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LG LMVM2277ST Service Manual

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See also: Owner's Manual , Training Manual
Website: http://us.lgservice.com

MICROWAVE OVEN

SERVICE MANUAL
MODEL: LMVM2277ST
CAUTION
BEFORE SERVICING THE UNIT, READ THE
SAFETY PRECAUTIONS IN THIS MANUAL.
June, 2007
P/NO : MFL06272504
Printed in Korea

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  • Page 1: Microwave Oven

    Website: http://us.lgservice.com MICROWAVE OVEN SERVICE MANUAL MODEL: LMVM2277ST CAUTION BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL. June, 2007 P/NO : MFL06272504 Printed in Korea...

  • Page 2: Warning To Service Technicians

    CAUTION WARNING TO SERVICE TECHNICIANS PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY a. Do not operate or allow the oven to be operated with the door open. b. Make the following safety checks on all ovens to be serviced before activating the magnetron or other microwave sources, and make repairs as necessary;...

  • Page 3: Table Of Contents

    FOREWORD Read this Manual carefully. Failure to adhere to or observe the information in this Manual may result in exposing yourself to the Microwave Energy normally contained within the oven cavity. TABLE OF CONTENTS (Page) SAFETY PRECAUTIONS ........................Inside front page SPECIFICATIONS ..............................

  • Page 4: Specifications

    SPECIFICATIONS Rated Power Consumption ........1700W maximum (Microwave oven+Cook top lamps+Ventilation fan) Microwave Output ..........1100W (IEC 60705) Frequency ............2450 MHz ± 50 MHz Power Supply .............120 VAC, 60 Hz Rated Current ............14.5 Amp. (Microwave oven+Cook top lamps+Ventilation fan) Magnetron Cooling ..........Forced Air Cooling Rectification ............Rectification Voltage Double Half-Wave Door Sealing ............Choke System Safety Devices ...........Magnetron Thermostat: Open at 145 °C ±...

  • 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. PRECAUTIONS ON INSTALLATION A. Plug the power supply cord into a 120V AC, 60Hz, single-phase power source with a capacity of at least 20 amperes. B. Avoid placing the unit in a location where there is direct heat or splashing water.

  • Page 7: Operating Instructions

    OPERATING INSTRUCTIONS CONTROL PANEL...

  • Page 8: Control Panel Instructions

    CONTROL PANEL INSTRUCTIONS NOTE: Styling and features vary by model. 13. REHEAT: Touch this key to reheat Pizza Slice, Dinner Plate, Soup/Sauce and Casserole. The oven’s sensor 1. DISPLAY: The Display includes a clock and indicators will tell the oven how long to cook depending on the to tell you time of day, cooking time setting, and amount of humidity coming from the food.

  • Page 9: Overall Circuit Diagram

    OVERALL CIRCUIT DIAGRAM SCHEMATIC DIAGRAM...

  • Page 10: General Information For Service

    GENERAL INFORMATION FOR SERVICE GENERAL PRECAUTIONS IN USE FEATURES AND SPECIFICATIONS FEATURES A. Never operate the unit when it is empty. A. The safety systems incorporated in this model are: Operating the oven with no load may shorten the (1) Primary interlock switch life of the magnetron.

  • Page 11: Service Information

    SERVICE INFORMATION PRECAUTIONS AND REPAIR SERVICE TIPS PRELIMINARY (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. SINCE NEARLY 4000 VOLTS EXISTS IN SOME (a) The door does not close firmly.

  • Page 12: Microwave Leakage Test

    MICROWAVE LEAKAGE TEST CAUTIONS EQUIPMENT- • Be sure to check microwave leakage prior to • TESTER (VOLTS-DC, AC, Ohmmeter) servicing the oven if the oven is operative prior to • Microwave survey meter servicing. - Holaday HI-1500 • The service personnel should inform the HI-1501 manufacture importer, or assembler of any certified - Narda...

  • Page 13: Power Output Measurement

    MEASUREMENT WITH THE OUTSIDE NOTE WHEN MEASURING REMOVED (1) Do not exceed meter full scale deflection. (2) The test probe must be removed no faster than (1) When you replace the magnetron, measure for 1 inch/sec (2.5cm/sec)along the shaded area, microwave energy leakage before the outer case otherwise a false reading may result.

  • Page 14: Disassembly Instructions

    DISASSEMBLY INSTRUCTIONS IMPORTANT NOTES: (4) Release PCB board from cavity and pull down it. (Figure 2) UNIT MUST BE DISCONNECTED FROM ELEC- TRICAL OUTLET WHEN MAKING REPAIRS, RE- PLACEMENTS, ADJUSTMENTS AND CONTIN- UITY CHECKS. WHEN RECONNECTING THE WIRE LEADS TO ANY PART, MAKE SURE THE WIRING CONNE- CTIONS AND LEAD COLORS ARE CORRECTLY MATCHED ACCORDING TO THE OVERALL CIR-...
  • Page 15 B. REMOVING THE OUTER CASE (Figure 5) (1) Remove the two vent grille mounting screws. (2) Remove four screws securing it to the air duct. (3) Remove the mounting plate by turning 2 screws securing it to the outer case. (4) Remove two screws on the left central edge and two screws on the right central edge of Base plate.
  • Page 16 C. REMOVING THE DOOR INTERLOCK SWITCHES (Figures 6, 7) (1) Disconnect the wire leads from the interlock switches. (2) Remove two screws securing the front cavity. (3) Make necessary replacements and check microwave energy leakage according to following the test method. Interlock Monitor Switch...
  • Page 17 D. REMOVING MAGNETRON E. REMOVING STIRRER FAN (Figures 8 and 9) (Figures 10 and 11) (1) Remove the outer case. See page 7-5. (1) Remove one screw securing it to the oven upper (2) Remove the damper bracket. plate by using knife blade. (3) Disconnect the transformer leadwire.
  • Page 18 F. REMOVING DOOR (Figure 12) WARNING: BE CAREFUL WHEN REMOVING THE GAS SPRING. IF YOU REMOVE ONE GAS (1) Remove the two vent grille mounting screws. SPRING FROM THE OVEN, THE DOOR (2) Remove the door hinge scews. SHOULD FALL DOWN. BE CAREFUL NOT (3) Remove the wire cover and open the hinge covers.
  • Page 19 HOW TO REMOVE THE F.P.C. CONNECTOR HOW TO INSERT THE F.P.C. CONNECTOR Follow the steps below as illustrated in Figures 14 Follow the steps below as illustrated in Figures 16 and 15 to remove the F.P.C.connector. and 17 to insert the F.P.C. connector. (1) Insert the F.P.C.
  • Page 20 I. REMOVING THE VENTILATION MOTOR J. REMOVING THE TURNTABLE MOTOR (1) Remove the mounting plate by loosening 2 mounting (1) Remove the glass tray and plastic tray. plate screws securing it to the back plate. (2) Remove the base plate by removing 8 screws (See Figure 18) securing it to the oven cavity.(Figure 20) (2) Remove blower plate by loosening two screws...
  • Page 21 K. REPLACING THE HUMIDITY SENSOR (1) Remove the sensor by removing one screw securing it to the air duct. (See Figure 22) (2) Mount the new humidity sensor to the air duct. Figure 22 7-11...

  • Page 22: Interlock Continuity Test

    INTERLOCK CONTINUITY TEST A. PRIMARY INTERLOCK SWITCH TEST B. SECONDARY INTERLOCK SWITCH TEST When the door is opened slowly, an audible click Disconnect the wire lead from the secondary should be heard at the same time or successively switch. at intervals and the latches should activate the Connect the ohmmeter leads to the common switches with an audible click (COM)and normally open (NO)terminals of the...

  • Page 23: Test And Checkout Procedures And Troubleshooting

    TEST AND CHECKOUT PROCEDURES AND TROUBLESHOOTING 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 LEAD WIRES FROM THE PRIMARY WINDING OF THE HIGH VOLTAGE TRANSFORMER. 2.
  • Page 24 COMPONENTS TEST RESULTS 1. Remove wire leads. CAPACITOR 2. Measure resistance. (ohm meter scale: Rx1000) • Terminal to terminal Normal: Momently indicates several ohm, and then gradually returns to infinite • Terminal to case Normal: Infinite. 1. Measure continuity. Forward. Normal:Continuity.
  • Page 25 COMPONENTS TEST RESULTS 1. Remove leads wire. L.V.T 2. Measure resistance. Normal: Approximately (ohm meter scale: Rx1) Terminal : 18 to 30 ohms Terminal : Red and White. Terminal : 18 to 30 ohms Terminal : Red and Black. Abnormal: Infinite. 1.
  • Page 26 NOTES: • A MICROWAVE ENERGY TEST MUST ALWAYS BE PERFORMED WHEN THE UNIT IS SERVICED FOR ANY REASON. • MAKE SURE THE WIRE LEADS ARE IN THE CORRECT POSITION. • WHEN REMOVING THE WIRE LEADS FROM THE PARTS,BE SURE TO GRASP THE CONNECTOR, NOT THE WIRES.

  • Page 27: Checkout Procedures

    B. CHECKOUT PROCEDURES (1) CHECKOUT PROCEDURES FOR FUSE BLOWING CAUTION: REPLACE BLOWN FUSE WITH 20 AMPERE FUSE. PROBLEMS CAUSES Fuse blows immediately after the door is closed. Improper operation of the primary interlock, secondary Fuse blows immediately after interlock switches and/or the interlock monitor switch. the door is opened.
  • Page 28 (2)CHECKOUT PROCEDURES FOR RELAY. -PROBLEM (A)- -PROBLEM (A)-- FAN motor turns on without touching START key when Oven lamp turns on without touching START key when the door is closed. the door is closed. Remove the mate connector of I/O Remove the mate connector of I/O GOOD GOOD...
  • Page 29 (3) CHECKOUT PROCEDURES FOR CIRCUIT BOARD The following symptoms indicate a defective circuit 5) Some segments of one or more digits do not light board. up, or they continue to light up, or segments light 1) Check the input current. If the input current is more when they should not.
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  • Page 34: Exploded View

    #EV# EXPLODED VIEW DOOR PARTS * CHOKE COVER MUST BE REPLACED WITH A NEW ONE AFTER REMOVING IT FROM THE DOOR. DON'T RE-USE IT. 1005 1004 W215 1006 1002 1000 1381 2041 W136 W130 1006 W214 1017 W130 W130 2006 2009 1022 1012...

  • Page 35: Oven Cavity Parts

    #EV# OVEN CAVITY PARTS W142 W142 3031 3010 W142 W142 W130 W216 2029 W109 2023 W142 3052 3024 3014 3029 W105 W142 W218 5069 3001 W109 W217 3053 6001 3036 3055 3005 3032 W178 W109 3045 W178 3045 3033 W219 W219 3053 3018...

  • Page 36: Latch Board Parts

    #EV# LATCH BOARD PARTS 4006 4003 4011 4002 4013 4014 4008 W217 4007 W217 4008 4012 4002 4013 4014 -8-3-...
  • Page 37 #EV# INTERIOR PARTS (I) 9000 W144 5707 W144 W101 5071 5012 W144 W144 3002 5003 W144 3384 W144 W101 5409 5063 5018 5063 W101 5000 5023 5067 5002 W104 5009 W101 W144 W144 W221 W101 3901 5028 W101 5024 3009 5008 W105 5062...
  • Page 38 #EV# INTERIOR PARTS (II) W144 5010 5049 5412 W109 5011 3027 5045 W150 5420 W178 5550 W109 5016 W202 9001 W109 3006 W140 5001 5006 5041 5014 W109 5037 W144 W140 -8-5-...
  • Page 39 #EV# INSTALLATION PARTS 6011 6008 6010 6009 VINYL COOKING MFL1 MFL3 MEZ1 MBM5 UPPER MBM4 WALL OWNERS INSTALLATION GUIDE TEMPLATE TEMPLATE MANUAL MANUAL LABEL -8-6-...

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