LG MS3447GR User's Manual
Contents
1. Replace fuse primary monitor secondary switches and RELAY RY2 of P C B Assembly Disconnect one side of the wire lead connected from transformer to the high voltage capacitor and operate the unit age transformer Normal Defective high Replace high voltage capacitor voltage capacitor Defective high volt Replace high volt Fuse blows again gt gt age transformer Refer to page 5 7 5 8 2 Fuse does not blow LGE Internal Use Only Check continuity No continuity gt of thermostat gt Continuity Check continuity gt 1 of power supply No continuity gt cord 5 13 Defective Replace thermostat thermostat Defective power Replace power supply cord supply cord Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes program times are set and START pad is touched TROUBLE 3 Display shows all figures set but oven does not start cooking while desired CONDITION CHECK RESULT CAUSE REMEDY 1 Setting time _ Check continuity continu2. STOP CLEAR gt AUTO COOK _ gt NUMBER OF TABLE NOTE Then the oven will start automatically LGE Internal Use Only SCHEMATIC DIAGRAM HOS AONVHO 01 SNOILOANNOO TVILYVd INOS SLNSNOdWO9 40 SHL AVHDVIC OISVd SI SIHL SONIS 8 40 SVSYV 5 NI SLNSANOdWOO YOs GASN SLYVd 121519345 SAYNLOVANNVW 11139559 SI LI 5 CNV MOOHS NOLLVIGVY NOILOALOYd LNVLYHOdNI 1 SIHL NO GAQVHS 310 ALSAVS LNVLYOdWM INTERLOCK SWITCH N0 PRIMARY 5 2 gt 9 5 a no 5 H V or T 85 x 50 2 LJ lt z O aS a gt Of T A T gt lt x 2 62 Z lt wo l Oe 02 52 5 1 9 amp xo 18 l 21 4 72 Se 2
3. Control Complement Touch Control System Clock 1 00 12 59 Microwave Power for Variable Cooking Power level Full power throughout the cooking time approx 90 of Full power 8 Reheat approx 80 approx 70 6 Medium approx 60 approx 50 4 Defrost approx 40 approx 30 2 Simmer approx 20 approx 10 Rating Label Location Back Side Accessories Owner s manual amp cooking guide Glass turntable Roller rest This microwave oven is designed for household use only It is not recommended for commercial purposes Copyright 2007 LG Electronics Inc All right reserved 1 1 Only for training and service purposes LGE Internal Use Only 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 during repair DO NOT operate on a 2 wire extension cord during repair and use NEVER TOUCH any oven components or wiring during operation BEFORE TOUCHING any parts of the oven always remove the power plug from the outlet e For about 30 seconds after the oven stops an electric charge remains in the high voltage capacitor When replacing or checking you must discharge the high voltage capacitor by shorting across the two terminals with an insulated screwdriver Remove your watches whenever working close to or replacing the Magnetron
4. ey a Switch 4 1 LGE Internal Use Only NOTE After checking for the continuity of switches make sure that they are connected correctly Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes COMPONENT TEST PROCEDURE CAUTIONS 1 DISCONNECT THE POWER SUPPLY CORD FROM THE OUTLET WHENEVER REMOVING THE OUTER CASE FROM THE UNIT PROCEED WITH THE TEST ONLY AFTER DISCHARGING THE HIGH VOLTAGE CAPACITOR AND REMOVING THE WIRE LEADS FROM THE PRIMARY WINDING OF THE HIGH VOLTAGE TRANSFORMER SEE PAGE 2 1 2 ALL OPERATIONAL CHECKS WITH MICROWAVE ENERGY MUST BE DONE WITH A LOAD 1 LITER OF WATER IN CONTAINER IN THE OVEN COMPONENTS TEST PROCEDURE RESULTS HIGH VOLTAGE TRANSFORMER Wire leads removed PRIMARY TERMINAL 1 Measure the resistance Ohm meter scale Rx1 and Rx100 Primary winding Approx 0 2 0 4 ohm Secondary winding Approx 70 100 ohm Filament winding Less than 1 ohm Measure the resistance Ohm meter scale Rx1000 e Primary winding to ground Normal Infinite Filament winding to ground Normal Infinite MAGNETRON Wire leads removed Measure the resistance Ohm meter scale Rx1 Normal Less than 1 ohm Filament terminal Measure the resistance Ohm meter scale Rx1000 Normal Infinite Filament to chassis Copyright 20
5. Measure the resistance Ohm meter scale R x 1 Normal A Approx 85 100 ohm B Approx 10 25 ohm Abnormal Infinite or several ohm TURNTABLE MOTOR Wire leads removed Measure the resistance Ohm meter scale R x 1 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 LEADS ARE IN THE CORRECT POSITION e WHEN REMOVING THE WIRE LEADS FROM THE PARTS BE SURE TO GRASP THE CONNECTOR NOT THE WIRES Copyright 2007 LG Electronics Inc All right reserved 5 10 Only for training and service purposes LGE Internal Use Only TROUBLE SHOOTING WHEN YOU GET A COMPLAINT FROM YOUR CUSTOMER EVALUATE THE COMPLAINT CAREFULLY IF THE FOLLOWING SYMPTOMS APPLY PLEASE INSTRUCT THE CUSTOMER IN THE PROPER USE OF THE MICROWAVE OVEN THIS CAN ELIMINATE AN UNNECESSARY SERVICE CALL CAUTIONS panel 1 Check grounding before checking for trouble 2 Be careful of the high voltage circuit 3 Discharge the high voltage capacitor See page 2 1 4 When checking the continuity of the switches or of the high voltage transformer disconnect one lead wire from these parts and then check continuity with the AC plug removed To do otherwise may result in a false reading or damage to your meter 5 Do not touch any part of the circuit on the PCB since static electric discharge may
6. Only for training and service purposes EV INTERIOR PARTS LGE Internal Use Only 6 6 Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes BASE PLATE PARTS LGE Internal Use Only 6 7 ed nics Inc All right reserv Copyright 2007 LG Electro Only for training and service purposes LG Electronics Inc
7. COMPLETELY AND CAREFULLY INSTALLING 1 Empty the microwave oven and clean inside it with a soft damp cloth Check for damage such as misaligned door damage around the door or dents inside the cavity or on the exterior Put the oven on a counter table or shelf that is strong enough to hold the oven and the food and utensils you put in it The control panel side of the oven is the heavy side Use care when handling Do not block the vent and the air intake openings Blocking vent or air intake openings can cause damage to the oven and poor cooking results Make sure the microwave oven legs are in place to ensure proper air flow The oven should not be installed in any area where heat and steam are generated because they may damage the electronic or mechanical parts of the unit Do not install the oven next to a conventional surface unit or above a conventional wall oven Use microwave oven in an ambient temperature less than 104 F 40 C Place the microwave oven on a sturdy and flat surface at least 10 4 inches from the wall Place the microwave oven as far away as possible from TV RADIO COMPUTER etc to prevent interference 10cm Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes EARTHING INSTRUCTIONS This microwave oven is designed to be used in a fully earthed condition It is imperative therefore to make sure it i
8. damage this control Always touch yourself to ground while working on this panel to discharge any static charge built up in your body Micom model only CONDITION CAUSE Microwave oven does not work Inserting many plugs into 5 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 REMEDY Avoid using other electrical appliances when you use the microwave oven Insert microwave oven plug securely Use the microwave oven at adequate line voltage Sparks occur Using metallic ware and allowing it to touch the oven wall This may not be a defect It is possible that the food should be cooked for a longer time period Do not use metallic ware for cooking except that noted in the cooking guide Ceramic ware trimmed in gold or silver powder is used Uneven cooking Do not use any type of cookware with metallic trimming LGE Internal Use Only Inconsistent intensity of microwave by their characteristics 5 11 1 Use plastic wrap or lid 2 Stir once or twice while cooking soup cocoa or milk etc Copyright 2007 LG Electronics Inc All right reserve
9. membrane key assembly and bea Loose Connect them gt PCB assembly Ne cominuity connection tightly 2 Some inputs Replace key Everything works Defective key Replace key cannot be membrane as specified membrane membrane programmed assembly and assembly assembly check operation 3 Display shows a L Still have trouble Defective PCB Replace PCB number or figure assembly assembly different from one touched 4 Random LGE Internal Use Only TROUBLE 2 Oven does not operate at all Display window does not display any figures and no input is accepted CONDITION CHECK RESULT CAUSE REMEDY 1 Fuse blows Check continuity Continuity Malfunction of the Replace fuse l of monitor monitor switch primary monitor switch with secondary door closed i switches and No continuity RELAY RY2 of NOTE All these switches must be replaced at the same time Replace fuse P C B Assembly Check continuity of primary switch with door opened Continuity No continuity Shorted contact at the primary switch Replace fuse primary monitor secondary switches and RELAY RY2 of P C B Assembly Check continuity of secondary switch with door opened Continuity No continuity Malfunction of secondary switch
10. near a corner of the door keep the probe perpendicular to the surface making sure the probe horizontally along the oven surface Hold vertically when testing the top and bottom and horizontally along RECORD KEEPING AND NOTIFICATION AFTER MEASUREMENT After adjustment and repair of any microwave energy interruption or microwave energy blocking device record the measured values for future reference Also enter the information on the service invoice The microwave energy leakage should not be more than 4 mW cm sq after determining that all parts are in good condition functioning properly and genuine replacement parts which are listed in this manual have been used At least once a year have the electromagnetic energy leakage monitor checked for calibration by its manufacturer LGE Internal Use Only MEASUREMENT OF MICROWAVE POWER OUTPUT e Microwave power output measurement is made with the microwave oven supplied at its rated voltage and operated at its maximum microwave power setting with a load of 1000 5 g of potable water The water is contained in a cylindrical borosilicate glass vessel having a maximum material thickness of 3 mm and an outside diameter of approximately 190mm The oven and the empty vessel are at ambient temperature prior to the start of the test The initial temperature 1 of the water is 10 2 C It is measured immediately before the water is added to the vessel After addition
11. 07 LG Electronics Inc All right reserved 5 8 LGE Internal Use Only Only for training and service purposes COMPONENTS TEST PROCEDURE RESULTS Antenna Chassis NOTE When testing the magnetron be sure to install the magnetron gasket in the correct position and be sure that the gasket is in good condition HIGH VOLTAGE CAPACITOR Measure the resistance Ohm meter scale Rx1000 Terminal to terminal Normal Momentarily indicates several ohms and then gradually returns to infinite Measure the resistance Ohm meter scale Rx1000 Terminal to case Normal Infinite HIGH VOLTAGE DIODE NOTE Some inexpensive meters may indicate infinite resistance in both direction LGE Internal Use Only Measure the continuity Forward Ohm meter scale Rx10000 Normal Continuity Abnormal Infinite Measure the continuity Reverse Ohm meter scale Rx10000 5 9 Copyright 2007 LG Electronics Inc All right reserved Normal Infinite Abnormal Continuity Only for training and service purposes COMPONENTS TEST PROCEDURE RESULTS RELAY 2 Check for continuity of relay 2 with an ohm meter Remove wire leads from relay 2 and operate the unit 4 sec 6 sec 8 sec 10 sec 12 sec 14 sec 16 sec 18 sec 20 sec 22 sec FAN MOTOR Wire leads removed
12. 5 koa 0 Zon nacre men aaa Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes 4 3 LGE Internal Use Only CIRCUIT DESCRIPTION GENERAL DETAILS The low voltage transformer supplies the necessary voltage to the micom controller when power cord is plugged in e When the door is closed the primary switch is ON the secondary switch is ON and the monitor switch opens contact COM and NO WHEN SELECTING COOKING POWER LEVEL AND TIME The micom controller memorizes the function you set The time you set appears the display window Each indicator light turns on to indicate that the stage has been set WHEN TOUCHING THE START PAD The coil of the relay is energized by the micom controller e Power input is supplied to the high voltage transformer through the fuse to the primary switch and relay 2 e Turntable rotates PRIMARY FUSE SWITCH MONITOR SWITCH SECONDARY 1 RELAY2 switcH MICOM CONTROLLER e The fan motor rotates and cools the magnetron by blowing the air coming from the intake on the base plate The air is also directed into the oven to exhaust the vapor in the oven through the upper plate e Cooking time starts counting down 3 3 volts AC is generated from the filament winding of the high voltage transformer This 3 3 vol
13. AKAGE TEST 5 1 MEASUREMENT OF MICROWAVE POWER OUTPUT 5 3 DISASSEMBLY AND ADJUSTMENT 5 3 INTERLOCK CONTINUITY 5 7 COMPONENT TEST PROCEDURE 5 8 TROUBLE SHOOTING 5 11 EXPLODED VIEW ccs sc ts ces a cs cases 6 1 REPLACEMENT PARTS LIST 7 1 LGE Internal Use Only Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes SPECIFICATIONS ITEM DESCRIPTION MODEL MS3447GR MS3447GRS Power Requiremen 230 240 Volts AC 50 Hz 1600 Watts Single phase 3 wire grounded Power Output 1100 Watts full microwave power IEC60705 Microwave Frequency 2450 MHz Magnetron 2M246 050GF Timer 0 99 min 99 sec Outside Dimensions 556mm W x 320mm x 438mm D Cavity Dimensions 374mm W x 254mm H x 406mm D Net Weight 16 5 kg approx Shipping weight 17 9 kg approx
14. ASSEMBLY 1 Open the door 2 Disconnect the lead wire from RELAY RY2 of the PCB SUB ASSEMBLY 3 Disconnect the leadwire from connector CN1 of the PCB SUB ASSEMBLY 4 Remove screw which hold the controller assembly to the cavity 5 Lift up and pull out control panel assembly carefully from the cavity CAUTION DISCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE SERVICING refer to page 2 1 LGE Internal Use Only 5 3 Remove the screw ground 9 screw Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes D PCB ASSEMBLY REMOVAL 1 Remove the control panel assembly from the cavity Refer to control panel assembly removal on previous page 2 Remove screws which hold the PCB SUB ASS Y to the control panel 3 Disconnect the flat cable from the PCB SUB ASS Y and take off the PCB SUB ASS Y E DOOR MAIN ASSEMBLY REMOVAL 1 Open the door 2 Remove the choke cover very carefully with a flat blade screwdriver CAUTION Be careful not to damage door seal plate by screwdriver 3 Lift up and push the door NOTE 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 cm with a 275 ml water lo
15. DO NOT touch any parts of the control panel circuit A resulting static electric discharge may damage this P C B NEVER operate the oven with no load e NEVER injure the door seal and front plate of the oven cavity NEVER put iron tools on the magnetron NEVER put anything into the latch hole and the interlock switches area LGE Internal Use Only MICROWAVE RADIATION Personnel should not be exposed to the microwave energy which may radiate from the magnetron or other microwave generating device if it is improperly used or connection All input and output microwave connections waveguide flange and gasket must be secure never operate the device without a microwave energy absorbing load attached Never look into an open waveguide or antenna while the device is energized Proper 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 ANTENNA Gasket COOLING FIN FILAMENT TERMINALS MAGNETRON CHASSIS GROUND MAGNETRON THE OVEN IS TO BE SERVICED ONLY BY PROPERLY QUALIFIED SERVICE PERSONNEL Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes INSTALLATION BEFORE YOU BEGIN READ THE FOLLOWING INSTRUCTIONS
16. OK 3 AUTO COOK Used to select the auto cook 4 AUTO REHEAT Used to select the auto reheat 5 AUTO DEFROST This feature provides you with the best defrosting method for frozen foods 6 MORE LESS All of the one touch cook and TIMED COOK can be adjusted to cook food for a longer or shorter time MORE Pressing MORE will add 10 seconds to the cooking time LESS Pressing LESS will subtract 10 seconds of cooking time 7 QUICK DEFROST You can thaw specific foods and weight very quickly 8 NUMBER These used to set for time of day cooking time power level or defrost weight 9 CLOCK It is used to set the time of day 10 POWER You can select power level for cooking 11 STOP CLEAR It used to stop oven and clear all entries except time of day 12 START Q START To quickly set the cooking time directly Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes OPERATING SEQUENCE The following is a description of component functions during oven operation 1 CANCEL FUNCTION Touch the STOP CLEAR pad whenever you need to cancel an entry or a function currently in use The display will return either to the last item entered or to the clock 2 AUTO TOUCH STOP CLEAR gt POPCORN y NUMBER OF TABLE NOTE Heat only 1 package at a time Then the oven will start automatically 3 TIME CO
17. OKING STOP CLEAR gt TIME NUMBER POWER NUMBER gt START 4 MULTI STAGE COOKING You can program your oven to switch from one power level to another for up to 3 stages To set a 2 stage cook cycle 1ST STAGE STOP CLEAR m TIME gt NUMBER POWER NUMBER E 2ND STAGE TIME NUMBER POWER NUMBER START 5 AUTO DEFROST COOKING STOP CLEAR NUMBER OF WEIGHT DEFROST NUMBER START Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes 6 CHILD LOCK This oven has a CHILD LOCK feature TO SET CHILD LOCK Touch STOP CLEAR pad e Touch and hold appears on the TO CANCEL CH e Touch and hold disappears STOP CLEAR display ILD LOCK STOP CLEAR 7 LESS The cook time is adjustable by pad LESS pad pad LOCKED pad STOPICLEAR COOKING gt MORELESS 8 AUTO REHEAT STOPICLEAR gt NUMBER OF TABLE REHEAT NOTE Then the oven will start automatically 9 Q UICK DEFROST STOP CLEAR QUICK DEFROST 10 AUTO COOK
18. TCH H V TRANS FORMER MONITOR SWITCH SECONDARY ty SWITCH MICOM CONTROLLER LGE Internal Use Only SERVICE INFORMATION TOOLS AND MEASURING INSTRUMENTS NECESSARY TOOLS Tools normally used for TV servicing are sufficient Standard tools are listed below Diagonal pliers Long nose pliers e Phillips screwdriver Flat blade screwdriver e Wrench size 5mm e Nutdriver size 5mm e Adjustable wrench Soldering iron Solder Vinyl insulation tape e Polishing cloth MICROWAVE LEAKAGE TEST CAUTIONS Be sure to check microwave leakage prior to servicing the oven if the oven is operative prior to servicing The service personnel should inform the manufacture importer or assembler of any certified oven unit found to have a microwave emission level in excess of 5 mW cm and should repair any unit found to have excessive emission levels at no cost to the owner and should ascertain the cause of the excessive leakage The service personnel should instruct the owner not to use the unit until the oven has been brought into compliance the oven operates with the door open the service personnel should Tell the user not to operate the oven Contact the manufacturer e The service personnel should check all surface and vent openings for microwave leakage e Check for microwave leakage after every servicing The power density of the m
19. Website http biz lgservice com LG MICROWAVE OVEN MODEL M 3447GR MS3447GRS CAUTION BEFORE SERVICING THE UNIT READ THE SAFETY PRECAUTIONS IN THIS MANUAL July 2007 P NO MFL381039007 Printed in Korea SAFETY PRECAUTIONS This device is to be serviced only by properly qualified service personnel Consult the service manual for proper service procedures to assure continued safety operation and for precautions to be taken to avoid possible exposure to excessive microwave energy PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY A Do not operate or allow the oven to be operated with the door open B Make the following safety checks on all ovens to be serviced before activating the magnetron or other microwave source and make repairs as necessary 1 interlock 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 D Any defective or misadjusted components in the interlock monitor door seal and microwave generation and transmission systems shall be repaired replaced or adjusted by procedures described
20. ad 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 frame assembly If the door assembly is not mounted properly microwaves may leak from the clearance between the door and the oven Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes 5 4 Remove choke cover Remove door assembly LGE Internal Use Only F AIR DUCT ASSEMBLY REMOVAL 1 Disconnect the leadwire from the lamp 2 Remove the mounting screw to the magnetron G MAGNETRON REMOVAL 1 Disconnect the lead wire from the magnetron 2 Carefully remove the mounting screws holding the magnetron and the waveguide 3 Remove the magnetron ASS Y until the tube is clear from the waveguide NOTE 1 When removing the magnetron make sure its dome does not hit any adjacent parts or it may be damaged 2 When replacing the magnetron be sure to install the magnetron gasket in the correct position and be sure that the gasket is in good condition 3 After replacing the magnetron check for microwave leakage with a survey meter around the magnetron Microwave energy must be below the limit of 5 mW cm With a 275 ml water load Make sure that gasket is rigidly attached to the magnetron To prevent microwave leakage tighten the m
21. d Only for training and service purposes TROUBLE 1 The following visual conditions indicate a probable defective control circuit Incomplete segments e Segment missing Partial segment missing e Digit flickering NOTE Slight flickering is normal Colon does not turn or blink A distinct change in the brightness of one or more numbers in display One or more digits in the display are not lighting Display indicates a number different from one touched for example key in 5 and 3 appears in the display Specific numbers for example 7 or 9 will not display when key pad is touched Display does not count down with time blinking or up with clock operation Display obviously jumps in time while counting down Display counts down too fast while cooking Each indicator light does not turn on after setting cooking cycle Display time of day does not reappear when cooking is finished programming when touching other pads 5 Display is fixed at some figure and can not accept any input Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes 5 12 CONDITION CHECK RESULT CAUSE REMEDY 1 No input can be Check the conn Continuit Defective PCB Replace PCB programmed ection between assembly assembly
22. e 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 this adjustment Make sure that the latch moves smoothly after adjustment is completed and that the screws are tight Make sure the primary monitor and secondary switches operate properly by following the continuity test procedure LGE Internal Use Only INTERLOCK CONTINUITY TEST WARNING FOR CONTINUED PROTECTION AGAINST EXCESSIVE RADIATION EMISSION REPLACE ONLY WITH IDENTICAL REPLACEMENT PARTS TYPE NO SZM V 16 FA 63 OR VP 533A OF FOR PRIMARY SWITCH TYPE NO SZM V 16 FA 62 OR VP 532A OF FOR MONITOR SWITCH TYPE NO SZM V 16 FA 63 OR VP 533A OF FOR SECONDARY SWITCH A PRIMARY INTERLOCK SWITCH TEST When the door release button is depressed slowly with the door closed an audible click should be heard at the same time or successively at intervals When the button is released slowly the latches should activate the switches with an audible click If the latches do not activate the switches when the door is closed the switches should be a adjusted in accordance with the adjustment procedure Disconnect the wire lead from the primary switch Connect the ohmmeter leads to the common COM and normally open NO terminal of the switch The met
23. er should indicate an open circuit in the door open condition When the door is closed the meter should indicate a closed circuit When the primary switch operation is abnormal make the necessary adjustment or replace the switch only with the same type of switch COMPONENTS TEST PROCEDURE B SECONDARY INTERLOCK SWITCH TEST Disconnect the wire lead from the secondary switch Connect the ohmmeter leads to the common COM and normally open NO terminals of the switch The meter should indicate a open circuit in the door open condition When the door is 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 open condition When the door is closed meter should indicate an open circuit When the monitor switch operation is abnormal replace with the same type of switch NOTE After repairing the door or the interlock system it is necessary to do this continuity test before operating the oven RESULTS SWITCHES Wire leads removed Check for continuity of the switch with an Ohm meter Door Door open closed Primary Switch Monitor Switch LA
24. icrowave radiation leakage emitted by the microwave oven should not exceed 4 mW cm Always start measuring of an unknown field to assure safety for operating personnel from radiation leakage LGE Internal Use Only NECESSARY MEASURING INSTRUMENTS e TESTER VOLTS DC Ohmmeter e Microwave survey meter Holaday HI 1500 1501 Narda 8100 8200 Inch scale 600 non conductive material beaker glass or plastic inside diameter approx 8 5 cm 3 2 in e Cylindrical and made of borosilicate glass vessel max thickness 3 mm outside diameter approx 190mm height approx 90mm e Glass thermometer 100 C or 212 F 1 deg scale MEASURING MICROWAVE ENERGY LEAKAGE Pour 275 15cc of 20 5 C 68 9 F water 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 Operate the oven at its maximum output Measure the microwave radiation using and electromagnetic radiation monitor by holding the probe perpendicular to the surface being measured Move probe along shaded area Midd Probe scanning speed Less than 2 5 cm sec 1 in sec Copyright 2007 LG Electronics Inc All right reserved Only for trai
25. in this manual before the oven is released to the owner E A microwave leakage check to verify compliance with the Federal Performance Standard should be performed on each oven prior to release to the owner CAUTION MICROWAVE RADIATION DO NOT BECOME EXPOSED TO RADIATION FROM THE MICROWAVE GENERATOR OR OTHER PARTS CONDUCTING MICROWAVE ENERGY Copyright 2007 LG Electronics Inc All right reserved LGE Internal Use Only Only for training and service purposes CONTENTS Page SAFETY PRECAUTIONS Inside front cover SBECIFICA TIONS A 1 1 CAUTIONS 2 1 Date a 3 1 OPERATING INSTRUC TIONG 4 1 FEATURES 4 1 CONTROL PANEL 4 1 OPERATING SEQUENCE sessssissssnsecsestsasereaseessnenstannenaievessdonesensndsenseasenssaesbesaennennivany 4 2 SCHEMATIC DIAGRAM 4 4 CIRCUIT DESCRIPTION 14 estesssseeseseesenssessnsansenesessesesesinsnssnnnareseesnnstannasisensensenenunestnaandane 4 5 SERVICE 5 1 TOOLS AND MEASURING INSTRUMENTS 5 1 MICROWAVE LE
26. ity Defective Replace _ does not count of secondary secondary switch secondary switch down when switch with touching START door closed L Continuity pad Check the con gt Continuity Defective PCB Replace PCB nection between assembly assembly CN1 connector Ta gt and PCB L No continuity gt Loose connection gt i em assembly igntly 2 Fan motor or Check fan motor gt Abnormal Defective fan motor Replace fan motor oven lamp do not turn on gt Check oven lamp Abnormal m Defective oven lamp Replace oven lamp Normal TROUBLE 4 Oven seems to be operating but little heat is produced in oven load CONDITION CHECK RESULT CAUSE REMEDY Check the Lower than 90 of Decrease in power Suggest customer Output is low power source rating voltage source voltage contact local voltage with load electric power utility co or Normal qualified electrician Disconnect the Defective PCB Replace PCB y wire leads from assembly assembly relay 2 and check on andoff gt Normal time with multitester Measure the Abnornial Defective Replace output power magnetron magnetron NOTE Simple test of power output conducted by heating one liter water for one min if available Minimum 8 5 C
27. ning and service purposes MEASUREMENT WITH OUTER CASE REMOVED When you replace the magnetron measure for microwave energy leakage before the outer case is installed and after all necessary components are replaced or adjusted Special care should be taken in measuring the following parts Circled area of Fig below Around the magnetron The waveguide WARNING AVOID CONTACTING ANY HIGH VOLTAGE PARTS MEASUREMENT WITH A FULLY ASSEMBLED OVEN After all components including the outer case are fully assembled measure for microwave energy leakage around the door viewing window the exhaust opening and air inlet openings e Microwave energy leakage must not exceed the values prescribed below NOTE Leakage with the outer case removed less than 5 mW cm sq Leakage for a fully assembled oven Before the latch switch primary is interrupted with the door in a slightly opened position less than 2 mW cm sq Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes 5 2 NOTES WHEN MEASURING Do not exceed meter full scale 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 by 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
28. of the water to the vessel the load is immediately placed on the center of the turntable which is in thd lowest position and the microwave power switched on The time T for the temperature of the water to rise by a value A T of 10 2 K is measured where T is the time in seconds and AT is the temperature rise The initial and final water temperatures are selected so that the maximum difference between the final water temperature and the ambient temperature is 5 K The microwave power output in watts is calculated from the following formula 4187 x AT 0 55 X T2 To XM T e T2 Temperature after heating e To Temperature of bowl e M Weight of bowl is measured while the microwave generator is operating at full power Magnetron filament heat up time is not included about 3 sec e The water is stirred to equalize temperature throughout the vessel prior to measuring the final water temperature e Stirring devices and measuring instruments are selected in order to minimize addition or removal of heat WATER LOAD C lt TURNTABLE DISASSEMBLY AND ADJUSTMENT A OUTER CASE REMOVAL 1 Disconnect the power supply cord from the outlet 2 Remove the screws from the rear of the case The outer case must be moved backward to be lifted off B POWER SUPPLY CORD 1 Remove the outer case 2 Disconnect two terminals and remove one screw of the ground terminal C CONTROL PANEL
29. ounting screws properly making sure there is no gap between the waveguide and the magnetron H 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 leadwire from the turntable motor terminals 5 Remove the screw securing the turntable motor to the oven cavity ASS Y 6 After repairing the motor rotate the removed turntable motor cover 7 Fit the turntable motor cover s projecting part to the base plate slit 8 The taptite screw shall be used when a turntable motor cover is secured with a screw NOTE 1 Remove the wire lead from the turntable motor VERY CAREFULLY 2 Be sure to grasp the connector not the wires when removing Waveguide Dome Waveguide Bracket Magnetron Gasket Magnetron LGE Internal Use Only A Wire Leads y Turntable Motor Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes HIGH VOLTAGE TRANSFORMER REMOVAL 1 Discharge the high voltage capacitor 2 Disconnect the lead wire from magnetron high voltage transformer and capacitor 3 Remove the screw holding the high voltage transformer to the baseplate J FAN MOTOR ASSEMBLY REMOVAL 1 Discharge the high voltage ca
30. pacitor 2 Disconnect the lead wire from fan motor and high voltage capacitor 3 Remove the two screws holding the the suction guide ASS Y to the oven cavity and remove the high voltage diode earth screw 4 Remove the two screws holding the fan motor ASS Y to the suction guide ASS Y K HIGH VOLTAGE CAPACITOR AND DIODE REMOVAL 1 Discharge the high voltage capacitor 2 Disconnect the lead wire from fan motor and high voltage capacitor 3 Remove the screw holding the suction guide ASS Y to the oven cavity and remove the high voltage diode earth screw 4 Remove the screw holding the high voltage capacitor bracket L INTERLOCK SYSTEM 1 INTERLOCK MECHANISM The door lock mechanism is a device which has 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 ADJUSTMENT 5 DIRECTION SECONDARY a SWITCH 1 MONITOR o SWITCH PRIMARY 1 3 SWITCH Fan Motor Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes 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 th
31. s properly earthed before servicing WARNING THIS APPLIANCE MUST BE EARTHED IMPORTANT The wires in this mains lead are colored in accordance with the following code Green and yellow Earth Blue Neutral Brown Live As the colors of the wires in the mains lead of this appliance may not correspond with the colored markings identifying the terminals in your plug proceed as follows The wire which is colored green and yellow must be connected to the terminal in the plug which is marked with the letter E or by the earth symbol L or colored green or green and yellow The wire which is colored blue must be connected to the terminal in the plug which is marked with the letter N or colored black The wire which is colored brown must be connected to the terminal in the plug which is marked with the letter L or colored red LGE Internal Use Only OPERATING INSTRUCTIONS FEATURES Oven Front Plate Window Door Screen Door Seal Display Window Control Panel Door Open Button Safety Door Lock System Turntable Roller Rest CONTROL PANEL AUSSIE MENU Sensor Reheat PINNER RICE SOUP CASSEROLE RISOTTO PIZZA SENSOR COOK VEGETABLE RICE PASTA DESSERT AUTO MENU AUTO COOK AUTO REHEAT 4 Time Weight AUTO QUICK I5 6 DEFROST DEFROST 7 10 2 5 8 0 12 LGE Internal Use Only 1 SENSOR REHEAT 2 SENSOR CO
32. temperature rise is normal condition Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes 5 14 LGE Internal Use Only TROUBLE 5 No microwave oscillation even though oven lamp and fan motor run Display operates properly CONDITION CHECK RESULT CAUSE REMEDY No microwave Disconnect the No continuity Defective PCB Replace PCB oscillation wire leads from assembly assembly relay 2 and check continuity Continuity of relay 2 Operate the unit Check high vol Defective high Replace high L gt tage transformer pene voltage voltage transformer transformer Normal Check high vol Abnormal Defective high Replace high tage capacitor voltage capacitor voltage capacitor Normal Check high vol Defective high Replace high tage diode Annormal voltage diode voltage diode Normal Check Defective Replace magnetron abhormel magnetron magnetron 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 O
33. ts is applied to the magnetron to heat the magnetron filament through two noise preventing choke coils Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes 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 e The negative 4000 Volts DC is applied to the filament of the magnetron WHEN THE OVEN IS SET AT ANY LEVEL EXCEPT MAXIMUM e The micom controller controls the ON OFF time of relay 2 by the applied signal to vary the average output power of microwave oven as POWER LEVEL refer to page 1 1 One complete cycle of relay 2 is 22 seconds WHEN THE DOOR IS OPENED DURING COOKING Both the primary switch and relay 2 cut off the primary winding voltage of the high voltage transformer e ON OFF of relay 2 is coupled electrically with opening and closing of the secondary switch When the door is opened the secondary switch is opened and when the door is closed the secondary switch is closed e The cooking time stops counting down e Relay stops functioning As the door is opened if the contact of primary switch and relay 2 and or secondary switch fail to open the fuse opens due to the large current surge caused by the monitor switch activation which in turn stops magnetron oscillation PRIMARY FUSE SWI
34. utput is full power when you set lower power level r LGE Internal Use Only Disconnect the wire leads from relay 2 and check continuity relay 2 Operate the unit Abnormal Defective PCB assembly Replace PCB assembly 5 15 Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes EV EXPLODED VIEW INTRODUCTION MODEL MS3447GR MS3447GRS OVEN CAVITY PARTS INTERIOR PARTS DOOR PARTS 7 BASE PLATE PARTS LATCH BOARD PARTS CONTROL PANEL PARTS Copyright 2007 LG Electronics Inc All right reserved 6 1 LGE Internal Use Only Only for training and service purposes EV DOOR PARTS LGE Internal Use Only 6 2 Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes CONTROL PANEL PARTS LGE Internal Use Only 6 3 ed nics Inc All right reserv pu Copyright 2007 LG Electro rposes Only for training and service EV OVEN CAVITY PARTS LGE Internal Use Only 6 4 Copyright 2007 LG Electronics Inc All right reserved Only for training and service purposes EV LARCH BOARD PARTS LGE Internal Use Only 6 5 Copyright 2007 LG Electronics Inc All right reserved
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