LG MB-319ML Service Manual Download Page 8

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4-2

OPERATING SEQUENCE

The following is a description of component functions
during oven operation.

1. SETTING THE CLOCK

NOTE: 1) This is a 24 hour clock.

2) Clock will operate as long as power is

applied to the oven.

2. CANCEL FUNCTION

Touch the pad whenever you need to
cancel an entry or a function currently in use.
The display will either return to the last item entered
or to the clock.

3. QUICK START

4. ONE TOUCH COOKING

5. TIME COOKING

6. MULTI-STAGE COOKING

7. AUTO WEIGHT DEFROST COOKING

8. CHILD LOCK

This oven has a CHILD LOCK feature

TO SET CHILD LOCK

• Touch the button
• Touch and hold Desliga/Cancela button

DESATIVADO appear on the display.

TO CANCEL CHILD LOCK
• Touch the button
• Touch and hold Desliga/Cancela button

ATIVADO appears.

9. CUSTOM SET

You can select ON/OFF of beeper, language speed,
DEMO mode.

• To select sound ON/OFF

• To select language speed.

• To select DEMO mode.

Desliga/Cancela

Pratos Brosileiros

Desliga/Cancela

Liga

Desliga/Cancela

1ST STAGE

Liga

Desliga/Cancela

Auto Descongela

Dial

(Number)

Liga

Desliga/Cancela

Opções

Liga

Desliga/Cancela

Opções

Liga

Dial

Liga

Desliga/Cancela

Opções

Liga

Desliga/Cancela

Manual

Dial(Power)

Liga

Dial(Time)

Liga

Desliga/Cancela

Dial

Liga

Dial(Time)

Manual

Dial(Power)

Liga

Dial(Time)

2ND STAGE

Desliga/Cancela

Manual

Dial

Liga

Dial

Liga

Dial

2 X

Summary of Contents for MB-319ML

Page 1: ...MICROWAVE OVEN SERVICE MANUAL MODEL MB 319ML MB 319MLA CAUTION BEFORE SERVICING THE UNIT READ THESAFETY PRECAUTIONS IN THIS MANUAL ...

Page 2: ...tron or other microwave source and make repairs as necessary 1 interlock operation 2 proper door closing 3 seal and sealing surfaces arcing wear and other damage 4 damage to or loosening of hinges and latches 5 evidence of dropping or abuse C Before turning on microwave power for any service test or inspection within the microwave generating compartments check the magnetron wave guide or transmiss...

Page 3: ... CIRCUIT DESCRIPTION 4 4 SERVICE INFORMATION 5 1 TOOLS AND MEASURING INSTRUMENTS 5 1 MICROWAVE LEAKAGE TEST 5 1 MEASUREMENT OF MICROWAVE POWER OUTPUT 5 3 DISASSEMBLY AND ADJUSTMENT 5 3 INTERLOCK CONTINUITY TEST 5 7 COMPONENT TEST PROCEDURE 5 8 TROUBLE SHOOTING 5 12 EXPLODED VIEW 6 1 REPLACEMENT PARTS LIST 7 1 SCHEMATIC DIAGRAM OF P C B 8 1 PRINTED CIRCUIT BOARD 8 2 P C B PARTS LIST 9 1 CONTENTS ...

Page 4: ...L 1 050 Watts Single phase 2 wire grounded 1 000 Watts full microwave power IEC60705 2 450 MHz 2M246 0 99 min 99 sec 530 W x 315 H x 394 D 350 W x 240 H x 365 D 16 3 kg approx 18 7 kg approx Touch Control System Clock 1 00 12 59 Microwave Power for Variable Cooking Power level HIGH Full power throughout the cooking time 9 Saute approx 90 of Full power 8 Reheat approx 80 7 Med High approx 70 6 Medi...

Page 5: ... operation of the microwave oven requires that the magnetron be assembled to the waveguide and cavity Never operate the magnetron unless it is properly installed Be sure that the magnetron gasket is properly installed around the dome of the tube whenever installing the magnetron 2 1 CAUTIONS Unlike other appliances the microwave oven is high voltage and high current equipment Though it is free fro...

Page 6: ...ven should not be installed in any area where heat and steam are generated because they may damage the electronic or mechanical parts of the unit Do not install the oven next to a conventional surface unit or above a conventional wall oven 5 Use microwave oven in an ambient temperature less than 104 F 40 C 6 Place the microwave oven on a sturdy and flat surface at least 10 cm 4 inches from the wal...

Page 7: ...ogrammed to automatically reheat food 6 AUTO DEFROST To select the desired auto weight defrost programmed with dial 7 AUTO CRISP 8 STOP CLEAR To stop oven and clear all entries except time of day 9 MANUAL 10 START This feature allows oven to begin functioning 11 DISPLAY WINDOW Provides indications of the functions selected normally current time displayed 4 1 OPERATING INSTRUCTIONS Oven Front Plate...

Page 8: ... Touch and hold Desliga Cancela button DESATIVADO appear on the display TO CANCEL CHILD LOCK Touch the button Touch and hold Desliga Cancela button ATIVADO appears 9 CUSTOM SET You can select ON OFF of beeper language speed DEMO mode To select sound ON OFF To select language speed To select DEMO mode Desliga Cancela Pratos Brosileiros Desliga Cancela Liga Desliga Cancela 1ST STAGE Liga Desliga Can...

Page 9: ...SCHEMATIC DIAGRAM 4 3 ...

Page 10: ...ately 2100 volts AC is generated in the secondary of the high voltage transformer which is increased by the action of the high voltage diode and charging of the high voltage capacitor The negative 4 000 Volts DC is applied to the filament of the magnetron WHEN THE OVEN IS SET AT ANY LEVEL EXCEPT MAXIMUM The micom controller controls the ON OFF time of relay 2 by the applied signal to vary the aver...

Page 11: ...ich is graduated to 600 cc and place the beaker on the center of the turntable Set the energy leakage monitor to 2 450 MHz and use it following the manufacturer s recommended test procedure to assure correct result When measuring the leakage always use the 2 inch 5cm spacer supplied with the probe Operate the oven at its maximum output Measure the microwave radiation using and electromagnetic radi...

Page 12: ...on The test probe must be removed no faster than 1 inch sec 2 5 cm sec along the shaded area otherwise a false reading may result The test probe must be held with the grip portion of the handle A false reading may result if the operator s hand is between the handle and the probe When testing near a corner of the door keep the probe perpendicular to the surface making sure the probe horizontally al...

Page 13: ... The microwave power output P in watts is calculated from the following formula 4187 x T T is measured while the microwave generator is operating at full power Magnetron filament heat up time is not included about 3 sec The water is stirred to equalize temperature throughout the vessel prior to measuring the final water temperature Stirring devices and measuring instruments are selected in order t...

Page 14: ...door NOTE 1 After replacing the door be sure to check that the primary switch monitor switch and secondary switch operate normally 2 After replacing the door check for microwave energy leakage with a survey meter Microwave energy must be below the limit of 4 mW cm with a 275 ml water load 3 When mounting the door assembly to the oven assembly be sure to adjust the door assembly parallel to the cha...

Page 15: ... to the magnetron To prevent microwave leakage tighten the mounting screws properly making sure there is no gap between the waveguide and the magnetron G REMOVING THE TURNTABLE MOTOR 1 Remove the turntable and rotating ring 2 Lay the unit down on its back 3 Remove the turntable motor cover The turntable base cover is easily removed by pinching the eight parts with a wire cutting 4 Disconnect the l...

Page 16: ...K MECHANISM The door lock mechanism is a device which has been specially designed to eliminate completely microwave activity when the door is opened during cooking and thus to prevent the danger resulting from the microwave leakage 2 MOUNTING OF THE PRIMARY MONITOR SECONDARY SWITCHES TO THE LATCH BOARD 3 INSTALLATION AND ADJUSTMENT OF THE LATCH BOARD TO THE OVEN ASSEMBLY Mount the latch board to t...

Page 17: ... an closed circuit When the secondary switch operation is abnormal make the necessary adjustment or replace the switch only with the same type of switch C MONITOR SWITCH TEST Disconnect the wire lead from the monitor switch Connect the ohmmeter leads to the common COM and normally closed NC terminals of the switch The meter should indicate closed circuit in the door open condition When the door is...

Page 18: ... PROCEDURE RESULTS HIGH VOLTAGE TRANSFORMER Wire leads removed MAGNETRON Wire leads removed 1 Measure the resistance Ohm meter scale Rx1 and Rx100 Primary winding Secondary winding Filament winding 2 Measure the resistance Ohm meter scale Rx1000 Primary winding to ground Filament winding to ground 1 Measure the resistance Ohm meter scale Rx1 Filament terminal 2 Measure the resistance Ohm meter sca...

Page 19: ... Terminal to case Measure the continuity Forward Ohm meter scale Rx10000 Measure the continuity Reverse Ohm meter scale Rx10000 Normal Momentarily indicates several ohms and then gradually returns to infinite Normal Infinite Normal Continuity Abnormal Infinite Normal Infinite Abnormal Continuity NOTE When testing the magnetron be sure to install the magnetron gasket in the correct position and be ...

Page 20: ...ith an Multi meter Normal Gill heater Approx 15 at 20 30ûC Normal more than 1 0M NOTE Make sure heater is fully cooled when tested NOTE If the fuse is blown check primary the secondary 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 Replace just the fuse if the switches opera...

Page 21: ...ec 2 6 sec 16 sec 3 8 sec 14 sec 4 10 sec 12 sec 5 12 sec 10 sec 6 14 sec 8 sec 7 16 sec 6 sec 8 18 sec 4 sec 9 20 sec 2 sec 10 22 sec 0 sec Normal A Approx 85 100 ohm B Approx 10 25 ohm Abnormal Infinite or several ohms Normal Approx 100 150 ohm Abnormal Infinite or several ohm NOTE A MICROWAVE LEAKAGE TEST MUST ALWAYS BE PERFORMED WHEN THE UNIT IS SERVICED FOR ANY REASON MAKE SURE THE WIRE LEADS...

Page 22: ... panel to discharge any static charge built up in your body Micom model only CONDITION Microwave oven does not work Inserting many plugs into one outlet and using them at the same time blown fuse or breaker Microwave oven plug is not inserted tightly Output power is too low Low AC input voltage Food temperature is too low Using metallic ware and allowing it to touch the oven wall Sparks occur Inco...

Page 23: ... does not turn on after setting cooking cycle 11 Display time of day does not reappear when cooking is finished 5 13 TROUBLE 1 The following visual conditions indicate a probable defective control circuit CONDITION CHECK RESULT CAUSE REMEDY 1 No input can be programmed Continuity No continuity Defective PCB assembly Loose connection Replace PCB assembly Connect them tightly Check the conn ection b...

Page 24: ...of primary switch with door opened Disconnect one side of the wire lead connected from transformer to the high voltage capacitor and operate the unit Replace fuse Continuity Malfunction of secondary switch Replace fuse primary monitor secondary switches and RELAY RY2 of P C B Assembly No continuity Check continuity of secondary switch with door opened 2 Fuse does not blow No continuity Continuity ...

Page 25: ... all figures set but oven does not start cooking while desired program times are set and START pad is touched TROUBLE 4 Oven seems to be operating but little heat is produced in oven load NOTE Simple test of power output conducted by heating one liter water for one min if available Minimum 8 5 C temperature rise is normal condition CONDITION CHECK RESULT CAUSE REMEDY Output is low Lower than 90 of...

Page 26: ... 2 and check continuity relay 2 Operate the unit Abnormal Defective high voltage capacitor Replace high voltage capacitor Normal Check high vol tage capacitor Abnormal Defective high voltage diode Replace high voltage diode Normal Check high vol tage diode Abnormal Defective magnetron Replace magnetron Check magnetron TROUBLE 5 No microwave oscillation even though oven lamp and fan motor run Displ...

Page 27: ...DOOR PARTS LATCH BOARD PARTS CONTROL PANEL PARTS INTERIOR PARTS BASE PLATE PARTS OVEN CAVITY PARTS 6 1 EXPLODED VIEW INTRODUCTION ...

Page 28: ...6 2 13213A 13552A 13536A 14026A 14970A 13581A 15006A 14890A 13720D DOOR PARTS ...

Page 29: ...6 3 24510L 268711 WTT028 WTP004 268712 250202 250205 249401 250204 243501 250201 23790D 23572A 250203 24970A 24781S CONTROLLER PARTS ...

Page 30: ...6 4 33052M 948504 340511 36549S WTP013 948501 WTT010 WTT021 33112U WSZ184 35300S WNZ015 33550H 34036W 33390G 35889A 33390M 34370T 35026G OVEN CAVITY PARTS ...

Page 31: ...6 5 43501A WSZ085 466001 466003 466001 43500A LATCH BOARD PARTS ...

Page 32: ... 568771 WSZ002 WSZ002 WSZ002 WSZ002 WTT028 54826A 56930V 56930V 55006F 56549F 54974S WTT037 55900A WSZ002 55262A 56324A 35012A 948502 54810C WTT028 50CZZH 56851D 50FZZA 56912B 34930W 56411A INTERIOR PARTS ...

Page 33: ...6 7 63302L 63303L 56170D 63302R 948503 WSZ002 WTT021 63303R WTT028 647781 368771 BASE PLATE PARTS ...

Page 34: ...2A158A BUTTON R 250203 5020W3A141A BUTTON B 250204 5020W2A084A BUTTON R 250205 5020W3A140A BUTTON B 268711 6871W2S234B PWB PCB ASSEMBLY SUB R 268712 6871W2S233A PWB PCB ASSEMBLY SUB R 33052M 3052W3M011C CANOPY MICA R 33112U 3112W1U015S OUT CASE U BENDING R 33390G 3390W1G010A TRAY GLASS R 33390M 3390W1A011A TRAY METAL R 33550H 3550W1A084B COVER HEATER R 34036W 4036W3W001A SEAL R 340511 4051W3A001A ...

Page 35: ...3B001K 568771 6877W1A283B HARNESS R 56912B 6912W3B002G LAMP DRAWING R 56930V 6930WRT001B THERMOSTAT R 63302L 3302W1A036G BASE PLATE R 63302R 3302W1A035G BASE PLATE R 63303L 3303W1A028M BASE PLATE ASSEMBLY R 63303R 3303W2A004K BASE PLATE ASSEMBLY R 647781 4B73900A LEG R 948501 4850W4C001D CUSHION R 948502 4850W4C001J CUSHION R 948503 3B72244G CUSHION R 948504 3B72244C CUSHION R WNZ015 4B71028B NUT ...

Page 36: ...8 1 SCHEMATIC DIAGRAM OF P C B ...

Page 37: ...8 2 PRINTED CIRCUIT BOARD ...

Page 38: ... 1N4148 PYUNG CHANG TP52 DO35 R D31 0DD414809AD DIODE SWITCHING 1N4148 PYUNG CHANG TP52 DO35 R D32 0DD414809AD DIODE SWITCHING 1N4148 PYUNG CHANG TP52 DO35 R D33 0DD414809AD DIODE SWITCHING 1N4148 PYUNG CHANG TP52 DO35 R DP1 6302W5A015A DIGITRON HNM 07SS30 7 AMB 314XF W POOL R EN01 6024WRYA06B VOLUME ROTARY ES1005A SEIL 24CLICK LGEAZ R LED1 0DLZW5A003A LED LITEON LTL 12BGE 1 BK GREEN NA R Q01 0TR1...

Page 39: ... FIXED CARBON FILM 5 6K OHM 1 6 W 5 TA52 R R94 0RD5601F609 RESISTOR FIXED CARBON FILM 5 6K OHM 1 6 W 5 TA52 R R95 0RD5601F609 RESISTOR FIXED CARBON FILM 5 6K OHM 1 6 W 5 TA52 R R96 0RD5601F609 RESISTOR FIXED CARBON FILM 5 6K OHM 1 6 W 5 TA52 R RY1 6920W5A008A RELAY DQ1U DAIICHI 250VAC 3A 12VDC R 6920W5A007A RY1 6920W5A008A RELAY DQ1U DAIICHI 250VAC 3A 12VDC R 6920W2D010B RY1 6920W5A008A RELAY DQ1U...

Page 40: ...P NO 3828W5S1726 Aug 2002 Printed in Korea ...

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