LG Sunbeam MA-6400B2 Service Manual Download Page 8

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SCHEMATIC DIAGRAM

4-2

** NOTE : DOOR IS OPENED.

BK : BLACK N BL : BLUE BN : BROWN

RD : RED WH : WHITE GN: GREEN

OVEN

THERMOSTAT

SECONDARY

SWITCH

MONITOR

SWITCH

OVEN

LAMP

FAN

MOTOR

TURN

TABLE

MOTOR

TIMER

MOTOR

T.M

F.M

T.T.M

O.L

H.V DIODE

MAGNETRON

CHOKE FILTER(optional)

FUSE

15A

PRIMARY

SWITCH

TIMER

SWITCH

H.V

TRANSFORMER

H.V

CAPACITOR

AC 120V

60Hz

IMPORTANT SAFETY NOTE: THE COMPONENTS IN SHADED AREAS ON THIS SCHEMATIC DIAGRAM INCORPORATE SPECIAL FEATURES

IMPORTANT FOR PROTECTION FROM MICROWAVE RADIATION, FIRE, NELECTRICAL SHOCK, AND OTHER

HAZARDS. WHEN SERVICING IT IS ESSENTIAL THAT ONLY MANUFACTURER'S SPECIFIED PA

RTS

BE USED FOR THE CRITICAL COMPONENTS IN THE SHADED AREAS OF THE SCHEMATIC DIAG

RAM.

NOTICE: SINCE THIS IS A BASIC SCHEMATIC DIAGRAM, THE VALUES OF COMPONENTS AND

SOME PARTIAL CONNECTIONS ARE SUBJECT TO CHANGE FOR IMPROVEMENT.

Summary of Contents for Sunbeam MA-6400B2

Page 1: ...ROWAVE OVEN SERVICE MANUAL MODEL MA 6400W2 MA 6400B2 CAUTION BEFORE SERVICING THE UNIT READ THE SAFETY PRECAUTIONS IN THIS MANUAL website http www lgservice com e mail http www lgeservice com techsup html ...

Page 2: ...eration 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 de...

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 11 EXPLODED VIEW 6 1 REPLACEMENT PARTS LIST 7 1 CONTENTS ...

Page 4: ...et Weight Shipping weight Control Complement Nameplate Location Accessories DESCRIPTION MA 6400W2 MA 6400B2 120 Volts AC 60 Hz 910 Watts 8 5A Single phase 3 wire grounded 600 Watts full microwave power IEC60705 2 450 MHz 2M213 09B 0 30 min 19 W x 11 H x 12 7 8 D 11 7 8 W x 7 5 8 H x 12 1 2 D 24 7 lbs approx 26 9 lbs approx Mechanical Rotary System Full Power Cooking Owner s manual cooking guide Gl...

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: ...ical 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 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 INSTRUCTI...

Page 7: ...o the desired setting 2 The door can be opened during the cooking process by pushing the Door Open Button The timer will stop and the microwave activity will cease When the door is closed cooking will resume until the full cooking time has elapsed After cooking is finished the Timer will be at OFF After unpacking this appliance examine the new oven for evidence of shipping damage This is most impo...

Page 8: ...MER SWITCH H V TRANSFORMER H V CAPACITOR N AC 120V 60Hz IMPORTANT SAFETY NOTE THE COMPONENTS IN SHADED AREAS ON THIS SCHEMATIC DIAGRAM INCORPORATE SPECIAL FEATURES IMPORTANT FOR PROTECTION FROM MICROWAVE RADIATION FIRE N E LECTRICAL SHOCK AND OTHER HAZARDS WHEN SERVICING IT IS ESSENTIAL THAT ONLY MANUFACTURER S SPECIFIED PARTS BE USED FOR THE CRITICAL COMPONENTS IN THE SHADED AREAS OF THE SCHEMATI...

Page 9: ...applied to the magnetron to heat the magnetron filament through two noise preventing choke coils 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 DOOR IS OPEN...

Page 10: ...tion leakage MEASURING MICROWAVE ENERGY LEAKAGE Pour 275 15cc of 20 5 C 68 9 F water in a beaker which 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 Op...

Page 11: ...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 12: ...he 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 devices and measuring instru...

Page 13: ...placing the door be sure to check that the primary switch monitor 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 5 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 ...

Page 14: ... to the magnetron To prevent microwave leakage tighten the mounting screws properly making sure there is no gap between the waveguide and the magnetron G REMOVING THE TURNTABLE MOTOR 1 Remove the turntable and rotating ring 2 Lay the unit down on its back 3 Remove the turntable motor cover The turntable base cover is easily removed by pinching the eight parts with a wire cutting 4 Disconnect the l...

Page 15: ...rowave 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 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...

Page 16: ...hould 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 condition Wh...

Page 17: ...LTS 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 Filam...

Page 18: ... 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 19: ... 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 B Approx 65 80 ohm B C Approx 10 30 ohm A C Approx 85 105 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 ...

Page 20: ...ting 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 Inconsistent intensity of microwave by their characteristics 1 Use plastic wrap or lid 2 Stir once or twice while cooking sou...

Page 21: ...condary switches 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 22: ...lable 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 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 ...

Page 23: ...gh 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 3 No microwave oscillation even though oven lamp and fan motor run NOTE Make sure the wire leads are in the correct position When removing the wire leads from the parts be s...

Page 24: ...DOOR PARTS LATCH BOARD PARTS CONTROL PANEL PARTS INTERIOR PARTS BASE PLATE PARTS OVEN CAVITY PARTS 6 1 EXPLODED VIEW INTRODUCTION ...

Page 25: ...6 2 13552A 13213A 13581A 13720D 14970A 14026A 13536A 13352A DOOR PARTS ...

Page 26: ...6 3 24781T 23572A 24510L 250201 24970A 249401 26549T CONTROLLER PARTS ...

Page 27: ...6 4 33390G 35889A WSZ185 33112U WTP013 36549S 33052A 948502 WTT010 OVEN CAVITY PARTS WTT020 ...

Page 28: ...6 5 466001 466003 WTT028 466001 43500A 56912B 55262A WSZ085 SUCTION GUIDE PARTS ...

Page 29: ...6 6 INTERIOR PARTS 568771 56930V 56411A 54974S 56549F WTT037 WTT028 WSZ002 55900A 56324A WSZ002 55006F 50FZZA ...

Page 30: ...6 7 56170D 63302A 63303A WTT021 WSZ002 948501 65006B 65006B 50CZZH WSZ002 54810C 56851D BASE PLATE PARTS ...

Page 31: ...Apr 2002 Printed in Korea P NO 3828W5S1905 ...

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LG Sunbeam MA-6400B2, Service Manual

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