background image

MICROWAVE OVEN

SERVICE MANUAL

MODEL: MV1502W

MV1502B

CAUTION

BEFORE SERVICING THE UNIT, READ THE 

SAFETY PRECAUTIONS

IN THIS MANUAL.

Website: http://us.lgservice.com 

P/NO : 3828W5S4060

June, 2004

Printed in Korea

Summary of Contents for MV1502B

Page 1: ...MICROWAVE OVEN SERVICE MANUAL MODEL MV1502W MV1502B CAUTION BEFORE SERVICING THE UNIT READ THE SAFETY PRECAUTIONS IN THIS MANUAL Website http us lgservice com P NO 3828W5S4060 June 2004 Printed in Korea ...

Page 2: ... 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 manual before the oven is released to the owner e A Microwave leakage check to verify compliance with the CSA Standard should be performed on each oven prior ...

Page 3: ...ALL 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 CONTIN...

Page 4: ...tat Open at 90 C 5 C Fuse 20A Primary Interlock Switch Secondary Interlock Switch Interlock Monitor Magnetron 2M214 39F High Voltage Capacitor Capacitor 1 0µF 2 1 KV AC High Voltage Diode Diode 350mA 9 0 KV Cook top Lamp 125 V 30 W Cavity Lamp 125 V 30 W Timer Digital up to 99 mim 99 sec in each cooking stage Tray Tempered Safety Glass Overall Dimensions 2915 16 W x167 16 D x153 8 H Oven Cavity Si...

Page 5: ...per 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 CAUTIONS Unlike other appliances the microwave oven is high voltage and high current equipment Though it is free from...

Page 6: ... 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 INSTALLATIONS BEFORE YOU BEGIN READ THE FOLLOWING INSTRUCTIONS COMPLETELY AND CAREFULLY CAUTION This unit is equipped with a 3 prong plug for your safety If the wall outlet is a grounded 3 hole type the unit will be grounded aut...

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

Page 8: ...ME DEFROST Touch this pad to defrost most other frozen foods 11 Number 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 select a cooking power level 14 custom set Touch this pad to change the oven s default settings for sound clock display speed defrost weight and demo mode operations 15 KIT...

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

Page 10: ...5 2 MATRIX CIRCUIT FOR TOUCH KEY BOARD CUSTOM SET AUTO COOK TIME COOK KITCHEN TIMER POWER LEVEL N C N C Ez On CLOCK STOP CLEAR TIME DEFROST AUTO DEFROST AUTO REHEAT ...

Page 11: ...ght 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 Touch the START key each time the door is closed E Continue operating the unit Two short and a long be...

Page 12: ...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 that may cause microwa...

Page 13: ...e microwave oven should not exceed 4 mW cm2 Always start measuring of an unknown field to assure safety for operating personnel from radiation leakage EQUIPMENT TESTER VOLTS DC AC Ohmmeter Microwave survey meter Holaday HI 1500 HI 1501 Narda 8100 8200 600 cc non conductive material beaker glass or plastic inside diameter approx 8 5 cm 3 1 2 in Glass thermometer 100 C or 212 F 1 deg scale MEASURING...

Page 14: ...energy leakage not be more than 2 mW cm2 after determining that all parts are in good condition functioning properly and genuine replacement parts which are listed in this manual have been used 3 At least once a year have the electromagnetic energy leakage monitor checked for calibration by its manufacturer 1 Microwave power output measurement is made with the microwave oven supplied at its rated ...

Page 15: ...ERALL CIR CUIT DIAGRAM ESPECIALLY SWITCHES AND HIGH VOLTAGE CIRCUIT A REMOVING POWER AND CONTROL CIRCUIT BOARD 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 connector CN1 and wire leads Relay6 from the circuit board 4 Remove 2 screws securing the circuit board 5 Remove the FPC connector from ...

Page 16: ...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 connector are properly engaged with the hooks on the plastic fastener 3 Lock the level of the plastic fastener into the hoo...

Page 17: ... Remove the base plate by removing six screws securing it to the out case Remove the Mount All from the out case by removing two screws securing it to the out case and one screw securing it to the ventilation motor ASS Y and cavity 6 Remove the power cord cover from outcase by removing a screw 7 Remove the power cord to the inner of the out case with turning power cord and remove the out case with...

Page 18: ... 7 12 Latch Board WH from H V Transformer WH from Monitor S W WH from Oven Thermostat WH from Cooktop lamp Secondary Interlock Switch Monitor Interlock Switch Primary Interlock Switch GN from P C B YL from P C B WH from Secondary switch RD from Ry 7 Latch Board Secondary Interlock Switch Interlock Monitor Switch Primary Interlock Switch WIRE COLOR SYMBOL COLOR WH BK BR RD BL PK GY N P WHITE BLACK ...

Page 19: ...s 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 adjustments should be made for minimum microwave energy leakage reading...

Page 20: ...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 F DISASSEMBLING DOOR Figure 15 1 Remove the dielectric choke by using knife blade or small screw driver etc 2 Remove two screws securing it to the door handle CAUTION Be careful not to damage door s...

Page 21: ...mounted properly microwaves may leak from the clearance between the door and the oven H REMOVING THE VENTILATION FAN ASS Y 1 Remove the mounting plate by removing two screws securing it to the back plate See Figure 16 2 Remove the two screws securing the MOUNT ALL and one screw securing the ventilation fan ASS Y See Figure 17 3 Carefully pull the ventilation motor ASS Y out of the microwave oven S...

Page 22: ...6 screws securing it to the oven cavity Figure 20 4 Disconnect the leadwire from the turntable motor terminals 5 Remove the 2 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 Wire Leads Turntable Motor Figure 19 Figure 20 Figure 21 ...

Page 23: ...justment of the latch board may not be necessary Go to Steps 5 and 6 to check the sequence of the switches NOTE To correct sequence of the Primary Interlock Switch Secondary Interlock Switch and the Interlock Monitor Switch is very important If any gap is larger than 1 64 0 5 mm you will need to adjust the latch board Go to step 3 and follow all steps in order ADJUST THE LATCH AND SWITCH CLOSING 3...

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

Page 26: ...re leads are removed HIGH VOLTAGE TRANSFORMER Wire leads are removed 1 Measure the resistance Across the filament terminals of the magnetron with an ohm meter on Rx1 scale 2 Measure the resistance Between each filament terminal of the magnetron and the chassis ground with an ohm meter on high test scale 1 Measure the resistance With an ohm meter on Rx1 scale a Primary winding b Filament winding c ...

Page 27: ...omentarily indicates several ohms and then gradually returns to infinite ohms Abnormal reading Indicates continuity or infinite ohms from the beginning Normal readings Infinite Abnormal reading Indicates continuity Normal readings continuity Abnormal reading Infinite Normal readings Infinite Abnormal reading continuity Ohm meter Ohm meter Ohm meter Ohm meter Figure 25 a Figure 25 b Figure 26 a Fig...

Page 28: ...gaged with hooks on the plastic fastener MATRIX CIRCUIT FOR TOUCH KEY BOARD CONNECTOR KEY CON For detail matrix circuit of each model refer to page 5 2 FPC CONNECTOR Top Resistance value When touched Less than 400 ohms When not touched More than 1 mega ohm Figure 27 CUSTOM SET AUTO COOK TIME COOK KITCHEN TIMER POWER LEVEL N C N C Ez On CLOCK STOP CLEAR TIME DEFROST AUTO DEFROST AUTO REHEAT 1 2 3 4...

Page 29: ...E BLOWING CAUTION REPLACE BLOWN FUSE WITH 20 AMPERE FUSE NOTES If the fuse is blown by an improper switch operation replace the all Interlock switches PCB Ass y and the fuse at the same time After replacing the the all Interlock switches PCB Ass y Fuse with new ones make sure that they are correctly connected Check for microwave energy leakage according to interlock adjustment procedures on page 7...

Page 30: ...d Does the unit still operate Replace the circuit board Replace RELAY3 NO NO YES YES GOOD Defective RELAY3 PROBLEM B TT motor and oven lamp turn on When the door is closed and START key is touched Measure the voltage at pin NO 4 of U01 Voltage reading 0 Vdc Replace the circuit board Defective RELAY3 or poor connection of RELAY3 Replace RELAY3 or correct the connection YES NO NO YES GOOD ...

Page 31: ...usly operates 3 Proper temperature measurement is not obtained 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 Some of the indicators do no flicker light up 9 The clock does not keep time properly NOTE A MICROWAVE ENERGY LE...

Page 32: ... 2 FUSE See CHECKOUT PROCEDURES FOR FUSE BLOWING on page 7 18 3 OVEN CAVITY THERMOSTAT 1 1 WH RD Measure voltage between pin 1 and pin 3 of connector CN1 Runs Runs 0 120 0 120 120V Replace circuit board Normal resistance Voltage incorrect Correct connections Normal circuit board Runs Runs Runs Measure resistance of touch key board after removing connector S1 See page 7 4 and 7 17 Normal resistance...

Page 33: ...circuit board Contact OK Normal contact Correct seating Check contact of connector S1 Check the contact of relay 6 see page 7 18 NO continuity Resistance incorrect Check the continuity of H V C see page 7 16 Normal H V T Resistance incorrect Normal H V C Abnormal Replace H V D Normal Magnetron Replace Magnetron Normal Normal H V D Check the continuity of H V D see page 7 16 Replace H V C Normal re...

Page 34: ...7 23 PROBLEM D No buzzing when touching the key between stages or at end of cooking 1 Normal circuit board Check normal operation circuit board Replace circuit board Runs ...

Page 35: ...K NO contact Replace oven thermostat Poor contact Replace circuit board Normal circuit board Contact OK Normal contact Correct seating Check contact of connector S1 see page 7 4 Replace ventilation motor ASS Y NO runs Normal ventilation motor ASS Y Check the contact of oven thermostat Check 1 POWER SUPPLY 2 FUSE ...

Page 36: ...8 1 EXPLODED VIEW DOOR PARTS 13581A 13552A 13536A 13213A 14890A 13720D 13650A 14970A 14026A WTT028 ...

Page 37: ...8 2 CONTROLLER PARTS 24810P 23572A 23506A 07 268711 24781M WTP018 WTT029 ...

Page 38: ...N CAVITY PARTS 36912C 33550L 63302A WTT022 WTT028 368771 56804A WTT029 34810T 33530A 34890C WTT022 35230A 63303A 34810Q 34960A WTT021 02 01 04 05 WTT027 WTT029 For model MV1502A 33112U WTT027 For model MV1502B ...

Page 39: ...8 4 LATCH BOARD PARTS 466001 43500A 466003 466001 44510A 43501A WSZ084 ...

Page 40: ...8 5 INTERIOR PARTS I WTT021 56170D 33390G 34370T 35889A 36549S WTP013 WTT021 33740A 54810C 50CZZH WSZ002 56851D WSZ002 53300A 53300B 33052A 56324A WSZ002 ...

Page 41: ...8 6 INTERIOR PARTS II 36549V 56912B 53550L 55262A 55231C 56804A WTT028 WSZ002 56930V 55006F 50FZZA 568771 56411A ...

Page 42: ...8 7 INSTALLATION PARTS 63300M 65862D 65862B VINYL BAG 63861A ...

Page 43: ......

Reviews: