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CAUTIONS

• Be sure to check microwave leakage prior to

servicing the oven if the oven is operative prior to
servicing.

• The service personnel should inform the

manufacture importer, or assembler of any certified
oven unit found to have a microwave emission
level in excess of 5 mW/cm

2

and should repair any

unit found to have excessive emission levels at no cost
to the owner and should ascertain the cause of the
excessive leakage. The service personnel should
instruct the owner not to use the unit until the oven has
been brought into compliance.

• If the oven operates with the door open, the service

personnel should:

- Tell the user not to operate the oven.
- Contact the manufacturer and CDRH

(Center for Devices and Radiological Health)

immediately.

NOTE: Address on CDRH

Office of Compliance(HFZ-312)
Center for Devices and Radiological
Healthe 1390, Piccard Drive,
Rockville. MD 20850

• The service personnel should check all surface and

vent openings for microwave leakage.

• Check for microwave leakage after every servicing. The

power density of the microwave radiation leakage
emitted by the microwave oven should not exceed 
4 mW/cm

2

. Always start measuring of an unknown field

to assure safety for operating personnel from radiation
leakage.

MEASURING MICROWAVE ENERGY

LEAKAGE

• Pour 275±15cc of 20±5°C (68±9°F) water in a beaker

which 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 radiation monitor by holding the
probe perpendicular to the surface being measured

Move probe along shaded area

Probe scanning speed
Less than 2.5 cm/sec
(1 in/sec)

5-1

SERVICE INFORMATION

TOOLS AND MEASURING INSTRUMENTS

MICROWAVE LEAKAGE TEST

NECESSARY TOOLS

Tools normally used for TV servicing are sufficient.
Standard tools are listed below.

• Diagonal pliers
• Long nose pliers
• Phillips screwdriver
• Flat blade screwdriver
• Wrench (size 5mm)
• Nutdriver (size 5mm)
• Adjustable wrench
• Soldering iron
• Solder
• Vinyl insulation tape
• Polishing cloth

NECESSARY MEASURING INSTRUMENTS

• TESTER (VOLTS-DC, AC, Ohmmeter)
• Microwave survey meter

- Holaday HI-1500

HI-1501

- Narda     8100

8200

• Inch scale
• 600 cc non conductive material beaker (glass or plastic),

inside diameter: approx. 8.5 cm (3

1

/2

in.)

• Cylindrical and made of borosilicate glass vessel.

max. thickness: 3 mm
outside diameter: approx. 190mm
height: approx. 90mm

• Glass thermometer: 100°C or 212°F (1 deg scale)

Содержание MS-2642DP

Страница 1: ...MICROWAVE OVEN SERVICE MANUAL MODEL MS 2642DP CAUTION BEFORE SERVICING THE UNIT READ THESAFETY PRECAUTIONS IN THIS MANUAL website http biz lgservice com ...

Страница 2: ...eration 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 transmission line and cavity for proper alignment integrity and connections D Any de...

Страница 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 11 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 ...

Страница 4: ...1 300 Watts Single phase 3 wire grounded 900 Watts full microwave power IEC60705 2 450 MHz 2M248 2M246 0 99 min 99 sec 512 W x 301 H x 410 D mm 360 W x 238 H x 373 D mm 16 5 kg approx 17 9 kg approx 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 Medium approx 60 5 Med Low approx ...

Страница 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...

Страница 6: ...nal 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 wall 7 Place the microwave oven as far away as possible from TV RADIO COMPUTER etc to prevent interference GROUNDING INSTRUCTIONS For personal safety this appliance must be fully grounded at a...

Страница 7: ...T This feature provides you with the quick defrosting method for 0 5kg of beef 6 AUTO DEFROST This feature provides you with the best defrosting method for frozen foods 7 NUMBER These used to set for time of day cooking time power level or defrost weight 8 POWER You can select the desired power level for cooking 9 CLOCK It is used to set the time of day 10 STOP CLEAR It used to stop oven and clear...

Страница 8: ... the last item entered or to the clock 3 EZ ON 4 ONE TOUCH COOKING NOTE Heat only 1 package at a time 5 TIME COOKING 6 MULTI STAGE COOKING 7 AUTO DEFROST COOKING 8 CHILD LOCK This oven has a CHILD LOCK feature TO SET CHILD LOCK Touch and hold 0 pad LOCKED appears on the display TO CANCEL CHILD LOCK Touch and hold 0 pad LOCKED disappears STOP CLEAR CLOCK NUMBER POPCORN STOP CLEAR STOP CLEAR STOP CL...

Страница 9: ...M MICROWAVE RADIATION FIRE ELECTRICAL SHOCK AND HAZARDS WHEN SERVICING IT IS ESSENTIAL THAT ONLY MANUFACTURER S SPECIFIED PARTS BE USED FOR THE CRITICAL COMPONENTS IN THE SHADED AREAS OF THE SCHEMATIC DIAGRAM NOTICE SINCE THIS IS BASIC SCHEMATIC DIAGRAM THE VALUES OF COMPONENTS AND SOME PARTIAL CONNECTIONS ARE SUBJECT TO CHANGE FOR IMPROVEMENT ...

Страница 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...

Страница 11: ...ion leakage MEASURING MICROWAVE ENERGY LEAKAGE Pour 275 15cc of 20 5 C 68 9 F water in a beaker which 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 Ope...

Страница 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...

Страница 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...

Страница 14: ...and push the 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 parall...

Страница 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...

Страница 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...

Страница 17: ...it 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 closed meter sh...

Страница 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...

Страница 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 Infinite Abnormal Continuity Normal Continuity Abnormal Infinite NOTE When testing the magnetron be sure to install the magnetron gasket in the correct position and be ...

Страница 20: ...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...

Страница 21: ... 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...

Страница 22: ... does not turn on after setting cooking cycle 11 Display time of day does not reappear when cooking is finished 5 12 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...

Страница 23: ...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 ...

Страница 24: ... 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...

Страница 25: ... 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...

Страница 26: ...6 1 EXPLODED VIEW INTRODUCTION EV ...

Страница 27: ...6 2 13213A 13552A 15006A 13581A 13536A 14026A 14970A 13720D 14890A DOOR PARTS EV ...

Страница 28: ...6 3 23572A 24781M WTP018 268711 24510L 250201 24970A 23506A CONTROLLER PARTS EV ...

Страница 29: ...6 4 36549S WTP013 33390G 34370T WTT010 WTT021 33112U 35889A WTT011 33052M OVEN CAVITY PARTS EV ...

Страница 30: ...6 5 LATCH BOARD PARTS WSZ085 466001 466001 466003 43500A EV ...

Страница 31: ...71 WSZ002 WSZ002 WSZ002 WSZ002 WSZ002 WSZ002 WTT028 56411A 56930V 56549F 54974S 56201A WTT037 55900A 54810C 56201B WTT028 50CZZH 34930W 35012A 56851C 50FZZA WSZ002 56912B 55262A 948501 56324A INTERIOR PARTS EV ...

Страница 32: ...6 7 WTT021 63302A 63303A 56170D WSZ002 948502 WTT030 647781 BASE PLATE PARTS EV ...

Страница 33: ...8 1 SCHEMATIC DIAGRAM OF P C B ...

Страница 34: ...8 2 PRINTED CIRCUIT BOARD ...

Страница 35: ...P NO 3828W5S2692 July 2002 Printed in Korea ...

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