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LG MB-4342A Service Manual
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LG MB-4342A Service Manual

LG MB-4342A Service Manual

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MICROWAVE OVEN
SERVICE MANUAL
MODEL: MB-4342A
MH-6342A
CAUTION
BEFORE SERVICING THE UNIT, READ THE
SAFETY PRECAUTIONS IN THIS MANUAL.

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Summary of Contents for LG MB-4342A

  • Page 1 MICROWAVE OVEN SERVICE MANUAL MODEL: MB-4342A MH-6342A 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 MB-4342A / MH-6342A Power Requirement 230 Volts AC 50 Hz Single phase, 3 wire grounded Microwave 1,200W Grill 1,100W Combination 2,250W Power Output 800 Watts full microwave power (IEC 60705) Microwave Frequency 2,450 MHz Magnetron 2M214 - 39F Timer 90 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 Display Window Control Panel Safety Door Lock System Glass Tray Grill Rack Rotating Ring CONTROL PANEL 1. INDICATORS 2. SET CLOCK: Used to set the time of day. 3. MICRO: Used to select the desired power level for microwave cooking.

  • Page 8: Operating Sequence

    OPERATING SEQUENCE The following is a description of component functions 6. GRILL COOKING during oven operation. Desired 1. SETTING THE CLOCK Stop Grill Start cooking Time Set the Touch 7. COMBINATION COOKING Stop clock correct hour start Desired Desired Stop combi Start Touch...

  • Page 9: Schematic Diagram

    SCHEMATIC DIAGRAM...

  • Page 10: Circuit Description

    CIRCUIT DESCRIPTION power of microwave oven as POWER LEVEL. GENERAL DETAILS (refer to page 1-1) • The low voltage transformer supplies the necessary voltage to the micom controller when power cord is WHEN THE DOOR IS OPENED DURING plugged in. COOKING •...

  • 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 with 4187 X (∆T) + 0.55 X (T ) X M a load of (1000±5) g of potable water.
  • Page 14 D. DOOR GROSS ASSEMBLY REMOVAL E. HIGH VOLTAGE TRANSFORMER 1) Open the door. REMOVAL 2) Remove the choke cover cap very carefully with a 1) Discharge the high voltage capacitor. flat-blade screwdriver. 2) Disconnect the leadwire from magnetron, high voltage CAUTION : Be careful not to damage door seal plate transformer, and capacitor.
  • Page 15 H. AIR DUCT ASSEMBLY REMOVAL J. REMOVING THE TURNTABLE MOTOR 1) Disconnect the leadwire from lamp. 1) Remove the turntable. 2) Remove the Rotating Ring. 2) Remove the mounting screw to Latch Board. 3) Lay the unit down on its back. 4) Remove the turntable motor cover.
  • 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-62 OR VP-532A-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 COMPONENTS TEST PROCEDURE RESULTS Disconnect the 8 pin Cooking Start connector from P.C.B. (Refer to schemetic diagram on page 4-3) Cooking Start Relay 3 RELAY 2, RELAY 3 OF P.C.B. (Wire leads removed.) Note: Relay Relay 1: Fan motor Turntable motor Oven lamp Relay 2: Microwave Relay 2...

  • Page 22: 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 23 (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 24 (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 25 (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 26 (TROUBLE 5) No microwave oscillation even though oven lamp and fan motor run (Display operates properly) CONDITION CHECK RESULT CAUSE REMEDY Defective P.C.B No microwave Disconnect the Replace P.C.B No continuity. oscillation. wire leads from assembly assembly relay 2 and check continuity Continuity.
  • Page 27 (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 28: Exploded View

    EXPLODED VIEW INTRODUCTION OVEN CAVITY PARTS INTERIOR PARTS BASE PLATE PARTS DOOR PARTS LATCH BOARD PARTS CONTROL PANEL PARTS...
  • Page 29 DOOR PARTS 13581A 15006A 13536A 13552A 13213A 13720D 13352A 14026A 14970A...
  • Page 30 CONTROL PANEL PARTS 24781M 268711 23550D 23572A WTP015 26638A...
  • Page 31 OVEN CAVITY PARTS 33808A WTT021 33112U WTT021 35264A 33550H WNZ015 33052M 340511 35026G 33390G 35300S 34370T WSZ184 36549S 35889A WTP013...
  • Page 32 LATCH BOARD PARTS WSZ085 466001 43501A 43500A 466003 44510A 466001...
  • Page 33 INTERIOR PARTS 568771 WSZ062 56411A 56930V 56930G 50FZZA WTT028 56201A 56549F 54974S WSZ112 55900A WTT037 56912B WSZ002 50CZZH 55262A 56851D WSZ002 WTT028 54810C 34930W 56324A 948502 WSZ002...
  • Page 34 BASE PLATE PARTS 56170D 63302A 63303A 948501 WTT021 65006B WSZ002...

  • Page 35: Schematic Diagram Of P.c.b

    SCHEMATIC DIAGRAM OF P.C.B...

  • Page 36: Printed Circuit Board

    PRINTED CIRCUIT BOARD...
  • Page 37 Jan., 2003 P/NO : 3828W5S2647 Printed in Korea...
  • Page 38 EXPLODED VIEW INTRODUCTION OVEN CAVITY PARTS INTERIOR PARTS BASE PLATE PARTS DOOR PARTS LATCH BOARD PARTS CONTROL PANEL PARTS...
  • Page 39 DOOR PARTS 13581A 15006A 13536A 13552A 13213A 13720D 13352A 14026A 14970A...
  • Page 40 CONTROL PANEL PARTS 24781M 268711 23550D 23572A WTP015 26638A...
  • Page 41 OVEN CAVITY PARTS 33808A WTT021 33112U WTT021 35264A 33550H WNZ015 33052M 340511 35026G 33390G 35300S 34370T WSZ184 36549S 35889A WTP013...
  • Page 42 LATCH BOARD PARTS WSZ085 466001 43501A 43500A 466003 44510A 466001...
  • Page 43 INTERIOR PARTS 568771 WSZ062 56411A 56930V 56930G 50FZZA WTT028 56201A 56549F 54974S WSZ112 55900A WTT037 56912B WSZ002 50CZZH 55262A 56851D WSZ002 WTT028 54810C 34930W 56324A 948502 WSZ002...
  • Page 44 BASE PLATE PARTS 56170D 63302A 63303A 948501 WTT021 65006B WSZ002...
  • Page 45 Sales Model Loc No. C/Part No Description MB-4342A 3828W5A2947 MANUAL,OWNERS MB-4342A 3828W5S2647 MANUAL,SERVICE MB-4342A 3878W5B0013 COOK BOOK MB-4342A 3890W3W330A BOX,WHITE MB-4342A 13213A 3213W1A027G DOOR FRAME ASSY MB-4342A 13352A 3352W1A108N FRONT SCREEN MB-4342A 13536A 3536WRA001J SEAL TAPE MB-4342A 13536A 3536WRA001J SEAL TAPE...
  • Page 46 MB-4342A 56912B 6912W3B002D LAMP[OVEN/BASELESS] MB-4342A 56912B 6912W3B002D LAMP[OVEN/BASELESS] MB-4342A 56912B 6912W3B002D LAMP[OVEN/BASELESS] MB-4342A 56930G 6930W1A003C THERMOSTAT MB-4342A 56930G 6930W1A003C THERMOSTAT MB-4342A 56930V 6930W1A003A THERMOSTAT MB-4342A 56930V 6930W1A003A THERMOSTAT MB-4342A 63302A 3302W0A018A BASE PLATE MB-4342A 63303A 3303W1A043A BASE PLATE ASSY MB-4342A...
  • Page 47 MB-4342A 0DD400209AA DIODE,RECTIFIERS MB-4342A 0DD400209AA DIODE,RECTIFIERS MB-4342A 0DD414809AA DIODE,SWITCHING MB-4342A 0DD414809AA DIODE,SWITCHING MB-4342A 0DD414809AA DIODE,SWITCHING MB-4342A 0DD414809AA DIODE,SWITCHING MB-4342A 0DD414809AA DIODE,SWITCHING MB-4342A 0DD414809AA DIODE,SWITCHING MB-4342A 0DD414809AA DIODE,SWITCHING MB-4342A 0DD414809AA DIODE,SWITCHING MB-4342A 0DD414809AA DIODE,SWITCHING MB-4342A 0DLZZW5A01B LED,DRAWING MB-4342A 0DLZZW5A01B LED,DRAWING MB-4342A...
  • Page 48 MB-4342A R117 0RD1000F608 RESISTOR,FIXED CARBON FILM MB-4342A R117 0RD1000F608 RESISTOR,FIXED CARBON FILM MB-4342A R117 0RD1000F608 RESISTOR,FIXED CARBON FILM MB-4342A R120 0RD2001F608 RESISTOR,FIXED CARBON FILM MB-4342A R120 0RD2001F608 RESISTOR,FIXED CARBON FILM MB-4342A R120 0RD2001F608 RESISTOR,FIXED CARBON FILM MB-4342A R121 0RD2001F608 RESISTOR,FIXED CARBON FILM...
  • Page 49 MB-4342A 0RD1001G608 RESISTOR,FIXED CARBON FILM MB-4342A 0RD1001G608 RESISTOR,FIXED CARBON FILM MB-4342A 0RD1001G608 RESISTOR,FIXED CARBON FILM MB-4342A 0RD4702F608 RESISTOR,FIXED CARBON FILM MB-4342A 0RD4702F608 RESISTOR,FIXED CARBON FILM MB-4342A 0RD4702F608 RESISTOR,FIXED CARBON FILM MB-4342A 0RD4702F608 RESISTOR,FIXED CARBON FILM MB-4342A 0RD4702F608 RESISTOR,FIXED CARBON FILM...
  • Page 50 MB-4342A WTT028 1TTL0402818 SCREW TAPPING,TRUSS HEAD MB-4342A WTT028 1TTL0402818 SCREW TAPPING,TRUSS HEAD MB-4342A WTT028 1TTL0402818 SCREW TAPPING,TRUSS HEAD MB-4342A WTT037 1TTL0403818 SCREW TAPPING,TRUSS HEAD MB-4342A WTT037 1TTL0403818 SCREW TAPPING,TRUSS HEAD MB-4342A WTT037 1TTL0403818 SCREW TAPPING,TRUSS HEAD MB-4342A 0DZ510009AE DIODE,ZENERS MB-4342A...
  • Page 51 Spec Level MB-4342A BWT-RUSSIA RUSSIAN MB-4342A BWT-RUSSIA ENGLISH A4 MB-394AA MC-783RC CIS RUSSIAN MB-4342A MB-4342A BWT-RUSSIA LG RUSSIA W 0.7CU.FT BLACK PAINT(E.D) SCP PC CLEAR HMB-392A_LGEES LGENE 150*259 150*259 0.7CU.FT MS-194 PP LGECW BLACK(CAP ONLY) WHITE BWT-RUSSIA MB-4342A LGECW ABS HG-173 03587 BLUE WHITE HMS-392A STARCO LGE...
  • Page 52 24025W-25 DUKWOO/KYUNGJUN 240V 25W CLEAR 24025W-25 DUKWOO/KYUNGJUN 240V 25W CLEAR 24025W-25 DUKWOO/KYUNGJUN 240V 25W CLEAR 145 /60 KSD-WI HORIZONTAL 125V/15A, 250V/10A [CHIN 145 /60 KSD-WI HORIZONTAL 125V/15A, 250V/10A [CHIN 90 /75 KSD-WI HORIZONTAL 125V/15A, 250V/10A [CHINA 90 /75 KSD-WI HORIZONTAL 125V/15A, 250V/10A [CHINA MS-192A,SBHG1-R,0.7T,CW MS-192A,LGECW MS-193XD,XR-401-9001,LEG,BK...
  • Page 53 1N4002 TP KEC - - - - - - 1N4002 TP KEC - - - - - - 1N4148 TP GRANDE - - - - - - 1N4148 TP GRANDE - - - - - - 1N4148 TP GRANDE - - - - - - 1N4148 TP GRANDE - - - - - - 1N4148 TP GRANDE - - - - - - 1N4148 TP GRANDE - - - - - -...
  • Page 54 100 OHM 1/6 W 5.00% TA26 100 OHM 1/6 W 5.00% TA26 100 OHM 1/6 W 5.00% TA26 2K OHM 1/6 W 5.00% TA26 2K OHM 1/6 W 5.00% TA26 2K OHM 1/6 W 5.00% TA26 2K OHM 1/6 W 5.00% TA26 2K OHM 1/6 W 5.00% TA26 2K OHM 1/6 W 5.00% TA26 2K OHM 1/6 W 5.00% TA26...
  • Page 55 4.7K OHM 1/6 W 5.00% TA26 4.7K OHM 1/6 W 5.00% TA26 JQ1A-12V,MATSUSHITA G5G-1A-DT1-LG OMRON DC12V 41.7MA 250V 16A 288 OHM G5G-1A-DT1-LG OMRON DC12V 41.7MA 250V 16A 288 OHM G5G-1A-DT1-LG OMRON DC12V 41.7MA 250V 16A 288 OHM G5G-1A-DT1-LG OMRON DC12V 41.7MA 250V 16A 288 OHM...
  • Page 56 + 2 CUT D4.0 L12.0 MSWR3/FZY + 2 CUT D4.0 L12.0 MSWR3/FZY + 2 CUT D4.0 L12.0 MSWR3/FZY + 2 CUT D4.0 L28.0 MSWR3/FZY + 2 CUT D4.0 L28.0 MSWR3/FZY + 2 CUT D4.0 L28.0 MSWR3/FZY UZ5.1BS TP26 SM 0.5W UZ5.1BS TP26 SM 0.5W 5.6V 0.5W SMALL(0.5PITCH) TP PYUNG CHANG - - - - -...

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