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LG MS0747C, Service Manual

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This microwave oven is designed for household use only.

It is not recommended for commercial purposes.

DESCRIPTION

MS0747C

120 Volts AC 60 Hz

1000 Watts

Single phase, 3 wire grounded

700 Watts full microwave power (IEC60705)

2450 MHz

2M213 - 240GP

10 sec.~ 99 min. 50 sec

455 (W)x 284 (H)x 320 (D)mm

327 (W)x 202 (H)x 286 (D)mm

9.5 kg (approx.)

11 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 Full power

LOW/WARM........................................ approx. 20% of Full power

Owner's manual

Glass turntable

Rotating ring

1-1

ITEM

MODEL

Power Requirement

Power Output

Microwave Frequency

Magnetron

Timer

Outside Dimensions

Cavity Dimensions

Net Weight

Shipping weight

Control Complement

Rating Label Location

Accessories

SPECIFICATIONS

Back Side

Summary of Contents for MS0747C

Page 1: ...ROWAVE OVEN SERVICE MANUAL MODEL MS0747C CAUTION BEFORE SERVICING THE UNIT READ THE SAFETY PRECAUTIONS IN THIS MANUAL Website http biz lgservice com P NO MFL38637301 February 2007 Printed in Korea 삼 흥 정 판 ...

Page 2: ...r 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...

Page 3: ...TING 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 CONTENTS ...

Page 4: ... 5 kg approx 11 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 Full power LOW WARM approx 20 of Full power Owner s manual Glass turntable Rotating ring 1 1 ITEM MODEL Power Requirement Power Output Microwave Frequency Magnetron Timer Outside Dimensions Cavity ...

Page 5: ...tron 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 du...

Page 6: ...nal 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 GROUNDING INSTRUCTIONS For personal safety this appliance must be fully grounded at a...

Page 7: ...CH CONTROL Used to cook the foods listed by one touch 3 Q DEFROST 4 CLOCK Used to set the time of day 5 NUMBER Used to set for time of day cooking time power level or defrost weight 6 TIME Used to cook food for a desired time 7 POWER Used to select the desired power level for cooking 8 STOP CLEAR Used to stop oven and clear all entries except time of day 9 START One tap allows over to begin functi...

Page 8: ...3 ONE TOUCH COOKING 4 MICROWAVE COOKING 5 TIME COOKING 6 MULTI STAGE MICROWAVE COOKING 1ST STAGE 2ND STAGE 7 AUTO DEFROST COOKING 8 CHILD LOCK This oven has a CHILD LOCK feature TO SET CHILD LOCK Touch the 0 pad Touch and hold 0 pad L appear on the display TO CANCEL CHILD LOCK Touch the 0 pad touch and hold 0 pad L disappears 4 2 TIEMPO NUMBER POTENCIA PARAR BORRAR PARAR BORRAR DESCONGELADO AUTOMÁ...

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

Page 10: ...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 WHEN THE OVEN IS SET AT ANY LEVEL EXCEPT MAXIMUM The micom controller controls the ON OFF time of relay 2 by the applie...

Page 11: ...hich 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 2 inch 5cm spacer supplied with the probe Operate the oven at its maximum output Measure the microwave radiation using and electromagnetic radi...

Page 12: ...e 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 horizontally along t...

Page 13: ...rature 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 the water to rise by a value T of 10 2 ...

Page 14: ...ORMER 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 sucti...

Page 15: ... 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 co...

Page 16: ...RY 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 les than 0 5 mm 1 64 inch ...

Page 17: ...s 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 o...

Page 18: ...PONENTS TEST PROCEDURE 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 s...

Page 19: ...r scale 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...

Page 20: ...rowave 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 Check for P C B connector Normal Abnormal 0 C Appro...

Page 21: ...stance Ohm meter scale R x 1000 Normal Abnormal or several Normal Approx 100 200 Ω Abnormal or several 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 CONNECTOR NOT THE WIRES A B C A B A C 40 60 300 500 ...

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: ...isual 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 indicates a number different from one touched for exampl...

Page 24: ...nuity of magnetron thermostat No continuity 1 Fuse blows Continuity Malfunction of the monitor switch Replace primary and monitor switches Check continuity of monitor switch with door closed Check continuity of primary switch with door opened No continuity Disconnect one side of the wire lead connected from transformer to the high voltage capacitor and operate the unit No continuity Continuity Sho...

Page 25: ...with door closed Check fan motor Check oven lamp Abnormal Abnormal Normal Defective fan motor Defective oven lamp Replace fan motor Replace oven lamp Loose connection Connection then tightly CONDITION CHECK RESULT CAUSE REMEDY Output is low Lower than 90 of rating voltage Normal Normal Abnormal Abnormal Measure the output power Disconnect the wire leads from relay 2 and check on and off time with ...

Page 26: ...high voltage transformer Check H V transformer normal normal Abnormal Defective high voltage Diode Replace high voltage Diode Check H V diode Abnormal Defective high voltage capacitor Replace high voltage capacitor Check H V capacitor Abnormal Defective magnetron Replace magnetron Check Magnetron normal Abnormal Defective Protector Diode Replace Protector Diode Check Protector Diode TROUBLE 5 No m...

Page 27: ...e set power level Operates properly on HIGH CONDITION CHECK RESULT CAUSE REMEDY Output is full when you set lower power level Abnormal Disconnect the wire leads from relay 2 and check continuity relay 2 Operate the unit Defective P C B assembly Replace P C B assembly ...

Page 28: ...DOOR PARTS LATCH BOARD PARTS CONTROL PANEL PARTS INTERIOR PARTS BASE PLATE PARTS OVEN CAVITY PARTS 6 1 EXPLODED VIEW INTRODUCTION EV MODEL MS0747C ...

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

Page 30: ...6 3 23506A 23572A 268711 24781M WTT021 CONTROL PANEL PARTS EV ...

Page 31: ...6 4 35889A 34370T 33390G WTT021 33112U WTP013 36549S 33052A WTT010 OVEN CAVITY PARTS EV ...

Page 32: ...6 5 466003 466001 43501A 43500A 466001 WSZ085 44510A LATCH BOARD PARTS EV ...

Page 33: ...6 6 WSZ002 56411A 568771 56930V 56324A 55900A WTT037 56549F WTT028 WSZ002 54974S WEB001 WEB001 56851D 50CZZH WTT028 54810C 56912B 55262A 948501 55006F 50FZZA INTERIOR PARTS EV ...

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

Page 35: ......

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