LG MS-2324F User manual

MICROWAVE OVEN
SERVICE MANUAL
MODEL: MS-2324F
CAUTION
BEFORE SERVICING THE UNIT,READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
Website http://biz.lgservice.com
P/NO : 3828W5S3766
April, 2004
Printed in Korea

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
CAUTION
MICROWAVE RADIATION
DO NOT BECOME EXPOSED TO RADIATION FROM THE MICROWAVE GENERATOR
OR OTHER PARTS CONDUCTING MICROWAVE ENERGY.

CONTENTS
(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 ----------------------------------------------------------------------------------------------------- 5-12
EXPLODED VIEW
----------------------------------------------------------------------------------------------------- 6-1
REPLACEMENT PARTS LIST
------------------------------------------------------------------------------------ 7-1

SPECIFICATIONS
1-1
This microwave oven is designed for household use only.
It is not recommended for commercial purposes.
DESCRIPTION
MS-2324F
230 Volts AC 50 Hz
1,250 Watts
Single phase, 3 wire grounded
850 Watts full microwave power (IEC60705)
2,450 MHz
2M167B - M47J1
0 ~ 60 min.
507 (W) x 283 (H) x 418 (D) mm
331 (W) x 203 (H) x 360 (D) mm
14.0 kg (approx.)
16.0 kg (approx.)
Microwave Power for Variable Cooking
Power level
Max
620W
380W
c Defrost
90W
Owner's manual
Glass turntable
Roller Rest
ITEM
MODEL
Power Requirement
Power Output
Microwave Frequency
Magnetron
Timer
Outside Dimensions
Cavity Dimensions
Net Weight
Shipping weight
Control Complement
Nameplate Location
Accessories
Back Side

• 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 stop, 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

3-1
INSTALLATIONS
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.
EARTHING INSTRUCTIONS
This microwave oven is designed to be used in a fully
earthed condition.
It is imperative, therefore, to make sure it is properly
earthed before servicing
WARNING-
THIS APPLIANCE
MUST BE EARTHED
IMPORTANT
As the colors of the wires in the mains lead of this
appliance may not correspond with the colored
markings identifying the terminals in your plug,
proceed as follows.
The wire which is colored green-and-yellow must be
connected to the terminal in the plug which is marked
with the letter Eor by the earth symbol ( ) or
colored green or green-and-yellow.
The wire which is colored blue must be connected to
the terminal in the plug which is marked with the letter
Nor colored black.
The wire which is colored brown must be connected
to the terminal in the plug which is marked with the
letter Lor colored red.
BEFORE YOU BEGIN, READ THE FOLLOWING INSTRUCTIONS COMPLETELY AND CAREFULLY.
10cm
The wires in this mains lead are colored in
accordance with the following code:
Green-and-yellow: Earth
Blue: Neutral
Brown: Live

FEATURES
CONTROL PANEL
4-1
OPERATING INSTRUCTIONS
Glass Tray
Roller Rest
Oven Front Plate
Door Seal
Control Panel
Safety Door Lock System
Window Door Screen
1
2
2
1. POWER CONTROL KNOB: Used in selected the
desired power level for cooking.
2. TIMER KNOB: Used to set the cooking time.

4-2
OPERATING SEQUENCE
MICROWAVE COOKING
1. Open the oven door, place the food on the turntable
in the oven, and close the oven door.
2. Set the microwave power selector to the desired
power level. There are five power levels from 90W
to MAX. The power selector can be set to any one
of these positions.
3. Set the timer to the desired cooking time. The
turntable begins to rotate and cooking starts. At the
end of cooking time you will a single ring sound,
and the lamp is turn off.
NOTE:
•Each number represents minutes. To ensure
accurate timing, it is advisable to turn the timer knob
slightly passed the desired cooking time and then
back to the proposed setting.
•Press the door opener to check the cooking
condition during oven operation. Opening the door
during oven operation automatically turns off the
oven and stops the timer. If cooking is to continue,
close the door. Cooking will be resumed until the full
cooking time has elapsed.
POSITIONS
Max
620W
380W
c Defrost
90W

SCHEMATIC DIAGRAM
4-3
SCHEMATIC DIAGRAM

CIRCUIT DESCRIPTION
•As the door is closed, the contact of MONITOR
SWITCH opens. This switch creates the short circuit to
blow fuse during operation under abnormal condition.
(ie, should the contacts of primary and secondary
switch fail to open the circuit)
•The latches are secured by latch board. The oven light
turns on while the oven is in operation.
WHEN MICROWAVE POWER LEVEL
AND COOKING TIME SET
•The contacts of the timer switch changes to ON
position when the timer knob is rotated.
(While power control knob is set at “Full Power”)
•The contacts of primary and secondary switch close
the circuit.
•Input Volts AC. is applied to the high voltage
transformer through power control switch as shown by
the solid line.
•Turntable rotates.
•The fan motor rotates and cools the magnetron by
blowing the air (coming from the intake holes on the
baseplate) over the magnetron.
•The air is also directed into the oven to exhaust the
vapor in the oven through the upper plate.
•Timer starts rotating.
•3.2 volts AC is generated from the filament winding of
the high voltage transformer. This 3.2 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
diode and charging of the high voltage capacitor.
The negative DC voltage is then applied to the filament
of the magnetron
WHEN THE DOOR IS OPENED DURING
COOKING
•Both primary switch and secondary switch open to cut
off the primary winding voltage to the high voltage
transformer to stop microwave oscillation.
•Timer, turntable and fan motor stop.
•As the door is opened, if the contact of primary switch
and 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
FUSE
PRIMARY
SWITCH
SECONDARY
SWITCH
MONITOR
SWITCH
L
N
H.V.T
RELAY
TIMER
SWITCH
POWER
CONTROL
SWITCH
FUSE
PRIMARY
SWITCH
SECONDARY
SWITCH
L
N
H.V.T
RELAY
TIMER
SWITCH
POWER
CONTROL
SWITCH
MONITOR
SWITCH

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
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
5 mW/cm2. Always start measuring of an unknown field
to assure safety for operating personnel from radiation
leakage.
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)
MEASURING MICROWAVE ENERGY
LEAKAGE
•Pour 275±15 cc 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
(5 cm) 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)
5-1
SERVICE INFORMATION
TOOLS AND MEASURING INSTRUMENTS
MICROWAVE LEAKAGE TEST

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 below Fig.)
- 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 removedless 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/cm.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
befween 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 possibly
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.
5-2
WARNING : AVOID CONTACTING ANY
HIGH VOLTAGE PARTS
(Magnetron, H.V. Transformer,
H.V. Capacitor, H.V. Cable Ass’y,
H.V. Circuit Protector)

•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 (±1) 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 thd 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)°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.
•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.
A. OUTER CASE REMOVAL
1) Disconnect the power supply cord from the outlet.
2) Remove the screws from the rear and along side
edges of the case.
The outer case must be moved backward to be lifted
off.
B. POWER SUPPLY CORD
1) Remove the outer case.
2) Disconnect two terminals, and remove one screw of
the earth terminal.
CAUTION: DISCHARGE THE HIGH VOLTAGE
CAPACITOR BEFORE SERVICING
(refer to page 2-1)
C. CONTROL PANEL ASSEMBLY
1) Disconnect the leadwire from the Timer motor
2) Remove the screws for securing the control panel.
3) Lift control panel ASS ’Y from the oven by the tab
unhooked.
5-3
WATER LOAD
TURNTABLE
MEASUREMENT OF MICROWAVE POWER OUTPUT
DISASSEMBLY AND ADJUSTMENT
P =

D. 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. (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.
E. 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.
F. FAN MOTOR ASSEMBLY REMOVAL
1) Discharge the high voltage capacitor.
2) Disconnect the leadwire from fan motor, noise filter
and high voltage capacitor.
3) Remove the two screws holding the the suction guide
ASS’Y to the oven cavity and remove the high voltage
diode earth screw.
4) Remove the screw of the capacitor bracket.
5) Remove the two screws holding the fan motor ASS’Y
to the suction guide ASS’Y.
G. HIGH VOLTAGE CAPACITOR AND
DIODE REMOVAL
1) Discharge the high voltage capacitor.
2) Disconnect the leadwire from fan motor, noise filter
and high voltage capacitor.
3) Remove the screw holding the suction guide ASS’Y to
the oven cavity and remove the high voltage diode
earth screw.
4) Remove the screw holding the high voltage capacitor
bracket.
5-4
Remove Hinge Plate
Remove Door Assembly
H.V
Transformer
Suction
Guide
Fan Motor ASS Y
H.V
Capacitor
H.V.
Diode

H. AIR DUCT ASSEMBLY REMOVAL
1) Disconnect the leadwire from lamp, A.C Relay and
monitor resistor.
2) Remove the mounting screw to the magnetron.
I. MAGNETRON REMOVAL
1) Disconnect the leadwire from the high voltage
transformer and high voltage capacitor.
2) Carefully remove the mounting screws holding the
magnetron and the waveguide.
3) Remove the magnetron ASS’Y 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.
J. REMOVING THE TURNTABLE MOTOR
1) Remove the turntable.
2) Remove the turntable shaft VERY CAREFULLY.
3) Lay the unit down on its back.
4) Remove the turntable motor cover.
The turntable base cover is easily removed by
pinching the six parts with a wire cutting.
5) Disconnect the leadwire from the turntable motor
terminals.
6) Remove the screw securing the turntable motor to
the oven cavity ASS’Y
7) After repairing the motor, rotate the removed
turntable motor cover.
8) 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.
5-5
Waveguide
Magnetron
Gasket
Magnetron
Dome
Waveguide
Bracket
Magnetron
Wire Leads
Turntable Motor

K. TIMER MOTOR REMOVAL
1) Remove the control panel assembly from the
cavity.
2) Remove screws which hold the timer motor to the
control panel.
3) Remove the timer motor from the control panel.
4) Remove the power control knob and the timer
knob.
L. 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
adjustment. Make sure that the latch moves
smoothly after adjustment are completed and that
the screws are tight. Make sure the primary, monitor,
and secondary switches operate properly by
following the continuity test procedure.
5-6
PRIMARY
SWITCH
ADJUSTMENT
DIRECTION
MONITOR
SWITCH
SECONDARY
SWITCH
CAUTION: CHECK THE CORRECT POSITION
MAGNETRON
H.V. TRANSFORMER
PRIMARY CIRCUIT PROTECTOR
H.V. CAPACITOR
H.V.
DIODE
FIG. 1

COM
NO
COM
NC
COM
NO
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.
5-7
INTERLOCK CONTINUITY TEST
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 FOR PRIMARY SWITCH
TYPE NO.SZM-V 16-FA-62 OR VP-532A-OF FOR MONITOR SWITCH
TYPE NO.SZM-V 16-FA-63 OR VP-533A-OF 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 are
connected correctly.

5-8
COMPONENT TEST PROCEDURE
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. (SEE PAGE 2-1)
2. ALL OPERATIONAL CHECKS WITH MICROWAVE ENERGY MUST BE DONE WITH A LOAD (1 LITER
OF WATER IN CONTAINER) IN THE OVEN.
HIGH VOLTAGE
TRANSFORMER
(Wire leads removed)
MAGNETRON
(Wire leads removed)
Approx.: 1.4 ohm
Approx.: 90 ohm
Less than: 1 ohm
Normal: Infinite
Normal: Infinite
Normal: Less than 1 ohm
Normal: Infinite
PRIMARY
TERMINAL
SECONDARY
TERMINAL
WINDING
FILAMENT
TERMINAL
COMPONENTS TEST PROCEDURE RESULTS
1. Measure the resistance.
(Ohm-meter scale: Rx1)
•Primary winding
•Secondary winding
•Filament winding
2. Measure the resistance.
(Ohm-meter scale: Rx1000)
•Primary winding to ground
•Filament winding to ground
1. Measure the resistance.
(Ohm-meter scale: Rx1)
•Filament terminal
2. Measure the resistance.
(Ohm-meter scale: Rx1000)
•Filament to chassis

5-9
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
HIGH VOLTAGE
CAPACITOR
Measure the resistance.
(Ohm-meter scale: Rx1000)
•Terminal to terminal.
Normal: Momentarily indicates
several ohms, and
then gradually returns
to infinite.
Normal: ∞
Normal: ∞
Abnormal: Continuity.
Normal: Continuity.
Abnormal: ∞
Measure the resistance.
(Ohm-meter scale: Rx1000)
•Terminal to case.
Measure the continuity (Forward).
(Ohm-meter scale: Rx10000)
Measure the continuity (Reverse).
(Ohm-meter scale: Rx10000)
HIGH VOLTAGE
DIODE
NOTE :
Some inexpensive meters
may indicate infinite
resistance in both direction.
COMPONENTS TEST PROCEDURE RESULTS

5-10
COMPONENTS TEST PROCEDURE RESULTS
MAIN FUSE Check for continuity of the fuse with an
multi-meter.
NOTE: If the fuse is blown, check the primary, the secondary, and the monitor
switches, H.V.D. and H.V.C. before replacing the fuse.
If the fuse is blown by improper switch operation replace the defective switch
and the fuse at the same time. Replace just the fuse if the switches operate
normally.
Normal Abnormal