LG MS-197W Page 4 Service Manual Download

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SPECIFICATIONS

This microwave oven is designed for household use only.

It is not recommended for commercial purposes.

ITEM

MODEL

Power Requirement

Power Output

Microwave Frequency

Magnetron

Timer

Outside Dimensions

Cavity Dimensions

Net Weight

Shipping weight

Control Complement

Nameplate Location

Accessories

DESCRIPTION

MS-197W

230 Volts AC 50 Hz

1,200 Watts

Single phase, 3 wire grounded

800 Watts full microwave power (IEC60705)

2,450 MHz

2M214 - 240GP

10 sec. ~ 99 min. 50 sec

455 (W) x 281 (H) x 313 (D) mm

312 (W) x 203 (H) x 293 (D) mm

12.5 kg

14 kg

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 Full power

Low/Warm

approx. 20% of Full power

Owner's manual

Glass turntable

Roller Rest

Control panel side

Summary of Contents for MS-197W

Page 1: ...MICROWAVE OVEN SERVICE MANUAL MODEL MS 197W CAUTION BEFORE SERVICING THE UNIT READ THE SAFETY PRECAUTIONS IN THIS MANUAL Jun 2002 Printed in Korea P NO 3828W5S2279 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 11 EXPLODED VIEW 6 1 REPLACEMENT PARTS LIST 7 1 SCHEMATIC DIAGRAM OF P C B 8 1 PRINTED CIRCUIT BOARD 8 2 P C B PARTS LIST 9 1 CONTENTS ...

Page 4: ...s DESCRIPTION MS 197W 230 Volts AC 50 Hz 1 200 Watts Single phase 3 wire grounded 800 Watts full microwave power IEC60705 2 450 MHz 2M214 240GP 10 sec 99 min 50 sec 455 W x 281 H x 313 D mm 312 W x 203 H x 293 D mm 12 5 kg 14 kg 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 ...

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: ...lect the desired power level for cooking 2 AUTO COOK Used to cook the foods listed by one touch 3 INDICATORS 4 AUTO DEFROST Used to select the auto weight defrost 5 QUICK DEFROST Used to select the auto weight defrost 6 STOP CLEAR Used to stop over and clear all entries except time of day 7 CLOCK Used to set the time of day 8 START QUICK START One tap allows over to begin functioning 9 DIAL ...

Page 8: ...ay will either return to the last item entered or to the clock 3 QUICK START 4 MICROWAVE COOKING 5 AUTO DEFROST COOKING 6 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 7 AUTO COOK STOP CLEAR CLOCK NUMBER STOP CLEAR START quick start STOP CLEAR CLOCK STOP...

Page 9: ...SCHEMATIC DIAGRAM 4 3 6 ...

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: ...al 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 de...

Page 14: ... 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 ...

Page 15: ... 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 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 tur...

Page 16: ...D 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...

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 Continuity Abnormal Normal Abnormal Continuity NOTE When testing the magnetron be sure to install the magnetron gasket in the correct position and be sure that the gask...

Page 20: ...rt OFF 1 3 5 Relay 2 Relay 1 Cooking Start OFF FUSE THERMAL CUT OUT 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...

Page 21: ...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 CONNECTOR NOT THE WIRES A B C FAN MOTOR Wire leads removed TURNTABLE MOTOR Wire leads removed Normal Abnormal or several Ω Normal Approx 100 200 Ω Abnormal or several Ω A B A C 40 60Ω 300 500Ω ...

Page 22: ... does not work Inserting many plug into one plug outlet and using them at the same time causes overloading 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 occurring Inconsistent intensity of microwave by their characteristics 1 Wrap the thinner part with aluminum f...

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 CONTROL PANEL PARTS DOOR PARTS 6 1 EXPLODED VIEW INTRODUCTION MODEL MS 197W EV ...

Page 29: ...6 2 13581A 14970A 14026A 13552A 13213A 14890A 13720D 13536A DOOR PARTS EV ...

Page 30: ...6 3 268711 24781S 23790D 23572A 250202 249402 250201 249401 250203 WTP004 CONTROL PANEL PARTS EV ...

Page 31: ...6 4 OVEN CAVITY PARTS 33112U WTT021 WTT010 33390G 35889A WTP013 36549S 33052A EV ...

Page 32: ...6 5 43500A 466001 WSZ085 466003 466001 44510A LATCH BOARD PARTS EV ...

Page 33: ...6 6 INTERIOR PARTS WSZ062 56411A 56201B WSZ002 56930V 56324A WTT028 50FZZA 56201A WTT037 56549F 54974S 55900A WSZ002 50CZZH 56851C WSZ002 56851H 54810C WTT028 568771 55262A 948502 56912B EV EV ...

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

Page 35: ...8 1 SCHEMATIC DIAGRAM OF P C B ...

Page 36: ...8 2 PRINTED CIRCUIT BOARD ...

Page 37: ......

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