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1. Incomplete segments.

¥ Segment missing.
¥ Partial segment missing.
¥ Digit flickering (NOTE: Slight flickering is normal.)

2. Colon does not turn on or blink.
3. A distinct change in the brightness of one or more numbers in display.
4. One or more digits in the display are not lighting.
5. Display indicates a number different from one touched, for example, key in 

5

and 

3

appears in the display.

6. Specific numbers (for example 7 or 9) will not display when key pad is touched.
7. Display does not count down with time blinking or up with clock operation.
8. Display obviously jumps in time while counting down.
9. Display counts down too fast while cooking.

10. Each indicator light does not turn on after setting cooking cycle.
11. Display time of day does not reappear when cooking is finished.

5-14

(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 between
membrane key
assembly and
PCB assembly.

2. Some inputs

cannot be
programmed.

3. Display shows a

number or figure
different from one
touched.

4. Random

programming
when touching
other pads.

5. Display is fixed

at some figure
and can not
accept any
input.

Everything works
as specified.

Still have trouble.

Defective key
membrane
assembly.

Defective PCB
assembly.

Replace key
membrane
assembly.

Replace PCB
assembly.

Replace key
membrane
assembly and
check operation.

Содержание GoldStar MA-1302S

Страница 1: ...MICROWAVE OVEN SERVICE MANUAL MODEL MA 1302S CAUTION BEFORE SERVICING THE UNIT READ THE SAFETY PRECAUTIONS IN THIS MANUAL http www LGEservice com ...

Страница 2: ...rlock 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 transmission line and cavity for proper alignment integrity and connections ...

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 8 COMPONENT TEST PROCEDURE 5 9 TROUBLE SHOOTING 5 13 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: ...3 wire grounded 1 150 Watts full microwave power IEC705 2 450 MHz 2M246 0 99 min 99 sec 217 8 W x 125 8 H x 171 4 D 143 4 W x 91 4 H x 16 D 38 6 lbs approx 41 9 lbs 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 Medium approx 60 5 Med ...

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: ...l 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 all...

Страница 7: ... Control Panel Display Window Turntable Defrost Rack Rotating Ring START EZ ON 1 2 3 4 5 Sensor Cook Defrost Hot Potato Fresh Vegetable Frozen Vegetable Frozen Entree Ground Meat Beverage S ensor Cook Cook Ti m e Power Stop Clear Timer Popcorn Auto Cook Sensor Reheat More Sensor Defrost Less CONTROL PANEL ...

Страница 8: ...AR pad LOCKED appear on the display TO CANCEL CHILD LOCK Touch the pad Touch and hold STOP CLEAR pad LOCKED disappears 9 MORE LESS The cook time is adjustable by MORE pad or LESS pad 10 TIMER 11 SENSOR POPCORN 12 SENSOR BEVERAGE REHEAT DEFROST 4 2 STOP CLEAR TIMER For 3 seconds Time setting once STOP CLEAR REHEAT STOP CLEAR DEFROST STOP CLEAR EZ on STOP CLEAR COOKING STOP CLEAR POPCORN STOP CLEAR ...

Страница 9: ...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 L N FUSE 20A CN3 RY2 CN2 ...

Страница 10: ...roximately 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...

Страница 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...

Страница 12: ...ed 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 probe damage RECORD KEEPING AND NOTIFICA...

Страница 13: ...is 5 K The microwave power output P in watts is calculated from the following formula 4187 x ÆT 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 ...

Страница 14: ... 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 chassis Also adjust so the door has no play between the inner door surface and oven fram...

Страница 15: ...L 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 base plate I 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 suction guide AssÕy ...

Страница 16: ...nate 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 5 6 Wire Leads Turntable Motor PRIMARY SWITCH ADJUSTMENT DIRECTION MONITOR SWITCH SECONDARY SWITCH 3 INSTALLATION AND ADJUSTMENT OF THE LATCH BOARD TO THE OVEN ASSEMBLY Mount the latch b...

Страница 17: ... cavity 2 Remove the screw of the holder 3 Remove the Holder 4 Remove the screw of sensor case 5 Remove the sensor PCB AssÕy 6 Remove the reflector 5 7 Sensor PCB Ass y Connector Holder Sensor Connector HOOK Reflector Holder Sensor Case Sensor Connector CN4 Pin ...

Страница 18: ...losed 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 open...

Страница 19: ...ULTS 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 scale Rx1000 Fila...

Страница 20: ...0 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...

Страница 21: ...8 sec 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 ohm 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 LEA...

Страница 22: ... from P C B See Schematic Diagram on page 4 3 RY1 Turn table Fan Motor Oven Lamp SENSOR Wire leads removed Measure the resistance Port Resistance 1 and 2 Approx 470 Kohm 1 and 3 Approx 1 5 Kohm 1 and 4 Approx 2 0 Kohm Cooking Start OFF 1 CN2 2 3 BK CONNECTOR SHIELD WIRE WH RD GN 4 3 2 1 ...

Страница 23: ... 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 24: ... does not turn on after setting cooking cycle 11 Display time of day does not reappear when cooking is finished 5 14 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 25: ...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 26: ...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 27: ... relay 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...

Страница 28: ...hield wire connector Refer to page 5 12 Replace sensor assy ÒGuide sensorÓ stuck Check and adjust the ÒGuide sensorÓ Refer to schematic diagram and adjust it Unsuitable utensil was used Use suitable utensil Refer to the ownerÕs manual Incorrect connection of shield wire Refer to page 5 12 Replace sensor assy Incorrect resistance of shield wire connector TROUBLE 6 Uneven cooking and error during se...

Страница 29: ...DOOR PARTS CONTROL PANEL PARTS LATCH BOARD PARTS BASE PARTS INTERIOR PARTS OVEN CAVITY PARTS 6 1 EXPLODED VIEW INTRODUCTION ...

Страница 30: ...6 2 13581A 13720D 13213A 13552A 15006A 13536A 14890A 14026A 14970A WTT040 13650A DOOR PARTS ...

Страница 31: ...6 3 24781S 23806C 23572A 268712 268711 249401 250201 CONTROL PANEL PARTS ...

Страница 32: ...6 4 33416Z 948503 33112U WSZ185 33052M 340511 WTT010 24890C 35889A WSZ002 WTT028 WTP013 36549S OVEN CAVITY PARTS ...

Страница 33: ...6 5 WSZ085 43501A 466001 466003 466001 43500A LARCH BOARD PARTS ...

Страница 34: ...6 6 54974T 55900A 50CZZH 54810C WSZ002 WSZ002 WTT037 56549F 54974S 56201A SUCTION GUIDE PARTS ...

Страница 35: ...6 7 WSZ002 568771 56930V 56411A 54811A 56501A 568772 53551S WSZ002 35012A WSZ002 948501 55262A 948502 56324A WSZ002 56912B INTERIOR PARTS ...

Страница 36: ...6 8 63302L 56170D 63302R WSZ002 WTT021 647781 647781 WTT030 63303R 63303L 948502 BASE PLATE PARTS ...

Страница 37: ...8 1 SCHEMATIC DIAGRAM OF P C B ...

Страница 38: ...8 2 PRINTED CIRCUIT BOARD ...

Страница 39: ...P NO 3828W5S0845 June 1999 Printed in Korea ...

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