LMVM2277ST - MSA World
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1. Over the Range Microwave LMVM2277ST Spring 2008 Published January 2008 by LG Electronics USA Trainng Center Customer Service and Part Sales 800 243 0000 Technical Support and Part Sales 800 847 7597 Training Center 256 774 4051 USA Website www lgusa com us lge com Customer Service Website us lgservice com B2B Service Website aic lgservice com Training Website www LGCSAcademy com LMVM2277ST MICROWAVE OVEN LMVM2277ST Over The Range Microwave Oven CONTENTS 1 Safety Notice Other Notices and Disclaimer 3 Introduction 4 Specifications 5 Warranty Page 6 General Warnings and Safety Information 7 Oven Installation 8 Turntable Installation 9 Operating Instructions 10 Power Levels 12 Care and Cleaning 13 Oven Exterior 13 Oven Interior 13 Grease Filters 13 Charcoal Filter 14 Oven Light Replacement 15 Disassembly and Repair 16 Power Board and Main Board 16 Outer Case Removal 18 Door Interlock Switches 19 Interlock Switch Continuity Test 20 Primary and Secondary Switches 20 Monitor Switch 20 Magnetron Removal and Replacement 21 Stirrer Fan and Cover 21 Door Removal 22 Door Disassembly 23 Flat Plastic Connector 24 Vent Fan Motor Replacement 26 Turntable Motor Replacement with oven installed 26 Humidity Sensor 26 Component Test Procedures 27 Transformer Test 27 Magnetron Test 27 Capacitor 28 Relay 29 Fan Motor 29 Low Voltage Transformer 29 E LMVM2277ST Page 1 TRAINING MANUAL LMV2. Remove the glass tray and all other parts of the turntable assembly Pull the turntable drive arm off the motor shaft Remove the base plate by removing eight screws along its perimeter Disconnect the light assembly cable and set the base on a protective surface like a blanket or pad The turntable motor is attached to the base with a tab and a screw Replacement is the reverse of these steps With the outer case removed remove one screw and lift out the humidity sensor Unplug the connector at the main board and replace the defective sensor Replacement is the reverse of these steps Page 26 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN COMPONENT TEST PROCEDURES TRANSFORMER TEST FILAMENT p SECONDARY WINDING amp WINDING E amp F P PRIMARY SER WINDING SEE MAGNETRON TEST LMVM2277ST To test the transformer remove all leads to take it out of the circuit Measure the resistance between the following points Meter scale Rx1 Primary A amp B High 0 2 1 00 Primary A amp C Low 02 150 HV Secondary G amp GND 50 120 Q Filament E amp F 0 5 2 00 Meter scale Rx1000 Primary to ground Normal infinity Filament to ground Normal infinity Lead D connects to the High Voltage Capacitor diode side To test the magnetron remove the connector to take it out of the circuit Measure the resistance between the fol
3. Remove the wire cover and open the hinge covers Open the door Remove the vent grille Disconnect the two flat cables at the face plate connectors Use a small screwdriver to remove the clip on the end of the pneumatic damper and take the spring out of the oven USE CAUTION because the damper could expand without notice Flat Wire Hinge Cover Lift the door off the hinges and remove it Set it on a protective surface like a blanket to prevent scratches or damage When replacing the door always check the interlock switches and perform a microwave leakage test See page 33 E LMVM2277ST Page 22 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN DOOR DISASSEMBLY Remove the four screws securing the choke cover to the door Separate them carefully using a small screwdriver or a knife Remove the two screws securing the handle Remove the door frame Remove the two screws securing the PCB Printed Circuit Board Disconnect the flat plastic connector See page 24 UT When replacing the door adjust it to be parallel to the chassis There should be no play between the inner door surface and the oven frame If the door is not mounted properly microwaves may leak between the door and oven or the monitoring and safety switches will prevent usage Always perform a microwave leakage test whenever the door is adjusted or repaired LMVM2277ST Page 23 TRAINI
4. Door Assembly Handle Assembly Locker Base PCB PCB Assembly Main PCB Assembly PCB Assembly Power Harness Single Harness Single Reflector Reflector Case Flat Tray Glass Tray Assembly Grille Vent Cover Lamp Cover Power Cord Cover Wire Decor Front Damper Absorbing Ring Assembly Roller Bracket Mount Bracket Holder Cook Auxiliary Page 56 TRAINING MANUAL LMVM2277ST Loc 34930W 34960A 349861 35026A 35230A 35889A 36549S 36549V 368771 368772 36912H 43500L 43500R 43501L 43501R 44510L 449701 449702 449703 466001 466003 50CZZH 50CZZM 5OFZZA 53301A 53550L 5355158 54790A 54810A 54810C 54810U 54811A 54931A 5497458 55012A 55231C 55238A 55262A 55893A 56170D LMVM2277ST Part No 4B72510F MCK36305401 4350W4A007J MHL38867201 MDJ37601501 5889W1A014B 6549W1S018C EAU37364801 EAD37950902 EAD37950904 6912W3H001C MEG36304701 MEG36304701 AEJ33593401 AEJ33593402 MFC34659201 4970W1A006B 4970W1A007B 4970W1A007B 6600W1K004C 6600W1K004B 0CZZW1H004A 0CZZW1M001D 3B74133K AGU33587601 MCK30584402 ACQ33587501 MAL38267301 MAZ38267101 MAZ36531801 MAZ39866701 ABA33739501 4931W3A004B MEA36304601 MEV39815201 5230W1A003C MEA36304401 MCZ36304201 ADP33587401 6170W1D100C MICROWAVE OVEN Description Holder Wire Cover Motor Gasket Turntable drive shaft Shelf Wire rack Filter Grease 2 each Turntable Assembly Rotating ring Motor AC Synchronous turnt
5. PRIMARY Type SZM V16 FA 63 or VP 533A OF or V5230Q SECONDARY Type SZM V16 FA 63 or VP 533A OF or V5230Q MONITOR Type SZM V16 FA 62 or VP 532A OF or V5220Q NOTE After repairing the door interlock system or switches these continuity tests must be performed LMVM2277ST Page 20 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN MAGNETRON REMOVAL and REPLACEMENT Fan Motor 38 Assembly U GE al etai Transformer LMVM2277ST Damper bracket Page 21 Remove the outer case See page 18 Remove the damper bracket Disconnect the transformer lead wire Remove the four screws securing the transformer Remove two screws securing the fan motor Remove four screws securing the magnetron and lift it out carefully When removing or replacing the magnetron ensure the woven metal gasket is undamaged and properly positioned The stir fan cover is in the top of the oven It is held in place by one screw and three tabs This cover must be in place to operate the microwave oven safely Remove the screw and pull the cover out of the tabs being careful not to bend or break the cover The stir fan presses onto the shaft The cover is secured by three tabs and a single screw TRAINING MANUAL LMVM2277ST MICROWAVE OVEN DOOR REMOVAL Remove the two vent grille mounting screws Remove the door hinge screws
6. WIRE COLORS RD RED BN BROWN
7. AIR VENTS motor when START ENTER Check operation of fan key is touched Page 43 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN TROUBLESHOOTING FLOW CHARTS continued CHART D COUNTS DOWN BUT NO HEAT Check the primary and secondary interlock switches Check both thermostats TCO for the oven cavity and the magnetron Either switch could render the oven inoperable Check Relay 8 PROBLEM D Unit does not heat up even if display counts down when START key is touched for HIGH POWER cooking LMVM2277ST Page 44 Check 1 PRIMARY AND SECONDARY INTERLOCK SWITCHES 2 THERMOSTAT E o 8 D circuit board continuity circuit board circuit board Check contact of connector a E Check the contact of relay 8 see page 7 14 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN TROUBLESHOOTING FLOW CHARTS continued CHART D continued Check the resistance of the high voltage transformer See page 27 Magnetron Check the high voltage capacitor See page 28 Normal H V C Replace H V D Replace Magnetron Check the high voltage diode See page 30 QC SS eo v ica N Abnormal oS om o tz SE 27 Nomal Replace H V C V D lt o s pcd EIn x O O gt D do G g 9083 c D x po Resistance incorrect uu S N D GENE Normal resistance Normal H V T Check the continuity of H V C see page 7 14 Replace
8. Relay Connector CN1 Cooktop Lights Connector amp Vent Motor Secondary switch RY 2 Power Relay i 3 Tap CN6 14 pin enka Power Relay Main Door PCB TH1 hermistor Ambient Oven Temp LMVM2277ST Page 48 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN EXPLODED VIEW 135810 EEE 13552A a I P I e E tr A 135360 ee T N Hi 355145 ar 2132 ET aa P J3 I I m LMVM2277ST Page 49 TRAINING MANUAL MICROWAVE OVEN LMVM2277ST EXPLODED VIEW TRAINING MANUAL Page 50 LMVM2277ST MICROWAVE OVEN LMVM2277ST EXPLODED VIEW TRAINING MANUAL Page 51 LMVM2277ST MICROWAVE OVEN LMVM2277ST EXPLODED VIEW TRAINING MANUAL Page 52 LMVM2277ST MICROWAVE OVEN LMVM2277ST EXPLODED VIEW 77 1 LES A LENNI Y RAR ST Sd TRAINING MANUAL Page 53 LMVM2277ST LMVM2277ST MICROWAVE OVEN EXPLODED VIEW OWNERS
9. 90 80 70 60 90 40 C LMVM2277ST MICROWAVE OVEN CONVERSION INFORMATION 212 210 200 190 180 170 160 150 140 130 120 110 100 F Page 60 FORMULAE F 9 5 C 32 C 5 9 x F 32 TRAINING MANUAL OTR Microwave Spring 2008 a MAIN PCB CNICIOP CNe 14P c fuus DIRSUHE TG CNSC10P CN6C14P MICDM CONTROLLER ASSY L V TRANSFORMER RY yon P RELAY mn itt al 7 RY11 C TOP rie HI i eve C TOP LAMP 3 Low RELAY RY13 r von ce g a LOW RELAY RY14 VENT FAN MEDIUM RELAY o Q es f wu HT RELAY RYI6 oo BT TURBO RELAY k m O 00000000000000 QUUUUUUUUUUUUU H V CAPACITOR H V DIODE ABSOLUTE HUMIDTY SENSOR MAGNETRON CONTROL MODULE BL WH YL YL PK BL WH RD BK BN BN GY WH BK Dese 7 PIN CONNECTOR CN1 9 PIN CONNECTOR CN2 3 PIN CN3 CONNECTOR 3 PIN CN4 C L Counter Light S M Stirrer Motor CONNECTOR F M Fan Motor T T M Turn Table Motor FOR SENSOR O L Oven Light V M Vent Motor TH1 Ambient Oven Thermistor Cut In 180 F Cut Out 130 F Oven Thermostat Opens 250 F Closes 32 F MGT Thermostat Opens 320 F Closes 32 F OVEN TAT 5 110 C 0 C Li PRIMARY o x SWITCH H V TRANSFORMER I HY Transformer I BN Tap Defrost l BL Tap Normal Power L WH Tap Neutral i
10. DISCLAIMER The information in this training manual was accurate at the time of publication Every effort has been made to ensure accuracy Updates changes etc are available via GCSC and LGCSacademy The information in this manual is intended for persons with adequate backgrounds in electronics mechanical and electronic servicing The manufacturer and seller are not to be held responsible for any liability incurred from its use COMPLIANCE The responsible party for this device s compliance is LG Electronics Alabama Inc 201 James Record Road Huntsville AL 35813 L LMVM2277ST Page 3 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN INTRODUCTION Cooking Guide The LMVM2277ST is part of the new UAE HS Window with LG complete kitchen suite It can be Metal Shield Door Safety Lock System Door Handle Gas Spring N E Nasser Vent Grill Glass Tray buse Guide Tray Cooktop Countertop Light Grease Filter Move probe along shaded area LMA Probe scanning speed Less than 2 5 cm sec 1 in sec LMVM2277ST Page 4 purchased separately but is designed to be sold with the matching refrigerator range and dishwasher This diagram illustrates the major parts of the oven as seen by the customer The door opens upward rather than swinging out from the left hinge The grease filters charcoal filter cooktop lights and cooking cavity light can all be serviced by the customer No other parts a
11. Description Transformer power Filter AC Line Magnetron 2M282H Power Cord Assembly 1 6 m 4 ft sensor Assembly Motor AC Synchronous stir fan 21 V 180 MA 34 9 RPM Motor AC Circulation Magnetron cooling cavity circulation Cable Assembly incl HV Diode Harness Single Lamp Halogen Cavity 20 W See also 36912H Thermostat TCO Thermal Cut Off magnetron Thermostat TCO Thermal Cut Off cavity vent Plate Assembly Mounting bracket 3 piece welded Plate Base Base Assembly Kit Assembly Installation hardware kit Bracket Idle Damper Housing Damper Flap Damper Polyethylene foam adhesive Damper Polyethylene foam adhesive screw Machine Pan head 3 X 12 mm screw Machine Pan head 4 X 18 mm Nut Common Hex 3 mm Screw Taptite Locking head 4 X 8mm Screw Custom 4 mm X 10 mm Screw Custom 5 mm X 25 mm screw Taptite 3 mm X 8 mm screw Custom Hex head 4 X 14 mm Screw Custom 4 mm X 14 mm screw Tapping Flat head 4 X 10 mm TRAINING MANUAL LMVM2277ST MICROWAVE OVEN OHM S LAW and WATT S LAW P WATTS I AMPERES Watts Volts x Ohms Amperes Volts Ohms Watts Amperes x Ohms Amperes Watts Volts Watts Volts x Amperes Amperes V Watts Ohms E VOLTS R OHMS Volts WWatts xOhms Ohms Volts Amperes Volts Watts Amperes Ohms Volts Amperes Volts Amperes x Ohms Ohms Watts Amperes M LMVM2277ST Page 59 TRAINING MANUAL LMVM2277ST 100
12. Example 70 x 14 5 1015 watts The output power of a microwave oven is greatly affected by the voltage under load of the AC power supply Measure the voltage under load at the wall receptacle where the oven is powered and operating The following chart shows the percentages of full power that are within limits at voltages from 108 Vac to 132 Vac 125 120 115 110 105 100 95 90 85 80 15 70 108 110 112 114 116 118 120 122 124 126 128 130 132 SUPPLY VOLTAGE E LMVM2277ST Page 36 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN EN Note Power output measurements should never be made on microwave ovens operating on less than 108 Vac Below this point the power output drops sharply in an unpredictable manner Likewise operating an oven at voltages greater than 132 Vac should be avoided as damage to components may occur due to excessive electrical pressure Example A 1 000 watt oven operated at 114 Vac would be within limits at any point between 85 and 112 of the rated power 85 of 1000 850 watts 112 of 1000 1120 watts Therefore the oven would be nominal normal if the output power was between 850 watts to 1120 watts RESULTS AND CORRECTIONS When chart 1 2 the power output measured falls outside the nominal normal range on the take the following steps Verify operation or rotation of the waveguide stirrer Disconnect power discharge the high voltage capacitor and check the h
13. SERVICE NSTALLATIO E MANUAL MANUAL MANUAL on E LMVM2277ST Page 54 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN MODEL AND SERIAL NUMBERS Example 801KW3400251 801 KW I a T producto Number LE code Made in Korea Manufactured January 2008 Newer Style With Barcode New Serial Code ETA Mid 2008 12345 KR T T Options mure number LE code LE and month of production YMM Production site 2 Letters Model ID E LMVM2277ST Page 55 TRAINING MANUAL LMVM2277ST Loc Part No 01 MFL37191403 02 MFL06272504 04 MFL06208702 05 MEZ37728002 06 1 4922W5A060A 06 2 MBM3896880 1 10 MAY39948401 13213A ADV32254902 13536A 3536W1A007G 13550L MCK36295901 13551A AGM34503401 13552A MCK36296601 13581A ADC33594001 13651A AED33315201 14026A MFG34660001 23040B MAM36532001 268711 EBR35323401 268712 EBR35324101 26871P EBR35323801 268771 EAD37950903 268772 EAD37950901 33034L MGW36299201 33034R MGW37450401 33112U MBN36305302 33390G 3390W1A033A 33391A 3391W1A002B 33530A MDX36305501 33550L MCK36298901 33550P 3550W3A084A 33550W MCK37457001 33806F MCR36532701 33940A MCQ38867501 34351A 4351W1A003B 345801 4580W3A001B 34810Q 4810W3G062A 34810T MAZ36299101 34930R MEG37236101 LMVM2277ST MICROWAVE OVEN PARTS LIST Description Manual Owners Manual Service Manual Installation Label Cooking Guide Card Template Card Template Box Frame Assembly Door Tape Sealing Cover LED Parts Assembly Cover Choke
14. and move laterally 1 Round glass tray 2 Rotating ring 3 Rectangular glass tray 4 Turntable drive arm Follow these steps to install the turntable components and to ensure they function correctly 1 Install the 2 Install the 3 Place the 4 Be sure the turntable drive arm rectangular glass rotating ring on drive arm can and position it tray and ensure it top of the rotate in the securely on the slides properly rectangular glass hollow area on the drive cam tray bottom of the rectangular tray Place the round glass tray on top of the rotating ring Put a cup of water on the turntable and operate the oven for a minute to ensure that the tray mechanism is seated properly and works as it should There should be rotation on the turntable AND lateral motion involving the rectangular tray s LMVM2277ST Page 9 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN OPERATING INSTRUCTIONS All functions are available from the control panel Operation is similar to most other microwave ovens For example to set two stage cooking with a cook time of 3 minutes at full power and 7 minutes thirty seconds at a power level of 70 press 3 0 0 and COOK TIME to set the 3 minutes at full power then press 7 3 and 0 to set the second cooking time of seven minutes thirty seconds then press POWER LEVEL and 7 to set the power level of the second cooking period to 70 and then press START All other functions ope
15. by pulling it out and replacing it with a new one Pr The bulb is not equipped with a a e eee filament anchor so there is no top or eA TG 777 bottom The socket pigtail is attached to the lamp holder by two bolts The socket need not be removed to change the bulb J LMVM2277ST Page 15 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN DISASSEMBLY and REPAIR POWER BOARD and MAIN BOARD The main board and power board can be serviced without dismounting the oven Remove the screws around the perimeter of the base plate Disconnect the wiring harness for the lights and set the base aside Remove the four screws toward the bottom of the face plate on the left side Pull the latch board down and push it aside Release the main board and pull it down You ll have to roll it to the right a little bit to make it clear easily Note The photo is in the lab but this can be achieved while the microwave is mounted on the wall s n LMVM2277ST Page 16 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN This drawing shows the location of the main board upper item and the ventilation duct inside the microwave oven case The latch board is the lower item Remove the wires and connectors from the main board SACHE DORUM Remove the screws that hold it in the case to change the board Power Transformer mu M LMVM2277ST Page 17 TRAIN
16. light light continuously or light when they should not 6 Incorrect numbers or letters appear in the display 7 Clock fails to keep time accurately M LMVM2277ST Page 38 TRAINING MANUAL LMVM2277ST RELAY Fan turns on when door is closed but START is not pressed Fan does not turn on when door is closed and START is pressed LMVM2277ST GOOD MICROWAVE OVEN PROBLEM FAN motor turns on without touching START key when the door is closed NO YES GOOD Remove the male connector of I O CON from the circuit board Does the unit still operate Defective Wire Assembly Replace the circuit board Replace Wire Assembly PROBLEM FAN motor turns on When the door is closed and START key is touched Measure the voltage at pin NO 1 5 of CN1 Voltage reading 120 V AC Defective FAN motor Replace the circuit board Replace FAN motor Page 39 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN RELAY continued Oven lamp turns on when PROBLEM door is closed without pressing START Oven lamp turns on without touching START key when the door is closed NO YES Remove the male connector of I O CON from the circuit board Does the unit still operate Replace the Defective circuit board Wire Assembly Replace Wire Assembly Oven lamp does not turn PROBLEM on when door is closed Oven lamp turns on When the door is closed and and
17. unpainted metal in the appliance Before removing a replacement part from its package touch the anti static bag to a ground connection point or unpainted metal in the appliance Handle the electronic control assembly by its edges only When repackaging a failed electronic control assembly in an anti static bag observe these same precautions REGULATORY INFORMATION This equipment has been tested and found to comply with the limits for a Class B digital device pursuant to Part 15 of the FCC Rules These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a residential installation This equipment generates uses and can radiate radio frequency energy and if not installed and used in accordance with the instruction manual may cause harmful interference to radio communications However there is no guarantee that interference will not occur in a particular installation If this equipment does cause harmful interference to radio or television reception which can be determined by turning the equipment off and on the user is encouraged to try to correct the interference by one or more of the following measures Reorient or relocate the receiving antenna Increase the separation between the equipment and the receiver Connect the equipment to an outlet on a different circuit than that to which the receiver is connected or consult the dealer or an experienced radio TV technician for help
18. H fr LU i I I i i i K Fn LMVM2277ST Page 19 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN INTERLOCK SWITCH CONTINUITY TEST The door interlock switches should click audibly when the door is opened or closed If the latches do not activate the switches properly they can be adjusted PRIMARY and SECONDARY SWITCHES Disconnect the wire lead from the switch Connect an ohmmeter to the COM common and NO normally open terminals of the switch With the door open the meter should indicate an open circuit Closing the door should indicate a closed circuit See chart below MONITOR SWITCH Disconnect the wire lead from the switch Connect an ohmmeter to the COM common and NC normally closed terminals of the switch With the door open the meter should indicate a closed circuit Closing the door should indicate an open circuit See chart below COMPONENTS TEST PROCEDURE RESULTS i Check for continuity of the Door Door Wire leads removed switch with an Ohmmeter open closed Primary wol co 0 oo ED o Indicates Switch Contacts Are Open Monitor n x Switch gt CN Indicates Switch Contacts Are Closed I B Secondary _ I ar Switch aM NOTE After checking for the continuity of switches make sure that they are connected correctly WARNING For continued protection against microwave emission replace switches ONLY with identical replacement parts
19. H V T Resistance incorrect SRE iy ne Normal resistance Measure resistance of H V Transformer see page 7 13 YFh LMVM2277ST Page 45 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN TROUBLESHOOTING FLOW CHARTS continued CHART E NO SOUND AT BUTTON OPERATION OR END OF CYCLE Check the PCB Printed Circuit Board and all connectors EI 28 Replace circuit board stages or at end of cooking Check no rmal operation circuit board PROBLEM E No buzzing when touching the key between T LMVM2277ST Page 46 TRAINING MANUAL MICROWAVE OVEN LMVM2277ST TROUBLESHOOTING FLOW CHARTS continued CHART F CHECK THE POWER SUPPLY A SSV 00w uonejjusn ASSY 10101 LIO e pnus azejdaH peog naa JELLUOPY peog prana aaejday 30 AUOT OS Iepa jeuuon Bunees euo 28 uo2 1004 Check the ventilation fan for proper operation DT 6 2 ebed eas J0RAULC jo MO j2ejuoa2 yaan peuo jejsowueg uaAo pue lt jejsounayj vonsu eu oy Jo Peluos ayl Say jejsounayj uaAo pue jejsouueut vonsu ew 128109 a3ejdaH ON ET D O A kddf1S dH3MOd Peu p uonol si ASY JJO NO LN3A Way ejexedo jou saop LE LONE Ua 3 Wi THOHd TRAINING MANUAL Page 47 LMVM2277ST LMVM2277ST MICROWAVE OVEN MAIN BOARD CN1 Main Relay Connector CN5 10 Pin Oven Light Connector Main Door PCB CN1 Connector Oven AB Humidity Sensor CN2
20. ING MANUAL LMVM2277ST MICROWAVE OVEN OUTER CASE REMOVAL These instructions assume you are removing replacing or servicing an oven that has been installed If it is a new oven be sure to remove two screws and the mounting bracket from the back of the oven before proceeding e Remove the two vent grille screws e Remove the four screws securing the oven case to the oven Four on the top one on the right side e Remove two screws on each side of the base plate e Remove the four screws holding the outer case to the back of the oven e Lift the outer case carefully from the oven Store it to prevent damage while you are working on the oven TS p Power cord Vent Grille A Door Controller Outer Case m LMVM2277ST Page 18 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN DOOR INTERLOCK SWITCHES Interlock Disconnect the interlock switches more er witc nm RO irom PB MAT Remove the two screws attaching the WHitrom VT SSNS switch to the front of the oven You ll RE SSP RQ need a Torx T 20T Tamperproof bit i BL from RCE gt en ae PK from PTE ISIN CE cm After replacing the switch perform a microwave leakage check See page 33 a j u M fo rex RTE The connectors are keyed to prevent improper connection It is still a good idea to check the wire colors especially where there are multiple connectors Primary Interlock Monitor Switch LEFT SIDE SWITC
21. M2277ST MICROWAVE OVEN Component Test Procedures continued 30 High Voltage Diode 30 Turntable Motor 31 Ventilation Van Motor 31 Humidity Sensor 31 Stirrer Fan Motor 32 Microwave Leakage Test Procedure 33 Microwave Power Test Procedure Traditional Method 34 Microwave Power Test Procedure Alternate Method 39 Checkout Procedures 38 Blown Fuse 38 Main PCB Printed Circuit Board 38 Relay 39 Troubleshooting Flow Charts 41 Chart A No Power 41 Chart B Power Doesn t Run 42 Chart C Runs No Heat 43 Chart D Counts Down No Heat 44 Chart E No Beeper Buttons or End of Cycle 46 Chart F Power Supply 47 Main Board 48 Exploded View 49 Exploded View Door Parts 49 Exploded View Case Parts 50 Exploded View Safety Switched 51 Exploded View Internal Parts 52 Exploded View Air Duct Fan Sensor and Wiring Parts 53 Exploded View Installation Parts 54 Parts List 55 Model Number Serial Number Decoding Chart 58 Supplemental Materials 59 Chart Ohm s Law and Watts Law 59 Conversion Formulae F C 60 Schematic Oversize folded in back of book E LMVM2277ST Page 2 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN IMPORTANT SAFETY NOTICE The information in this training manual is intended for use by persons possessing an adequate background in electrical equipment electronic devices and mechanical systems In any attempt to repair a major appliance personal injury and property damage
22. NG MANUAL LMVM2277ST FLAT PLASTIC CONNECTOR Terminal socket Plastic fastener Terminal socket Plastic fastener Connector LMVM2277ST MICROWAVE OVEN The flat plastic connector FPC is opened and closed by moving the plastic slide at the top to release or secure the flat cable To release the cable pull the latch away from the connector Lift the flat cable out It is held in place by two hooks that fit into the two square holes on the cable To replace the flat cable be sure the latch is pulled up away from the connector Insert the flat cable and secure the hooks in the two square holes Press the latch into place and gently tug on the cable to be sure it is Secure TRAINING MANUAL LMVM2277ST MICROWAVE OVEN VENTILATION FAN MOTOR REPLACEMENT If the oven has not been installed be sure the mounting bracket has been removed from the back of the oven Remove the two screws securing the blower plate cover One on the top and one on the back Lift the motor out and turn it to face the proper direction front top or back for venting Replace the screws in the top and back to secure it against vibration Replace the top plate unless you are venting the oven through the roof Attach the adapter and duct work for venting ff LMVM2277ST Page 25 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN TURNTABLE MOTOR REPLACEMENT With Oven Installed LMVM2277ST
23. START is pressed START key is touched Measure the voltage at pin NO 1 7 of CN1 Voltage reading 120 V AC NO YES Replace the Defective circuit board Oven lamp Replace Oven lamp T LMVM2277ST Page 40 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN TROUBLESHOOTING FLOW CHARTS Before starting the troubleshooting charts check to see if the oven is operable For display problems use charts A B and C If the oven does not heat try charts D and E If the ventilation fan does not operate use chart F CHART A NO POWER Check connector CN1 on the main board Reading across pins 1 and 3 blue wire and white wire the voltage should be 120 Vac LMVM2277ST Page 41 PROBLEM A PLEASE SET TIME OF DAY does not appear in display window when power supply cord is plugged into wall outlet Check 1 POWER SUPPLY 3 OVEN CAVITY THERMOSTAT 2 FUSE Normal circuit board Normal resistance Replace circuit board Correct connections EL LIN Q 120 Voltage incorrect f Measure voltage between pin 1 and pin 3 of connector CMI TRAINING MANUAL MICROWAVE OVEN TROUBLESHOOTING FLOW CHARTS continued LMVM2277ST uams youms Bursuas Aynumnuoo iepuooas pewon Joop asedau 10 snip ON p soj i peua upees 128107 SI Joop ay ueu 18 E uid l pue Md 1 uig usaMjad END 1O 28UILIO2 JO Anunua 28u7 EULION 9810 1004 PO l LS 10 2euuo2 HO Jo 126 u02 428u7 Ayn
24. able fan Motor Assembly AC Vent fan Harness Single Harness Single Lamp Halogen Cooktop 10 W Holder Locker Holder Locker Holder Assembly Locker Holder Assembly Locker Lever Spring Spring Spring Switch Micro Switch Micro Capacitor High Voltage 0 95uUF 3 Capacitor Film Box Vent fan 14uF Fuse Time Delay Ceramic 250 V 20 A Plate Assembly Bottom Cover Lamp Internal shield Cover Assembly Stirrer Fan Mica Barrier Bracket Thermostat TCO Bracket Capacitor Bracket Damper Fan Duct on XFMR Bracket Assembly Holder Assembly Cavity Lamp Guide Suction Insulator Filter Charcoal Guide Air Duct Upper plastic air guide Fan Assembly Stir fan blade Transformer high voltage Page 57 TRAINING MANUAL LMVM2277ST Loc 56170G 56201A 56324A 56411A 56501A 56549B 56549F 56851D 968 71 56912H 56930M 56930V 63300M 63302A 63303A 63861A 65862B 65862D 948501 948502 WMP026 WMP033 WNH001 WSZ002 WSZ062 WSZ064 WSZ210 WSZ236 WSZ237 WTC007 LMVM2277ST Part No 6010W2L003D 2B72130F 6324W1A001S 6411W1A014T 6501W1A013A 6549W1S002G EAUS37848601 6021W3B001Q EAD37851801 6912W3H001D 6930W1A003K 6930W1A003J 3301WOA003C MGJ36298102 AAN32256101 2B 2771H 3B72144A 3B71432A 3B72244R 3B72244P 1MPC0302818 1MPC0403218 1NHA0300018 1SBF0402418 4000W4A003A 4000W4A004A 1SBF0302418 FAB30134901 1SZZW2E001A 1TCL0402622 Page 58 MICROWAVE OVEN
25. agnetron on and off magnetron warm up period of two seconds is included in each ON cycle Power Level Warm up Time On Time Off Time 0 magnetron is off 10 2 sec 2 sec 18 sec 20 2 sec 4 sec 16 sec 30 2 SEC 6 sec 14 sec 40 2 sec 8 sec 12 sec 50 2 SEC 10 sec 10 sec 60 2 sec 12 sec 8 sec 10 2 sec 14 sec 6 sec 80 2 sec 16 sec A sec 90 2 sec 18 sec 2 sec 100 magnetron is on Lower power levels can be used to thaw frozen items and to soften butter or margarine Intermediate power levels are used to cook foods more delicately than using high power 0 power can be used to insert standing time between two cook cycles such as between defrosting and cooking to allow the food to stand and defrost completely before beginning the cooking process m n LMVM2277ST Page 12 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN CARE and CLEANING Cleaning the oven is easy Always unplug the oven before cleaning the control panel to avoid touching too many buttons at once and damaging the microprocessor OVEN EXTERIOR To clean the outside of the oven use a soft cloth and spray glass cleaner Spray the glass cleaner onto the cloth rather than onto the oven DO NOT USE abrasive cleanser steel wool scrubbing pads gritty washcloths rough paper towers and those sorts of things They can damage the finish on your oven OVEN INTERIOR To clean the inside of the oven remember that it is easiest if you wipe out t
26. can result The manufacturer or seller maintains no liability for the interpretation of this information nor can it assume any liability in conjunction with its use When servicing this product under no circumstances should the original design be modified or altered without permission from LG Electronics Unauthorized modifications will not only void the warranty but may lead to property damage or user injury If wires screws clips straps nuts or washers used to complete a ground path are removed for service they must be returned to their original positions and properly fastened CAUTION To avoid personal injury disconnect the power before servicing this product If electrical power is required for diagnosis or test purposes disconnect the power immediately after performing the necessary checks Also be aware that many household appliances present a weight hazard At least two people should be involved in the installation or servicing of such devices Failure to consider the weight of an appliance could result in physical injury ESD NOTICE Some of the electronics in appliances are electrostatic discharge ESD sensitive ESD can weaken or damage the electronics in these appliances in a manner that renders them inoperative or reduces the time until their next failure Connect an ESD wrist strap to a ground connection point or unpainted metal in the appliance Alternatively you can touch your finger repeatedly to a ground connection point or
27. e connector and measure the resistance across the terminals using meter scale Rx1000 Normal 2 3 3 5 kO Defective any other reading Unplug the connector and read the resistance between the various terminals using meter scale Rx1 NORMAL TURBO Blue amp Black 4 20 Q HIGH Blue amp White 19 35 O MEDIUM Blue amp Gray 26 420 LOW Blue amp Brown 34 50 O DEFECTIVE Infinity The humidity sensor can be tested Unplug the three wire connector to the sensor at the circuit board end Set your ohm meter to Rx1000 The resistance should be as indicated on the table within 10 Infinite resistance or a dead short indicates a sensor failure 1 and 3 Black amp red 6 kQ 2 and 3 Red amp white 3 kO 1 and 2 Black amp white 3 kQ Page 31 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN STIRRER FAN MOTOR Remove the connector and measure the resistance across the terminals using meter scale Rx1000 Normal 120 135 Q Defective any other reading See page 21 The turntable left and stirrer fan motors right look similar but are not interchangeable The differences include rotation speed and shaft shape input voltage length and size T LMVM2277ST Page 32 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN MICROWAVE LEAKAGE TEST PROCEDURE If the oven is operational it should be checked for microwave leakage before servicing begins The standard for microwave emission is 5mW cm LG s volu
28. et an average 4 Place the 2 beakers side by side in the microwave making sure that the beakers are as near the center as possible If a shelf or rack is used place the rack at a level that will center the beakers in the oven cavity and place the beakers on the rack 5 Set the microwave oven for HIGH highest or 100 power level and set the cook time for 2 minutes Press the START button and heat the water for 2 minutes 6 After heating for 2 minutes immediately remove the beakers stir the water with the thermometer and record the water temperature of both beakers Note The average temperature rise of the water in the two beakers must be determined because of possible uneven power distribution within the oven cavity This could affect the ending temperatures of both beakers water If the water temperature in the 2 beakers differs add the two Celsius numbers and divide by 2 to get the average ending temperature LMVM2277ST Page 35 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN Example Starting Average Temperature of the 2 beakers 20 C Ending Temperature of the 1 beaker 36 52 C Ending Temperature of the 2 beaker 32 52 C POWER OUTPUT 1 Beaker 36 5 C ond Beaker 32 5 C Total 69 0 C Average the sum by dividing by 2 69 2 34 5 average temperature Subtract the starting Temperature 20 starting temperature 14 5 temperature rise To determine the power output multiply the temperature rise by 70
29. excluding the magnetron filament warm up time MENNA After inspecting or servicing the magnetron ensure the gasket is properly installed around the dome of the tube COOLING FIN EN Check for microwave leakage CHASSIS GROUND Sn following the procedure on page 33 CSS TERMINALS F n LMVM2277ST Page 34 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN MICROWAVE POWER ALTERNATE METHOD Several methods have been used to measure the output of microwave ovens over the past years In order to assure accuracy and consistency among the testers the following method is recommended The procedure is to measure and record the average Celsius temperature rise of 2 liters of water cooking on High Power for 2 minutes Then multiply the temperature rise by 70 to determine the power output REQUIREMENTS Microwave Power Output testing requires the ability of the technician to measure water temperature in degrees Celsius C to have two 2 one 1 liter plastic measuring beakers and a voltmeter that is capable of measuring 120 Vac with 1 volt accuracy EQUIPMENT Celsius thermometer Two 1 Liter Plastic Beakers Plastic does not absorb heat energy like glass AC Voltmeter TEST PROCEDURE 1 Fill both of the 1 liter beakers to the 1000 ml 1 Liter measuring line 2 Stir the water and determine that the tap water is cooler than 25 C record the temperature 3 If the temperatures differ add the 2 numbers and divide by 2 to g
30. he oven and clean any spatters as soon as the cooking is completed This prevents the spatters from being baked onto the oven surfaces during subsequent cooking Be especially careful to clean the area where the door closes and touches the frame of the oven For stubborn soils inside the oven put a large container of water in the oven and run the oven for 10 minutes A 2 cup microwave safe glass measuring cup works well for this The steam will soften soils and allow them to be wiped away with a damp towel If you cut up a lemon and put it into the water during the cooking your oven and entire kitchen will be citrusy fresh GREASE FILTERS The grease filters on the bottom of the oven should be removed and cleaned monthly Push the tab backward and allow the filters to drop out of their holders Clean them by swishing them in hot soapy water and rinsing them Shake them to dry them and replace them in their holders DO NOT OPERATE the oven without the grease filters in place a LMVM2277ST Page 13 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN CHARCOAL FILTER If the oven is vented to the outside the charcoal filter is not used Leaving it in place will not cause a problem If the oven recirculates the air back into the kitchen the charcoal filter should be replaced every 6 12 months It is not washable and must be replaced DO NOT OPERATE the oven without the charcoal filter in place unless of course the oven is vented
31. igh voltage transformer a A layer short circuit of the high voltage transformer may cause a low power output b If burned places are found in the high voltage transformer and a smell of burning insulation is sensed replace the high voltage transformer lf no other parts are defective and line voltage under a load is within tolerance replace the magnetron and retest LMVM2277ST Page 37 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN En erg CHECKOUT PROCEDURES BLOWN FUSE PROBLEM SOLUTION Fuse blows immediately when door is Improper operation of primary and closed secondary interlock switches and or monitor switch Check and adjust as Fuse blows immediately when door is necessary opened Fuse blows immediately when START Malfunction of high voltage transformer is pressed with door closed circuit including transformer diode Capacitor magnetron blower motor or main board MAIN PCB Printed Circuit Board The following symptoms indicate a defective main board 1 Input current of more than 20 amps If the input current is more than 20 amps check the magnetron and related wiring If the input current is less than 0 5 amps there is no input to the high voltage transformer 2 START fails but high voltage interlock switches door sensing and relay check good 3 Oven operates continuously with a normal relay 4 Buzzer sounds continuously or fails to sound 5 Segments of the LED display fail to
32. lowing points Meter scale Rx1 Filament terminals gt 1 Q Meter scale Rx1000 Filament to chassis Normal z infinity Page 27 TRAINING MANUAL LMVM2277ST CAPACITOR LMVM2277ST MICROWAVE OVEN Remove the wire leads They may be equipped with press tab releases Measure the resistance between the following points Meter scale Rx1000 Terminal to terminal Normally indicates several ohms then gradually drifts toward infinity Terminal to case Normal infinity The capacitor can be serviced while the oven is still mounted Remove the door See page 22 Remove a single screw and take off the cover that covers the capacitor Installed correctly the filament lead 3 Vpc and the high voltage diode are attached to the top terminal and the high voltage lead is attached to the bottom terminal MARK THESE at disassembly to avoid incorrect re assembly The capacitor can be removed through this opening by releasing the mounting bracket one screw at the top and pulling the entire assembly out through the access hole Page 28 TRAINING MANUAL LMVM2277ST RELAY LMVM2277ST MICROWAVE OVEN Test the relay by removing its connector and measuring the continuity between the terminals Operate the oven for 1 minute at power level 5 50 The relay should energize for 12 seconds and release for 10 ona continuous cycle You can check the relay more thoroughly by testing more than one power level See
33. nt or voltage or commercial use or use for other than intended purpose The cost of repair or replacement under these excluded circumstances shall be borne by the consumer CUSTOMER INTERACTIVE CENTER NUMBERS To obtain Customer Assistance Product Infor mation or Dealer or Authorized Service Center Call 1 800 243 0000 24 hours a day 365 days per year and select the appropriate option from the menu Or visit our website at http us lgservice com location TO CONTACT LG ELECTRONICS BY MAIL LG Customer Interactive Center P O Box 240007 201 James Record Road Huntsvile Alabama 35824 LMVM2277ST Page 6 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN GENERAL WARNINGS and SAFETY INFORMATION e Always unplug the oven to disassemble or repair it e Never operate the microwave oven when it is empty When cooking very small amounts of food put a glass of water in the cooking compartment e Do not operate the oven on a 2 wire extension cord during repair or use e Use proper ESD precautions when handling the PCB e Never put anything into the latch holes and interlock switches e Remove your watch before working on or around the magnetron e Do not operate the oven without the glass tray turntable in place Be sure the magnetron gasket is properly installed around the dome of the tube whenever installing the magnetron see magnetron section page 21 Always use a properly wired and grounded 3 wire dedica
34. ntary standard is much lower at 1mW cm A microwave leakage test MUST be performed after the oven is serviced for any reason Test for microwave emission using the following procedure Equipment microwave survey meter such as a Holaday HI 1500 or HI 1501 ora Narda 8100 or 8200 non conductive 600 cc beaker glass or plastic approximately 32 inches 900 mm in diameter glass thermometer 32 F to 212 F 0 C to 100 C in 1 graduations Procedure Pour 275115 cc of water into the beaker Verify the temperature to be 68 F 9 F 20 C 5 C Set the leakage meter to 2 450 MH Use the 2 inch 5b cm spacer Operate the oven at high maximum output Check for microwave emissions by holding the probe perpendicular a 90 angle to the surface and scanning less than 1 inch 2 5 cm per second in the area shown in the diagram m LMVM2277ST Page 33 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN MICROWAVE POWER TRADITIONAL METHOD Magnetron output and microwave power tend to deteriorate with age To determine whether an oven s output is within specification use the following formula and procedure FORMULA P 4 187 Mw T2 T1 0 55 Mc T2 T0 t P microwave power output in watts Mw mass of the water in grams Mc mass of the container in grams TO ambient temperature in C T1 initial temperature of the water in C T2 final temperature of the water in C t heating time in seconds
35. rate in a similar manner See the owners manual for complete operating instructions m F Fh LMVM2277ST Page 10 TRAINING MANUAL LMVM2277ST LMVM2277ST MICROWAVE OVEN When the oven is first plugged in or after a power failure the display will flash the message PLEASE SET THE TIME OF DAY If the time is not set the colon will display until you touch CLOCK To set the clock touch CLOCK the numbers 0 through 9 to set the time START and START again To operate the ventilation fan touch VENT ON OFF then touch or to adjust the speed To run the fan for a set period turn it on and set the desired speed as illustrated above Then touch AUTO TIME SET several times to increase the time before the fan Is turned off To toggle the CHILD LOCK feature ON or OFF touch and hold the START CHILD LOCK button for 5 seconds until a beep sounds The EZ ON button turns the oven on at full power for 30 seconds To cook for 2 minutes press it four times To use the timer without operating the oven press TIMER ON OFF the numbers of the time to set and TIMER ON OFF The timer will count down and beep at the end of the set period Page 11 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN POWER LEVELS Eleven power levels are available from 0 to 100 in 10 increments The magnetron output is not adjustable that is it is either on or off To achieve lower power levels a relay is used to cycle the m
36. re user serviceable The turntable rotating ring rectangular cooking tray and turntable drive cam are dishwasher safe and may be removed for cleaning Do not use abrasive cleansers Always run a microwave leak test If the oven is operational test it before and after the repair The Federal standard for leakage is less than 5 mW cm but LG s standard is less than 1 mW cm See the service manual for complete information regarding testing for microwave leakage TRAINING MANUAL LMVM2277ST MICROWAVE OVEN SPECIFICATIONS Rated Power Consumption Microwave Output Frequency Power Supply Rated Current Magnetron Cooling Rectification Door Ceiling Safety Devices Magnetron Cooktop Lamps Cavity Lamp Timer Tray Cavity Capacity Accessories 1 700 W max MWO lights fan 1 100 W IEC 60705 2 450 MHz 50 MHz 120 V ac 600 14 5 Amps MWO lights fan Forced Air Cooling Voltage Double Half Wave Choke System Magnetron Thermostat Open 145 C 5 C 293 F 9 F Close 60 C 5 C 140 F 9 F Oven Thermostat Open 110 C 5 C 230 9 P Close 0 C 5 C 82 F 9 P Ambient Oven Thermistor Open 82 C 5 C 180 F 9 F Close 54 C 5 C 130 F 9 F Fuse 20 Amps Primary Interlock Switch secondary Interlock Switch Interlock Monitor Switch 2M282H Toshiba 12 V 10 W Halogen 12 V 20 W Halogen Digital to 99 99 in each cooking stage Tempered Safety Gla
37. ss 2 2 CU ft Owner s manual cooking guide exhaust adapter exhaust damper mounting kit filter rotating ring assembly glass tray metal rack defrost plate SWITCH CHART Switch Mode Primary Secondary Monitor Conditions COM COM NO NO OPEN OPEN Door Closed CLOSE CLOSE LMVM2277ST Page 5 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN WARRANTY LG MICROWAVE OVEN LIMITED WARRANTY USA Model LMVM2277ST LG Electronics Inc will repair or replace your product at LG s option if it proves to be defective in material or workmanship under normal use during the warranty period set forth below effective from the date of original consumer purchase of the product This warranty is good only to the original purchaser of the product and effective only when used in the United States including U S Territories WARRANTY PERIOD LABOR One Year from the Date of Purchase PARTS except as listed below One Year from the Date of Purchase HOW SERVICE IS HANDLED Please call 1 800 243 0000 and choose the appropriate option Phones are answered 24 hours a day 365 days per year Please have the product type Microwave and your ZIP code ready MAGNETRON Ten Years from the Date of Purchase Replacement Units and Repair Parts are warranted for the remaining portion of the original unit s warranty period Retain your Sales Receipt to prove the date of purchase A copy of your Sales Receipt m
38. ted outlet to power the oven 120 Vac 20 A Never cut the ground prong off the plug or otherwise defeat the grounding of this appliance LMVM2277ST Page 7 ANTENNA COOLING FIN MAGNETRON FILAMENT CHASSIS GROUND TERMINALS Prong Properly Polarized and Grounded Outlet TRAINING MANUAL LMVM2277ST MICROWAVE OVEN OVEN INSTALLATION OUTLET in cabinet The LMVM2277ST must be properly installed before operation Installation includes mounting the bracket on the wall with toggle bolts and or lag bolts and drilling holes in the cabinet above the oven to Upper Mounting Bolt Toggle Inside wall Bolt accommodate the electric cord di and the upper mounting bolts _ Damper Flap Es IE A template is provided for Mounting II locating the holes properly Bracket The ventilation fan can exhaust air in any of three directions through the back wall through the roof or recirculated through the charcoal filter into the kitchen If the air is vented through a duct to the outside the damper and flap must be installed T LMVM2277ST Page 8 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN TURNTABLE INSTALLATION The turntable is a multi part arrangement that includes a round glass tray that rotates and a rectangular glass tray that moves laterally at the same time Smaller dishes sit on the round tray while they rotate and move laterally larger dishes sit on the rectangular tray
39. the chart on page 12 Unplug the fan connector and measure the resistance between the terminals Terminal A Red Terminal B Brown Terminal C Yellow A C 12 160 A B 9 230 Other readings or infinite resistance indicates a motor failure Unplug the transformer connector and measure the resistance between the terminals Terminal A Red Terminal B Black Terminal C White A C 18 300 A B 18 300 Page 29 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN HIGH VOLTAGE DIODE Measure the continuity in both EE directions using meter scale Rx1000 FO o Forward Normal continuity RI Defective infinity Reverse Normal infinity Defective continuity CAUTION Be sure to discharge the capacitor before attempting to disconnect it or testing the diode Set the meter for VOLTSpc and connect the diode in series with a 9 volt battery Test in both directions The diode should pass current in one direction but not the other The simplest solution is to replace it with a known good diode This photo shows the diode connected with 9 Vpc applied to the cathode The meter reads 0 00 Vpc because the diode is blocking the flow This photo shows the diode s forward bias with 9 Vpc connected to the anode m HH LMVM2277ST Page 30 TRAINING MANUAL LMVM2277ST TURNTABLE MOTOR m Los VENTILATION FAN MOTOR LMVM2277ST MICROWAVE OVEN Remove th
40. to the outside The charcoal filter part number is 5230W1A0003A Remove the two screws at the top of the oven housing These are the two middle screws If the oven is properly installed these screws will be accessible in front of the edge of the cabinet Remove the wire cover It is a small plastic guide that fits with the vent grille on the left end It can be pulled out through the top when the door is closed Open the door and tip the vent grille forward Lift it out to remove it mr Remove the old filter and replace it with a new one It is not reusable nn LMVM2277ST Page 14 TRAINING MANUAL LMVM2277ST MICROWAVE OVEN OVEN LIGHT REPLACEMENT To replace the oven cooking cavity light remove the vent grille screws the two middle ones and take out the wire cover Open the door and tip the vent grille forward Lift it out to remove it This procedure is illustrated on the previous page Push the metal tab of the lampholder off the plastic tab and pull the lamp and holder out Replace the bulb and reinstall the holder The lampholder tab rests against a plastic tab on the oven vent housing It is a simple snap fit Push it aside to remove or replace the lamp assembly Lift out the lamp holder which includes the bulb and the socket which is attached to the reflector with two bolts Do not touch the bulb with your fingers Use a clean protective cloth or paper towel The bulb can be replaced
41. uquos pieoq noua peog uno MO A A jeunong N NOLLONN AJH 1Hv LS QHVO8 A34 HONOL L 359u5 E peuonoi si fex LHW LS ueuw umopjunoo urs jou seop ejdsi g W318OHd Check the continuity of connector CN3 between pins 1 PK pink and 3 BL POWER BUT DOESN T RUN black when the door is closed CHART B TRAINING MANUAL Page 42 LMVM2277ST LMVM2277ST MICROWAVE OVEN TROUBLESHOOTING FLOW CHARTS continued CHART C RUNS BUT NO HEAT Check to make sure the fan motor runs when START ENTER is pressed If the fan doesn t run check the resistance of the fan motor Pins A and C 160 20 Pins AandB 110 20Q If the fan motor is defective it will also affect the stirrer fan motor because the center tap of the main fan motor provides the 21 Vac supply for the stirrer fan LMVM2277ST magnetron ar amp EY N gt n Li Jj j Replace fan motor Normal fan motor Normal circuit board g I Replace circuit board Auns Runs Huns Normal resistance Replace H V C o MC Normal r sistance aga Resistance incorrect T gt PNE Resistance incorrect Measure resistance of fan motor Measure resistance of H V capacitor see page 14 Terminal A C 12 to 16 ohms Terminal A B 9 to 13 ohms Normal operation No operalion no heating is produced in oven load PROBLEM C Unit operation seems to be normal but Check 1
42. ust be submitted at the time warranty service Is provided Or visit our website at http us lgservice com THIS WARRANTY IS IN LIEU OF ANY OTHER WARRANTY EXPRESS OR IMPLIED INCLUDING WITHOUT LIMITATION ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE TO THE EXTENT ANY IMPLIED WARRANTY IS REQUIRED BY LAW IT IS LIMITED IN DURATION TO THE EXPRESS WARRANTY PERIOD ABOVE LG WILL NOT BE LIABLE FOR ANY INCIDENTAL CONSEQUENTIAL INDIRECT SPECIAL OR PUNITIVE DAMAGES OF ANY NATURE INCLUDING WITHOUT LIMITATION LOST REVENUES OR PROFITS OR ANY OTHER DAMAGE WHETHER BASED IN CONTRACT TORT OR OTHERWISE Some states do not allow the exclusion or limitation of incidental or consequential damages or limitations on how long an implied warranty lasts so the above exclusion or limitation may not apply to you This warranty gives you specific legal rights and you may also have other rights that vary from state to state THIS LIMITED WARRANTY DOES NOT APPLY TO e Service trips to your home to deliver pick up and or install the product instruct or replace house fuses or correct wiring or correction of unauthorized repairs e Damages or operating problems that result from misuse abuse operation outside environmental specifications or contrary to the requirements of precautions in the Operating Guide accident vermin fire flood improper installation acts of God unauthorized modification or alteration incorrect electrical curre
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