LG MS-304W Service Manual
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LG MS-304W Service Manual

LG MS-304W Service Manual

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MICROWAVE OVEN
SERVICE MANUAL
MODEL: MS-304W
MS-304WB
MS-304WG
MS-304WS
CAUTION
BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.

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Summary of Contents for LG MS-304W

  • Page 1 MICROWAVE OVEN SERVICE MANUAL MODEL: MS-304W MS-304WB MS-304WG MS-304WS CAUTION BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.

  • Page 2: Safety Precautions

    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...

  • Page 3: Table Of Contents

    CONTENTS (Page) SAFETY PRECAUTIONS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Inside front cover SPECIFICATIONS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1-1 CAUTIONS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2-1 INSTALLATIONS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3-1...

  • Page 4: Specifications

    SPECIFICATIONS ITEM DESCRIPTION MODEL MS-304W / MS-304WB / MS-304WG / MS-304WS Power Requirement 230 Volts AC 50 Hz Single phase, 3 wire grounded Microwave 1,300W Power Output 900 Watts full microwave power (IEC60705) Microwave Frequency 2,450 MHz Magnetron 2M214 - 39F, 2M254J Timer 0 ~ 99 min.

  • Page 5: Cautions

    CAUTIONS Unlike other appliances, the microwave oven is MICROWAVE RADIATION high-voltage and high-current equipment. Personnel should not be exposed to the Though it is free from danger in ordinary use, microwave energy which may radiate from the extreme care should be taken during repair. magnetron or other microwave generating device if it is improperly used or connection.

  • Page 6: Installations

    INSTALLATIONS BEFORE YOU BEGIN, READ THE FOLLOWING INSTRUCTIONS COMPLETELY AND CAREFULLY. INSTALLING EARTHING INSTRUCTIONS 1. Empty the microwave oven and clean inside it with This microwave oven is designed to be used in a fully a soft, damp cloth. Check for damage such as earthed condition.

  • Page 7: Operating Instructions

    OPERATING INSTRUCTIONS FEATURES Oven Front Plate Window Door Screen Door Seal Key pad Safety Door Lock System Turntable Rotating Ring CONTROL PANEL 1. AUTO WEIGHT DEFROST: Used to select the auto weight defrost. 2. AUTO COOK: Used to select the auto cook. 3.

  • Page 8: Operating Sequence

    Operating Sequence The following is a description of component functions 5. CHILD LOCK during oven operation. This oven has a CHILD LOCK feature. To Set CHILD LOCK 1. SETTING THE CLOCK Stop/Clear Stop/Clear (Touch and Hold) Desired Stop/Clear Clock hour To Cancel CHILD LOCK Desired Stop/Clear...

  • Page 9: Schematic Diagram

    SCHEMATIC DIAGRAM...

  • Page 10: Circuit Description

    CIRCUIT DESCRIPTION GENERAL DETAILS WHEN THE OVEN IS SET AT ANY LEVEL • The low voltage transformer supplies the necessary EXCEPT MAXIMUM. voltage to the micom controller when power cord is • The micom controller controls the ON-OFF time of plugged in.

  • Page 11: Service Information

    SERVICE INFORMATION TOOLS AND MEASURING INSTRUMENTS NECESSARY TOOLS NECESSARY MEASURING INSTRUMENTS Tools normally used for TV servicing are sufficient. • TESTER(VOLTS-DC, AC., Ohmmeter) Standard tools are listed below. • Microwave survey meter • Diagonal pliers - Holaday HI-1500 • Long nose pliers HI-1501 •...
  • Page 12 MEASUREMENT WITH OUTER CASE NOTES WHEN MEASURING REMOVED • Do not exceed meter full scale deflection. • The test probe must be removed no faster than • When you replace the magnetron, measure for 1 inch/sec (2.5 cm/sec) along the shaded area, microwave energy leakage before the outer case is otherwise a false reading may result.

  • Page 13: Measurement Of Microwave Power Output

    MEASUREMENT OF MICROWAVE POWER OUTPUT • Microwave power output measurement is made with • The microwave power output P in watts is calculated the microwave oven supplied at its rated voltage and from the following formula: operated at its maximum microwave power setting 4187 X (∆T) + 0.55 X (T ) X M with a load of (1000 ±...
  • Page 14 D. DOOR GROSS ASSEMBLY REMOVAL F. AIR DUCT ASSEMBLY REMOVAL 1) Open the door. 1) Disconnect the leadwire from lamp and MGT 2) Remove the choke cover very carefully with a flat- thermostat. blade screwdriver. 2) Remove the mounting screw to the magnetron. CAUTION : Be careful not to damage door seal plate by screwdriver.
  • Page 15 H. FAN MOTOR ASSEMBLY REMOVAL J. THE TURNTABLE MOTOR REMOVAL 1) Remove the turntable. 1) Discharge the high voltage capacitor. 2) Remove the turntable shaft VERY CAREFULLY 2) Disconnect the leadwire from fan motor, noise filter with a slotted screwdriver. and high voltage capacitor.
  • Page 16 K. PCB ASSEMBLY REMOVAL L. INTERLOCK SYSTEM 1) Remove the control panel assembly from the 1) INTERLOCK MECHANISM cavity. (Refer to control panel assembly removal The door lock mechanism is a device which has on previous page.) been specially designed to eliminate completely 2) Remove screws which hold the PCB SUB ASS’Y to microwave activity when the door is opened during the control panel.

  • Page 17: Interlock Continuity Test

    INTERLOCK CONTINUITY TEST WARNING : FOR CONTINUED PROTECTION AGAINST EXCESSIVE RADIATION EMISSION, REPLACE ONLY WITH IDENTICAL REPLACEMENT PARTS. TYPE NO. SZM-V 16-FA-63 OR VP-533A-OF FOR PRIMARY SWITCH TYPE NO. SZM-V 16-FA-61 OR VP-531A-OF FOR MONITOR SWITCH TYPE NO. SZM-V 16-FA-63 OR VP-533A-OF FOR SECONDARY SWITCH B.

  • Page 18: Component Test Procedure

    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.
  • Page 19 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 then...
  • Page 20 COMPONENTS TEST PROCEDURE RESULTS FUSE Check for continuity of the fuse with an Normal Abnormal multi-meter. NOTE: If the fuse is blown, check the primary, the secondary, and the monitor switches, H.V.D. and H.V.C. before replacing the fuse. If the fuse is blown by improper switch operation replace the defective switch and the fuse at the same time.

  • Page 21: Trouble Shooting

    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.
  • Page 22 (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.) 2. Colon does not turn on or blink. 3. A distinct change in the brightness of one or more numbers in display. 4.
  • Page 23 (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 Replace primary Malfunction of the Check continuity 1. Fuse blows. Continuity. and monitor monitor switch. of monitor switches.
  • Page 24 (TROUBLE 3) Display shows all figures set, but oven does not start cooking while desired program times are set and START pad is touched. CONDITION CHECK RESULT CAUSE REMEDY Defective Replace Check continuity 1.Setting time does No continuity. secondary switch. secondary switch.
  • Page 25 (TROUBLE 5) No microwave oscillation even though oven lamp and fan motor run (Display operates properly) CONDITION CHECK RESULT CAUSE REMEDY No microwave Disconnect the Defective P.C.B Replace P.C.B No continuity. oscillation. wire leads from assembly assembly relay 2 and check continuity Continuity.
  • Page 26 (TROUBLE 6) Oven does not cook properly when programmed for the set power level (Operates properly on HIGH) CONDITION CHECK RESULT CAUSE REMEDY Output is full when Defective P.C.B. Replace P.C.B. Disconnect the Abnormal. you set lower assembly. assembly. wire leads from power level.

  • Page 27: Exploded View

    EXPLODED VIEW INTRODUCTION OVEN CAVITY PARTS INTERIOR PARTS DOOR PARTS BASE PLATE PARTS LATCH BOARD PARTS CONTROL PANEL PARTS...
  • Page 28 DOOR PARTS 13581A 15006A 13552A 13536A 13213A 14890A 13720D 14026A 14970A...
  • Page 29 CONTROL PANEL PARTS 24781M WTP004 268711 23572A WTP015 23506A...
  • Page 30 OVEN CAVITY PARTS WTT021 33112U WTT010 33052A 33390G 34960A 34370T 35889A 36549S WTP013...
  • Page 31 LATCH BOARD PARTS WSZ085 43501A 466001 466003 466001 43500A 44510A...
  • Page 32 INTERIOR PARTS 568771 WSZ062 56411A 56930V 948502 50FZZA WTT028 56201A 56549F WSZ002 55900A WTT037 54974S 50CZZH 56851D 56912B WSZ002 WSZ002 WSZ002 948501 55262A 34930W WTT028 54810C 56324A 948504 WSZ002...
  • Page 33 BASE PLATE PARTS 56170D 63302A 63303A 948503 647781 WSZ002 WTT030 WTT021...

  • Page 34: Replacement Parts List

    REPLACEMENT PARTS LIST For MODEL: MS-304W LOC. PART NO. DESCRIPTION ALTER 3828W5A2742 MANUAL,OWNERS 3828W5S2207 MANUAL,SERVICE 13213A 3213W1A028K DOOR FRAME ASSEMBLY 13536A 3536WRA001L SEAL TAPE 13552A 3552W1A037A CHOKE COVER 13581A 3581W1A324E DOOR ASSEMBLY 13720D 3720W0D232B PANEL,DOOR 14026A 4026W2A015A LATCH 14890A 4890W1A001D...
  • Page 35 For MODEL: MS-304W LOC. PART NO. DESCRIPTION ALTER WSZ085 4B70188C SCREW,DRAWING WTP004 1TPL0302418 SCREW TAPPING,PAN HEAD WTP013 1TPL0402418 SCREW TAPPING,PAN HEAD WTP015 1TPL0402618 SCREW TAPPING,PAN HEAD WTT010 1TTG0402422 SCREW TAPPING,TRUSS HEAD WTT021 1TTL0402418 SCREW TAPPING,TRUSS HEAD WTT028 1TTL0402818 SCREW TAPPING,TRUSS HEAD...
  • Page 36 For MODEL: MS-304WB LOC. PART NO. DESCRIPTION ALTER 3828W5A2742 MANUAL,OWNERS 3828W5S2207 MANUAL,SERVICE 13213A 3213W1A028K DOOR FRAME ASSEMBLY 13536A 3536WRA001L SEAL TAPE 13552A 3552W1A037A CHOKE COVER 13581A 3581W1A324K DOOR ASSEMBLY 13720D 3720W0D232H PANEL,DOOR 14026A 4026W2A015A LATCH 14890A 4890W1A001D GLASS 14970A 4970WRA001C SPRING 15006A 5006W3A017A...
  • Page 37 For MODEL: MS-304WB LOC. PART NO. DESCRIPTION ALTER WSZ085 4B70188C SCREW,DRAWING WTP004 1TPL0302418 SCREW TAPPING,PAN HEAD WTP013 1TPL0402418 SCREW TAPPING,PAN HEAD WTP015 1TPL0402618 SCREW TAPPING,PAN HEAD WTT010 1TTG0402422 SCREW TAPPING,TRUSS HEAD WTT021 1TTL0402418 SCREW TAPPING,TRUSS HEAD WTT028 1TTL0402818 SCREW TAPPING,TRUSS HEAD WTT030 1TTL0403118 SCREW TAPPING,TRUSS HEAD...
  • Page 38 For MODEL: MS-304WG LOC. PART NO. DESCRIPTION ALTER 3828W5A2742 MANUAL,OWNERS 3828W5S2207 MANUAL,SERVICE 13213A 3213W1A028K DOOR FRAME ASSEMBLY 13536A 3536WRA001L SEAL TAPE 13552A 3552W1A037A CHOKE COVER 13581A 3581W1A324L DOOR ASSEMBLY 13720D 3720W0D232J PANEL,DOOR 14026A 4026W2A015A LATCH 14890A 4890W1A001D GLASS 14970A 4970WRA001C SPRING 15006A 5006W3A017A...
  • Page 39 For MODEL: MS-304WG LOC. PART NO. DESCRIPTION ALTER WSZ085 4B70188C SCREW,DRAWING WTP004 1TPL0302418 SCREW TAPPING,PAN HEAD WTP013 1TPL0402418 SCREW TAPPING,PAN HEAD WTP015 1TPL0402618 SCREW TAPPING,PAN HEAD WTT010 1TTG0402422 SCREW TAPPING,TRUSS HEAD WTT021 1TTL0402418 SCREW TAPPING,TRUSS HEAD WTT028 1TTL0402818 SCREW TAPPING,TRUSS HEAD WTT030 1TTL0403118 SCREW TAPPING,TRUSS HEAD...
  • Page 40 For MODEL: MS-304WS LOC. PART NO. DESCRIPTION ALTER 3828W5A2742 MANUAL,OWNERS 3828W5S2207 MANUAL,SERVICE 13213A 3213W1A028K DOOR FRAME ASSEMBLY 13536A 3536WRA001L SEAL TAPE 13552A 3552W1A037A CHOKE COVER 13581A 3581W1A324M DOOR ASSEMBLY 13720D 3720W0D232K PANEL,DOOR 14026A 4026W2A015A LATCH 14890A 4890W1A001D GLASS 14970A 4970WRA001C SPRING 15006A 5006W3A017A...
  • Page 41 For MODEL: MS-304WS LOC. PART NO. DESCRIPTION ALTER WSZ085 4B70188C SCREW,DRAWING WTP004 1TPL0302418 SCREW TAPPING,PAN HEAD WTP013 1TPL0402418 SCREW TAPPING,PAN HEAD WTP015 1TPL0402618 SCREW TAPPING,PAN HEAD WTT010 1TTG0402422 SCREW TAPPING,TRUSS HEAD WTT021 1TTL0402418 SCREW TAPPING,TRUSS HEAD WTT028 1TTL0402818 SCREW TAPPING,TRUSS HEAD WTT030 1TTL0403118 SCREW TAPPING,TRUSS HEAD...

  • Page 42: Schematic Diagram Of P.c.b

    SCHEMATIC DIAGRAM OF P.C.B...

  • Page 43: Printed Circuit Board

    PRINTED CIRCUIT BOARD...

  • Page 44: P.c.b Parts List

    P.C.B PARTS LIST LOC. PART NO DESCRPTION SPECIFICATION ALTER 6908W3YA01C BUZZER TFM-57 CW NINGBO EAST PIEZO 2048HZ 70D 6908W3YA01A 0CE4776H618 CAPACITOR,FIXED ELECTROLYTIC 470UF SMS,SG 25V 20% FL TP 5 0CE4776H618 CAPACITOR,FIXED ELECTROLYTIC 470UF SMS,SG 25V 20% FL TP 5 0CE1076D638 CAPACITOR,FIXED ELECTROLYTIC 100UF SMS,SG 10V 20% FM5 TP 5 0CK2230K948...
  • Page 45 LOC. PART NO DESCRPTION SPECIFICATION ALTER Q121 0TRAU90018A TRANSISTOR,BIPOLARS AUK KOREA 2SA1980G-AT TP TO92M 50V 150MA 0TRFC80002A Q121 0TRAU90018A TRANSISTOR,BIPOLARS AUK KOREA 2SA1980G-AT TP TO92M 50V 150MA 0TR126609AA Q122 0TRAU90018A TRANSISTOR,BIPOLARS AUK KOREA 2SA1980G-AT TP TO92M 50V 150MA 0TRFC80002A Q122 0TRAU90018A TRANSISTOR,BIPOLARS AUK KOREA 2SA1980G-AT TP TO92M 50V 150MA 0TR126609AA...
  • Page 46 4.7K OHM 1/4 W 5% TA26 6920WRD008A RELAY JQ1A-12V MATSUSHITA 250VAC 5A 12VDC 1A N 6920W2D010B 6920W5A012A RELAY G5G-1A-DT1-LG OMRON 250VAC 16A 12VDC 1A 0IZZW5A179A IC,DRAWING TMP87CH47U 44PIN, QFP BK LOCAL(SA,AU) MS 0DZ510009CA DIODE,ZENERS UZ5.1B PNONEC TP NONE 1.5V NONE NONE NON...
  • Page 47 May, 2002 P/NO : 3828W5S2207 Printed in Korea...

This manual is also suitable for:

Ms-304wbMs-304wgMs-304ws

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