LG MS 1146SQP Diagram

Internal Use Only
Website http://biz.lgservice.com
MICROWAVE OVEN
SERVICE MANUAL
MODEL: MS-1146SQP
CAUTION
BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
P/NO : MFL36414701
MS-1146WQP
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.
CONTENTS
(Page)
SAFETY PRECAUTIONS
SPECIFICATIONS
CAUTIONS
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INSTALLATIONS
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OPERATING INSTRUCTIONS
FEATURES
CONTROL PANEL
OPERATING SEQUENCE
SCHEMATIC DIAGRAM
CIRCUIT DESCRIPTION
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SERVICE INFORMATION
TOOLS AND MEASURING INSTRUMENTS
MICROWAVE LEAKAGE TEST
MEASUREMENT OF MICROWAVE POWER OUTPUT
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Inside front cover
1-1
2-1
3-1
4-1
4-1
4-1
4-2
4-3
4-4
5-1
5-1
5-1
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5-3
DISASSEMBLY AND ADJUSTMENT
INTERLOCK CONTINUITY TEST
COMPONENT TEST PROCEDURE
TROUBLE SHOOTING
EXPLODED VIEW
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REPLACEMENT PARTS LIST
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5-3
5-7
5-8
5-11
6-1
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7-1
SPECIFICATIONS
Back side
ITEM
Model
Power Requirement
Power Output
Microwave Frequency
Magnetron
Timer
Outside Dimensions
Cavity Dimensions
Net Weight
Shipping weight
Control Complement
DESCRIPTION
MS-1146SQP / MS-1146WQP
120 V~ 60 Hz
1450 watt
Single phase, 3 wire grounded
1000 watt full microwave power (IEC60705)
2450 MHz
2M246 - 050GF
0 ~ 9 min. 99 sec.
505 (W) x 291 (H) x 370 (D)
358 (W) x 226 (H) x 364 (D)
13.1kg
15.2kg
Touch Control System
Clock : 1:00 - 12:59
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%
Rating Label
Accessories
This microwave oven is designed for household use only.
Location
Owner's manual
Glass turntable
Roller Rest
It is not recommended for commercial purposes.
1-1
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.
• 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.
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.
• 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
• 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.
COOLING FIN
FILAMENT TERMINALS
MAGNETRON CHASSIS GROUND
MAGNETRON
THE OVEN IS TO BE SERVICED ONLY BY PROPERLY QUALIFIED SERVICE PERSONNEL.
2-1
INSTALLATIONS
BEFORE YOU BEGIN, READ THE FOLLOWING INSTRUCTIONS COMPLETELY AND CAREFULLY.
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).
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.
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.
PREFERRED METHOD
INSURE PROPER GROUND
EXISTS BEFORE USE
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.
TEMPORARY METHOD
(ADAPTER PLUGS ARE NOT
PERMITTED IN CANADA) ALIGN
LARGE PRONGS/SLOTS
INSURE PROPER GROUND AND
FIRM CONNECTION BEFORE USE
3-1
OPERATING INSTRUCTIONS
FEATURES
CONTROL PANEL
1. INDICATORS
2. LATIN MENU
3. AUTO DEFROST: Used to select the desired auto
weight defrost programmed with weight pad.
4. TIME: Used to cook food for a desired time.
5. QUICK DEFROST: Touch this pad to defrost
foods quickly.
6. HOLD WARM
7. NUMBER: Used to set for time of day, cooking time,
power level or defrost weight.
8. POWER: Used to select power level for cooking.
9. CLOCK: Used to set the time of day.
10. STOP/CLEAR: Used to stop oven and clear all
entries except time of day.
11. START/ADD 30 SECOND: One tap allows oven to begin functioning.
4-1
OPERATING SEQUENCE
The following is a description of component functions during oven operation.
1. SETTING THE CLOCK
PAUSA/BORRAR
ex.) To set 4:30, touch number key [4],[3], and [0].
NOTE: 1) This is a 12 hour clock.
2) Clock will operate as long as power is applied to the oven.
RELOJ RELOJNUMBER
2. CANCEL FUNCTION
Touch the pad whenever you need to cancel an entry or a function currently in use. The display will either return to the last item entered or to the clock.
PAUSA/BORRAR
3. ADD 30 SECOND
PAUSA/BORRAR
Más 30 Seg.
4. LATIN MENU
PAUSA/BORRAR
FRIJOLES
NUMBER
INICIO
7. AUTO WEIGHT DEFROST COOKING
PAUSA/BORRAR
AUTO DESCONG
POR PESO
NUMBER OF
WEIGHT
NUMBER
8. CHILD LOCK
This oven has a CHILD LOCK feature
• TO SET CHILD LOCK
• Touch the pad
• Touch and hold PARAR/BORRAR pad LOCK appear on the display.
• TO CANCEL CHILD LOCK
• Touch the pad
• Touch and hold PARAR/BORRAR pad LOCK disappears.
PAUSA/BORRAR
PAUSA/BORRAR
NOTE: Heat only 1 package at a time
5. TIME COOKING
PAUSA/BORRAR
TIME
NUMBER INICIO
NUMBER
6. MULTI-STAGE COOKING
1ST STAGE
PAUSA/BORRAR
2ND STAGE
TIME
NUMBER
TIME
NUMBER INICIO
NUMBER
NUMBER
POTENCIA
POTENCIA
POTENCIA
4-2
SCHEMATIC DIAGRAM
4-3
CIRCUIT DESCRIPTION
FUSE
H.V.
TRANS-
FORMER
RELAY 2
MICOM CONTROLLER
SECONDARY SWITCH
MONITOR
SWITCH
N
PRIMARY
SWITCH
L
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.
• 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 are cut off 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 relay 2 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 magnetron oscillation.
• The fan motor rotates and cools the magnetron by blowing the air (coming from the intake on the baseplate).
• The air is also directed into the oven to exhaust the vapor in the oven through the upper plate.
• Cooking time starts counting down.
• 3.2 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.
4-4
FUSE
N
L
PRIMARY
SWITCH
MONITOR
SWITCH
RELAY 2
MICOM CONTROLLER
H.V.
TRANS-
FORMER
SECONDARY SWITCH
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