. TIMER ON/OFF: Touch this key to set the timer.
19. VENT ON/OFF: Touch this key to turn the fan on/off.
20. VENT 5-SPEED: Touch this key to choose one of 5
fan speeds.
21. VENT AUTO TIMESET: Touch this key when setting
the ventilation time. (1, 3, 5, 10, and 30 minutes.)

5-1
OVERALL CIRCUIT DIAGRAM
SCHEMATIC DIAGRAM
CAUTIONS
• Disconnect from electrical supply before servicing unit.
• Sharp edges. Wear gloves when replacing main fuse or
servicing the product to prevent injuries.

6-1
GENERAL INFORMATION FOR SERVICE
GENERAL PRECAUTIONS IN USE
A. Never operate the unit when it is empty.
Operating the oven with no load may shorten the
life of the magnetron. Whenever cooking dry foods
(dried fish, bread, etc.)or a small amount of food,
be sure to put a glass of water into the cooking
compartment. The glass turntable may become hot
after operating, be careful when touching it.
B. Aluminum foil should be avoided because it will
disrupt cooking and may cause arcing. However,
small pieces may be used to cover some parts of
food to slow the cooking. Any aluminum foil used
should never be closer than 2.5 cm to any side wall
of the oven.
TRIAL OPERATION
After installation, the following sequences and results
should be checked carefully.
A. Put a container filled with water (about 1 liter)into
the oven, and close the door tightly.
B. Set cooking time for 10 minutes by touching “1 ”
and then “0” three times.“1, 0, 0, 0” appears in the
display window.
C. Touch the START/ENTER key.
Make sure the cavity light comes on. The unit will
begin cooking and the display window will show the
time counting down by seconds.
D. After about 5 minutes, make sure the primary
interlock switch, the secondary interlock switch
and the interlock monitor switch operate properly
by opening and closing the door several times.
Touch the START/ENTER key each time the door is
closed.
E. Continue operating the unit. Two short and a long
beep sound signal is heard when the time is up.
The unit will shut off automatically.
F. Confirm the water is hot.
G. Finally, measure the output power according to
“POWER OUTPUT MEASUREMENT” on
page 7-3.
FEATURES AND SPECIFICATIONS
FEATURES
A. The safety systems incorporated in this model are:
(1) Primary interlock switch
(2) Secondary interlock switch
(3) Interlock monitor switch
(4) Choke system
(5) Oven cavity thermostat
(Note This thermostat located on the oven cavity
will open and stop the unit from operation only
if a high temperature is reached, such as, a fire
created by overcooking food.)
B. Any one of 10 power output levels ranging 0W to
950W can be selected by the touch control and
electronic computer system.
C. Cooking time can be displayed on the digital
readout.
D. Three different cooking stages (Include Defrost) can
be changes from one cooking stage to another. This
is made possible with the memory function of the
microprocessor.

7-1
SERVICE INFORMATION
PRELIMINARY
A. SINCE NEARLY 4000 VOLTS EXISTS IN SOME
CIRCUITS OF THIS UNIT REPAIRS SHOULD
BECARRIED OUT WITH GREAT CARE.
The filament leads of magnetron carry High
Voltage with respect to ground. Extreme caution
must be exercised. Never plug the unit into a
power source to determine which component is
defective in high voltage section.
B. TO AVOID POSSIBLE EXPOSURE TO
MICROWAVE ENERGY LEAKAGE, THE
FOLLOWING PRECAUTIONS MUST BE TAKEN
BEFORE SERVICING.
(1) Before the power is applied:
(a) Make sure the primary interlock switch, the
secondary interlock switch and the interlock
monitor switch operate properly by opening
and closing the door several by opening and
closing the door several times.
(b) Make sure the perforated screen and the
dielectric choke of the door are correctly and
firmly mounted.
(2) After power is applied:
(a) Make sure the interlock switch mechanism
is operating properly by opening and closing
the door.
(b)
Check microwave energy leakage must be below
the limit of 5 mW/cm2.
(All service adjustments should be made for
minimum microwave energy leakage
readings).
(3) Do not operate the unit until it is completely
repaired, if any of the following conditions exist.
The unit must not be operated.
(a) The door does not close firmly.
(b) The hinge is broken.
(c) The door seal is damaged.
(d) The door is bent or warped, or there is any
other visible damage on the unit that may
cause microwave energy leakage.
NOTE: Always keep the seal clean.
(e) Make sure that there are no defective parts
in the interlock mechanism.
(f) Make sure that there are no detective parts
in the microwave generating and transmission
assembly (especially waveguide).
(4) The following items should be checked after the
unit is repaired:
(a) The interlock monitor switch is connected
correctly and firmly.
(b) The magnetron gasket is properly positioned
and mounted.
(c) The waveguide and the oven cavity are intact.
(no microwave energy leakage)
(d) The door can be properly closed and the
safety switches work properly.
(e) The unit must stop when the door is opened or
the time is up.
The unit must not be operated with any of the above
components removed or by-passed.
PRECAUTIONS AND REPAIR SERVICE TIPS

7-2
MICROWAVE LEAKAGE TEST
CAUTIONS
• Be sure to check microwave leakage prior to
servicing the oven if the oven is operative prior to
servicing.
• The service personnel should inform the
manufacture importer, or assembler of any certified
oven unit found to have a microwave emission level
in excess of 5 mW/cm2 and should repair any unit
found to have excessive emission levels at no cost to
the owner and should ascertain the cause of the
excessive leakage. The service personnel should
instruct the owner not to use the unit until the oven has
been brought into compliance.
• If the oven operates with the door open, the service
personnel should;
- Tell the user not to operate the oven
- Contact the manufacturer and CDRH (Center for
Devices and Radiological Health)immediately.
NOTE: Address on CDRH
Office of Compliance (HFZ-312)
Center for Devices and Radiological Health
1390 Piccard Drive Rockville, Maryland 20850
• The service personnel should check all surface and
vent openings for microwave emission testing.
• Check for microwave energy leakage after every
servicing. The power density of the microwave
radiation leakage emitted by the microwave oven
should not exceed 1mW/cm.sq. And always start
measuring of an unknown field to assure safety for
operating personnel from radiation leakage.
NOTE: The standard is 5mW/cm.sq. while in the
customerʼs home.1mW/cm.sq.stated here is
manufacturerʼs own voluntary standard for units in
customer ʼs home.
Move probe along shaded area.
Probe scanning speed
Less than 2.5 cm/sec. ( 1 in/sec)
EQUIPMENT-
• TESTER ((VOLTS-DC, AC, Ohmmeter)
• Microwave survey meter
- Holaday HI-1500
HI-1501
- Narda 8100
8200
• 600 cc non conductive material beaker (glass or
plastic), inside diameter:approx.8.5 cm (31/2 in.)
• Glass thermometer: 100 °C or 212 °F (1 deg scale)
MEASURING MICROWAVE ENERGY
LEAKAGE
• Pour 275±15cc of 20±5°C(68±9°F) water in a beaker
which is graduated to 600 cc, and place the beaker
on the oven.
• Set the energy leakage monitor to 2,450 MHz and
use it following the manufacturer's recommended
test procedure to assure correct result.
• When measuring the leakage, always use the 2-inch
(5cm) spacer supplied with the probe.
• Operate the oven at its maximum output.
• Measure the microwave radiation using and
electromagnetic radiation monitor by holding the
probe perpendicular to the surface being measured.
Move probe along shaded area.
Probe scanning speed
Less than 2.5 cm/sec. ( 1 in/sec)

7-3
MEASUREMENT WITH THE OUTSIDE CASE
REMOVED
(1) When you replace the magnetron, measure for
microwave energy leakage before the outer case
is installed and after all necessary components
are replaced or adjusted. Special care should be
taken in measuring the following parts.
-Around the magnetron
-The waveguide
WARNING: AVOID CONTACTING ANY HIGH
VOLTAGE PARTS.
MEASUREMENT WITH A FULLY
ASSEMBLED OVEN
(1) After all components, including the outer
panels, are fully assembled, measure for
microwave energy leakage around the door
viewing window, the exhaust opening and air
inlet openings.
(2) Microwave energy leakage must not exceed the
values prescribed below.
NOTES:
Leakage with the outer panels removed -less
than 5 mW/cm2.
Leakage for a fully assembled oven (“Before the
latch switch (primary)is interrupted”)with the door
in a slightly opened position -less than 1 mW/cm2
NOTE WHEN MEASURING
(1) Do not exceed meter full scale deflection.
(2) The test probe must be removed no faster than
1 inch/sec (2.5cm/sec)along the shaded area,
otherwise a false reading may result.
(3) The test probe must be held with the grip portion
of the handle. A false reading may result if the
operator ʼs hand is between the handle and the
probe.
(4) When testing near a corner of the door, keep
the probe perpendicular to the surface making
sure the probe is moved horizontally along the
oven surface.
RECORD KEEPING AND NOTIFICATION
AFTER MEASUREMENT
(1) After adjustment and repair of any microwave
energy interruption or microwave energy blocking
device, record the measured values for future
reference. Also enter the information on the
service invoice.
(2) Should the microwave energy leakage not be
more than 1 mW/cm2 after determining that all
parts are in good condition, functioning properly
and genuine replacement parts which are listed in
this manual have been used.
(3) At least once a year, have the electromagnetic
energy leakage monitor checked for calibration
by its manufacturer.
POWER OUTPUT MEASUREMENT
(1) Microwave power output measurement is made
with the microwave oven supplied at its rated voltage and
operated at its maximum microwave power setting with a
load of (1000 ± 5)g of potable water.
(2) The water is contained in a cylindrical borosilicate
glass vessel having a maximum material thickness
of 1/8” (3 mm)and an outside diameter of approximately
7.6” (190mm).
(3) The oven and the empty vessel are at ambient
Temperature(T0)prior to the start of the test.
(4) The initial temperature (T1)of the water is
(10 ± 1)°C (50 °F)It is measured immediately before the
water is added to the vessel. After addition of the water to
the vessel, the load is immediately placed on the center
of the turntable which is in the lowest position and the
microwave power switched on.
(5) The time t for the temperature of the water to rise
by a value T of (10 ± 1)°K is measured, where t is the
time in seconds and T is the temperature rise.
The initial and final water temperatures are selected so
that the maximum difference between the final water
temperature and the ambient temperature is 5 °K.
(6) The microwave power output P in watts is calculated
from the following formula :
4.187 Mw(T2 –T1)+0.55Mc(T2 –T0)
t
is measured while the microwave generator is
operating at full power. Magnetron filament heat-up
time is not included. (about 3 sec)
(7) The water is stirred to equalize temperature
throughout the vessel, prior to measuring the final
water temperature.
(8) Stirring devices and measuring instruments are
selected in order to minimize addition or removal of
heat.
P =
Where
P is the microwave power output, in watts:
Mw is the mass of the water, in grams:
Mc is the mass of the container, in grams:
T0 is the ambient temperature, in °C:
T1 is the initial temperature of the water, in °C:
T2 is the final temperature of the water, in °C:
t is the heating time in seconds, excluding the magnetron filament heat-up time.
WATER LOAD
GLASS TRAY

7-4
IMPORTANT NOTES:
UNIT MUST BE DISCONNECTED FROM ELEC-
TRICAL OUTLET WHEN MAKING REPAIRS,
RE-PLACEMENTS, ADJUSTMENTS AND CONTIN-
UITY CHECKS. WAIT AT LEAST ONE MINUTE,
UNTIL THE HIGH VOLTAGE CAPACITOR IN THE
HIGH VOLTAGE POWER SUPPLY HAS FULLY
DISCHARGED.
THE CAPACITOR SHOULD BE DISCHARGED BY
USING INSULATED WIRE - I.E. TEST PROBE
CONNECTED TO 10K-OHM RESISTOR IN SERIES
TO GROUND.
WHEN RECONNECTING THE WIRE LEADS TO
ANY PART, MAKE SURE THE WIRING CONNE-
CTIONS AND LEAD COLORS ARE CORRECTLY
MATCHED ACCORDING TO THE OVERALL CIR-
CUIT DIAGRAM. (ESPECIALLY SWITCHES AND
HIGH VOLTAGE CIRCUIT.)
A. REMOVING POWER AND CONTROL
CIRCUIT BOARD (Figures 1, 2 and 3)
(1) Remove a screw securing the control panel
assembly to the oven cavity.
(2) Remove the control panel with pushing it upward.
(3) Remove the five connectors (CN1, CN2, CN3,
CN5, CN6, CN8, CN10, CN11) and wire leads
(Relay1, Relay2, Relay4) from the circuit board.
Control Panel
(Relay1)
(Relay2)
(Relay4)
(CN6)
(CN10)
(CN8)
(CN5)
(CN4)
(CN11)
Screw
Circuit Board
(CN1)
(CN2)
(CN3)
Figure 1
(4) Remove 4 screws securing the circuit board.
Circuit Board
Circuit Boar
d
Figure 2
(5) Remove the circuit board from the control bracket
carefully.
Control Bracket
Circuit Board
Figure 3
DISASSEMBLY INSTRUCTIONS

7-5
B. REMOVING THE OUT CASE(Figure 4)
(1) Remove the vent grille by removing two screws
securing it to the out case.
(2) Remove two screws securing it to the air duct.
(3) Remove the mounting plate by turning the
screws(1 or 2 screws)securing it to the out case.
(4) Remove two screws on the left central edge and
one screw on the right central edge of Base plate.
Remove the Mount, All from the out case by
removing one screw securing it to the out case.
(5) Remove six screws of the rear cavity.
(6) Remove the outcase.
Figure 4

7-6
C. REMOVING THE DOOR INTERLOCK
SWITCHES (Figures 5, 6)
(1) Disconnect the wire leads from the interlock
switches.
(2) Remove two screws securing the Latch Board.
(3) Make necessary replacements and check
microwave energy leakage according to
“ADJUSTMENT PROCEDURES” on page 7-11.
Latch Board
Primary
Interlock Switch
Monitor
Interlock Switch
Secondary
Interlock Switch
Latch Board
Primary Interlock Switch
Monitor Interlock Switch
Secondary Interlock Switch
Latch Board
Primary
Interlock Switch
Monitor
Interlock Switch
Secondary
Interlock Switch
Latch Board
Primary Interlock Switch
Monitor Interlock Switch
Secondary Interlock Switch
Figure 5
Figure 6

7-7
Figure 7
Figure 9-a Figure 9-b
Figure 8
(3 screws)
(1 or 2 screws)
D. REMOVING MAGNETRON
(Figures 7 Through 13b)
(1) Remove the vent grille by loosening two screws.
(Figure 7)
(2) Remove the outcase. See page 7-5.
(3) Remove four tap tite screws securing the
magnetron to the wave guide.
(4) Disconnect the leadwire.
(5) Remove the magnetron VERY CAREFULLY.
NOTES:
• When removing the magnetron, make sure that its
dome does not hit any adjacent parts, or it may be
damaged.
• When replacing the magnetron, be sure to install the
magnetron gasket in the correct position and be sure
that the gasket is in good condition.
• After replacing the magnetron, check for microwave
energy leakage with a survey meter Check
microwave energy leakage must be below the limit
of 5 mW/cm2. (All service adjustments should be
made for minimum microwave energy leakage
readings.)

7-8
E. REMOVING STIRRER FAN
(Figures 10 and 11)
(1) Remove two screws securing it to the oven
upper plate by using drive screw.
(2) Rotate slightly and pull out the stirrer fan cover.
(3) Remove the stirrer fan.
Figure 11
Figure 10
F. REMOVING DOOR (Figure 12)
(1) Remove the vent grille by two screws securing it to
the outcase loosening.
(2) Lift up and draw the door.
NOTES:
• After replacing the door, be sure to check that the
primary interlock switch, the secondary interlock
switch and the interlock monitor switch is in good
operating normally.
• After replacing the door, check for microwave energy
leakage with a survey meter. Microwave energy
leakage must be below the limit of 5mW/cm2. (With a
275 ml water load)
Figure 12
G. DISASSEMBLING DOOR (Figure 13)
(1) Remove the dielectric choke by using knife
blade or small screw driver, etc.
(2) Remove two screws securing it to the door handle.
CAUTION: Be careful not to damage door seal
plate with the screwdriver.
Figure 13

7-9
H. ASSEMBLING DOOR
(1) When mounting the door assembly to the oven
assembly, be sure to adjust the door assembly
parallel to the chassis. Also adjust so the door has no
play between the inner door surface and oven frame
assembly. If the door assembly is not mounted
properly, microwaves may leak from the clearance
between the door and the oven.
Space
I. REMOVING THE VENTILATION MOTOR
(1) Remove the mounting plate by loosening
mounting plate screws (1 or 2 screws)
securing it to the back plate.
(See Figure 14)
(2) Remove MOUNT ALL loosening one screw
loosening one screw securing the ventilation Motor
and back plate. (See Figure 15-a)
(3) Carefully pull the ventilation motor ASS'Y out of
the microwave oven. (See Figure 15-b)
J. REPLACING THE HUMIDITY SENSOR
(For sensor model only)
(1) Remove the sensor by removing two screws
securing it to the air duct. (See Figure 15-c).
(2) Mount the new humidity sensor to the air duct.
Figure 15-c
(1 or 2 screws)
MOUNT, ALL
Figure 14
Figure 15-a
Figure 15-b

7-10
K. REMOVING THE TURNTABLE MOTOR
(1) Remove the turntable.
(2) Remove the turntable shaft VERY CAREFULLY
with a slotted screwdriver. (Figure 16)
(3) Remove the base plate by removing 7 screws
securing it to the oven cavity. (Figure 17-a)
(4) Disconnect the leadwire from the turntable motor
terminals.
(5) Remove the 2 screws securing the turntable motor
to the oven cavity ASS'Y. (Figure 18-b)
NOTES:
• Remove the leadwire from the turntable motor
VERY CAREFULLY.
• Be sure to grasp the connector not the wires when
removing.
L. REMOVING CONVECTION HEATER
AND THERMISTOR (Figure 19)
(1) Remove the out case.
(2) Remove the air duct by removing six screws
securing it to the oven front plate, guide air and
glasswool-L cover.
(3) Disconnect the wire leads of air duct.
(4) Remove the magnetron.
(5) Remove the latch board assembly.
(6) Remove the bottom plate by removing four screws.
(7) Remove the four net screws securing chamber
assembly.
(8) Lift the chamber assembly from the oven cavity.
(9) Remove three screws securing the heater of the
chamber assembly.
(10) Lift the convection heater from the chamber
assembly.
Wire Leads
Turntable Motor
Figure 18-b
Figure 16
Figure 19
Figure 17-a