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Microwave Oven
Service Manual

RFS12SW2C

CAUTION

BEFORE SERVICING THE UNIT, READ THE
SAFETY PRECAUTIONS IN THIS MANUAL.

Summary of Contents for RFS12SW2C

Page 1: ...삼 흥 정 판 Microwave Oven Service Manual RFS12SW2C CAUTION BEFORE SERVICING THE UNIT READ THE SAFETY PRECAUTIONS IN THIS MANUAL ...

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: ...M 4 6 CIRCUIT DESCRIPTION 4 7 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 LGE Internal Use Only Copyright 2009 LG Electronics Inc All right reserved Only for ...

Page 4: ...x Touch Control System Clock 00 60 Microwave Power for Variable Cooking Power level HIGH Full power throughout the cooking time 70 Med High approx 70 of Full power 50 Med Low approx 50 of Full power 20 Low approx 20 of Full power Time chart ITEM MODEL Power Requiremen Power Output Microwave Frequency Magnetron Timer Outside Dimensions Cavity Dimensions Net Weight Shipping weight Control Complement...

Page 5: ...t 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 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 duri...

Page 6: ...ature less than 104 F 40 C 6 Place the microwave oven as far away as possible from TV RADIO COMPUTER etc to prevent interference 7 Place the microwave oven on a stardy and flat surface A Allow at least 11 2 inches 3 81 centimeters of clearance around top and sides of equipment Proper air flow around equipment cools electrical components With restricted air flow oven may not operate properly and li...

Page 7: ...egin heating with preprogrammed times and power levels or to enter times for Manual Time Entry cooking Use to select power level Oven can heat at full or reduced power If oven power level is set to 0 oven does not heat for programmed time If no power level is selected oven operates at 100 power Use to exit programming mode and stop cooking during cooking cycle Use to start Manual Time Entry progra...

Page 8: ...re than 1 heating stage is programmed total time for all stages displays COOK shows when oven is operating 20 indicates the microwave power level used If power level does not show oven is heating at 100 power 4 2 Programming Displays Indicates programming mode See Programming section of manual for programming procedure Indicates programming user options mode See User Options section of manual for ...

Page 9: ...med pads arrive set at full power Manual Time Entry Manual Time Entry feature allows the operator to enter time and power levels and heat without changing the preprogrammed pads 1 Open oven door place food in oven and close door Display shows READY If pad is not pressed in 30 seconds open and close oven door again 2 Press TIME ENTRY pad Display shows 00 00 3 Press number pads to nter desired cooki...

Page 10: ...ory Repeat step 3 6 to program additional pads 7 Press STOP RESET pad or close oven door to exit programming mode Multiple Heating Stages Follow instructions below to program oven to perform 3 consecutive heating cycles without interruption 1 Open oven door If door is closed or STOP RESET pad is pressed before finishing programming sequence oven exits programming mode 2 Press pad 1 for approximate...

Page 11: ...tely 5 seconds After 5 seconds signal sounds Display shows OPTION 3 Press number pad that matches desired option OP represents optional program mode first number represents option number and second number represents functions currently selected for option 4 Press START pad to advance to next option See table for options 5 Press number pad 0 1 3 to change option 6 Press START pad to save changes Re...

Page 12: ...SCHEMATIC DIAGRAM 4 6 ...

Page 13: ...oltage 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 OVEN IS SET AT ANY LEVEL EXCEPT MAXIMUM The micom controller controls the ON OFF time of relay 3 and relay 5 208V rel...

Page 14: ...pliance If the oven operates with the door open the service personnel should Tell the user not to operate the oven Contact the manufacturer and CDRH Center for Devices and Radiological Health immediately NOTE Address on CDRH Office of Compliance HFZ 312 Center for Devices and Radiological Healthe 1390 Piccard Drive Rockville MD 20850 The service personnel should check all surface and vent vent ope...

Page 15: ...e deflection The test probe must be moved 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 is move...

Page 16: ... an outside diameter of approximately 190 mm The oven and 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 ceramic plate which is in the lowest position and the mi...

Page 17: ...1 After replacing 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 4 mW cm2 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...

Page 18: ...f 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 G REMOVING THE BOTTOM STIRRER FAN MOTOR 1 Lay the unit down on its back 2 Remove the screw securing the base cover 3 Disconnect the leadwire from the stirrer fan motor ter...

Page 19: ...s been specially designed to eliminate 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 3 INSTALLATION AND ADJUSTMENT OF THE LATCH BOARD TO THE OVEN ASSEMBLY Mount the latch b oard to the oven assembly Adjust the latch board in the arrow di...

Page 20: ...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 21: ...ROCEDURE RESULTS 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...

Page 22: ... 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 23: ...EN 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 1 2 3 4 5 6 7 8 9 10 3 sec 4 sec 5 sec 6 sec 7 sec 8 sec 9 sec 10 sec 11 sec 12 sec 9 sec 8 sec 7 sec 6 sec 7 sec 4 sec 3 sec 2 sec 1 sec 0 sec POWER LEVEL Relay 3 0V 220 240V 208V Measure the resistance Ohm meter scale...

Page 24: ... 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 soup cocoa or milk etc Uneven cooking Ceramic ware trimmed in gold or silver powder is used Avoid using other electrical appliances when you use ...

Page 25: ...light does not turn on after setting cooking cycle 11 Display time of day does not reappear when cooking is finished TROUBLE 1 The following visual conditions indicate a probable defective control circuit CONDITION CHECK RESULT CAUSE REMEDY Everything works as specified Continuity No continuity Still have trouble Defective key membrane assembly Defective PCB assembly Loose connection Defective PCB...

Page 26: ...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 RY3 5 or RY4 6 of P C B Assembly No continuity Check continuity of secondary switch with door opened Normal Set is good condition defective fuse only Abnormal Measure to resistance high volta...

Page 27: ...r closed Check blower motor Check oven lamp Abnormal Abnormal Normal Defective blower motor Defective oven lamp Replace blower motor Replace oven lamp Loose connection Connect them 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 3 5 or relay 4 6 and check on and o...

Page 28: ...or Replace high voltage capacitor Check high vol tage capacitor Abnormal Defective magnetron Replace magnetron Check magnetron TROUBLE 5 No microwave oscillation even though oven lamp and blower motor run Display operates properly Output is full power when you set lower power level Abnormal Disconnect the wire leads from relay 3 5 or relay 4 6 and check continuity of relay 3 5 or relay 4 6 Operate...

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

Page 30: ... 6 2 DOOR PARTS 1384 W136 1006 1007 W108 W105 1386 1009 W207 W206 1385 1004 1005 1013 1000 1002 EV ...

Page 31: ...CONTROL PANEL PARTS 6 3 2004 2006 2381 2000 W130 W102 EV ...

Page 32: ...OVEN CAVITY PARTS 6 4 7037 3001 5045 W121 W108 W158 W121 W109 W101 3009 W105 5042 3009 3004 5024 W105 W109 W108 W109 5203 W101 3007 5018 EV ...

Page 33: ...LARCH BOARD PARTS 6 5 4003 4000 4009 W102 W160 4002 4004 4008 4001 EV ...

Page 34: ...6 6 W101 5016 5020 3006 5102 3031 5010 W101 W108 W108 W136 5001 5014 5106 5041 5020 5046 5302 W105 5009 W101 W101 W109 W109 W101 W101 W109 5201 5105 5000 W108 W109 5018 W108 5103 3381 3028 5104 5204 W105 9000 3007 EV ...

Page 35: ...BASE PLATE PARTS 6 7 5008 9001 6001 6000 W101 W101 W121 W108 6013 W121 3026 3901 3902 W162 5061 5022 EV ...

Page 36: ...P No MFL05869703 ...

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