LG MH9245XAB Service Manual
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LG MH9245XAB Service Manual

LG MH9245XAB Service Manual

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Internal Use Only
Website http://biz.lgservice.com
MICROWAVE OVEN
SERVICE MANUAL
MODEL: MH9245XAB
CAUTION
BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
June, 2015
P/NO : MFL41356533
Printed in Korea

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  • Page 1 Internal Use Only Website http://biz.lgservice.com MICROWAVE OVEN SERVICE MANUAL MODEL: MH9245XAB CAUTION BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL. June, 2015 P/NO : MFL41356533 Printed in Korea...

  • 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 Power Requirement 230V / 50Hz Microwave 1450W Grill 1150W Single phase, 3 wire grounded Power Output 1 000 watt full microwave power (IEC60705) Microwave Frequency 2 450 MHz Magnetron 2M246 - 050GF Timer 0 ~ 99 min. 99 sec Outside Dimensions 606 (W) x 344 (H) x 503 (D) (mm) Cavity Dimensions...

  • 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 Grill Rack Roller Rest CONTROL PANEL 1. DISPLAY WINDOW: GLOBAL MENU: me of day, power level of cooking, cooking category. 2. GLOBAL MENU: Used to set the GLOBAL MENU 3. AUTO DEFROST: Used to select the auto weight defrost.

  • Page 8: Operating Sequence

    OPERATING SEQUENCE The following is a description of component functions during oven operation. 7. AUTO WEIGHT DEFROST COOKING 1. SETTING THE CLOCK AUTO NUMBER OF STOP/CLEAR NUMBER STOP/CLEAR CLOCK NUMBER CLOCK DEFROST WEIGHT ex.) To set 4:30, touch number key [4],[3], and [0]. 8.

  • Page 9: Schematic Diagram

    SCHEMATIC DIAGRAM...

  • Page 10: Circuit Description

    CIRCUIT DESCRIPTION GENERAL DETAILS power of microwave oven as POWER LEVEL. (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 MEASURING INSTRUMENTS NECESSARY TOOLS Tools normally used for TV servicing are sufficient. • TESTER (VOLTS-DC, AC, Ohmmeter) Standard tools are listed below. • Microwave survey meter - Holaday HI-1500 • Diagonal 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 –...
  • Page 14 D. PCB ASSEMBLY REMOVAL Remove choke cover 1) Remove the control panel assembly from the cavity. (Refer to control panel assembly removal on previous page.) 2) Remove screws which hold the PCB SUB ASSEMBLY to the control panel. 3) Disconnect the flat cable from the PCB SUB ASSEMBLY and take off the PCB SUB ASSEMBLY.
  • Page 15 F. MAGNETRON REMOVAL G. REMOVING THE TURNTABLE MOTOR 1) Remove the turntable and rotating ring. 1) Disconnect the leadwire from the magnetron. 2) Lay the unit down on its back. 2) Carefully remove the mounting screws holding the 3) Remove the turntable motor cover. magnetron and the waveguide.
  • Page 16 H. HIGH VOLTAGE TRANSFORMER K. 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 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 A.

  • 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...
  • Page 20 COMPONENTS TEST PROCEDURE RESULTS Measure the resistance. Normal: HEATER ELEMENT (Multi-meter scale:RX1) Gill heater (Wire leads removed.) Approx.15 Ω (at 20-30 Normal: Measure the resistance with 500V-100M more than 1.0M Ω Ohm insulation resistance meter. NOTE: Make sure heater is fully cooled when tested. THERMOSTAT 0°C~Approx 110°C Over 110°C...
  • Page 21 COMPONENTS TEST PROCEDURE RESULTS RELAY 2 Check for continuity of relay 2 with an POWER ohm-meter. LEVEL (Remove wire leads from relay 2 and operate the unit.) 4 sec 18 sec 6 sec 16 sec 8 sec 14 sec 10 sec 12 sec 12 sec 10 sec...

  • 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 Malfunction of the Replace fuse, Check continuity 1. Fuse blows. Continuity. monitor switch. primary, monitor of monitor secondary switch (with...
  • 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 No continuity. secondary switch. secondary switch. of secondary does not count switch (with...
  • Page 26 (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 27 (TROUBLE 6) Oven does not cook properly when programmed for the set power level (Operates properly on HIGH) CONDITION CHECK RESULT CAUSE REMEDY Defective P.C.B. Replace P.C.B. Output is full when Disconnect the Abnormal. assembly. assembly. you set lower wire leads from power level.

  • Page 28: Exploded View

    #EV# EXPLODED VIEW INTRODUCTION MODEL: SVC Model Customer Model Product Code -6-1-...
  • Page 29 #EV# DOOR PARTS 13581A 13536A 13552A 13213A 13551C 14026A 14970A -6-2-...
  • Page 30 #EV# CONTROL PANEL PARTS 24781M 23551A 26871M 24510L 24970A -6-3-...
  • Page 31 #EV# OVEN CAVITY PARTS W178 33112U 44360A 34810A 3034 35026G 368771 3002 35300A 36549S 35889A -6-4-...
  • Page 32 #EV# LATCH BOARD PARTS W102 4000 43501A 4002 4003 4002 -6-5-...
  • Page 33 #EV# INTERIOR PARTS 568771 W140 56411A 5023 50 FZZA 56820A W101 56549F 54980A 55900A 54974S 35012A 56851D 56912B W101 56901A 56324A 50CZZH 54810C 55262A -6-6-...
  • Page 34 #EV# BASE PLATE PARTS 56170D 63303A W101 -6-7-...

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