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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

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.

• 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 
5 mW/cm

2

. Always start measuring of an unknown field

to assure safety for operating personnel from radiation
leakage.

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)

MEASURING MICROWAVE ENERGY
LEAKAGE

• Pour 275±15 cc 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

(5 cm) 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
( 1in/sec)

5-1

SERVICE INFORMATION

TOOLS AND MEASURING INSTRUMENTS

MICROWAVE LEAKAGE TEST

Содержание MS-2342W

Страница 1: ...Mar 2004 Printed in Korea P NO 3828W5S3656 MICROWAVE OVEN SERVICE MANUAL MODEL MS 2342W CAUTION BEFORE SERVICING THE UNIT READ THE SAFETY PRECAUTIONS IN THIS MANUAL website http biz lgservice com ...

Страница 2: ...nd 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 defective or misadjusted components in t...

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: ...342W 230 240 Volts AC 50 Hz 1 200 Watts Single phase 3 wire grounded 800 Watts full microwave power IEC 60705 2 450 MHz 2M214 39F 0 99 min 50 sec 485 W x 280 H x 400 D mm 332 W x 200 H x 331 D mm 12 5 kg approx 14 kg approx Microwave Power for Variable Cooking Power level Max Full power throughout the cooking time Med High approx 80 of Full power Medium approx 60 of Full power Defrost approx 40 of...

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: ...lat 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 EARTHING INSTRUCTIONS This microwave oven is designed to be used in a fully earthed condition It is imperative therefore to make sure it is properly earthed before servicing WARNING THIS APPLIANCE MUST BE EARTHED IMPORTANT As the colors of the wire...

Страница 7: ...ed time 4 CLOCK Used to set the time of day 5 AUTO COOK Used to cook the foods listed by one touch 6 AUTO DEFROST Used to select the auto weight defrost 7 POWER Used to select the desired power level for cooking 8 QUICK DEFROST Used to defrost frozen foods quickly 9 MORE LESS Used to increase or decrease the cooking time WEIGHT Used to select the weight of food 10 STOP CLEAR Used to stop over and ...

Страница 8: ...MICROWAVE COOKING 5 MULTI STAGE MICROWAVE COOKING 6 AUTO DEFROST COOKING 7 QUICK DEFROST COOKING 8 CHILD LOCK This oven has a CHILD LOCK feature TO SET CHILD LOCK Touch the pad Touch STOP CLEAR pad L appear on the display TO CANCEL CHILD LOCK Touch the pad touch STOP CLEAR pad L disappears 9 AUTO COOK STOP CLEAR CLOCK NUMBER STOP CLEAR START quick start STOP CLEAR 1ST STAGE CLOCK STOP CLEAR AUTO D...

Страница 9: ...SCHEMATIC DIAGRAM 4 3 ...

Страница 10: ...ximately 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 a...

Страница 11: ...ity of the microwave radiation leakage emitted by the microwave oven should not exceed 5 mW cm2 Always start measuring of an unknown field to assure safety for operating personnel from radiation leakage 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 d...

Страница 12: ...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 along the oven surface this may possibly cause...

Страница 13: ... the empty vessel are at ambient temperature prior to the start of the test The initial temperature T1 of the water is 10 2 C It is measured immediately before the water is added to the vessel After addition of the water to the vessel the load is immediately placed on the center of the turntable which is in the lowest position and the microwave power switched on The time T for the temperature of t...

Страница 14: ...REMOVAL 1 Discharge the high voltage capacitor 2 Disconnect the leadwire from magnetron high voltage transformer and capacitor 3 Remove the screw holding the high voltage transformer to the baseplate F FAN MOTOR ASSEMBLY REMOVAL 1 Discharge the high voltage capacitor 2 Disconnect the leadwire from fan motor noise filter and high voltage capacitor 3 Remove the two screws holding the the suction gui...

Страница 15: ... 275 ml water load Make sure that gasket is rigidly attached to the magnetron To prevent microwave leakage tighten the mounting screws properly making sure there is no gap between the waveguide and the magnetron L REMOVING THE TURNTABLE MOTOR 1 Remove the turntable 2 Remove the turntable shaft VERY CAREFULLY 3 Lay the unit down on its back 4 Remove the turntable motor cover The turntable base cove...

Страница 16: ...ARY MONITOR SECONDARY SWITCHES TO THE LATCH BOARD 3 INSTALLATION AND ADJUSTMENT OF THE LATCH BOARD TO THE OVEN ASSEMBLY Mount the latch board to the oven assembly Adjust the latch board in the arrow direction so that oven door will not have any play in it when the door is closed Tighten the mounting screw Check for play in the door by pushing the door release button Door movement should be less th...

Страница 17: ... closed meter should indicate 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 op...

Страница 18: ... TEST PROCEDURE RESULTS HIGH VOLTAGE TRANSFORMER Wire leads removed MAGNETRON Wire leads removed 1 Measure the resistance Ohm meter scale Rx1 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 Between Filament terminal 2 Measure the resistance Ohm meter ...

Страница 19: ...le Rx1000 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 Normal Abnormal Continuity Normal Continuity Abnormal NOTE When testing the magnetron be sure to install the magnetron gasket in the correct position and be sure that the gask...

Страница 20: ...cale R x 1000 POWER LEVEL 20 6 sec 16 sec 40 10 sec 12 sec 60 14 sec 8 sec 80 18 sec 4 sec 100 22 sec 0 sec Normal 350 450 Ω Abnormal or several Ω Normal 70 130 Ω Abnormal or several Ω NOTE A MICROWAVE LEAKAGE 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 C...

Страница 21: ...static charge built up in your body Micom model only CONDITION Microwave oven does not work Inserting many plug into one plug 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 Inconsistent intensity o...

Страница 22: ...ing cooking cycle 11 Display time of day does not reappear when cooking is finished 12 Beep sound is not heard when correct key is touched 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 tigh...

Страница 23: ...f P C B Assembly Check continuity of monitor switch with door closed Check continuity 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 2 Fuse does not blow No continuity Continuity No continuity Defective power supply cord Replace power supply cord Defective thermostat Replace thermost...

Страница 24: ...ws 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 ...

Страница 25: ... unit Check high vol tage transformer Abnormal Defective circuit protector Replace circuit protector Normal Check circuit protector 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 magnetr...

Страница 26: ...unit NOTE Make sure the wire leads correct position When Removing the wire leads from the parts be sure to grasp the connector not the wires When removing the magnetron be sure to install the magnetron gasket in the correct position and in good condition CONDITION CHECK RESULT CAUSE REMEDY TROUBLE 5 No microwave oscillation even though oven lamp and fan motor run Display operates properly ...

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

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

Страница 29: ...6 3 WTP018 23506A 23572A 23550D 24781M 268711 CONTROL PANEL PARTS ...

Страница 30: ...6 4 33112U WTT021 36549S WTP013 33390G 34370T 35889A 33052A OVEN CAVITY PARTS ...

Страница 31: ...6 5 43500A 466001 WSZ084 466003 466001 44510A LATCH BOARD PARTS ...

Страница 32: ...6 6 WSZ002 WTT028 WTT028 WSZ062 WSZ002 WTT037 50CZZH 56324A 55262A 54810C 55900A 56549F 56411A 56930V 568771 54974S 56912B WSZ002 34930W 50FZZA 56201A WSZ002 56851C INTERIOR PARTS ...

Страница 33: ...6 7 56170D 63302A 63303A WTT021 WSZ002 65006B 948501 BASE PLATE PARTS ...

Страница 34: ...8 1 SCHEMATIC DIAGRAM OF P C B ...

Страница 35: ...8 2 PRINTED CIRCUIT BOARD ...

Страница 36: ......

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