LG MS-2043AL Page 25 Service Manual Download

Page: 25 / 41

5-15

CONDITION

CHECK

RESULT

CAUSE

REMEDY

1. Setting time

does not count
down when
touching START
pad.

2. Fan motor or

oven lamp do
not turn on.

No continuity.

Continuity.

Continuity

Defective PCB
assembly.

Loose connection.

Replace PCB
assembly.

Connect them
tightly.

No continuity

Abnormal

Check fan motor.

Defective fan motor.

Replace fan motor.

Abnormal

Normal

Check oven lamp.

Defective oven lamp.

Replace oven lamp.

Defective
secondary switch.

Replace
secondary switch.

Check continuity
of secondary
switch (with
door closed).

Check the con-
nection between
CN1 connector
and PCB
assembly.

(TROUBLE 3) Display shows all figures set, but oven does not start cooking while desired

program times are set and START pad is touched.

(TROUBLE 4) Oven seems to be operating but little heat is produced in oven load.

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.

CONDITION

CHECK

RESULT

CAUSE

REMEDY

Output is low

Lower than 90% of
rating voltage.

Normal

Abnormal

Defective PCB
assembly.

Replace PCB
assembly.

Normal

Abnormal

Measure the
output power.

Defective
magnetron.

Replace
magnetron.

Decrease in power
source voltage
with load.

Suggest customer
contact local
electric power
utility co. or
qualified
electrician.

Check the
power source
voltage.

Disconnect the
wire leads from
relay 2 and
check on and off
time with
multitester.

Summary of Contents for MS-2043AL

Page 1: ...MICROWAVE OVEN SERVICE MANUAL MODEL MS 2043AL CAUTION BEFORE SERVICING THE UNIT READ THE SAFETY PRECAUTIONS IN THIS MANUAL website http biz lgservice com ...

Page 2: ...nd 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 t...

Page 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 SCHEMATIC DIAGRAM OF P C B 8 1 PRINTED CIRCUIT BOARD 8 2 P C B PARTS LIST 9 1 CONTENTS ...

Page 4: ...AL 230 Volts AC 50 Hz 1 200 Watts Single phase 3 wire grounded 800 Watts full microwave power IEC 60705 2 450 MHz 2M214 240GP 0 99 min 50 sec 455 W x 284 H x 311 D mm 310 W x 205 H x 294 D mm 12 kg approx 13 2 kg approx Microwave Power for Variable Cooking Power level Max Full power throughout the cooking time Med High approx 80 of Full power Medium approx 60 of Full power Defrost approx 40 of Ful...

Page 5: ... 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 fro...

Page 6: ...lat 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 wire...

Page 7: ...AT 6 STOP CLEAR Used to stop over and clear all entries except time of day 7 START QUICK START One tap allows over to begin functioning 8 MORE LESS Used to increase or decrease the cooking time and the weight of food 9 CLOCK Used to set the time of day 10 COOK TIME Used to cook food for a desired time 4 1 OPERATING INSTRUCTIONS Oven Front Plate Door Seal Control Panel Turntable Roller Rest Safety ...

Page 8: ...ING 5 AUTO DEFROST COOKING 6 QUICK DEFROST COOKING 7 CHILD LOCK This oven has a CHILD LOCK feature TO SET CHILD LOCK Touch the pad Touch STOP CLEAR pad L appear on the display TO CANCEL CHILD LOCK Touch the pad touch STOP CLEAR pad L disappears 8 AUTO COOK 9 AUTO REHEAT 10 MULTI STAGE MICROWAVE COOKING 4 2 STOP CLEAR START quick start STOP CLEAR 1ST STAGE STOP CLEAR AUTO DEFROST WEIGHT kg START ST...

Page 9: ...M MICROWAVE RADIATION FIRE ELECTRICAL SHOCK AND HAZARDS WHEN SERVICING IT IS ESSENTIAL THAT ONLY MANUFACTURER S SPECIFIED PARTS BE USED FOR THE CRITICAL COMPONENTS IN THE SHADED AREAS OF THE SCHEMATIC DIAGRAM NOTICE SINCE THIS IS BASIC SCHEMATIC DIAGRAM THE VALUES OF COMPONENTS AND SOME PARTIAL CONNECTIONS ARE SUBJECT TO CHANGE FOR IMPROVEMENT ...

Page 10: ...ximately 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 a...

Page 11: ...ity 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 d...

Page 12: ...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 possibly cause...

Page 13: ... 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 t...

Page 14: ...R 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 g...

Page 15: ...h 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 L 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 c...

Page 16: ...LLATION 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 wh...

Page 17: ... 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 op...

Page 18: ...EDURE RESULTS HIGH VOLTAGE TRANSFORMER Wire leads removed MAGNETRON Wire leads removed 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 Filam...

Page 19: ...le Rx1000 Terminal to case Measure the continuity Forward Ohm meter scale Rx10000 Measure the continuity Reverse Ohm meter scale Rx10000 Normal Momentarily indicates several ohms and then gradually returns to infinite Normal Normal Abnormal Continuity Normal Continuity Abnormal NOTE When testing the magnetron be sure to install the magnetron gasket in the correct position and be sure that the gask...

Page 20: ...ck 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 0 C Approx 110 C Approx 110 C ...

Page 21: ...cale R x 1000 POWER LEVEL 20 6 sec 16 sec 40 10 sec 12 sec 60 14 sec 8 sec 80 18 sec 4 sec 100 22 sec 0 sec Normal 350 450 Ω Abnormal or several Ω Normal 70 130 Ω Abnormal or several Ω NOTE A MICROWAVE LEAKAGE TEST MUST ALWAYS BE PERFORMED WHEN THE UNIT IS SERVICED FOR ANY REASON MAKE SURE THE WIRE LEADS ARE IN THE CORRECT POSITION WHEN REMOVING THE WIRE LEADS FROM THE PARTS BE SURE TO GRASP THE C...

Page 22: ...static charge built up in your body Micom model only CONDITION Microwave oven does not work Inserting many plug into one plug outlet and using them at the same time blown fuse or breaker Microwave oven plug is not inserted tightly Output power is too low Low AC input voltage Food temperature is too low Using metallic ware and allowing it to touch the oven wall Sparks occur Inconsistent intensity o...

Page 23: ...ing cooking cycle 11 Display time of day does not reappear when cooking is finished 12 Beep sound is not heard when correct key is touched 5 13 TROUBLE 1 The following visual conditions indicate a probable defective control circuit CONDITION CHECK RESULT CAUSE REMEDY 1 No input can be programmed Continuity No continuity Defective PCB assembly Loose connection Replace PCB assembly Connect them tigh...

Page 24: ...f P C B Assembly Check continuity of monitor switch with door closed 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 Replace fuse 2 Fuse does not blow No continuity Continuity No continuity Defective power supply cord Replace power supply cord Defective thermostat Replace thermost...

Page 25: ...ws all figures set but oven does not start cooking while desired program times are set and START pad is touched TROUBLE 4 Oven seems to be operating but little heat is produced in oven load 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 CONDITION CHECK RESULT CAUSE REMEDY Output is low Lower than 90 ...

Page 26: ... unit Check high vol tage transformer Abnormal Defective circuit protector Replace circuit protector Normal Check circuit protector Abnormal Defective high voltage capacitor Replace high voltage capacitor Normal Check high vol tage capacitor Abnormal Defective high voltage diode Replace high voltage diode Normal Check high vol tage diode Abnormal Defective magnetron Replace magnetron Check magnetr...

Page 27: ...unit NOTE Make sure the wire leads correct position When Removing the wire leads from the 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 CONDITION CHECK RESULT CAUSE REMEDY TROUBLE 5 No microwave oscillation even though oven lamp and fan motor run Display operates properly ...

Page 28: ...LATCH BOARD PARTS INTERIOR PARTS BASE PLATE PARTS OVEN CAVITY PARTS DOOR PARTS CONTROL PANEL PARTS 6 1 EXPLODED VIEW INTRODUCTION ...

Page 29: ...6 2 13581A 14970A 14026A 13552A 13213A 14890A 13551A 13536A DOOR PARTS ...

Page 30: ...6 3 268711 WTT021 24510L 24781M 23551A 23506A 24970A 23790D CONTROL PANEL PARTS ...

Page 31: ...6 4 33052A WTT020 WTT021 33112U 36549S WTP013 33390G 35889A OVEN CAVITY PARTS ...

Page 32: ...6 5 43500A 466001 WSZ085 466003 466001 LATCH BOARD PARTS ...

Page 33: ...6 6 568771 56930V WSZ002 56324A 50FZZA 56201A 55900A WTT037 56549F 54974S WSZ002 56851C 50CZZH WTT028 54810C WTT028 WSZ062 WSZ002 56411A 55262A 56912B 948501 56901A INTERIOR PARTS ...

Page 34: ...6 7 56170D 63302A 63303A WTT021 WSZ002 65006B BASE PLATE PARTS ...

Page 35: ...YNCHRONOUS R 6549W1S017A 43500A 3500W1A007A BOARD LATCH R 466001 6600W1K001D SWITCH MICRO R 466003 6600W1K001C SWITCH MICRO R 50CZZH 0CZZW1H004B CAPACITOR DRAWING HIGH VOLTAGE R 0CZZW1H001Q 50CZZH 0CZZW1H004B CAPACITOR DRAWING HIGH VOLTAGE R 0CZZW1H004G 50FZZA 3B70856T FUSE DRAWING R 54810C 4810W1A009B BRACKET CAPACITOR R 54974S 4974W1A001B GUIDE SUCTION R 55262A 5208W1A013A DUCT R 55900A 5900W1A0...

Page 36: ... R WTP013 1TPL0402418 SCREW TAPPING PAN HEAD R WTT020 1TTL0402416 SCREW TAPPING TRUSS HEAD R WTT021 1TTL0402418 SCREW TAPPING TRUSS HEAD R WTT028 1TTL0402818 SCREW TAPPING TRUSS HEAD R WTT037 1TTL0403818 SCREW TAPPING TRUSS HEAD R PART NO DESCRIPTION SVC ALTER R SERVICE PARTS ...

Page 37: ...8 1 SCHEMATIC DIAGRAM OF P C B ...

Page 38: ...8 2 PRINTED CIRCUIT BOARD ...

Page 39: ...OR FIXED CARBON FILM 100 OHM 1 6 W 5 TA26 R R114 0RD1000F608 RESISTOR FIXED CARBON FILM 100 OHM 1 6 W 5 TA26 R R115 0RD1000F608 RESISTOR FIXED CARBON FILM 100 OHM 1 6 W 5 TA26 R R116 0RD1000F608 RESISTOR FIXED CARBON FILM 100 OHM 1 6 W 5 TA26 R R117 0RD1000F608 RESISTOR FIXED CARBON FILM 100 OHM 1 6 W 5 TA26 R R120 0RD2001F608 RESISTOR FIXED CARBON FILM 2K OHM 1 6 W 5 TA26 R R121 0RD2001F608 RESIS...

Page 40: ... RESISTOR FIXED CARBON FILM 4 7K OHM 1 6 W 5 TA26 R RY1 6920W2D010A RELAY OJ SS 112LM OEG 250VAC 3A 12VDC 1A NO VE R 6920WRD008A RY2 6920W5A012A RELAY G5G 1A DT1 LG OMRON 250VAC 16A 12VDC 1A R U01 0IZZW5A213B IC DRAWING TMP87CH47U 44QFP TRAY MB 3883A EUROPE NE R U02 0IZZW5A192A IC DRAWING STCC02 DIP16 BK ASIC ALL MODEL R R SERVICE PARTS ...

Page 41: ...May 2003 Printed in Korea P NO 3828W5S3076 ...

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