LG LMVM2075SB Service Manual Download

Page: 31 / 44

7-20

(2)CHECKOUT PROCEDURES FOR RELAY.

-PROBLEM (A)-

FAN motor turns on without touching START key

when the door is closed.

-PROBLEM (B)-

FAN motor turns on When the door is closed and

START key is touched.

GOOD

Remove the mate connector of I/O
CON from the circuit board.
Does the unit still operate?

Defective

Wire Assembly

Replace the
circuit board

Replace

Wire Assembly

YES

-PROBLEM (A)--

Oven lamp turns on without touching START key

when the door is closed.

GOOD

Remove the mate connector of I/O
CON from the circuit board.
Does the unit still operate?

Defective

Wire Assembly

Replace the
circuit board

Replace

Wire Assembly

YES

GOOD

Measure the voltage at pin NO.
1, 6 of CN1
Voltage reading: 120 V AC

Replace the
circuit board

Defective
FAN motor

YES

Replace

FAN motor.

-PROBLEM (B)-

Oven lamp turns on When the door is closed and

START key is touched.

GOOD

Measure the voltage at pin NO.
1,4 of CN1
Voltage reading: 120 V AC

Replace the
circuit board

Defective
Oven lamp

YES

Replace

Oven lamp

Summary of Contents for LMVM2075SB

Page 1: ...VE OVEN SERVICE MANUAL MODEL LMVM2075SB LMVM2075ST LMVM2075SW CAUTION BEFORE SERVICING THE UNIT READ THE SAFETY PRECAUTIONS IN THIS MANUAL Website http us lgservice com P NO MFL06272503 February 2007 Printed in Korea ...

Page 2: ...roper 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 manual before the oven is released to the owner e A Microwave leakage check to verify compliance with the Federal performance standard should be performed on ea...

Page 3: ...VERALL CIRCUIT DIAGRAM 5 1 SCHEMATIC DIAGRAM 5 1 MATRIX CIRCUIT FOR TOUCH KEY BOARD 5 2 GENERAL INFORMATION FOR SERVICE 6 1 GENERAL PRECAUTIONS IN USE 6 1 TRIAL OPERATION 6 1 FEATURES AND SPECIFICATIONS FEATURES 6 1 SERVICE INFORMATION 7 1 PRECAUTIONS AND REPAIR SERVICE TIPS 7 1 MICROWAVE LEAKAGE TEST 7 2 POWER OUTPUT MEASUREMENT 7 3 DISASSEMBLY INSTRUCTIONS 7 4 INTERLOCK SYSTEM 7 12 INTERLOCK CON...

Page 4: ...itor Switch Magnetron 2M282J Toshiba Cook top Lamp 12 VAC 20 W Halogen Cavity Lamp 125 V 30 W or 40 W Timer Digital up to 99 min in each cooking stage Tray Tempered Safety Glass Overall Dimensions 2915 16 W x167 16 H x155 8 D Oven Cavity Size 231 2 W x10 H x141 2 D Effective Capacity of Oven Cavity 2 0 Cu ft Accessories Owner s Manual Cooking Guide Installation Manual Exhaust Adapter Exhaust Dampe...

Page 5: ...TOUCH any oven components or wiring during operation BEFORE TOUCHING any parts of the oven always remove the power plug from the outlet 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 ...

Page 6: ...io 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 CAUTION This unit is equipped with a 3 prong plug for your safety If the wall outlet is a grounded 3 hol...

Page 7: ...4 1 OPERATING INSTRUCTIONS CONTROL PANEL 14 16 27 24 22 19 17 12 15 18 20 21 23 26 25 13 11 10 1 6 9 8 7 3 5 4 2 ...

Page 8: ...pad to cook chicken wings chicken nugget spicy chicken and Mexican chicken 11 HOLD WARM Touch this pad to keep hot cooked foods warm in your microwave oven for up to 90 minutes 12 EZ ON Touch this pad to set and start quickly at 100 power level 13 CUSTOM SET Touch this pad to change the oven s default setting for sound clock disply speed and defrost weight 14 CLOCK Touch this pad to enter the time...

Page 9: ...5 1 OVERALL CIRCUIT DIAGRAM SCHEMATIC DIAGRAM ...

Page 10: ... STOP N C CLEAR ENTER START REHEAT HI LOW OFF COOK HOLD LIGHT AUTO DEFROST 8 9 0 TIME DEFROST MORE SOFTEN LESS MELT COOK TIME 2 3 N C 4 N C N C 5 6 N C 7 CHICKEN CHOICES CUSTOM SET N C POWER LEVEL AUTO TIME SET EZ ON QUICK DEFROST TIMER CUSTOM COOK KEY MATRIX 9 13 12 11 10 8 1 2 3 4 5 6 7 ...

Page 11: ...the cavity light comes on The unit will begin cooking and the display window will show the time counting down by seconds D After about 5 minutes make sure the primary interlock switch the secondary interlock switch and the interlock monitor switch operate properly by opening and closing the door several times Press the DIAL key each time the door is closed E Continue operating the unit For long be...

Page 12: ...w the limit of 5 mW cm2 All service adjustments should be made for minimum microwave energy leakage readings 3 Do not operate the unit until it is completely repaired if any of the following conditions exist The unit must not be operated a The door does not close firmly b The hinge is broken c The door seal is damaged d The door is bent or warped or there is any other visible damage on the unit th...

Page 13: ...servicing The power density of the microwave radiation leakage emitted by the microwave oven should not exceed 1mW cm sq And always start measuring of an unknown field to assure safety for operating personnel from radiation leakage NOTE The standard is 5mW cm sq while in the customer s home 1mW cm sq stated here is manufacturer s own voluntary standard for units in customer s home EQUIPMENT TESTER...

Page 14: ... this manual have been used 3 At least once a year have the electromagnetic energy leakage monitor checked for calibration by its manufacturer POWER OUTPUT MEASUREMENT 1 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 2 The water is contained in a cylindrica...

Page 15: ...D Figures 1 2 and 3 1 Remove a screw securing the control panel assembly to the oven cavity 2 Remove the control panel with pushing it upward 3 Remove the connectors CN1 CN3 CN6 CN7 and wire leads 3 Tap Power Relay RY8 from the circuit board 4 Remove 3 screws securing the circuit board Power Transformer Control Panel Screw Circuit Board CN3 RY8 3 Tap Power Relay CN1 CN7 CN6 Circuit Board Control B...

Page 16: ... INSERT THE F P C CONNECTOR Follow the steps below as illustrated in Figures 6 and 7 to insert the F P C connector 1 Insert the F P C connector into the terminal socket securely with the fingers 2 Hold the plastic fastener with thumb and forefinger of the other hand and push it slowly into the terminal socket Figure 6 NOTE When reconnecting the F P C connector make sure that the holes on the F P C...

Page 17: ...ounting plate by turning the screws 1 or 2 screws securing it to the out case 4 Remove two screws on the left central edge and two screws on the right central edge of Base plate Remove the Mount All from the out case by removing one screw securing it to the out case 5 Remove four screws of the rear cavity 6 Remove the outcase with disconnecting power cord connector Figure 8 ...

Page 18: ...interlock switches 2 Remove two screws securing the Latch Board 3 Make necessary replacements and check microwave energy leakage according to ADJUSTMENT PROCEDURES on page 7 12 WIRE COLOR SYMBOL COLOR WH WHITE BK BLACK BR BROWN RD RED YL YELLOW PK PINK BL BLUE GY GREY GN GREEN N P Not Provided ...

Page 19: ... the magnetron make sure that its dome does not hit any adjacent parts or it may be damaged 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 After replacing the magnetron check for microwave energy leakage with a survey meter Check microwave energy leakage must be below the limit of 5 mW cm2 All service ad...

Page 20: ...d draw the door NOTES After replacing the door be sure to check that the primary interlock switch the secondary interlock switch and the interlock monitor switch is in good operating normally After replacing the door check for microwave energy leakage with a survey meter Microwave energy leakage must be below the limit of 5mW cm2 With a 275 ml water load G DISASSEMBLING DOOR Figure 16 1 Remove the...

Page 21: ...s not mounted properly microwaves may leak from the clearance between the door and the oven I REMOVING THE VENTILATION MOTOR 1 Remove the mounting plate by loosening mounting plate screws 1 or 2 screws securing it to the back plate See Figure 17 2 Remove MOUNT ALL loosening two screw loosening two screw securing the ventilation Motor and back plate See Figure 18 a 3 Carefully pull the ventilation ...

Page 22: ...Disconnect the leadwire from the turntable motor terminals 5 Remove the 1 screws securing the turntable motor to the oven cavity ASS Y Figure 21 NOTES Remove the leadwire from the turntable motor VERY CAREFULLY Be sure to grasp the connector not the wires when removing K REPLACING THE HUMIDITY SENSOR 1 Remove the sensor by removing two screws securing it to the air duct See Figure 22 2 Mount the n...

Page 23: ... microwave oven on its side so that you can see the latch board and the switches as shown in Figure 23 a 2 Close the door tightly and check gaps A and B to be sure they are no more than 1 64 0 5 mm See Figure 23 b for close up view of gaps A and B door latches If all gaps are less than 1 64 0 5 mm adjustment of the latch board may not be necessary Go to Steps 5 and 6 to check the sequence of the s...

Page 24: ...ro to the body of the switches in the following sequence Interlock Monitor Switch Primary Interlock Switch Secondary Interlock Switch NOTE The Interlock Monitor Switch is an added safety check on the Primary and Secondary Interlock Switches If the Primary and Secondary Interlock Switches allow the oven to operate with the door open the Monitor Switch will blow the fuse 7 When you achieve the prope...

Page 25: ... When the secondary switch operation is abnormal make the necessary adjustment or replace the switch only with the same type of switch C MONITOR SWITCH TEST Disconnect the wire lead from the monitor switch Connect the ohmmeter leads to the common COM and normally closed NC terminals of the switch The meter should indicate closed circuit in the door open condition When the door is closed meter shou...

Page 26: ...eads 2 Measure resistance ohm meter scale Rx1 Primary winding High Low Secondary winding Filament winding 3 Measure resistance ohm meter scale Rx1000 Primary winding to ground Filament winding to ground 1 Remove wire leads Install the magnetron seal in the correct position Check that the seal is in good condition 2 Measure resistance ohm meter scale Rx1 Filament terminal 3 Measure resistance ohm m...

Page 27: ...scale Rx1000 CAPACITOR DIODE Some inexpensive ohm meters may indicate infinite resistance in both directions 1 Measure continuity ohm meter scale Rx1 2 Remove the lead wires and operate oven at power level 1 through power level 10 RELAY 8 1 Remove wire leads 2 Measure resistance ohm meter scale Rx1 Normal Approximately Terminal 35 to 50 ohms Terminal 5 to 15 ohms Abnormal Infinite or several FAN M...

Page 28: ... 0 ohm 1 Remove lead wires 2 Measure resistance ohm meter scale Rx1 1 Remove wire leads 2 Measure resistance ohm meter scale Rx1000 VENTILATION MOTOR TURNTABLE MOTOR 1 Disconnect sensor connector from micom computer board 2 Measure resistance terminal to terminal ohm meter scale R X 1000 ABSOLUTE HUMIDITY SENSOR 1 Remove lead wires 2 Measure resistance ohm meter scale Rx1000 Normal Approximately 1...

Page 29: ...plastic fastener MATRIX CIRCUIT FOR TOUCH KEY BOARD CONNECTOR KEY CON TOUCH KEY BOARD Resistance value When touched Less than 400 ohms When not touched More than 1 mega ohm FPC CONNECTOR Top NOTES A MICROWAVE ENERGY 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...

Page 30: ...JUSTMENT PROCEDURES on page 7 12 when the primary interlock secondary interlock switches and or the interlock monitor switches are adjusted or replaced Fuse blows immediately after the door is closed Fuse blows immediately after the door is opened Fuse blows when the door is closed and START ENTER key is touched Improper operation of the primary interlock secondary interlock switches and or the in...

Page 31: ...without touching START key when the door is closed GOOD Remove the mate connector of I O CON from the circuit board Does the unit still operate Defective Wire Assembly Replace the circuit board Replace Wire Assembly NO NO YES YES GOOD Measure the voltage at pin NO 1 6 of CN1 Voltage reading 120 V AC Replace the circuit board Defective FAN motor YES NO NO YES Replace FAN motor PROBLEM B Oven lamp t...

Page 32: ...t the high voltage Systems the interlock switches the door sensing and the relay check good 3 The unit with a normal relay continuously operates 4 The buzzer does not sound or continues to sound 5 Some segments of one or more digits do not light up or they continue to light up or segments light when they should not 6 Wrong figures appear 7 The figures of all digits 8 The clock does not keep time p...

Page 33: ...hru E BUZZER Problems F PROBLEM A PLEASE SET TIME OF DAY does not appear in display window when power supply cord is plugged into wall outlet PROBLEM B Display does not show correct numbers and or correct indications when programmed Check 1 POWER SUPPLY 2 FUSE See CHECKOUT PROCEDURES FOR FUSE BLOWING on page 7 19 3 OVEN CAVITY THERMOSTAT 1 1 ...

Page 34: ...EM E Display does not start countdown when START key is touched Check 1 TOUCH KEY BOARD START KEY FUNCTION Check 1 AIR VENTS PROBLEM D Unit operation seems to be normal but no heating is produced in oven load 1 1 ...

Page 35: ...7 24 PROBLEM E Unit does not heat up even if display counts down when START key is touched for HIGH POWER cooking Check 1 PRIMARY AND SECONDARY INTERLOCK SWITCHES 2 THERMOSTAT 1 2 ...

Page 36: ...7 25 PROBLEM F No buzzing when touching the key between stages or at end of cooking 1 PROBLEM G Ventilation fan does not operate when VENT ON OFF key is touched 1 Check 1 POWER SUPPLY 2 FUSE ...

Page 37: ...04 13651A 13651A For Model LMVM2075SW For Model LMVM2075SB For Model LMVM2075SW 13650A For Model LMVM2075SB For Model LMVM2075SB LMVM2075SB 01 LMVM2075SW LMVM2075SW 01 Check the Rating Model No For Model LMVM2075SB 02 Check the Rating Model No LMVM2075SW 02 For Model LMVM2075ST LMVM2075ST 01 Check the Rating Model No For Model LMVM2075ST 02 Check the Rating Model No 268771 268711 268771 268711 EV ...

Page 38: ...8 2 CONTROLLER PARTS 24781M 24781M 23572A 23551A 24810P 07 07 268712 WTP015 24810P 268712 WTP015 EV FOR MODEL LMVM2075SB LMVM2075SW FOR MODEL LMVM2075ST ...

Page 39: ...l LMVM2075ST 33531A 33530A 34960A 63302A 36912H 34931A 33550P 33112U 34810Q 34930R 35026G WTP033 WTP005 WTT025 35230A 330342 330341 33550L WTT029 WTT027 WTT029 WTT028 WTT027 For Model LMVM2075SW For Model LMVM2075SB LMVM2075ST WTT027 WTT029 WTT029 WTT027 63303A EV ...

Page 40: ...8 4 LATCH BOARD PARTS 44510A 43501A 43500A 466001 466001 466003 WSZ085 EV ...

Page 41: ...RTS I Back 33390G 55893A 55892A 54930F 53550F 36549S 35012A 56324A 56851D 55238A 54974S 56549F 56170D WTT037 WTT028 WSZ002 55900A 50CZZH 54810C WTT021 56930M 53301A WTP013 WTT028 WTT028 WTT021 340511 33700A 33391E EV ...

Page 42: ...8 6 INTERIOR PARTS II 56804A 56912B 53550L 568772 568774 36549V WTT028 WTP005 568773 56501A 56549B 56201A 50CZZM 568771 56411A 50FZZA 55262A 55231C 56930V WSZ062 56010L WTT024 EV ...

Page 43: ...8 7 INSTALLATION PARTS 01 USE CARE 07 TECHNICAL CARD 02 05 COOKING GUIDE LABEL 06 TEMPLATE 04 INSTALLATION MANUAL SVC MANUAL 63300M 63861A 65862B 65862D EV ...

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