LG GoldStar MA-1302S Page 1 Service Manual Download

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MICROWAVE OVEN

SERVICE MANUAL

MODEL: MA-1302S

CAUTION

BEFORE

SERVICING THE UNIT, READ THE

SAFETY PRECAUTIONS

IN THIS MANUAL.

http://www.LGEservice.com

Summary of Contents for GoldStar MA-1302S

Page 1: ...MICROWAVE OVEN SERVICE MANUAL MODEL MA 1302S CAUTION BEFORE SERVICING THE UNIT READ THE SAFETY PRECAUTIONS IN THIS MANUAL http www LGEservice com ...

Page 2: ...rlock 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 ...

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 8 COMPONENT TEST PROCEDURE 5 9 TROUBLE SHOOTING 5 13 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: ...3 wire grounded 1 150 Watts full microwave power IEC705 2 450 MHz 2M246 0 99 min 99 sec 217 8 W x 125 8 H x 171 4 D 143 4 W x 91 4 H x 16 D 38 6 lbs approx 41 9 lbs approx 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 ...

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: ...l 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 all...

Page 7: ... Control Panel Display Window Turntable Defrost Rack Rotating Ring START EZ ON 1 2 3 4 5 Sensor Cook Defrost Hot Potato Fresh Vegetable Frozen Vegetable Frozen Entree Ground Meat Beverage S ensor Cook Cook Ti m e Power Stop Clear Timer Popcorn Auto Cook Sensor Reheat More Sensor Defrost Less CONTROL PANEL ...

Page 8: ...AR pad LOCKED appear on the display TO CANCEL CHILD LOCK Touch the pad Touch and hold STOP CLEAR pad LOCKED disappears 9 MORE LESS The cook time is adjustable by MORE pad or LESS pad 10 TIMER 11 SENSOR POPCORN 12 SENSOR BEVERAGE REHEAT DEFROST 4 2 STOP CLEAR TIMER For 3 seconds Time setting once STOP CLEAR REHEAT STOP CLEAR DEFROST STOP CLEAR EZ on STOP CLEAR COOKING STOP CLEAR POPCORN STOP CLEAR ...

Page 9: ...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 L N FUSE 20A CN3 RY2 CN2 ...

Page 10: ...roximately 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...

Page 11: ...ich is graduated to 600 cc and place the beaker on the center of the turntable Set the energy leakage monitor to 2 450 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: ...ed 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 probe damage RECORD KEEPING AND NOTIFICA...

Page 13: ...is 5 K The microwave power output P in watts is calculated from the following formula 4187 x ÆT 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 devices and measuring instruments are selected in ...

Page 14: ... 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 4 mW cm 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 fram...

Page 15: ...L 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 base plate I 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 suction guide AssÕy ...

Page 16: ...nate completely 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 5 6 Wire Leads Turntable Motor PRIMARY SWITCH ADJUSTMENT DIRECTION MONITOR SWITCH SECONDARY SWITCH 3 INSTALLATION AND ADJUSTMENT OF THE LATCH BOARD TO THE OVEN ASSEMBLY Mount the latch b...

Page 17: ... cavity 2 Remove the screw of the holder 3 Remove the Holder 4 Remove the screw of sensor case 5 Remove the sensor PCB AssÕy 6 Remove the reflector 5 7 Sensor PCB Ass y Connector Holder Sensor Connector HOOK Reflector Holder Sensor Case Sensor Connector CN4 Pin ...

Page 18: ...losed 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 open...

Page 19: ...ULTS HIGH VOLTAGE TRANSFORMER Wire leads removed MAGNETRON Wire leads removed 1 Measure the resistance Ohm meter scale Rx1 and Rx100 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 Fila...

Page 20: ...0 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 Infinite Normal Continuity Abnormal Infinite Normal Infinite Abnormal Continuity NOTE When testing the magnetron be sure to install the magnetron gasket in the correct position and be...

Page 21: ...8 sec 2 6 sec 16 sec 3 8 sec 14 sec 4 10 sec 12 sec 5 12 sec 10 sec 6 14 sec 8 sec 7 16 sec 6 sec 8 18 sec 4 sec 9 20 sec 2 sec 10 22 sec 0 sec Normal A Approx 85 100 ohm B Approx 10 25 ohm Abnormal Infinite or several ohm Normal Approx 100 150 ohm Abnormal Infinite or several ohm NOTE A MICROWAVE LEAKAGE TEST MUST ALWAYS BE PERFORMED WHEN THE UNIT IS SERVICED FOR ANY REASON MAKE SURE THE WIRE LEA...

Page 22: ... from P C B See Schematic Diagram on page 4 3 RY1 Turn table Fan Motor Oven Lamp SENSOR Wire leads removed Measure the resistance Port Resistance 1 and 2 Approx 470 Kohm 1 and 3 Approx 1 5 Kohm 1 and 4 Approx 2 0 Kohm Cooking Start OFF 1 CN2 2 3 BK CONNECTOR SHIELD WIRE WH RD GN 4 3 2 1 ...

Page 23: ... panel to discharge any static charge built up in your body Micom model only CONDITION Microwave oven does not work Inserting many plugs into one 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 Inco...

Page 24: ... does not turn on after setting cooking cycle 11 Display time of day does not reappear when cooking is finished 5 14 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 tightly Check the conn ection b...

Page 25: ...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 Continuity Malfunction of secondary switch Replace fuse primary monitor secondary switches and RELAY RY2 of P C B Assembly No continuity Check continuity of secondary switch with door opened 2 Fuse does not blow No continuity Continuity ...

Page 26: ...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 27: ... relay 2 and check continuity relay 2 Operate the unit 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 magnetron TROUBLE 5 No microwave oscillation even though oven lamp and fan motor run...

Page 28: ...hield wire connector Refer to page 5 12 Replace sensor assy ÒGuide sensorÓ stuck Check and adjust the ÒGuide sensorÓ Refer to schematic diagram and adjust it Unsuitable utensil was used Use suitable utensil Refer to the ownerÕs manual Incorrect connection of shield wire Refer to page 5 12 Replace sensor assy Incorrect resistance of shield wire connector TROUBLE 6 Uneven cooking and error during se...

Page 29: ...DOOR PARTS CONTROL PANEL PARTS LATCH BOARD PARTS BASE PARTS INTERIOR PARTS OVEN CAVITY PARTS 6 1 EXPLODED VIEW INTRODUCTION ...

Page 30: ...6 2 13581A 13720D 13213A 13552A 15006A 13536A 14890A 14026A 14970A WTT040 13650A DOOR PARTS ...

Page 31: ...6 3 24781S 23806C 23572A 268712 268711 249401 250201 CONTROL PANEL PARTS ...

Page 32: ...6 4 33416Z 948503 33112U WSZ185 33052M 340511 WTT010 24890C 35889A WSZ002 WTT028 WTP013 36549S OVEN CAVITY PARTS ...

Page 33: ...6 5 WSZ085 43501A 466001 466003 466001 43500A LARCH BOARD PARTS ...

Page 34: ...6 6 54974T 55900A 50CZZH 54810C WSZ002 WSZ002 WTT037 56549F 54974S 56201A SUCTION GUIDE PARTS ...

Page 35: ...6 7 WSZ002 568771 56930V 56411A 54811A 56501A 568772 53551S WSZ002 35012A WSZ002 948501 55262A 948502 56324A WSZ002 56912B INTERIOR PARTS ...

Page 36: ...6 8 63302L 56170D 63302R WSZ002 WTT021 647781 647781 WTT030 63303R 63303L 948502 BASE PLATE PARTS ...

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

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

Page 39: ...P NO 3828W5S0845 June 1999 Printed in Korea ...

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LG GoldStar MA-1302S, Service Manual

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