MICROWAVE OVEN SERVICE MANUAL
Contents
1. CONDITION CHECK RESULT CAUSE REMEDY 1 Setting time Check continuity No continuity Defective Replace does not count of secondary secondary switch secondary switch down when switch with touching START door closed L Continuity pad gt Check the con Continuity Defective PCB Replace PCB nection between assembly assembly CN1 connector gt continuity Loose connection then assembly tightly 2 Fan motor or gt Check fan motor Abnormal Defective fan motor Replace fan motor oven lamp do not turn on Check oven lamp Defective oven lamp Defective oven lamp Normal TROUBLE 4 Oven seems to be operation but little heat is produced in oven load CONDITION CHECK RESULT CAUSE REMEDY Lower than 90 of Decrease in power Suggest customer Output is low gt Cheek the rating voltage source voltage contact local ice ans with load electric power votage Normal utility co or qualified electrician Disconnect the gt Defective PCB Replace PCB wire leads from Abnormal assembly assembly relay 2 and check on and off ps Normal time with multitester Measure the gt Abnormal Defective Replace output power magnetron magnetron2. 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 LGE Internal Use Only 5 15 Copyright O 2010 LG Electronics Inc All right reserved Only for training and service purposes TROUBLE 5 No microwave oscillation even though oven lamp and fan motor run Display operates properly CONDITION CHECK RESULT CAUSE REMEDY No microwave T Defective PCB Replace PCB oscillation Disconnect the No continuity assembly assembly wire leads from relay 2 and check continuity 4 Continuity of relay2 Operate the unit Check high vol Abnormal Defective high Replace high tage transformer voltage voltage transformer transformer normal Check high vol Abnormal Defective high Replace high l tage capacitor voltage capacitor voltage capacitor normal Check high vol Abn rmal Defective high Replace high tage diode voltage diode voltage diode normal Check Abnormal Defective Replace Magnetron 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
3. 4 SENSOR TOUCH STOP CLEAR gt POPCORN NOTE Heat only 1 package at a time Then the oven will start automatically 5 TIME COOKING TIME COOK POWER gt NUMBER gt LEVEL NUMBER gt gt START 6 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 8 CHILD LOCK This oven has a CHILD LOCK feature TO SET CHILD LOCK e Touch STOP CLEAR pad e Touch and hold START ENTER pad LOCKED appears on the display TO CANCEL CHILD LOCK e Touch and hold START ENTER pad LOCKED disappears 9 MORE LESS The cook time is adjustable by MORE pad or LESS pad STOP CLEAR 3 NUMBER START ENTER MORE STOP CLEAR gt NUMBER gt START ENTER LESS 10 QUICK DEFROST STOP CLEAR 9 QUICK DEFROST 11 KITCHEN TIMER KITCHEN TIMER NUMBER gt START 12 MELT STOP CLEAR 3 MELT NUMBER OF TABLE TIME POWER COOK LEVEL TIME NUMBER COOK gt NUMBER m POWER LEVEL 3 NUMBER gt NUMBER gt START 7 AUTO DEFROST
4. MAGNETRON HUMIDITY ubi SENSOR LLL Le LGE Internal Use Only 4 3 Copyright O 2010 LG Electronics Inc All right reserved Only for training and service purposes CIRCUIT DESCRIPTION GENERAL DETAILS The low voltage transformer supplies the necessary voltage to the micom controller when power cord is plugged in 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 in 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 Power input is supplied to the high voltage transformer through the fuse to the primary switch and relay 2 Turntable rotates PRIMARY FUSE SWITCH H V TRANS FORMER MONITOR SWITCH N RELAY 2 MICOM CONTROLLER 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 Cooking time starts counting down 3 3 volts AC is generated from the filament winding of the high voltage transformer This 3 2 volts is applied to the magn
5. 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 damage this control panel 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 REMEDY Microwave oven gt Inserting many plugs into one Avoid using other electrical does not work outlet and using them at the appliances when you use the same time microwave oven blown fuse or breaker Microwave oven plug is not Insert microwave oven plug inserted tightly securely Output power is too low Low AC input voltage Use the microwave oven adequate line voltage 3 Food temperature is too low This may not be a defect It is possible that the food should be cooked for a longer time period Sparks occur Using metallic ware and gt Do not use metallic ware for allowing it to touch the oven cooking except where noted in wall the cooking guide Ceramic ware trimmed in Do not use any type of gold or silver powder is used cookware with metallic trimming Uneven cooking Inconsistent i
6. p a a Ru uu iE lt ly On e lUs nal Inter E LG 6 4 d rve rese All right Inc ics es tron Elec e pu LG rvic se inin yrig train Cop for ly On EV LATCH BOARD PARTS 55262A LGE Internal Use Only 6 5 Copyright 2010 LG Electronics Inc All right reserved Only for training and service purposes EV INTERIOR PARTS Copyright 2010 LG Electronics Inc All right reserved 6 6 LGE Internal Use Only Only for training and service purposes EV BASE PLATE PARTS LGE Internal Use Only 6 7 Copyright 2010 LG Electronics Inc All right reserved Only for training and service purposes EV SENSOR PARTS Copyright 2010 LG Electronics Inc All right reserved 6 8 LGE Internal Use Only Only for training and service purposes LG Electronics Inc
7. COOKING NOTE Then the oven will start automatically 13 SOFTEN STOP CLEAR gt SOFTEN 3 NUMBER OF TABLE NOTE Then the oven will start automatically 14 CUSTOM SET STOP CLEAR gt NUMBER OF TABLE 15 EXPRESS DEFROST STOP CLEAR EXPRESS DEFROST 16 AUTO COOK AUTO gt NUMBER NUMBER OF _ START DEFROST WEIGHT AUTO COOK 1 NUMBER OF TABLE Copyright O 2010 LG Electronics Inc All right reserved Only for training and service purposes LGE Internal Use Only SCHEMATIC DIAGRAM AC 120V 60HZ SINGLE PHASE ONLY FUSE 20A NOTE ly A 1 1 DOOR IS OPEN j 1 2 RS SENSING i ELEMENT RC COMPENSATING NOISE FILTER ELEMENT A i ASSY 3 WIRE COLOR i MW SYMBOL COLOR WH WHITE i GY BK BLACK i 7 7 BL BLUE YL YELLOW SJ PK PINK lesse O RD RED BK GN MGT OVEN BN BROWN WH THERMOSTAT BK BK 1 PRIMARY WH INTERLOCK SWITCH i NO RELAY 1 l j 3 3 YL o gt gt PK 4 SECONDARY RELAY 2 INTERLOCK TURN TABLE e SWITCH MOTOR 3 MONITOR SWITCH YL D O BN NC H V TRANSFORMER
8. Control Panel Door Open Button Safety Door Lock System Turntable CONTROL PANEL 1 REHEAT POTATO RICE POPCORN 2 FRESH FROZEN FROZEN VEGETABLE VEGETABLE ENTREE 3 5 4 CUSTOM AUTO LESS 6 7 AUTO EXPRESS 9 8 DEFROST DEFROST SOFTEN MELT 10 1 2 3 11 4 5 6 7 8 9 TIME POWER 12 COOK 0 LEVEL 13 14 KITCHEN 15 17 STOP 18 ENTER CLEAR 19 LGE Internal Use Only 4 1 1 DISPLAY The display includes a clock and indicators that tell you time of day cooking time settings and cooking functions selected 2 SENSOR TOUCH This pad allows you to cook most of your favorite foods without having to select cooking times and power levels 3 AUTO COOK Touch this pad to select programming food items 4 CUSTOMSET Touch this pad to select sound on off clock on off scroll speed slow normal fast and unit Ibs kg 5 LESS Each time you touch this pad you subtract 10 seconds from the cooking time 6 MORE Each time you touch this pad you add 10 seconds to the cooking time 7 EXPRESS DEFROST Touch this pad to thaw only 116 of food very quickly 8 AUTO DEFROST Thispadis anaccurate defrosting method for meat poultryandfishupto6 Olbsor 4 0 kgs 9 SOFTEN Touch this pad to soften butter ice cream cream cheese or frozen juice 10 MELT TTouch this pads to melt butter margarine chocolate cheese or mas
9. NS FORMER SECONDARY RELAY 2 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 Phillips screwdriver Flat blade screwdriver Wrench size 5mm Nutdriver size 5mm Adjustable wrench Soldering iron Solder Vinyl insulation tape 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 If the oven operates with the door open the service personnel should Tell the user not to operate the oven Contact the manufacturer The service personnel should check all surface and vent openings for microwave leakage Check for microwave leakage after every servicing The power density of the microwave radiation leakage emitted by the microwave o
10. NUITY TEST tenete na tanta tatttan tata rata ta aeta tapa tanta kata aa 5 7 COMPONENT TEST PROCEDURE rentre xy ee oae ea Re ako eae E roa SE Denn aser atac 5 8 TROUBLE SHOOTING seais 5 11 EXPLODED VIE CT I D c mt 6 1 REPLACEMENT PARTS LIST 7 1 LGE Internal Use Only Copyright O 2010 LG Electronics Inc All right reserved Only for training and service purposes SPECIFICATIONS DESCRIPTION Model LCRT2010ST Power Requirement 120 V 60 Hz 1650 watt 14 0 A Single phase 3 wire grounded Power Output 1200 watt full microwave power IEC60705 Microwave Frequency 2450 MHz Magnetron 2M246 050GF Timer 0 9 min 99 sec Outside Dimensions 23 7 W x 13 9 4 x 19 134e D Cavity Dimensions 16 4 W x 11 1 x 18 44 D Net Weight 18Kg Shipping weight 20Kg Control Complement Touch Control System Clock 1 00 12 59 Microwave Power for Variable Cooking Power level approx 80 approx 60 approx 40 approx 20 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 O 2010 LG Electron
11. ONDARY 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 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 are 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 5 7 Copyright O 2010 LG Electronics Inc All right reserved Only for training and service purposes 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 OR V 5230Q FOR PRIMARY SWITCH TYPE NO SZM V 16 FA 62 OR VP 532A OF OR V 5220Q FOR MONITOR SWITCH TYPE NO SZM V 16 FA 63 OR VP 533A OF OR V 5230Q FOR SECONDARY SWITCH A PRIMARY INTERLOCK SWITCH TEST B SECONDARY INTERLOCK SWITCH TEST When the door release button is depressed slowly Disconnect the wire lead from the secondary with the door closed an audible click should be switch heard at the same time or successively a
12. SE 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 Microwave energy leakage must not exceed the values prescribed below NOTE Leakage with the outer case removedless 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 O 2010 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 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 befween the handle and the probe When testing near a corner of the door keep the probe perpendicular to the su
13. Website http biz Igservice com LG MICROWAVE OVEN MODEL LCRT2010ST CAUTION BEFORE SERVICING THE UNIT READ THE SAFETY PRECAUTIONS IN THIS MANUAL November 2010 P NO MFL06272518 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 b 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 in this m
14. anual 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 O 2010 LG Electronics Inc All right reserved LGE Internal Use Only Only for training and service purposes CONTENTS Page SAFETY PRECAUTIONS canina i Inside front cover SPECIFICATIONS a 1 1 CAUTIONS nui A RAR 2 1 INSTALLATIONS sanidad cocaina 3 1 OPERATING INSTRUCTIONS 4 1 FEATURES TU UI UU EN 4 1 CONTROL PANEL EI Lc 4 1 OPERATING SEQUENCE m ESTE LE Lm 4 2 SCHEMATIC DIAGRAM TE LEE 4 3 CIRCUIT DESCRIPTION ecoscccrncsananinnincicinncnnnncinnaniarancnc ententen 4 4 SERVICE INFORMATION ccrescsercseseccsesercnasercnasercnarenaensonsteennsestenstsecnstssonsesennsesananesenass 5 1 TOOLS AND MEASURING INSTRUMENTS tnter tentat ntn teta rhet innt tanta tanus 5 1 MICROWAVE LEAKAGE TEST netten nnne ta tanta tna rne arena 5 1 MEASUREMENT OF MICROWAVE POWER OUTPUT m RII 5 3 DISASSEMBLY AND ADJUSTMENT 5 3 INTERLOCK CONTI
15. 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 frame assembly If the door assembly is not mounted properly microwaves may leak from the clearance between the door and the oven Copyright 2010 LG Electronics Inc All right reserved 5 4 Only for training and service purposes Remove choke cover Remove door Assembly Spacer M d LGE Internal Use Only F AIR DUCT ASSEMBLY REMOVAL 1 Disconnect the leadwire from lamp 2 Remove the mounting screw to the magnetron G MAGNETRON REMOVAL 1 Disconnect the leadwire from themagnetron 2 Carefully remove the mounting screws holding the magnetron to 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 b
16. d service purposes L HIGH VOLTAGE TRANSFORMER 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 J FAN MOTOR ASSEMBLY REMOVAL 1 Discharge the high voltage capacitor 2 Disconnect the leadwire 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 leadwire 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 Fan Motor LGE Internal Use Only 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 DIRECTION PRIMARY SWITCH MONITOR SWITCH SECONDARY SWITCH 2 MOUNTING OF THE PRIMARY MONITOR SEC
17. e 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 O 2010 LG Electronics Inc All right reserved Only for training and service purposes INSTALLATIONS BEFORE YOU BEGIN READ THE FOLLOWING INSTRUCTIONS COMPLETELY AND CAREFULLY INSTALLING 1 Copyright O 2010 LG Electronics Inc All right reserved Only for training and service purposes 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 i
18. elay 2 and operate the unit Relay 2 m em 4 sec 6 sec 8 sec 10 sec 12 sec 14 sec 16 sec 18 sec 20 sec 22 sec k o FAN MOTOR Wire leads removed 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 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 LGE Internal Use Only 5 11 Copyright O 2010 LG Electronics Inc All right reserved Only for training and service purposes 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 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
19. elow 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 mounting screws properly making sure there is no gap between the waveguide and the magnetron Waveguide Bracket Magnetron Gasket Magnetron LGE Internal Use Only G REMOVING SENSOR 1 Disconnect the leadwire from PCB Assembly 2 Remove a screw securing the sensor duct Copyright O 2010 LG Electronics Inc All right reserved Only for training and service purposes 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 Wire Leads Turntable Motor Copyright O 2010 LG Electronics Inc All right reserved Only for training an
20. etron to heat the magnetron filament through two noise preventing choke coils Copyright O 2010 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 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 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 are cut off primary winding voltage of the high voltage transformer 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 The cooking time stops counting down Relay stops functioning As the door is opened if the contact of primary switch and relay 2 and or secondary switch fails 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 SWITCH MONITOR H V SWITCH TRA
21. g to ground MAGNETRON Measure the resistance Normal Less than 1 ohm Wire leads removed Ohm meter scale Rx1 Filament terminal Measure the resistance Normal Infinite Ohm meter scale Rx1000 Filament to chassis LGE Internal Use Only 5 9 Copyright O 2010 LG Electronics Inc All right reserved Only for training and service purposes COMPONENTS TEST PROCEDURE RESULTS Antenna Gasket Chassis Filament 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 Measure the resistance Normal Momentarily indicates CAPACITOR Ohm meter scale Rx1000 several ohms and Terminal to terminal then gradually returns to infinite Measure the resistance Normal Infinite Ohm meter scale Rx1000 Terminal to case HIGH VOLTAGE Measure the continuity Forward Normal Continuity DIODE Ohm meter scale Rx10000 Abnormal Infinite NOTE Some inexpensive meters may indicate infinite resistance in both direction Measure the continuity Reverse Normal Infinite Ohm meter scale Rx10000 Abnormal Continuity Copyright O 2010 LG Electronics Inc All right reserved 5 10 LGE Internal Use Only 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 r
22. hmallows 11 NUMBER PADS Touch number pads to enter cooking time power level quantities or weights 12 TIME COOK Touch this pad to set a cooking time 13 POWER LEVEL Touch this pad to set a cooking power 14 KITCHEN TIMER Touch this pad to use your microwave oven as a kitchen timer 15 EZ ON Touch this pad to cook at 10096 cook power for 30 seconds up to 3 minutes 30 seconds after 3 minutes 30 seconds every touch will add 1 minute up to 99 min 59 seconds 16 TrueCookPlus Touch this pad to cook food accord ing to TrueCookPlus code 17 START ENTE R This feature allows oven to begin functioning 18 STOP CLEAR Touch this pad to stop the oven or clear entries 19 CLOCK Touch this pad to enter the time of day Copyright O 2010 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 SETTING THE CLOCK STOP Set the CLEAR CLOCK correct hour START Set the correct minute START NOTE This is a 12 hour clock You can switch between AM and PM by touching 1 or 2 after step 4 2 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 3 Ez On STOP CLEAR Ez On
23. ics 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 For about 30 seconds after the oven stop 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 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 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 waveguid
24. nection Connect them tightly 2 Some inputs Replace key Everything works gt 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 gt Defective PCB Replace PCB number or figure assembly assembly different from one touched 4 Random programming when touching other pads 5 Display is fixed at some figure and can not accept any input LGE Internal Use Only 5 13 Copyright 2010 LG Electronics Inc All right reserved Only for training and service purposes 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 P uel Malfunction of the Replace fuse of monitor monitor switch primary monitor switch with secondary door closed 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 m
25. ntake 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 cm 4 inches from the wall 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 times In the event of an electrical short circuit grounding reduces the risk of electrical shock The plug must be plugged into an outlet that is properly installed and grounded WARNING Improper use of the grounding plug can result in a risk of electric shock Do not under any circumstances cut or remove the third ground prong from the power cord plug INSURE PROPER GROUND EXISTS BEFORE USE TEMPORARY METHOD ADAPTER PLUGS NOT PERMITTED IN CANADA ALIGN LARGE PRONGS SLOTS ENSURE PROPER GROUND AND FIRM CONNECTION BEFORE USE LGE Internal Use Only OPERATING INSTRUCTIONS FEATURES Oven Front Plate Display Window
26. ntensity of m 1 Use plastic wrap or lid microwave by their 2 Stir once or twice while characteristics cooking soup cocoa or milk etc Copyright 2010 LG Electronics Inc All right reserved 5 12 LGE Internal Use Only Only for training and service purposes TROUBLE 1 The following visual conditions indicate a probable defective control circuit 1 Incomplete segments Segment missing Partial segment missing Digit flickering NOTE Slight flickering is normal Colon does not turn on 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 CONDITION CHECK RESULT CAUSE REMEDY 1 No input can be programmed Check the conn ection between membrane key assembly and PCB assembly Continuity Defective PCB assembly Replace PCB assembly No continuity Loose con
27. ock system it is necessary to do this continuity test before operating the oven COMPONENTS TEST PROCEDURE RESULTS SWITCHES Check for continuity of the Door Door Wire leads removed switch with an Ohm meter open closed Primary Switch a Gas Monitor Switch L RES Secondary Switch EON a NOTE After checking for the continuity of switches make sure that they are connected correctly Copyright O 2010 LG Electronics Inc All right reserved 5 8 LGE Internal Use Only 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 Approx 0 2 0 4 ohm e Primary winding Approx 70 100 ohm Secondary winding Less than 1 ohm Filament winding Measure the resistance Ohm meter scale Rx1000 Normal Infinite Primary winding to ground Normal Infinite Filament windin
28. onitor 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 gt 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 L Normal Defective high voltage capacitor Replace high voltage capacitor Fuse blows again Defective high volt age transformer Replace high volt age transformer Refer to page 5 7 5 8 2 Fuse does not blow Check continuity No continuity m Defective Replace of thermostat thermostat thermostat Continuity Check continuity No continuity Defective power Replace power of power supply supply cord cord Copyright O 2010 LG Electronics Inc All right reserved Only for training and service purposes 5 14 LGE Internal Use Only TROUBLE 3 Display shows all figures set but oven does not start cooking while desired program times are set and START pad is touched
29. rface 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 SPECIAL TIP This oven used the button head screws Button Head Torx style 2 When you remove the screws use the tamper resistant Torx driver having a pin in head LGE Internal Use Only MEASUREMENT OF MICROWAVE POWER OUTPUT 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 e The initial temperature T1 of
30. sconnect two terminals and remove one screw of the ground terminal C CONTROL PANEL 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 Screw 9 securing Screw Copyright 2010 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 V 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
31. sure to install the magnetron gasket in the correct position and in good condition Output is full power when you set lower power level Disconnect the gt wire leads from relay 2 and check continuity relay 2 Operate the unit Copyright 2010 LG Electronics Inc All right reserved Only for training and service purposes Abnormal Defective PCB assembly Replace PCB assembly 5 16 LGE Internal Use Only EV EXPLODED VIEW INTRODUCTION MODEL LCRT2010ST SENSOR PARTS OVEN CAVITY PARTS INTERIOR PARTS DOOR PARTS BASE PLATE PARTS LATCH BOARD PARTS CONTROL PANEL PARTS LGE Internal Use Only 6 1 Copyright 2010 LG Electronics Inc All right reserved Only for training and service purposes EV DOOR PARTS Copyright 2010 LG Electronics Inc All right reserved 6 2 LGE Internal Use Only Only for training and service purposes EV CONTROLLER PARTS Copyright 2010 LG Electronics Inc All right reserved Only for training and service purposes 63 LGE Internal Use Only 5 RT PA 7 EN OV 9 fr d a Hone Bu 2 rx style To T E a Sag V i 68 Hd v
32. t Connect the ohmmeter leads to the common intervals When the button is released slowly the COM and normally open NO terminals of the latches should activate the switches with an Switch The meter should indicate a open circuit in audible click the door open condition When the door is closed If the latches do not activate the switches when meter should indicate an closed circuit When the the door is closed the switches should be a secondary switch operation is abnormal make the adjusted in accordance with the adjustment necessary adjustment or replace the switch only procedure Disconnect the wire lead from the with the same type of switch primary switch Connect the ohmmeter leads to the common COM and normally open NO C MONITOR SWITCH TEST terminal of the switch The meter should indicate Disconnect the wire lead from the monitor switch an open circuit in the door open condition Connect the ohmmeter leads to the common When the door is closed the meter should COM and normally closed NC terminals of the indicate a closed circuit switch The meter should indicate closed circuit in When the primary switch operation is abnormal the door open condition When the door is closed make the necessary adjustment or replace the meter should indicate an open circuit When the switch only with the same type of switch monitor switch operation is abnormal replace with the same type of switch NOTE After repairing the door or the interl
33. 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 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 P in watts is calculated from the following formula 4187 x AT 0 55 X T2 To XM T e Tz Temperature after heating To Temperature of bowl 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 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 order to minimize addition or removal of heat WATER LOAD 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 Di
34. ven 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 5 1 NECESSARY MEASURING INSTRUMENTS TESTER VOLTS DC AC Ohmmeter Microwave survey meter Holaday HI 1500 HI 1501 Narda 8100 8200 Inch scale 600 cc non conductive material beaker glass or plastic inside diameter approx 8 5 cm 31 2 in Cylindrical and made of borosilicate glass vessel max thickness 3 mm outside diameter approx 190mm height approx 90mm 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 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 5 cm 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 SSSSS IL II LI 1 F7 Probe scanning speed Less than 2 5 cm sec 1 in sec Copyright O 2010 LG Electronics Inc All right reserved Only for training and service purposes MEASUREMENT WITH OUTER CA
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