LG MS-4580MRC, LG MS-4580MRC Owner's manual

LG MS-4580MRC, LG MS-4580MRC Owner's manual
삼
정
흥
판
Internal Use Only
Website: http://biz.lgservice.com
LIGHT OVEN “SolarDOM”
SERVICE MANUAL
MODEL: MP9485FR
CAUTION
BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
P/NO : MFL62270002
March, 2010
Printed in Korea
SAFETY PRECAUTIONS
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.
CAUTION
MICROWAVE RADIATION
DO NOT BECOME EXPOSED TO RADIATION FROM THE MICROWAVE GENERATOR
OR OTHER PARTS CONDUCTING MICROWAVE ENERGY.
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
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
UPPER &LOWER HEATER- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 5-7
INTERLOCK CONTINUITY TEST- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 5-8
COMPONENT TEST PROCEDURE - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 5-9
TROUBLE SHOOTING- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 5-14
EXPLODED VIEW - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 6-1
REPLACEMENT PARTS LIST - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 7-1
LGE Internal Use Only
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
SPECIFICATIONS
ITEM
MODEL
Power Requirement
DESCRIPTION
MP9485FR
230 V~ 50 Hz
Single phase, 3 wire grounded
Microwave
Grill
Combination
Convection
1650 W
max. 1600 W
max. 2350 W
2300 W
Power Output
900 watt full microwave power (IEC60705)
Microwave Frequency
2450 MHz
Magnetron
2M248H - B
Timer
0 ~ 90 min.
Outside Dimensions
527 (W) x 394 (H) x 480 (D) mm
Cavity Dimensions
440 (W) x 204 (H) x 420 (D) mm
Net Weight
26 kg
Shipping weight
29 kg
Control Complement
1. Microwave Power level:
max. (900 W), 600 W, 360 W, 180 W, 90 W
2. GRILL
Category Display
Grill-1
gr-1
Grill-2
gr-2
Grill-3
gr-3
Heater operating
Upper heater (2000W)
Upper heater (1100W)
Upper heater (700W)
3. Convection: 40°C, 100~250°C
4. SPEED COMBI
Display Heater + Microwave power selection
Co-1 Grill-1 + 180W, 360W, 600W
Co-2 Grill-2 + 180W, 360W, 600W
Co-3 Grill-3 + 180W, 360W, 600W
Co-4 Upper heater(1550W) + Lower heater + Microwave power
Co-5 Upper heater(1100W) + Lower heater + Microwave power
5. SPEED AUTO COOK
Rating Label Location
Accessories
Owner's manual & Cook book
High rack, Low rack
Metal tray, Rotisserie
This oven is designed for household use only.
It is not recommended for commercial purposes.
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
1-1
LGE Internal Use Only
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.
• 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.
• 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.
ANTENNA
Gasket
COOLING FIN
FILAMENT
TERMINALS
MAGNETRON
• Remove your watches whenever working close to or
replacing the Magnetron.
• 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.
LGE Internal Use Only
MAGNETRON
CHASSIS GROUND
THE OVEN IS TO BE SERVICED ONLY
BY PROPERLY QUALIFIED SERVICE
PERSONNEL.
2-1
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
INSTALLATIONS
BEFORE YOU BEGIN, READ THE FOLLOWING INSTRUCTIONS COMPLETELY AND CAREFULLY.
INSTALLING
EARTHING INSTRUCTIONS
1. Empty the 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.
This oven is designed to be used in a fully earthed
condition.
It is imperative, therefore, to make sure it is properly
earthed before servicing
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. (Use care when handling.)
WARNINGTHIS APPLIANCE
MUST BE EARTHED
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 that the microwave oven legs are in
place to ensure proper air flow.
IMPORTANT
The wires in this mains lead are colored in
accordance with the following code:
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.
Green-and-yellow:
Blue:
Brown:
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.
5. Use the oven in an ambient temperature less than
104°F(40°C).
6. Place the oven on a sturdy and flat surface at least
10 cm(4 inches) from the wall.
The wire which is colored green-and-yellow must be
connected to the terminal in the plug which is marked
with the letter E or by the earth symbol ( ) or
colored green or green-and-yellow.
7. Place the oven as far away as possible from TV,
RADIO, COMPUTER, etc., to prevent interference.
8. Do not touch the front glass during or after cooking
of the Grill and convection and Combination mode.
This glass is very hot during heater operating.
The wire which is colored blue must be connected to
the terminal in the plug which is marked with the letter
N or colored black.
9. Do not operate the oven at microwave and
combination mode with Grill rack placed in the
cavity when the oven is empty.
The wire which is colored brown must be connected
to the terminal in the plug which is marked with the
letter L or colored red.
10cm
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
Earth
Neutral
Live
3-1
LGE Internal Use Only
OPERATING INSTRUCTIONS
FEATURES
HIGH Rack
LOW Rack
Metal Tray
Oven Front Plate
Window Door Screen
Control Panel Deco.
Control Panel
Door Frame
Choke Cover
Safety Door Lock System
Rotisserie
Handle
CONTROL PANEL
8. Enter: You can determine the selected cooking category,
microwave power level or temperature.
9. Defrost: You can select the food type and the weight of the food.
10. Micro: You can select five power level settings.
11. Stop/Clear: You can stop over and clear all entries except time of
day.
12. Start/Quick Start:
• In order to start cooking which is selected, press button one time.
• The quick start feature allows you to set 30 second intervals of HIGH
power cooking with a touch of the quick start button.
1. Clock: You can set the time of day.
2. Convection: You can select temperature and time of convection.
3. Grill: You can select the grill categories.
4. Speed Combi: You can select the combination categories.
5. Speed Auto Cook: Speed auto cook allows you to cook most of
your favorite food quickly by selecting the food type and the weight
of the food.
6. Dial Knob:
• You can set cooking times, temperature, weight and cooking
categories.
• While cooking with auto and manual function, you can set or
change the cooking time at any point by turning the dial
knob(except defrost mode).
7. Display Window: You can show time of day, cooking time, power
level and cooking categories.
LGE Internal Use Only
4-1
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
OPERATING SEQUENCE
6. SPEED COMBI COOKING
The following is a description of component functions
during oven operation.
*Speed combi Categories
Co-1
Co-2
Co-3
Co-4
Co-5
1. SETTING THE CLOCK
Stop/Clear
Turn Dial
Desired
hour
Clock
Turn Dial
Desired
minute
Enter
Enter
Grill-1 + Microwave Power
Grill-2 + Microwave Power
Grill-3 + Microwave Power
Upper Heater (1550W) + Lower Heater + Microwave power
Upper Heater (1100W) + Lower Heater + Microwave power
ex)
2. MICROWAVE COOKING
Stop/
Clear
Micro
Desired
power
level
Turn Dial
Desired
power level
Enter
Turn Dial
Desired
cooking time
Start
Stop/
Clear
Micro
Enter
Desired
cooking
time
Start
Defrost
Turn Dial
Desired defrost
category
Enter
Food
weight
Start
8. SPEED COMBI COOK
Stage 1
Stop/
Clear
Enter
Enter
7. DEFROST
3. MULTI STAGE COOKING (MICROWAVE)
Turn Dial
Desired
power level
Turn Dial
Desired
Co-1,2,3,4,5
Speed
Combi
Stop/
Clear
Stop/
Clear
Turn Dial
Desired
cooking time
Function
Speed
Combi
Turn Dial
Desired speed
Combi category
Food
weight
Start
9. SPEED AUTO COOK
Stage 2
Desired
power
level
Micro
Enter
Desired
cooking
time
Stop/
Clear
Start
Turn Dial
Desired
cooking time
Enter
Stop/Clear
Food
weight
Start
Stop/Clear
(Touch and Hold)
To Cancel CHILD LOCK
Start
Stop/Clear
*Grill Categories
Grill-1
Grill-2
Grill-3
Enter
This oven has a CHILD LOCK feature.
To Set CHILD LOCK
Turn Dial
Desired
Grill-1,2,3
Grill
Turn Dial Desired
Speed Auto Cook
category
10. CHILD LOCK
4. GRILL COOKING
Stop/
Clear
Speed
Auto
Cook
Upper Heater (1550W)
Upper Heater (1100W)
Lower Heater (700W)
Stop/Clear
(Touch and Hold)
11. QUICK START
Stop/Clear
5. CONVECTION COOKING
Start/Quick Start
To cook
Stop/
Clear
Convection
Turn Dial
Desired convection
temp(40°C, 100°C~250°C)
Enter
Desired
cooking
time
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
Start
4-2
LGE Internal Use Only
SCHEMATIC DIAGRAM
LGE Internal Use Only
4-3
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
CIRCUIT DESCRIPTION
power of oven as POWER LEVEL. (refer to page 1-1)
• One complete cycle of relay 4 is 32 seconds.
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 THE DOOR IS OPENED DURING
COOKING
• Both the primary switch and relay 4 are cut off primary
winding voltage of the high voltage transformer.
• ON-OFF of relay 4 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 relay 4 and/or secondary switch fails to open, the
fuse opens due to the large current surge caused by
the monitor switch activation, which in turn stops
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 BUTTON
• 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 4.
• Turntable rotates.
FUSE
FUSE
PRIMARY
SWITCH
L
PRIMARY
SWITCH
H.V.
TRANSFORMER
MONITOR
SWITCH
N
L
H.V.
TRANSFORMER
MONITOR
SWITCH
RELAY 4
N
SECONDARY
SWITCH
MICOM CONTROLLER
magnetron oscillation.
RELAY 4
SECONDARY
SWITCH
WHEN TOUCHING THE START BUTTON
WITH THE HEATER COOKING
FUNCTION SELECTED
MICOM CONTROLLER
• The fan motor rotates and cools the magnetron by
blowing the air (coming from the intake on the
back cover).
• 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 4000 Volts DC is applied to the filament
of the magnetron.
• The contacts of the primary switch and the secondary
switch close the circuit.
• A.C. voltage is applied to the heater through thermostat
as shown by the solid line.
L
L
N
HEATER
E
N
RELAY 5,6,7
THERMOSTAT
• Turntable rotates.
• The fan motor rotates.
• The air is also directed into the oven to exhaust the
vapor in the oven through the base plate and back
plate.
WHEN THE OVEN IS SET AT ANY LEVEL
EXCEPT MAXIMUM.
• The micom controller controls the ON-OFF time of relay
4 by the applied signal to vary the average output
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
G -Y
4-4
LGE Internal Use Only
SERVICE INFORMATION
TOOLS AND MEASURING INSTRUMENTS
NECESSARY TOOLS
NECESSARY MEASURING INSTRUMENTS
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
• 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)
MICROWAVE LEAKAGE TEST
CAUTIONS
MEASURING MICROWAVE ENERGY
LEAKAGE
• 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.
• 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 oven should not exceed 4 mW/cm2.
Always start measuring of an unknown field to assure
safety for operating personnel from radiation leakage.
LGE Internal Use Only
• 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 2450 MHz and
use it following the manufacturer's recommended
test procedure to assure correct result.
• When measuring the leakage, always use the 2inch (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
(1in/sec)
5-1
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
MEASUREMENT WITH OUTER CASE
REMOVED
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 is
moved horizontally along the oven surface, this may
possibly cause probe damage.
• 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
WARNING : AVOID CONTACTING ANY
HIGH VOLTAGE PARTS
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.
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/cm.sq.
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
5-2
LGE Internal Use Only
MEASUREMENT OF MICROWAVE POWER OUTPUT
• The microwave power output P in watts is calculated
from the following formula :
• Microwave power output measurement is made with
the oven supplied at its rated voltage and operated
at its maximum microwave power setting with a load
of (1000 ± 5)g 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
190 mm.
• 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 shelf 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)°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.
4187 X (∆T) + 0.55 X (T2 - T0 ) X M
P=
T
• T2 : Temperature after heating
• T0 : Temperature of bowl
• M : Weight of bowl
is measured while the microwave generator is
operating at full power. Magnetron filament heat-up
time is not included.
• 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
DISASSEMBLY AND ADJUSTMENT
A. OUTER CASE REMOVAL
C. CONTROL PANEL ASSEMBLY
1) Disconnect the leadwire from the PCB sub assembly.
2) Remove the screws for the control bracket and
securing the control panel.
3) Remove control panel assembly from the oven by the
moving control panel assembly right side.
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)
LGE Internal Use Only
5-3
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
D. PCB ASSEMBLY REMOVAL
1) Remove the control panel assembly from the
cavity. (Refer to control panel assembly removal
on previous page.)
2) Remove screws which hold the PCB sub assembly
to the PCB holder.
3) Remove the PCB holder & PCB bracket.
4) Remove screws which hold the control panel.
5) Disconnect the flat cable from the PCB sub
assembly and take off the PCB sub assembly.
Please use the JIG
(P/No. 383EW5A224A)
below for door removal.
JIG
mm
DOOR JIG P/No.
383EW5A224A
29
30mm
18mm
6mm
9mm
R1.5
F. BRACKET ASSEMBLY REMOVAL
1) Remove screws on the bracket assembly and release
a lug.
2) Disconnect the leadwire from thermostat and lift out
the bracket assembly.
G. MAGNETRON REMOVAL
1) Remove controller assembly and bracket assembly.
2) Disconnect the leadwire from the high voltage
transformer and Magnetron.
3) Carefully remove the mounting screws holding the
magnetron and the wave guide.
4) Remove the magnetron until its dome is clear from
the wave guide.
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. DOOR ASSEMBLY / REMOVAL
1) Disconnect the power cord.
2) Open the door from oven. insert “JIG ” into the choke
cover hole of door.
3) Lift the door from front cavity.
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/cm2. (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.
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
Bracket
5-4
Magnetron
LGE Internal Use Only
H. FAN MOTOR ASSEMBLY / REMOVAL
J. REMOVING THE TURNTABLE MOTOR
1) Remove controller assembly, bracket assembly,
power cord, latch board-R from upper.
2) Disconnect the leadwire from fan motor, latch board-R
and noise filter.
3) Remove the three screws holding the fan motor
assembly to the oven cavity.
4) Remove the fan motor assembly to the upper plate.
1) Remove the metal tray.
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 assembly.
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 and fasten a screw.
9) The taptite screw shall be used when a turntable
motor cover is secured with a screw.
I. HIGH VOLTAGE CAPACITOR, FUSE,
TRANSFORMER AND DIODE REMOVAL
1) Discharge the high voltage capacitor.
2) Disconnect the leadwire from transformer,
magnetron, Fuse and capacitor.
3) Remove the screw holding the transformer and
remove the high voltage diode earth screw.
NOTE:
1. Remove the wire lead from the turntable motor
VERY CAREFULLY.
2. Be sure to grasp the connector, not the wires, when
removing
Taptite Screw
Wire Leads
Turntable Motor
LGE Internal Use Only
5-5
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
K. C-MOTOR, THERMISTOR
REMOVAL
L. INTERLOCK SYSTEM
1) INTERLOCK MECHANISM
The door lock mechanism is a device which has
been specially designed to eliminate
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
1) Remove controller assembly.
2) Disconnect the leadwire from the circulation motor
terminal and oven thermostat.
3) Remove three screws of the air tunnel - U and
lift it up.
4) Remove the screws of the thermistor, guide assychamber and lift up the guide assy-chamber.
5) Remove a hex nut securing the circulation fan to
shaft of the C-motor.
6) Remove screws securing the motor shaft to the
guide assy-chamber.
7) Remove hex nut securing the C-motor to the motor
shaft.
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.
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
5-6
LGE Internal Use Only
M. UPPER SHEATH HEATER REMOVAL
O. LOWER HEATER REMOVAL
1) Remove two hex nuts holding the sheath heater.
2) Remove the sheath heater from the oven cavity.
1) Disconnect the leadwire from the sheath heater.
2) Remove the base plate from cavity.
3) Remove the nuts from the oven cavity of the side.
4) Remove the gasket, ring and heater bracket.
5) Remove the sheath heater in the oven cavity.
N. UPPER HALOGEN HEATER REMOVAL
• If there are broken glass pieces between the
reflector and the oven cavity.
1) Remove the magnetron, air tunnel and fan motor
assembly.
2) Remove the latch boards and air tunnel - L/R.
3) Remove two screws holding the insulator - U to the
back plate and lift it up.
4) Remove the heater holder.
5) Remove the reflector and glass pieces.
• If the hologen heater isn’t broken.
1) Remove the heater holder and halogen heater.
Chamber-U
Ring
Gasket
Heater Bracket
Upper Sheath Heater
Lower Sheath Heater
Insulator-U
Air-Tunnel-U
LGE Internal Use Only
5-7
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
INTERLOCK CONTINUITY TEST
WARNING : FOR CONTINUED PROTECTION AGAINST EXCESSIVE RADIATION
EMISSION, REPLACE ONLY WITH IDENTICAL REPLACEMENT PARTS.
TYPE NO. SZM-V 16-FA-63 FOR PRIMARY SWITCH
TYPE NO. SZM-V 16-FA-62 FOR MONITOR SWITCH
TYPE NO. SZM-V 16-FA-63 FOR SECONDARY SWITCH
A. PRIMARY INTERLOCK SWITCH TEST
B. SECONDARY INTERLOCK SWITCH TEST
When the door is closed slowly an audible click
should be heard at the same time or successively
at intervals. When the door is opened 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.
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.
COMPONENTS
SWITCHES
(Wire leads removed)
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.
TEST PROCEDURE
Check for continuity of the switch
with a Multi-meter
Primary
Switch
Monitor
Switch
Secondary
Switch
RESULTS
Door
open
Door
close
NO
COM
NC
COM
NO
COM
NOTE : After checking for the continuity of switches, make sure that are
correctly connected.
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
5-8
LGE Internal Use Only
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.
COMPONENTS
TEST PROCEDURE
RESULTS
HIGH VOLTAGE
TRANSFORMER
(Wire leads removed)
FILAMENT
WINDING
TERMINAL
SECONDARY
TERMINAL
PRIMARY
TERMINAL
1. Measure the resistance.
(Ohm-meter scale: Rx1 and Rx100)
• Primary winding
• Secondary winding
• Filament winding
Approx.: 1.7 ohm
Approx.: 130 ohm
Less than: 1 ohm
2. Measure the resistance.
(Ohm-meter scale: Rx1000)
• Primary winding to ground
• Filament winding to ground
Normal: Infinite
Normal: Infinite
MAGNETRON
(Wire leads removed)
LGE Internal Use Only
1. Measure the resistance.
(Ohm-meter scale: Rx1)
• Filament terminal
Normal: Less than 1 ohm
2. Measure the resistance.
(Ohm-meter scale: Rx1000)
• Filament to chassis
Normal: Infinite
5-9
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
COMPONENTS
TEST PROCEDURE
RESULTS
Antenna
Chassis
Gasket
Filament
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.
HIGH VOLTAGE
CAPACITOR
HIGH VOLTAGE
DIODE
NOTE :
Some inexpensive meters
may indicate infinite
resistance in both direction.
Measure the resistance.
(Ohm-meter scale: Rx1000)
• Terminal to terminal.
Normal: Momentarily indicates
several ohms, and then
gradually returns to
infinite.
Measure the resistance.
(Ohm-meter scale: Rx1000)
• Terminal to case.
Normal: Infinite.
Measure the continuity (Forward).
(Ohm-meter scale: Rx10000)
Normal: Continuity.
Abnormal: Infinite.
Measure the continuity (Reverse).
(Ohm-meter scale: Rx10000)
Normal: Infinite.
Abnormal: Continuity.
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
5-10
LGE Internal Use Only
COMPONENTS
FUSE
H.V. FUSE
TEST PROCEDURE
RESULTS
Check for continuity of the fuse with an
multi-meter.
Normal
Abnormal
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.
HEATER ELEMENT
(Wire leads removed.)
Measure the resistance.
(Multi-meter scale: Rx1)
Normal:
• Upper sheath heater:
Approx. 47 ohm (230V, 1100W)
• Lower sheath heater:
Approx. 74 ohm (230V, 700W)
• Upper Halogen heater:
Approx. 15 ohm (230V, 450W)
(at 20 ~30°C)
Measure the resistance with 500V-100M ohm
insulation resistance meter.
Normal: more than 0.5 Mohm
NOTE: Make sure heater is fully cooled when tested.
MAGNETRON and OVEN
THERMOSTAT
LGE Internal Use Only
5-11
OVEN Thermostat
0°C~160°C
160°C
M.G.T Thermostat
60°C~Approx.110°C
Over 110°C
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
COMPONENTS
Disconnect the 4 pin
connector from P.C.B.
(Refer to schematic diagram)
TEST PROCEDURE
Check for P.C.B.connector.
RELAY OF P.C.B.
(Wire leads removed.)
Note: Relay
Relay 1: Fan motor
Circulation motor
Relay 2: Oven lamp
Turntable motor
Rotisserie motor
Relay 3: P.T.C Relay
(Positive
Temperature
Coefficient)
Relay 4: Microwave
Relay 5: Up. sheath heater
Relay 6: Lo. sheath heater
Relay 7: Halogen Heater
RESULTS
Cooking Start
OFF
Cooking Start
OFF
FAN MOTOR
(Wire leads removed)
Measure the resistance.
(Ohm-meter scale:R x 1)
Normal: Approx. 60 ohm
Abnormal: Infinite or several
ohm.
TURNTABLE
MOTOR
(Wire leads removed)
Measure the resistance.
(Ohm-meter scale: R x 1000)
Normal: Approx. 10~20 kohm
Abnormal: Infinite or several
ohm.
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
5-12
LGE Internal Use Only
COMPONENTS
CIRCULATION MOTOR
(Wire leads removed)
KEY PCB
TEST PROCEDURE
Measure the resistance.
(Multi-meter scale: R x 1)
Key P.C.B.
RESULTS
Normal : Approx. 170 ohm.
Abnormal : Infinite or several ohm.
Main P.C.B
1
2
3
4
5
6
7
8
9
10~
1
2
3
4
5
6
7
8
9
10~
18
18
Check continuity between switch
terminals, by pressing an
appropriate pad on key board.
The contacts assignment of the
respective pads on the key board
is as shown left figures.
NOTE : A MICROWAVE ENERGY LEAKAGE TEST MUST ALWAYS BE PERFORMED WHEN THE UNIT IS
SERVICED FOR ANY REASON.
MAKE SURE THE WIRE LEADS ARE CORRECT POSITION.
WHEN REMOVING THE WIRE LEAD FROM THE PARTS, BE SURE TO GRASP THE
CONNECTOR, NOT THE WIRES.
LGE Internal Use Only
5-13
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
TROUBLE SHOOTING
WHEN YOU GET A COMPLAINT FROM YOUR CUSTOMER, EVALUATE THE COMPLAINT CAREFULLY. IF
THE FOLLOWING SYMPTOMS APPLY, PLEASE INSTRUCT THE CUSTOMER IN THE PROPER USE OF THE
OVEN. THIS CAN ELIMINATE AN UNNECESSARY SERVICE CALL.
CAUTIONS
1. Check grounding before checking for trouble.
2. Be careful of the high voltage circuit.
3. Discharge the high voltage capacitor. (See page 2-1)
4. When checking the continuity of the switches or of the high voltage transformer, disconnect one lead wire
from these parts and then check continuity with the AC plug removed. To do otherwise may result in a
false reading or damage to your meter.
5. Do not touch any part of the circuitry on the digital programmer circuit since static electric discharge may
damage this control panel.
Always touch yourself ground while working on this panel to discharge any static charge built up in your
body.
CONDITION
CAUSE
The oven
does not work.
Inserting many plug into one
plug outlet and using
them at the same time
(causes overloading).
Output power is too low.
Sparks occurring.
Uneven cooking.
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
REMEDY
Avoid using other electrical
appliances when you use
the oven.
The oven plug is not inserted
tightly.
Insert the oven plug securely.
Low AC input voltage.
Use the oven at adequate
line voltage.
Food temperature is too low.
This may not be a defect.
It is possible that the food
should be cooked for a
longer time period.
Using metallic ware and
allowing it to touch the oven
wall.
Do not use metallic ware for
cooking except where noted
in the cooking guide.
Ceramic ware trimmed in
gold or silver powder is used.
Do not use any type of
cookware with metallic
trimming.
Inconsistent intensity of
microwave by their
characteristics.
1. Wrap the thinner part with
aluminum foil.
2. Use plastic wrap or lid.
3. Stir once or twice while
cooking soup, cocoa or
milk, etc.
5-14
LGE Internal Use Only
(TROUBLE 1) The following visual conditions indicate a probable defective control circuit.
1. Incomplete segments.
• Segment missing.
• Partial segment missing.
• Digit flickering (NOTE: Slight flickering is normal.)
2. Colon does not turn on or blink.
3. A distinct change in the brightness of one or more numbers in display.
4. One or more digits in the display are not lighting.
5. Display does not count down with time blinking or up with clock operation.
6. Display obviously jumps in time while counting down.
7. Display counts down too fast while cooking.
8. Each indicator light does not turn on after setting cooking cycle.
9. Display time of day does not reappear when cooking is finished.
10. Beep sound is not heard when correct key is touched.
CONDITION
CHECK
1. No input can be
programmed.
Check the connection between
key assembly
and PCB
assembly.
2. Some inputs
cannot be
programmed.
3. Display shows a
number or figure
different from one
touched.
Replace key
assembly and
check operation.
RESULT
CAUSE
REMEDY
Continuity.
Defective PCB
assembly.
Replace PCB
assembly.
No continuity.
Loose
connection.
Connect them
tightly.
Defective key
assembly.
Replace key
assembly.
Defective PCB
assembly.
Replace PCB
assembly.
Everything works
as specified.
Still have trouble.
4. Random
programming
when touching
other pads.
5. Display is fixed
at some figure
and can not
accept any
input.
LGE Internal Use Only
5-15
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
(TROUBLE 2) Oven does not operate at all ; Display window does not display any figures and
no input is accepted.
CONDITION
1. Fuse blows.
CHECK
Check continuity
of monitor
switch (with
door closed).
RESULT
Continuity.
CAUSE
REMEDY
Malfunction of the
monitor switch.
Replace primary
and monitor
switches.
No continuity.
Replace fuse
Check continuity
of primary
switch (with
door opened).
Disconnect one
side of the wire
lead connected
from transformer
to the high
voltage
capacitor and
operate the unit.
Shorted contact at
the primary switch.
Replace primary
and monitor
switches.
Normal.
Defective high
voltage capacitor.
Replace high
voltage capacitor.
Fuse blows again
Defective high voltage transformer.
Replace high voltage transformer.
Continuity.
No continuity.
NOTE : All these switches must be replaced at the same time. Refer to page 5-6, 5-8
2. Fuse does not
blow.
Check continuity
of magnetron
thermostat.
No continuity.
Continuity.
Check continuity
of power supply
cord.
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
No continuity.
5-16
Defective magnetron thermostat,
oven thermostat
and Lower voltage
transformer.
Replace magnetron thermostat,
oven thermostat
and Lower voltage
transformer.
Defective power
supply cord.
Replace power
supply cord.
LGE Internal Use Only
(TROUBLE 3) Display shows all figures set, but oven does not start cooking while
desired program times are set and START button is touched.
CONDITION
CHECK
1.Setting time does
not count down
when touching
START button.
Check continuity
of secondary
switch (with
door closed).
CAUSE
REMEDY
Defective
secondary switch
and secondary
switch wire
connector.
Replace
secondary switch
and secondary
switch wire
connector.
No continuity.
Defective P.C.B
assembly.
Replace P.C.B
assembly.
Continuity.
Loose connection.
Connection then
tightly.
Check fan motor,
c-motor.
Abnormal
Defective fan
motor, c-motor.
Replace fan
motor, c-motor.
Check oven lamp,
turntable motor.
Abnormal
Defective oven
lamp, turntable
motor..
Replace oven
lamp, turntable
motor.
Check the connection between
connector and
P.C.B assembly.
2. Fan motor,
c-motor or
oven lamp,
turntable
motor,
rotisserie
motor do not
turn on.
RESULT
No continuity.
Continuity.
Normal.
(TROUBLE 4) Oven seems to be operation but little heat is produced in oven load.
CONDITION
Output is low.
CHECK
Check the
power source
voltage.
RESULT
CAUSE
REMEDY
Lower than 90% of
rating voltage.
Decrease in power
source voltage
with load.
Suggest customer
contact local
electric power
utility co. or
qualified
electrician.
Defective P.C.B
assembly.
Replace P.C.B
assembly.
Defective
magnetron.
Replace
magnetron.
Normal.
Disconnect the
wire leads from
relay 4 and check
on and off time
with multitester.
Measure the
output power.
Abnormal.
Normal.
Abnormal.
NOTE: Simple test of power output-conducted by heating one liter water for one min. if available.
Minimum 8.5°C temperature rise is normal condition.
LGE Internal Use Only
5-17
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
(TROUBLE 5) No microwave oscillation even though oven lamp and fan motor run.
(Display operates properly)
CONDITION
No microwave
oscillation.
CHECK
RESULT
Disconnect the
wire leads from
relay 4 and
check continuity
of relay 4.
(Operate the unit)
No continuity.
Check H.V.
transformer and
H.V. Fuse.
Abnormal
REMEDY
Defective P.C.B
assembly.
Replace P.C.B
assembly.
Defective high
voltage
transformer and
H.V. Fuse.
Replace high
voltage
transformer and
H.V. Fuse.
Defective high
voltage capacitor.
Replace high
voltage capacitor.
Defective high
voltage Diode.
Replace high
voltage Diode.
Defective
magnetron.
Replace
magnetron.
Continuity.
normal
Check H.V.
capacitor.
CAUSE
Abnormal
normal
Check H.V.
diode.
Abnormal
normal
Check
Magnetron.
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
Abnormal
5-18
LGE Internal Use Only
(TROUBLE 6) Oven does not cook properly when programmed for the set power level
(Operates properly on HIGH)
CONDITION
CHECK
Output is full when
you set lower
power level.
Disconnect the
wire leads from
relay 4 and check
continuity relay 4.
(Operate the unit)
(TROUBLE 7) Heater
CONDITION
1. Heater is not
operating.
RESULT
Abnormal.
CAUSE
REMEDY
Defective P.C.B
assembly.
Replace P.C.B
assembly.
CAUSE
REMEDY
Relay 5- Up. sheath Heater
Relay 6- Lo. sheath Heater
Relay 7- Halogen Heater
CHECK
Heater.
RESULT
Abnormal.
Malfunction of the
heater.
Replace.
Normal.
Thermostat and
relay 5, 6, 7.
Abnormal
Malfunction of the
thermostat and
relay 5, 6, 7
Replace.
Normal.
2. Lower temperature the oven.
Wire connection.
No continuity.
Open or loosen.
Replace or
connect tightly.
Heater.
Abnormal.
Malfunction of the
heater.
Replace.
Normal.
Thermostat and
relay 5, 6, 7.
Abnormal
Malfunction of the
thermostat and
relay 5, 6, 7
Replace.
NOTE: * Make sure the wire leads are in the correct position.
* When removing the wire leads from parts, Be sure to grasp the connector not the wires.
* When removing the magnetron, be sure to install the magnetron gasket in the correct position and in
good condition.
LGE Internal Use Only
5-19
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
#EV#
EXPLODED VIEW
INTRODUCTION
MODEL:
INTERIOR PARTS
CONTROL PANEL PARTS
OVEN CAVITY PARTS
BASE PLATE PARTS
LATCH BOARD PARTS
DOOR PARTS
OWNERS
MANUAL
COOK BOOK
MFL552
MAX171
-6-1-
MAY000
#EV#
DOOR PARTS
13581A
13552A
13213E
WPZ016
WTP002
140262
14970A
140261
WPZ016
14970A
WTT051
14891A
13650A
14980A
-6-2-
#EV#
CONTROL PANEL PARTS
268711
24781S
WTT028
24810L
WTT028
24810R
WTP004
24980A
268712
WTP004
250201
249401
23551A
250201
-6-3-
#EV#
OVEN CAVITY PARTS
35026C
33301L
33301R
34270A
33650T
34271A
35026G
WTT021
95001A
33112U
WTT029
33390M
34370T
WTT022
WTT029
WNZ015
WTT022
34930R
34681R
WSZ092
34370Z
33052M
34810R
36549R
348101
WSZ094
34960R
343501
353001
WNZ015
368771
36549S
WTP013
63302A
54790A
WTT028
647781
WTT028
63303A
647781
WTT028
-6-4-
WTP013
#EV#
LATCH BOARD PARTS
WSZ085
WSZ085
43501L
43501R
466001
43500R
466001
43500L
466003
44510A
-6-5-
#EV#
INTERIOR PARTS (I)
WTT028
55264A
353002
53550L
56324A
56912B
948502
WSZ002
WTT021
34890C
WSZ085
WTT028
350122
33034A
348102
552652
WTT021
35300H
WTT021
WSZ085
552651
-6-6-
#EV#
INTERIOR PARTS (II)
WTP002
WSZ002
56930V
WSZ002
56901A
948501
WTT021
54810A
34930W
WSZ002
WTT028
WTP002 56170D
WTT021
56201A
WSZ002
54980A WTT028
56549F
WNH002
56930M
WSZ002
50FZZA
350121
56411A
50CZZH
56322A
54810C
33660A
WMP021
55900A
36549W
56851D
WWS005
WWP008
WSZ085
WNH003
568771
-6-7-
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