Table of Contents
Related Manuals for LG MB-3949G
Summary of Contents for LG MB-3949G
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Page 1: Microwave Oven
삼 흥 정 판 Internal Use Only Website: http://biz.lgservice.com MICROWAVE OVEN SERVICE MANUAL MODEL: MB-3949G CAUTION BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL. March, 2010 P/NO : MFL30190712 Printed in Korea... -
Page 2: Safety Precautions
CAUTION MICROWAVE RADIATION DO NOT BECOME EXPOSED TO RADIATION FROM THE MICROWAVE GENERATOR OR OTHER PARTS CONDUCTING MICROWAVE ENERGY. Copyright © 2007 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes... -
Page 3: Table Of Contents
REPLACEMENT PARTS LIST - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 7-1 LGE Internal Use Only Copyright © 2007 LG Electronics. Inc. All right reserved. Only for training and service purposes... -
Page 4: Specifications
Glass tray Roller Rest Grill rack This microwave oven is designed for household use only. It is not recommended for commercial purposes. Copyright © 2007 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes... -
Page 5: Cautions
• NEVER put iron tools on the magnetron. • NEVER put anything into the latch hole and the interlock switches area. LGE Internal Use Only Copyright © 2007 LG Electronics. Inc. All right reserved. Only for training and service purposes... -
Page 6: Installations
L or colored red. 10cm Copyright © 2007 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes... -
Page 7: Operating Instructions
11. MORE/LESS: Used to change the cooking time & desired weight. 12. START/QUICK START: To quickly set the cooking time directly. LGE Internal Use Only Copyright © 2007 LG Electronics. Inc. All right reserved. Only for training and service purposes... -
Page 8: Operating Sequence
Start 7. AUTO WEIGHT DEFROST 12. MORE AND LESS Stop/Clear Auto Defrost Weight (kg) Start Stop/Clear Desired auto cook More Less Copyright © 2007 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes... -
Page 9: Schematic Diagram
SCHEMATIC DIAGRAM LGE Internal Use Only Copyright © 2007 LG Electronics. Inc. All right reserved. Only for training and service purposes... -
Page 10: Circuit Description
• The micom controller controls the ON-OFF time of relay plate. 2 by the applied signal to vary the average output Copyright © 2007 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes... -
Page 11: Service Information
4 mW/cm . Always start measuring of an unknown field to assure safety for operating personnel from radiation leakage. LGE Internal Use Only Copyright © 2007 LG Electronics. Inc. All right reserved. Only for training and service purposes... - Page 12 5 mW/cm.sq. Leakage for a fully assembled oven (Before the latch switch (primary) is interrupted) with the door in a slightly opened position-less than 2 mW/cm.sq. Copyright © 2007 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...
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Page 13: Measurement Of Microwave Power Output
2) Disconnect two terminals, and remove one screw of the earth terminal. CAUTION: DISCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE SERVICING (refer to page 2-1) LGE Internal Use Only Copyright © 2007 LG Electronics. Inc. All right reserved. Only for training and service purposes... -
Page 14: Diode Removal
4) Remove the screw holding the high voltage capacitor bracket. Fan Motor ASS Y Suction Guide Remove door assembly H.V. H.V. Diode Transformer H.V. Capacitor Copyright © 2007 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes... - Page 15 Taptite Screw Magnetron Magnetron Magnetron Wire Leads Gasket Waveguide Bracket Turntable Motor Dome Waveguide LGE Internal Use Only Copyright © 2007 LG Electronics. Inc. All right reserved. Only for training and service purposes...
- Page 16 CAUTION: CHECK THE CORRECT POSITION FIG. 1 MAGNETRON H.V. TRANSFORMER PROTECTOR DIODE H.V. DIODE H.V. CAPACITOR PRIMARY Copyright © 2007 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes...
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Page 17: Interlock Continuity Test
Primary Switch Monitor Switch Secondary Switch NOTE : After checking for the continuity of switches, make sure that are connected correctly. LGE Internal Use Only Copyright © 2007 LG Electronics. Inc. All right reserved. Only for training and service purposes... -
Page 18: Component Test Procedure
Normal: Less than 1 ohm • Filament terminal 2. Measure the resistance. (Ohm-meter scale: Rx1000) Normal: Infinite • Filament to chassis Copyright © 2007 LG Electronics. Inc. All right reserved. LGE Internal Use Only Only for training and service purposes... - Page 19 Some inexpensive meters may indicate infinite resistance in both direction. Normal: Infinite. Measure the continuity (Reverse). Abnormal: Continuity. (Ohm-meter scale: Rx10000) LGE Internal Use Only Copyright © 2007 LG Electronics. Inc. All right reserved. Only for training and service purposes...
- Page 20 (Wire leads removed.) Relay 1 Note: Relay Relay 1: Fan motor Turntable motor Oven lamp Relay 2: Microwave Relay 2 Copyright © 2007 LG Electronics. Inc. All right reserved. 5-10 LGE Internal Use Only Only for training and service purposes...
- Page 21 • 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. LGE Internal Use Only 5-11 Copyright © 2007 LG Electronics. Inc. All right reserved. Only for training and service purposes...
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Page 22: Trouble Shooting
Distribute food evenly. Cook Excessive weight on tray or noise. smaller portions and, or use improperly balanced. lighter weight cookware. Copyright © 2007 LG Electronics. Inc. All right reserved. 5-12 LGE Internal Use Only Only for training and service purposes... - Page 23 Continuity. Check continuity No continuity. Defective power Replace power of power supply supply cord. supply cord. cord. LGE Internal Use Only 5-13 Copyright © 2007 LG Electronics. Inc. All right reserved. Only for training and service purposes...
- Page 24 NOTE: Simple test of power output-conducted by heating one liter water for one min. if available. Copyright © 2007 LG Electronics. Inc. All right reserved. 5-14 LGE Internal Use Only Only for training and service purposes...
- Page 25 Check H.V. Defective high Replace high Abnormal diode. voltage Diode. voltage Diode. normal Check Defective Replace Abnormal Magnetron. magnetron. magnetron . LGE Internal Use Only 5-15 Copyright © 2007 LG Electronics. Inc. All right reserved. Only for training and service purposes...
- Page 26 2 and check continuity relay 2. (Operate the unit) Copyright © 2007 LG Electronics. Inc. All right reserved. 5-16 LGE Internal Use Only Only for training and service purposes...
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Page 27: Exploded View
#EV# EXPLODED VIEW INTRODUCTION MODEL: OVEN CAVITY PARTS INTERIOR PARTS BASE PLATE PARTS DOOR PARTS LATCH BOARD PARTS CONTROL PANEL PARTS MAY000 MFL552 -6-1-... -
Page 28: Door Parts
#EV# DOOR PARTS 13581A 13552A 13536A 13213A 14890A 13720D 14026A 14970A -6-2-... - Page 29 #EV# CONTROL PANEL PARTS 24781M 268711 23572A WTT028 23506A 24510L 24970A 250201 -6-3-...
- Page 30 #EV# OVEN CAVITY PARTS Button Head WNH001 (Torx style 2) WSZ185 WTT021 33112U 34810H 34810H 44360A 33052M 33808A WTT010 35300A 35026G 33390G 35889A 36549S WTP013 -6-4-...
- Page 31 #EV# LATCH BOARD PARTS 56912B 948503 43500A 55262A 466001 43501A 466003 466001 WSZ085 -6-5-...
- Page 32 #EV# INTERIOR PARTS WSZ062 568771 56411A 56930V WSZ002 50FZZA 56201A WTT028 56549F WTT028 WTT037 55900A 54974S WSZ002 56851D 55238A WSZ002 50CZZH 56324A 54810C 56901A WTT028 948501 WSZ002 -6-6-...
- Page 33 #EV# BASE PLATE PARTS 56170D 63302A 63303A 948502 WTT021 65006B WSZ002 65006B -6-7-...