LG MD-2642KT Service Manual
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LG MD-2642KT Service Manual

LG MD-2642KT Service Manual

Lg md-2642kt microwave oven service manual
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MICROWAVE OVEN

SERVICE MANUAL
MODEL : MD-2642KT
CAUTION
BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
Website http://biz.lgservice.com

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  • Page 1: Microwave Oven

    Website http://biz.lgservice.com MICROWAVE OVEN SERVICE MANUAL MODEL : MD-2642KT 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 MD-2642KT MODEL 230/240 Volts AC 50 Hz Power Requirement 1,250 Watts Single phase, 3 wire grounded Microwave oven 900 Watts full microwave power (IEC60705) Power Output Toaster 800 Watts 2,450 MHz Microwave Frequency 2M214-39F Magnetron 0 ~ 99 min. 99 sec.

  • 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 GROUNDING INSTRUCTIONS 1. Empty the microwave oven and clean inside it with For personal safety, this appliance must be fully a soft, damp cloth. Check for damage such as grounded at all times.

  • Page 7: Operating Instructions

    OPERATING INSTRUCTIONS FEATURES Control Easy-Clean See-Through Door Panel Oven Cavity Glass Turntable Toaster Indicator Light Slots Toaster Door Crumb Rotating Ring Tray Microwave Oven Toaster Safety Interlock System CONTROL PANEL MICROWAVE CONTROL AREA 1. DISPLAY. The Display includes a clock and indicators that tell 6.
  • Page 8 MICROWAVE OVEN TOASTER (1) KITCHEN TIMER (1) TOAST 1. Touch STOP/CLEAR. 1. Touch STOP/CLEAR. 2. Touch KITCHEN TIMER. 2. Touch TOAST. 3. Touch correct number for time. 3. Touch Darkness Control (1~9 step) 4. Touch START. 4. Touch START. (2) CHILD LOCK (2) BAGEL To set: 1.

  • Page 9: Schematic Diagram

    SCHEMATIC DIAGRAM FUSE 250V, 10A...

  • Page 10: Circuit Description

    CIRCUIT DESCRIPTION GENERAL DETAILS • A high voltage of approximately 2100 volts AC is • The low voltage transformer supplies the necessary generated in the secondary of the high voltage voltage to the micom controller when power cord is transformer which is increased by the action of the high 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: Precautions On Installation

    PRECAUTIONS ON INSTALLATION TRIAL OPERATION (Figure 2) After installation, the following sequences and results A. Plug the power supply cord into a 250 V AC, 50 Hz, should be checked carefully. single-phase power source with a capacity of at Microwave Oven least 10 amperes.

  • Page 13: Record Keeping And Notification After Measurement

    MEASUREMENT WITH OUTER CASE • Microwave energy leakage must not exceed the values prescribed below. REMOVED NOTE: Leakage with the outer case removed less than 5 • When you replace the magnetron, measure for microwave mW/cm.sq. Leakage for a fully assembled oven energy leakage before the outer case is installed and after (Before the latch switch (primary) is interrupted) with all necessary components are replaced or adjusted.

  • Page 14: Disassembly And Adjustment

    DISASSEMBLY AND ADJUSTMENT A. REMOVING OUT CASE (Figures 7) Remove screw (1) Remove four screws from the rear section. securing (2) Remove one screw from the side section. screw (3) Push the outer case back about 1 inch (3cm). (4) Lift the case from the set. Lift up and pull out toaster assembly Figure 7 B.
  • Page 15 C. DOOR GROSS ASSEMBLY Remove choke cover cap REMOVAL (1) Open the door. (2) Remove the choke cover cap very carefully with a flat- blade screwdriver. CAUTION : Be careful not to damage door seal plate by screwdriver. (3) Lift up and push the door. NOTE: 1.
  • Page 16 D. MAGNETRON REMOVAL E. REMOVING THE TURNTABLE (Figure 10) MOTOR (Figure 11) (1) Disconnect the wire lead from the magnetron. 1) Remove the turntable and rotating ring. 2) Lay the unit down on its back. (2) Carefully remove the mounting screws holding the 3) Remove the turntable motor cover.

  • Page 17: Diode Removal

    F. HIGH VOLTAGE TRANSFORMER I. INTERLOCK SYSTEM REMOVAL 1) INTERLOCK MECHANISM The door lock mechanism is a device which has 1) Discharge the high voltage capacitor. been specially designed to eliminate completely 2) Disconnect the leadwire from magnetron, high voltage microwave activity when the door is opened during transformer, and capacitor.

  • Page 18: 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 OR V-5230Q FOR PRIMARY SWITCH TYPE NO. SZM-V 16-FA-62, VP-532A-OF OR V-5220Q FOR MONITOR SWITCH TYPE NO. SZM-V 16-FA-63 OR VP-533A-OF OR V-5230Q FOR SECONDARY SWITCH A.

  • Page 19: 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 20 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 1. Check DC 9V battery before performing Normal: Approximately 9V CAPACITOR tests.
  • Page 21 COMPONENTS TEST PROCEDURE RESULTS STEP 1. Test the diode to see if it is shorted. H.V.Diode (rectifer) Procedure: 1. Select the Ω scale on the meter. 2. Place the meter leads across the diode as pictured in Figure 14-a. The reading should be “40MΩ,”...

  • Page 22: Test Procedure

    COMPONENTS TEST PROCEDURE RESULTS 1. Measure continuity. RELAY 2 POWER (Power Relay) 2. Remove the lead wires and operate oven LEVEL at power level 1 through power level 10. 4 sec 18 sec 6 sec 16 sec 8 sec 14 sec 10 sec 12 sec 12 sec...
  • Page 23 B. CHECKOUT PROCEDURES (1) CHECKOUT PROCEDURES FOR FUSE BLOWING CAUTION: REPLACE BLOWN FUSE WITH 10 AMPERE FUSE. PROBLEMS CAUSES Fuse blows immediately after Improper operation of the primary interlock, the door is closed. secondary interlock switches and/or the interlock monitor switch. Fuse blows immediately after the door is opened.
  • Page 24 (2) CHECKOUT PROCEDURES FOR RELAY Microwave Oven Toaster - PROBLEM (A) - - PROBLEM (A) - FAN motor and oven lamp turn on without touching FAN motor and indicator light turn on without START key when the door is closed. touching START key when the door is closed.
  • Page 25 (3) CHECKOUT PROCEDURES FOR CIRCUIT BOARD The following symptoms indicate a defective circuit (4) Some segments of one or more digits do not light board. up, or they continue to light up, or segments light (1) The start function fails to operate but the high when they should not.

  • Page 26: Trouble Shooting

    C. 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 TOASTER AND MICROWAVE OVEN. THIS CAN ELIMINATE AN UNNECESSARY SERVICE CALL. CAUTIONS 1.
  • Page 27 (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 28 (TROUBLE 2) Microwave oven does not operate at all, Display window does not display any figures, and no input is accepted. CONDITION CHECK RESULT CAUSE REMEDY Malfunction of the Replace fuse, Check continuity 1. Fuse blows. Continuity. monitor switch. primary, monitor of monitor switches, and switch (with...
  • Page 29 (TROUBLE 3) Display shows all figures set, but microwave 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 No continuity. secondary switch. secondary switch.
  • Page 30 (TROUBLE 5) No microwave oscillation even though oven lamp and fan motor run. (Display operates properly) CONDITION CHECK RESULT CAUSE REMEDY No microwave Defective PCB Replace PCB Disconnect the No continuity. oscillation. assembly. assembly. wire leads from relay 2 and check continuity Continuity.
  • Page 31 (TROUBLE 6) When toaster operates, strange code can be seen on the display and stop with beep sound. CONDITION CHECK RESULT CAUSE REMEDY Check continuity Defective 1. “F-1” code. No continuity. Replace thermistor of thermistor. thermistor Continuity. Replace toaster Check the No continuity.

  • Page 32: Exploded View

    EXPLODED VIEW INTRODUCTION LATCH BOARD PARTS OVEN CAVITY PARTS INTERIOR PARTS DOOR PARTS BASE PLATE PARTS TOASTER PARTS...

  • Page 33: Door Parts

    DOOR PARTS 13552A 15006A 13581A 13536A 13213A 14890A 14026A 14970A WTP004 268712 13720D 23506A...

  • Page 34: Controller Parts

    CONTROLLER PARTS WTP004 268712 23506A...

  • Page 35: Oven Cavity Parts

    OVEN CAVITY PARTS WTT021 33112U 33052A WTT010 33390G 34370T 36549S 35889A WTP013...

  • Page 36: Latch Board Parts

    LATCH BOARD PARTS 43501A WSZ085 56912B 466001 466003 43500A 55262A 466001 44510A...

  • Page 37: Interior Parts

    INTERIOR PARTS 568771 WSZ002 56411A 56930V WTT024 50FZZA 56201A WTT028 56549F 268711 55900A WTT037 54974S 50CZZH WSZ002 56324A WSZ002 56851C 56201B 54810C WTT028...

  • Page 38: Base Plate Parts

    BASE PLATE PARTS 56170D 63302A 63303A 65006A 647781 WTT021 WTT028 WSZ002 WTT021...
  • Page 39 TOASTER PARTS 753003 759301 749701 753002 753001 75993M 768771 73808A WTT021 76322A 749321 75026C 75264A 76930V 749703 759302 WTT028 749322 73550A 749703 73446A 74830A WTT028 74830A 73300A 75026G WTT021 768711 53550L 749702 73550D 466001 74510L 73390M 73550H 73740A 73720D 73572A 73213A 73552A...

  • Page 40: Schematic Diagram Of P.c.b

    SCHEMATIC DIAGRAM OF P.C.B. 0DLZW5A018...

  • Page 41: Printed Circuit Board

    MAIN PRINTED CIRCUIT BOARD...
  • Page 42 KEY PRINTED CIRCUIT BOARD...
  • Page 43 April, 2003 P/NO : 3828W5S3131 Printed in Korea...

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