LG MD-2642KT User manual

MICROWAVE OVEN
SERVICE MANUAL
MODEL : MD-2642KT
CAUTION
BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
Website http://biz.lgservice.com

This device is to be serviced only by properly qualified service personnel.
Consult the service manual for proper service procedures to assure continued safety operation and for precautions to be
taken to avoid possible exposure to excessive microwave energy.
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.
SAFETY PRECAUTIONS

(Page)
SAFETY PRECAUTIONS
--------------------------------------------------------------------- Inside front cover
SPECIFICATIONS
-----------------------------------------------------------------------------------------------------
1-1
CAUTIONS
-------------------------------------------------------------------------------------------------------------- 2-1
INSTALLATIONS
------------------------------------------------------------------------------------------------------ 3-1
OPERATING INSTRUCTIONS
------------------------------------------------------------------------------------
4-1
FEATURES ------------------------------------------------------------------------------------------------------------------------ 4-1
CONTROL PANEL
------------------------------------------------------------------------------------------------------------- 4-1
OPERATING SEQUENCE
---------------------------------------------------------------------------------------------------- 4-2
SCHEMATIC DIAGRAM
------------------------------------------------------------------------------------------------------ 4-3
CIRCUIT DESCRIPTION
----------------------------------------------------------------------------------------------------- 4-4
SERVICE INFORMATION ------------------------------------------------------------------------------------------ 5-1
TOOLS AND MEASURING INSTRUMENTS
--------------------------------------------------------------------------- 5-1
MICROWAVE LEAKAGE TEST
-------------------------------------------------------------------------------------------- 5-1
MEASUREMENT OF MICROWAVE POWER OUTPUT
----------------------------------------------------------- 5-3
DISASSEMBLY AND ADJUSTMENT ------------------------------------------------------------------------------------- 5-3
INTERLOCK CONTINUITY TEST
------------------------------------------------------------------------------------------ 5-7
COMPONENT TEST PROCEDURE
-------------------------------------------------------------------------------------- 5-8
TROUBLE SHOOTING
------------------------------------------------------------------------------------------------------ 5-11
EXPLODED VIEW ----------------------------------------------------------------------------------------------------- 6-1
REPLACEMENT PARTS LIST
------------------------------------------------------------------------------------ 7-1
SCHEMATIC DIAGRAM OF P.C.B.
------------------------------------------------------------------------------ 8-1
PRINTED CIRCUIT BOARD ------------------------------------------------------------------------------------------------- 8-2
P.C.B. PARTS LIST
---------------------------------------------------------------------------------------------------
9-1
CONTENTS

1-1
This microwave oven is designed for household use only.
It is not recommended for commercial purposes.
ITEM
MODEL
Power Requirement
Power Output
Microwave Frequency
Magnetron
Timer
Outside Dimensions
Cavity Dimensions
Net Weight
Shipping weight
Control Complement
Nameplate Location
Accessories
DESCRIPTION
MD-2642KT
230/240 Volts AC 50 Hz
1,250 Watts
Single phase, 3 wire grounded
2,450 MHz
2M214-39F
0 ~ 99 min. 99 sec.
618 (W) x 357 (H) x 467 (D) mm
343 (W) x 221 (H) x 361 (D) mm
15.7 kg (approx.)
17.7 kg (approx.)
Touch Control System
Microwave Power for Variable Cooking
Power level
HIGH ----------------------------------------Full power throughout the cooking time
9 (Saute) -------------------------approx. 90% of Full power, 8 (Reheat) --------approx. 80%
7 (Med.-High)--------------------approx. 70%, 6 (Medium) --------approx. 60%
5 (Med.-Low) --------------------approx. 50%, 4 (Defrost) ---------approx. 40%
3 (Low) ---------------------------approx. 30%, 2 (Simmer)---------approx. 20%
1 (Warm)--------------------------approx. 10%
Owner's manual & cooking guide
Glass turntable
Rotating ring
Back Side
SPECIFICATIONS
Microwave oven
Toaster
900 Watts full microwave power (IEC60705)
800 Watts

• 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.
• For about 30 seconds after the oven stops, an electric
charge remains in the high voltage capacitor. When
replacing or checking, you must discharge the high
voltage capacitor by shorting across the two terminals
with an insulated screwdriver.
• 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.
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.
THE OVEN IS TO BE SERVICED ONLY
BY PROPERLY QUALIFIED SERVICE
PERSONNEL.
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.
Gasket
ANTENNA
COOLING FIN
MAGNETRON
CHASSIS GROUND
FILAMENT
TERMINALS
MAGNETRON

INSTALLATIONS
3-1
INSTALLING
1. Empty the microwave oven and clean inside it with
a soft, damp cloth. Check for damage such as
misaligned door, damage around the door or dents
inside the cavity or on the exterior.
2. Put the oven on a counter, table, or shelf that is
strong enough to hold the oven and the food and
utensils you put in it. (The control panel side of the
oven is the heavy side. Use care when handling.)
3. Do not block the vent and the air intake openings.
Blocking vent or air intake openings can cause
damage to the oven and poor cooking results.
Make sure the microwave oven legs are in place to
ensure proper air flow.
4. The oven should not be installed in any area where
heat and steam are generated, because they may
damage the electronic or mechanical parts of the
unit.
Do not install the oven next to a conventional
surface unit or above a conventional wall oven.
5. Use microwave oven in an ambient temperature
less than 104°F(40°C).
6. Place the microwave oven on a sturdy and flat
surface at least 10 cm(4 inches) from the wall.
7. Place the microwave oven as far away as possible
from TV, RADIO, COMPUTER, 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.
BEFORE YOU BEGIN, READ THE FOLLOWING INSTRUCTIONS COMPLETELY AND CAREFULLY.
10cm
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.

FEATURES
4-1
OPERATING INSTRUCTIONS
Easy-Clean
Oven Cavity
See-Through Door
Safety Interlock System
Toaster
Control
Panel
Rotating Ring
Glass Turntable
Slots
Toaster
Indicator
Light
Toaster
Door
Microwave Oven
Crumb
Tray
CONTROL PANEL
1. Toast. Toast bread
2. Stop/Clear. Touch this pad to stop the toaster or clear entries.
3. Start. Touch this pad to start the toasting process.
4. Darkness Control. Adjust darkness control to desired setting
before cooking foods.
(Default : 5, "1" is the lightest and "9" is the darkest)
5. Indicator Light. When operating toaster with door closed, this will
be illuminated. If you open the door during toasting, this will blink.
TOASTER CONTROL AREA
5
1 4
3 2
1. DISPLAY. The Display includes a clock and indicators that tell
you time of day, cooking time settings, and cooking functions
selected.
2. STOP/CLEAR. Touch this pad to stop the oven or clear entries.
3. START. Touch this pad to start all entries (except the Auto Cook
and Add Minute function which start automatically) and to turn
Child Lock on or off.
4. AUTO COOK. Touch this pad to select programming food items.
5. ADD MINUTE. Touch this pad to cook at 100% cook power for 1
minute to 99 minutes 59 seconds.
6. AUTO DEFROST. This pad is an accurate defrosting method for
frozen meat, poultry and fish up to 4.0 kg.
7. COOK TIME. Touch this pad to set a cooking time.
8. POWER. Touch this pad to set a cooking power.
9. CLOCK. Touch this pad to set the time of day.
10. KITCHEN TIMER. Touch this pad to use your microwave oven
as a kitchen timer.
11. NUMBER PADS. Touch Number Pads to enter cooking time,
power level, quantities, or weights.
MICROWAVE CONTROL AREA
2 4
1
75 9
36 8 11
10

4-2
MICROWAVE OVEN
(1) KITCHEN TIMER
1. Touch STOP/CLEAR.
2. Touch KITCHEN TIMER.
3. Touch correct number for time.
4. Touch START.
(2) CHILD LOCK
To set:
1. Touch STOP/CLEAR.
2. Touch “START” more than 4 seconds.
To cancel:
1. Touch STOP/CLEAR.
2. Touch “START” more than 4 seconds.
(3) AUTO COOK
1. Touch STOP/CLEAR.
2. Touch AUTO COOK Category.
3. Touch START.
(Although you don’t touch start, it will start after
4 seconds automatically)
(4) ADD MINUTE
1. Touch STOP/CLEAR.
2. Touch ADD MINUTE.
(5) AUTO DEFROST
1. Touch STOP/CLEAR.
2. Touch AUTO DEFROST.
Three different defrosting levels are provided.
(Touch 1 : Meat
Touch 2 : Poultry
Touch 3 : Fish)
3. Enter the weight of your food in decimal
increments from 0.1 to 6.0 pounds.
4. Touch START
5. At beeping, turn food over by following the
instructions in the manual.
6. After turning food over, touch START to resume
defrosting.
(6) TIMED COOKING
1. Touch STOP/CLEAR.
2. Touch COOK TIME.
3. Touch number for cooking time.
4. Touch POWER.
5. Touch number for cooking power level.
6. Touch START.
(7) MULTI-STAGE COOKING
1. Touch STOP/CLEAR.
2. Touch COOK TIME.
3. Touch number for cooking time.
4. Touch POWER.
5. Touch number for cooking power level.
6. Repeat steps 2-5 to set 2nd cooking stage.
7. Touch START.
TOASTER
(1) TOAST
1. Touch STOP/CLEAR.
2. Touch TOAST.
3. Touch Darkness Control (1~9 step)
4. Touch START.
(2) BAGEL
1. Touch STOP/CLEAR.
2. Touch BAGEL.
3. Touch Darkness Control (1~9 step)
4. Touch START.
(3) DARKNESS SETTINGS
Degree of darkness Select darkness level
Light 1~3
Medium 4~6
Dark 7~9

SCHEMATIC DIAGRAM
4-3
SWITCH
TOASTER DOOR
WH
WH
BL
CUT-OUT
OVEN THERMAL
BK
WH
SECONDARY
SWITCH
WHBL GN
NOISE FILTER
G-Y
POWER
INPUT
BN
FUSE
250V, 10A
TOASTER
THERMOSTAT
YL
FAN MOTOR
O.L
OVEN LAMP
RD
BK
RD
BK
T.T.M
F.M
TURNTABLE MOTOR
PRIMARY
TOASTER HEATER
SWITCH
RD
BK
YL
RD
WH
MAGNETRON
PROTECTOR
H.V CIRCUIT
CAPACITOR
H.V.DIODE
MONITOR
SWITCH
BL
HIGH VOLTAGE
TRANSFORMER
BN H.V
CHOKE FILTER(OPTION)
FA
F
RELAY 2
RELAY2
Capacitor by shorting the negative high voltage
Discharge the high voltage
L.V.TRANSFORMER
BEFORE SERVICING
POWER AND
Terminal of it to chassis ground.
THERMISTOR
LED LAMP
WH BK
CN2
3
1
WH WH
CN1
1
CN3
2
1
CIRCUIT BOARD
RELAY1
CONTROL RELAY4
43578
PK BN
9
YL
GN
RELAY3
COLOR
YELLOW
BLACK
BLUE WHITE BROWN GREEN-YELLOW
NOTE:1.DOOR IS OPENED
G-Y
RELAY3
YL BK PK PINK RD BL
WH
BN
RED
2.COOK OFF.
SYMBOL
N
L

CIRCUIT DESCRIPTION
GENERAL DETAILS
• The low voltage transformer supplies the necessary
voltage to the micom controller when power cord is
plugged in.
• When the door is closed, the primary switch is ON, the
secondary switch is ON, and the monitor switch opens
(contact COM and NO).
WHEN SELECTING COOKING POWER
LEVEL AND TIME
• The micom controller memorizes the function you set.
• The time you set appears in the display window.
• Each indicator light turns on to indicate that the stage
has been set.
WHEN TOUCHING THE START PAD
• The coil of the relay is energized by the micom controller.
• Power input is supplied to the high voltage transformer
through the fuse to the primary switch and relay 2.
• Turntable rotates.
• The fan motor rotates and cools the magnetron by
blowing the air (coming from the intake on the base-
plate).
• The air is also directed into the oven to exhaust the
vapor in the oven through the upper plate.
• Cooking time starts counting down.
• 3.3 volts AC is generated from the filament winding of the
high voltage transformer. This 3.3 volts is applied to the
magnetron to heat the magnetron filament through two
noise-preventing choke coils.
• A high voltage of approximately 2100 volts AC is
generated in the secondary of the high voltage
transformer which is increased by the action of the high
voltage diode and charging of the high voltage capacitor.
• The negative 4,000 Volts DC is applied to the filament of
the magnetron.
WHEN THE OVEN IS SET AT ANY LEVEL
EXCEPT MAXIMUM.
• The micom controller controls the ON-OFF time of relay
2 by the applied signal to vary the average output power
of microwave oven as POWER LEVEL. (refer
to page 1-1)
• One complete cycle of relay 2 is 22 seconds.
WHEN THE DOOR IS OPENED DURING
COOKING
• Both the primary switch and relay 2 cut off the primary
winding voltage of the high voltage transformer.
• ON-OFF of relay 2 is coupled electrically with opening
and closing of the secondary switch.
• When the door is opened, the secondary switch is
opened and when the door is closed, the secondary
switch is closed.
• The cooking time stops counting down.
• Relay stops functioning.
• As the door is opened, if the contact of primary switch
and relay2 and/or secondary switch fail to open, the fuse
opens due to the large current surge caused by the
monitor switch activation, which in turn stops magnetron
oscillation.
4-4
L
FUSE
H.V.
TRANS-
FORMER
RELAY 2
MICOM CONTROLLER
SECONDARY
SWITCH
PRIMARY
SWITCH
MONITOR
SWITCH
N
L
FUSE
RELAY 2
MICOM CONTROLLER
SECONDARY
SWITCH
PRIMARY
SWITCH
MONITOR
SWITCH
H.V.
TRANS-
FORMER
N

5-1
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/cm2and 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.
• The service personnel should check all surface and vent
openings for microwave leakage.
• Check for microwave leakage after every servicing. The
power density of the microwave radiation leakage
emitted by the microwave oven should not exceed
4 mW/cm2. Always start measuring of an unknown field
to assure safety for operating personnel from radiation
leakage.
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 center of the turntable.
•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)
SERVICE INFORMATION
TOOLS AND MEASURING INSTRUMENTS
MICROWAVE LEAKAGE TEST
NECESSARY TOOLS
Tools normally used for TV servicing are sufficient.
Standard tools are listed below.
• Diagonal pliers
• Long nose pliers
• Phillips screwdriver
• Flat blade screwdriver
• Wrench (size 5mm)
• Nutdriver (size 5mm)
• Adjustable wrench
• Soldering iron
• Solder
• Vinyl insulation tape
• Polishing cloth
NECESSARY MEASURING INSTRUMENTS
• TESTER (VOLTS-DC, AC, Ohmmeter)
• Microwave survey meter
- Holaday HI-1500
HI-1501
- Narda 8100
8200
• Inch scale
• 600 cc non conductive material beaker (glass or plastic),
inside diameter: approx. 8.5 cm (31/2 in.)
• Cylindrical and made of borosilicate glass vessel.
max. thickness: 3 mm
outside diameter: approx. 190mm
height: approx. 90mm
• Glass thermometer: 100°C or 212°F (1 deg scale)

5-2
PRECAUTIONS ON INSTALLATION
(Figure 2)
A. Plug the power supply cord into a 250 V AC, 50 Hz,
single-phase power source with a capacity of at
least 10 amperes.
B. Since the unit weights about 17kg, be sure to place
it on a sturdy and flat surface.
C. Avoid placing the unit in a location where there is
direct heat or splashing water.
D. Place the unit as far away as possible from TV,
radio, etc. to prevent interference. And do not place
on or near a hot gas or electric burner or in a heated
oven.
CAUTION
GENERAL PRECAUTIONS IN USE
Microwave Oven
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 turntable tray 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.
Toaster
A. Never operate the toaster when it is empty.
Operating the toaster with no load may overheat this
appliance.
B. Oversized food, metal foil packages or utensils must
not be inserted in this toaster, as they may create a
fire or electrical hazards.
TRIAL OPERATION
After installation, the following sequences and results
should be checked carefully.
Microwave Oven
A. Put a container filled with water (about 1 liter) into
the oven, and close the door tightly.
B. Touch the STOP/CLEAR and the COOK TIME keys.
C. Set cooking time for 10 minutes by touching “1”
and then “0” three times. “1000” appears in the
display window.
D. Touch the START 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.
E. After about 5 minutes, make sure the primary
interlock switch, the secondary interlock switch and
the interlock monitor and oven lamp switch operate
properly by opening and closing the door several
times. Touch the START key each time the door is
closed.
F. Continue operating the unit. Four long beep sound
signal is heard when the time is up. The unit will
shut off automatically.
G. Confirm the water is hot.
Toaster
A. Make sure the crumb tray is pushed all the way in
place plugging in.
B. Remove all protective wrappings from food before
placing into toasting slots. Then place bread into
slots and close the door.
C. Select one mode(Toast).
D. Press the Darkness Control to the desired setting.
E. Press the Start button. Make sure indicator light
comes on. The unit will begin cooking and the
display will show the browning level you selected.
F. After 1 minute, make sure the toaster door switch
and indicator light operate properly by opening and
closing the door several times (In normal state,
indicator light blinks when door is opened).
G. Continue operating the unit by pressing the Start
button. Beep sound signal is heard when the time is
up. The unit will shut off automatically and fan will
blow for 1 minute to cool this toaster.
H. Confirm the bread is cooked.
NOTE : If you operate this toaster for the first time, you
will notice an odor, that is a characteristic of
burning off residues on the new heating
elements. This is normal.
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.
Three-Pronged(Grounding)
Plug
Figure 2
Properly Polarized and
Grounded
Outlet

5-3
• 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.
• The water is contained in a cylindrical borosilicate glass vessel
having a maximum material thickness of 3 mm and an outside
diameter of approximately 190mm.
• The oven and the empty vessel are at ambient temperature prior
to the start of the test.
• The initial temperature (T1) of the water is (10±2)°C 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.
• The time T for the temperature of the water to rise by a value ∆T
of (10±2)° 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°.
• The microwave power output P in watts is calculated from
the following formula :
4187 x (∆T)
T
is measured while the microwave generator is operating at
full power. Magnetron filament heat-up time is not included.
(about 3 sec)
• The water is stirred to equalize temperature throughout the
vessel, prior to measuring the final water temperature.
• Stirring devices and measuring instruments are selected in
order to minimize addition or removal of heat.
WATER LOAD
TURNTABLE
MEASUREMENT OF MICROWAVE POWER OUTPUT
P =
MEASUREMENT WITH OUTER CASE
REMOVED
• 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. (Circled area of Fig. below)
- Around the magnetron
- The waveguide
MEASUREMENT WITH A FULLY
ASSEMBLED OVEN
• After all components, including the outer case, are fully
assembled, measure for microwave energy leakage around
the door viewing window, the exhaust opening, and air inlet
openings.
• Microwave energy leakage must not exceed the values
prescribed below.
NOTE: Leakage with the outer case removed less than 5
mW/cm.sq. Leakage for a fully assembled oven
(Before the latch switch (primary) is interrupted) with
the door in a slightly opened position-less than 2
mW/cm2.sq.
NOTES WHEN MEASURING
• Do not exceed meter full scale deflection.
• The test probe must be removed no faster than
1 inch/sec (2.5 cm/sec) along the shaded area, otherwise a
false reading may result.
• The test probe must be held with the grip portion of the
handle. A false reading may result if the operator's hand is
between the handle and the probe.
• When testing near a corner of the door, keep the probe
perpendicular to the surface making sure the probe
horizontally along the oven surface; this may cause probe
damage.
RECORD KEEPING AND NOTIFICATION
AFTER MEASUREMENT
• 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.
• The microwave energy leakage should not be more than 4
mW/cm.sq. after determining that all parts are in good
condition, functioning properly and genuine replacement
parts which are listed in this manual have been used.
• At least once a year, have the electromagnetic energy
leakage monitor checked for calibration by its manufacturer.
WARNING : AVOID CONTACTING ANY
HIGH VOLTAGE PARTS

5-4
DISASSEMBLY AND ADJUSTMENT
A. REMOVING OUT CASE (Figures 7)
(1) Remove four screws from the rear section.
(2) Remove one screw from the side section.
(3) Push the outer case back about 1 inch (3cm).
(4) Lift the case from the set.
B. REMOVING TOASTER ASSEMBLY
(Figure 8)
CAUTION: BE CAREFUL HOT SURFACE!
AFTER TOASTING, ENTIRE TOASTER’S
SURFACES ARE VERY HOT. BEFORE
SERVICING, COOL DOWN THE
TOASTER PARTS ENOUGH NOT TO
GET BURNT.
(1) Open the door.
(2) Remove 2 screws, holding the toaster.
(3) Disconnect the 2 lead wires from
connectors(CN2,CN3).
(4) Disconnect the wires at the secondary interlock
switch and wires at the toaster door switch.
(5) Disconnect the wires from the toaster thermostat
and wires at the Toaster Assembly.
(6) Lift up and pull out Toaster Assembly carefully from
the cavity.
Lift up and pull out toaster assembly
securing
screw
Remove screw
Figures 8
Figure 7

C. DOOR GROSS ASSEMBLY
REMOVAL
(1) Open the door.
(2) Remove the choke cover cap very carefully with a flat-
blade screwdriver.
CAUTION : Be careful not to damage door seal plate
by screwdriver.
(3) Lift up and push the door.
NOTE:
1. After replacing the door, be sure to check that the
primary switch, monitor switch, and secondary switch
operate normally.
2. After replacing the door, check for microwave energy
leakage with a survey meter. Microwave energy must
be below the limit of 5 mW/cm.sq. (with a 275 ml water
load)
3. 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.
5-5
Remove choke cover cap
Remove Door
Figure 9

5-6
D. MAGNETRON REMOVAL
(Figure 10)
(1) Disconnect the wire lead from the magnetron.
(2) Carefully remove the mounting screws holding the
magnetron and the waveguide.
(3) Remove the magnetron assembly until the tube is
clear from the waveguide.
NOTE:
1. When removing the magnetron, make sure its dome
does not hit any adjacent parts, or it may be
damaged.
2. 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.
3. After replacing the magnetron, check for microwave
leakage with a survey meter around the magnetron.
Microwave energy must be below the limit of 5
mW/cm2. (With a 275 ml. water load).
Make sure that gasket is rigidly attached to the
magnetron. To prevent microwave leakage, tighten
the mounting screws properly, making sure there is
no gap between the waveguide and the magnetron.
E. REMOVING THE TURNTABLE
MOTOR (Figure 11)
1) Remove the turntable and rotating ring.
2) Lay the unit down on its back.
3) Remove the turntable motor cover.
The turntable base cover is easily removed by
pinching the eight parts with a wire cutting.
4) Disconnect the leadwire from the turntable motor
terminals.
5) Remove the screw securing the turntable motor to
the oven cavity ASSEMBLY.
6) After repairing the motor, rotate the removed
turntable motor cover.
7) Fit the turntable motor cover’s projecting part to the
base plate slit.
NOTE:
1. Remove the wire lead from the turntable motor
VERY CAREFULLY.
2. Be sure to grasp the connector, not the wires, when
removing.
Magnetron
Waveguide
Magnetron
Gasket
Magnetron
Dome
Waveguide
Bracket
Figures 10
Wire Leads
Shaft
Turntable
Motor
Figures 11

5-7
F. HIGH VOLTAGE TRANSFORMER
REMOVAL
1) Discharge the high voltage capacitor.
2) Disconnect the leadwire from magnetron, high voltage
transformer, and capacitor.
3) Remove the screw holding the high voltage
transformer to the baseplate.
G. FAN MOTOR ASSEMBLY REMOVAL
1) Discharge the high voltage capacitor.
2) Disconnect the leadwire from fan motor and high
voltage capacitor.
3) Remove the two screws holding the the suction guide
ASSEMBLY to the oven cavity.
4) Remove the two screws holding the fan motor
ASSEMBLY to the suction guide ASSEMBLY.
H. HIGH VOLTAGE CAPACITOR AND
DIODE REMOVAL
1) Discharge the high voltage capacitor.
2) Disconnect the leadwire from fan motor and high
voltage capacitor.
3) Remove the screw holding the suction guide
ASSEMBLY to the oven cavity.
4) Remove the screw holding the high voltage capacitor
bracket and remove the high voltage diode earth
screw.
I. INTERLOCK SYSTEM
1) INTERLOCK MECHANISM
The door lock mechanism is a device which has
been specially designed to eliminate completely
microwave activity when the door is opened during
cooking and thus to prevent the danger resulting
from the microwave leakage.
2) MOUNTING OF THE PRIMARY/MONITOR/
SECONDARY SWITCHES TO THE LATCH
BOARD
3) INSTALLATION AND ADJUSTMENT OF THE
LATCH BOARD TO THE OVEN ASSEMBLY
• Mount the latch board to the oven assembly.
• Adjust the latch board in the arrow direction so that
oven door will not have any play in it when the door
is closed.
• Tighten the mounting screw.
•Check for play in the door by pushing the door
release button. Door movement should be less
than 0.5 mm. (1/64 inch)
Don't push the door release button while making this
adjustment. Make sure that the latch moves smoothly
after adjustment is completed and that the screws
are tight. Make sure the primary, monitor, and
secondary switches operate properly by following the
continuity test procedure.
H.V.
Transformer
Suction
Guide
H.V.
Capacitor
Fan Motor
Assembly
Figures 12
PRIMARY
SWITCH
SECONDARY
SWITCH
ADJUSTMENT
DIRECTION
MONITOR
SWITCH
Figures 13

5-8
A. PRIMARY INTERLOCK SWITCH TEST
When the door release button is depressed slowly
with the door closed, an audible click should be
heard at the same time or successively at
intervals. When the button is released slowly, the
latches should activate the switches with an
audible click.
If the latches do not activate the switches when
the door is closed, the switches should be a
adjusted in accordance with the adjustment
procedure. Disconnect the wire lead from the
primary switch. Connect the ohmmeter leads to
the common (COM) and normally open (NO)
terminal of the switch. The meter should indicate
an open circuit in the door open condition.
When the door is closed, the meter should indicate
a closed circuit.
When the primary switch operation is abnormal,
make the necessary adjustment or replace the
switch only with the same type of switch.
B. SECONDARY INTERLOCK SWITCH TEST
Disconnect the wire lead from the secondary
switch.
Connect the ohmmeter leads to the common
(COM) and normally open (NO) terminals of the
switch. The meter should indicate a open circuit in
the door open condition. When the door is closed,
meter should indicate an closed circuit. When the
secondary switch operation is abnormal, make the
necessary adjustment or replace the switch only
with the same type of switch.
C. MONITOR SWITCH TEST
Disconnect the wire lead from the monitor switch.
Connect the ohmmeter leads to the common
(COM) and normally closed (NC) terminals of the
switch. The meter should indicate closed circuit in
the door open condition. When the door is closed,
meter should indicate an open circuit. When the
monitor switch operation is abnormal, replace with
the same type of switch.
NOTE: After repairing the door or the interlock
system, it is necessary to do this continuity test
before operating the oven.
WARNING : FOR CONTINUED PROTECTION AGAINST EXCESSIVE RADIATION
EMISSION, REPLACE ONLY WITH IDENTICAL REPLACEMENT PARTS.
TYPE NO. SZM-V 16-FA-63 OR VP-533A-OF OR V-5230Q FOR PRIMARY SWITCH
TYPE NO. SZM-V 16-FA-62, VP-532A-OF OR V-5220Q FOR MONITOR SWITCH
TYPE NO. SZM-V 16-FA-63 OR VP-533A-OF OR V-5230Q FOR SECONDARY SWITCH
COMPONENTS TEST PROCEDURE RESULTS
SWITCHES Check for continuity of the Door Door
(Wire leads removed) switch with an Ohm-meter open closed
Primary
Switch
Monitor
Switch
Secondary
Switch
NOTE : After checking for the continuity of switches, make sure that they are
connected correctly.
NO
COM
NC
COM
NO
COM
INTERLOCK CONTINUITY TEST

5-9
CAUTIONS
1. DISCONNECT THE POWER SUPPLY CORD FROM THE OUTLET WHENEVER REMOVING THE
OUTER CASE FROM THE UNIT. PROCEED WITH THE TEST ONLY AFTER DISCHARGING THE HIGH
VOLTAGE CAPACITOR AND REMOVING THE WIRE LEADS FROM THE PRIMARY WINDING OF THE
HIGH VOLTAGE TRANSFORMER.
2. ALL OPERATIONAL CHECKS WITH MICROWAVE ENERGY MUST BE DONE WITH A LOAD (1 LITER
OF WATER IN CONTAINER) IN THE OVEN.
COMPONENT TEST PROCEDURE
COMPONENTS TEST PROCEDURE RESULTS
HIGH VOLTAGE
TRANSFORMER
(Wire leads removed)
MAGNETRON
(Wire leads removed)
1. Measure the resistance.
(Select the ohm scale on the meter)
• Primary winding
• Secondary winding
• Filament winding
2. Measure the resistance.
(Select the ohm scale on the meter)
• Primary winding to ground
• Filament winding to ground
1. Measure the resistance.
(Select the ohm scale on the meter)
• Filament terminal
2. Measure the resistance.
(Select the ohm scale on the meter)
• Filament to chassis
Approx.: 1.0 ~ 2.5 ohm
Approx.: 90 ~ 120 ohm
Less than: 1 ohm
Normal: Infinite
Normal: Infinite
Normal: Less than 1 ohm
Normal: Infinite
FILAMENT
WINDING
PRIMARY
TERMINAL
SECONDARY
WINDING
A. TEST PROCEDURES

5-10
COMPONENTS TEST PROCEDURE RESULTS
HIGH VOLTAGE
CAPACITOR 1. Check DC 9V battery before performing
tests.
2. Select the DCV scale on the meter.
3. Using the meter, battery, and jump wire,
connect the items as illustrated in figures.
• Terminal to terminal.
1. Check DC 9V battery before performing
tests.
2. Select the DCV scale on the meter.
3. Using the meter, battery, and jump wire,
connect the items as illustrated in figures.
• Terminal to case.
Normal: Approximately 9V
Normal: Approximately 0V or
a value displayed in
mV Will be seen.
NOTE: When testing the magnetron, be sure to install the magnetron
gasket in the correct position and be sure that the gasket is in
good condition.
Antenna
Gasket
Chassis
Filament