Goldstar MA-2005ST Owner's Manual
Contents
1. CONDITION CHECK RESULT CAUSE REMEDY Lower than 90 of Decrease in power Suggest customer tput is gt gt SUIBURIE ew Check the rating voltage source voltage contact local ft with load electric power L Normal utility qualified electrician Disconnect the Abnormal Defective PCB Replace PCB wire leads from assembly assembly relay 2 and check on and off Normal time with multitester Measure the Abnormal Defective Replace output power magnetron magnetron 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 5 14 TROUBLE 5 No microwave oscillation even though oven lamp and fan motor run Display operates properly CONDITION CHECK RESULT CAUSE REMEDY No microwave Disconnect the gt No continuity Defective PCB Replace PCB oscillation wire leads from assembly assembly relay 2 and check continuity Continuity of relay 2 Operate the unit Check high vol Abnormal Defective high Replace high tage transformer voltage voltage transformer transformer Normal Check high vol Abh rm l Defective high Replace high2. programming when touching other pads al Display is fixed at some figure and can not accept any input 5 12 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 CONDITION CHECK RESULT CAUSE REMEDY 1 No input can be Check the conn Continuity Defective PCB Replace PCB programmed ection between assembly assembly membrane key assembly and Sh Loose Connect them PCB assembly connection tightly 2 Some inputs Replace key Everything works Defective key Replace key cannot be membrane as specified membrane membrane programmed assembly and assembly assembly check operation 3 Display shows a Still have trouble Defective PCB Replace PCB number or figure assembly assembly different from one touched 4 Random TROUBLE 2
3. Check continuity m gt No continuity Defective gt Replace of thermostat thermostat thermostat gt Continuity Check continuity No continuity Defective power Replace power of power supply supply cord supply cord cord 5 13 TROUBLE 3 Display shows all figures set but oven does not start cooking while desired program times are set and START pad is touched CONDITION CHECK RESULT CAUSE REMEDY 1 Setting time I Check continuity No continuity Defective Replace does not count of secondary secondary switch secondary switch down when switch with door closed touching START gt Continuity pad Check the con Continuity Defective PCB Replace PCB nection between assembly assembly CN1 connector gt ake 3 continuity gt Loose connection assembly tightly 2 Fan motor or gt Check fan motor gt Abnormal m Defective fan motor Replace fan motor oven lamp do not turn gt Check oven lamp 3 Abnormal m Defective oven lamp Replace oven lamp Normal TROUBLE 4 Oven seems to be operating but little heat is produced in oven load
4. i aga nga Bine Su ie A Rs El as eE al SCHEMATIC DIAGRAM OF P C B eR T yp Ke y 1 mL 1 As 1E9 otf dezz S609 VFrOOVSMZZIO 8 1 PRINTED CIRCUIT BOARD 2
5. USE MUSIC SHIP RADIO RADIO RADIO T V MWO RADAR RADAR 13 3 2 Conventional heating vs dielectric heating 1 Conventional heating FIRE FIRE FOOD FIRE TRANSMITTED BY CONDUCTION It shall be heated by the sources of the electric heater the gas and the briquet The heat energy from the sources of the heating power shall be transmitted from the warm surface to the cold inside Heating with the strong fire The surface of the food shall be well done but be burnt to have a black side and the center of the food shall not be well done Heating with the weak fire The surface of the food shall be burnt and have a little black side but it shall be taken lots of time for the center to be well done The thermal conductivity in the water or in the food is low 2 Dielectric heating 1 The heating is uniform 2 The temperature rise is fast high 3 If you break the electric power The microwave oven stops heating at once so you can t heat something with the heat of their surroundings 4 Since it heats inside the surface isn t damaged WAVE WAVE WAVE y If you give microwave to food with the microwave oven the food and molecules of the water included in the food is turned or moved and generate heat with the friction among the the molecules The water the oil and the foods shall absorb the electric wave well I
6. Jr PRIMARYO SWITCH 2 MOUNTING OF THE PRIMARY MONITOR SECONDARY SWITCHES TO THE LATCH BOARD 3 INSTALLATION AND ADJUSTMENT OF THE LATCH BOARD TO THE OVEN ASSEMBLY e 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 than 0 5 mm 1 64 inch Don t push the door release button while making this adjustment Make sure that the latch moves smoothly after adjustment is completed and that the screws are tight Make sure the primary monitor and secondary switches operate properly by following the continuity test procedure INTERLOCK CONTINUITY TEST WARNING FOR CONTINUED PROTECTION AGAINST EXCESSIVE RADIATION EMISSION REPLACE ONLY WITH IDENTICAL REPLACEMENT PARTS TYPE NO SZM V 16 FA 63 OR VP 533A OF FOR PRIMARY SWITCH TYPE NO SZM V 16 FA 62 OR VP 532A OF FOR MONITOR SWITCH TYPE NO SZM V 16 FA 63 OR VP 533A OF FOR SECONDARY SWITCH A PRIMARY INTERLOCK SWITCH TEST B SECONDARY INTERLOCK SWITCH TEST When the door release button is depressed slowly Disconnect the wire lead from the secondary with the door closed an audible click should be switch heard at the same time or successively at Connect the ohmmeter leads t
7. A BK YL SOFT START 3 RESISTOR l II w Eee 5 E E CAPACITOR amp O 2 e O Q E y E ZO 5 IE H V DIODE 3 5 INPUT BL POWER gt NOISE FILTER F Qo 4 5 BL lt BL Br SECONDARY SWITCH 16 4 3 WARNING High voltage circuit 4 000 volt INPUT INPUT NAAA lt ENONDARY INDING AT 2000V 3 A SECONDARY WINDING AT 2000V MAGNETRON MAGNETRON The half wave voltage doubler circuit consists of the secondary winding of the high voltage transformer H V diode rectifier and H V capacitor The H V diode allows alternating current AC to flow in one direction only and rectifies it to pulsating direct current DC The H V capacitor is able to store energy on one half of the AC cycle and release it on the other half cycle During the first half cycle of operation the secondary winding of the transformer supplies 2000 Volts to the capacitor current flows through the diode and returns to the transformer for a complete circuit This half cycle of AC charges the capacitor to approximately 2000 Volts During the second half cycle of operation the current flows in the opposite direction again supplies 2000 Volts to the circuit This permits the capacitor to discharge its 2000 Volts on top of the 2000 Volts gener
8. NUMBER START SET SCHEMATIC DIAGRAM ININIAOYANI HOA AONVHO OL 193P8NS SNOILOANNOO TVILYVd AWOS SLNFINO4NOD SINTVA SHL WVHDVIC OLLVINIHOS 215 SI SIHL 5 3OLLON WVHSVIG OLLVWAIHOS 3HL AO SWAYV GSGVHS AHL SLNSANOdWOO TWOILIHO AHL 39 O SLYVd GAlsIOAdS SYAYNLOVANNVW AINO LVHL IVILN3SS3 SI ONIOIAU3S NAHM MOOHS 1VOIHLOSTA 3813 NOILVIGWY JAVMOYOIAN NOILOSLOYd HOS INVLHOAN I OSSYNLVAsA IVI9F4S ALVHYOdHOONI WVWHSVIC 5 SIHL NO SVAYV GSCVHS AHL ALON ALAAVS 1 NOYyYLINOVIA AH HOLIOVdVO N3349 N9 ALIHM HM MOTISA 1 And 19 MOV1d O G4SN3d0 SI ILON x HM HOLIMS HOLINOWN USWHOSSNVHL NH HOLIMS AYVWdd HOLIMS O AYVGNOOSS ZH09 DAO3L OV NO 09514 ME 4 3 CIRCUIT DESCRIPTION GENERAL DETAILS The low voltage transformer supplies the necessary voltage to the micom controller when power cord is plugged in When the door is closed the primary switch is ON the secondary switch is ON and the monitor switch opens contact COM and NO WHEN SELECTING COOKING POWER LEVEL AND TIME The micom controller memorizes the fun
9. Oven does not operate at all Display window does not display any figures and no input is accepted CONDITION CHECK RESULT CAUSE REMEDY Check continuity ne Malfunction of the Replace fuse 1y FUSS DIOWS of monitor monitor switch primary monitor switch with door closed RR switches an gt No continuity RELAY RY2 of P C B Assembly Replace fuse Check continuity Continuity Shorted contact at gt Replace fuse of primary the primary switch primary monitor switch with secondary door opened No continuity switches and RELAY RY2 of P C B Assembly inui a Replace fuse nn nn Continuity gt Malfunction of ana monitor ia ll secondary door opened ae switches and No continuity RELAY RY2 of P C B Assembly Disconnect one gt N Defective high Replace high side of the wire voltage capacitor voltage capacitor lead connected from transformer Defective high volt Replace high volt to the high SED again age transformer age transformer voltage capacitor and operate the unit NOTE All these switches must be replaced at the same time Refer to page 5 7 5 8 2 Fuse does not blow
10. TIME gt NUMBER POWER gt NUMBER 2ND STAGE TIME NUMBER POWER NUMBER gt START 4 2 7 AUTO DEFROST COOKING AUTO DEFROST NUMBER OF WEIGHT STOP CLEAR START 8 CHILD LOCK This oven has a CHILD LOCK feature TO SET CHILD LOCK Touch and hold 0 pad gt LOCKED appears on the display TO CANCEL CHILD LOCK Touch and hold O pad LOCKED disappears 9 MORE LESS The cook time is adjustable by MORE pad or LESS pad STOP CLEAR COOKING gt STOP CLEAR COOKING LESS 10 CUSTOM COOK You can program the cook time and power level by using CUSTOM COOK pad ex To set cook time 10 mine 30seconds touch number key 1 0 3 and 0 CUSTOM STOP CLEAR COOK NUMBER POWER I gt gt NUMBER gt START 11 CUSTOM SET You can select Sound On Off Clock On Off Scroll Speed Lbs Kg Choice Demo On Off modes To turn ON OFF sound CUSTOM STOP CLEAR p gt NUMBER NUMBER gt START SET select scroll speed CUSTOM NUMBER STOP CLEAR gt
11. AT T is measured while the microwave generator is operating at full power Magnetron filament heat up time is not included about 3 sec P 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 to minimize addition or removal of heat WATER LOAD TURNTABLE DISASSEMBLY AND ADJUSTMENT A OUTER CASE REMOVAL 1 Disconnect the power supply cord from the outlet 2 Remove the screws from the rear of the case The outer case must be moved backward to be lifted off B POWER SUPPLY CORD 1 Remove the outer case 2 Disconnect two terminals and remove one screw of the ground terminal C CONTROL PANEL ASSEMBLY 1 Open the door 2 Disconnect the leadwire from RELAY RY2 of the PCB SUB ASS Y 3 Disconnect the leadwire from connector CN1 of the PCB SUB ASS Y 4 Lift up and pull out control panel assembly carefully from the cavity CAUTION DISCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE SERVICING refer to page 2 1 5 3 Remove the screw Yo N D PCB ASSEMBLY REMOVAL 1 Remove the control panel assembly from the cavity Refer to control panel assembly removal on previous page 2 Remove screws which hold the PCB SUB ASS Y to the control panel 3 Disconnect the flat cable from the PCB S
12. ohm Abnormal Infinite or several ohm TURNTABLE MOTOR Wire leads removed Measure the resistance Ohm meter scale R x 1 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 ARE IN THE CORRECT POSITION WHEN REMOVING THE WIRE LEADS FROM THE PARTS BE SURE TO GRASP THE CONNECTOR NOT THE WIRES 5 10 TROUBLE SHOOTING WHEN YOU GET A COMPLAINT FROM YOUR CUSTOMER EVALUATE THE COMPLAINT CAREFULLY IF THE FOLLOWING SYMPTOMS APPLY PLEASE INSTRUCT THE CUSTOMER IN THE PROPER USE OF THE MICROWAVE OVEN THIS CAN ELIMINATE AN UNNECESSARY SERVICE CALL CAUTIONS 1 Check grounding before checking for trouble Be careful of the high voltage circuit 2 3 Discharge the high voltage capacitor See page 2 1 4 When checking the continuity of the switches or of the high voltage transformer disconnect one lead wire from these parts and then check continuity with the AC plug removed To do otherwise may result in a false reading or damage to your meter 5 Do not touch any part of the circuit on the PCB since static electric discharge may damage this control panel Always touch yourself to ground while working on this panel to discharge any static charge built up in your body Micom model only CONDITION CAUSE Microwave oven does n
13. ohm Filament terminal 2 Measure the resistance Ohm meter scale Rx1000 Normal Infinite e Filament to chassis 5 8 COMPONENTS TEST PROCEDURE RESULTS Antenna Chassis NOTE When testing the magnetron be sure to install the magnetron gasket in the correct position and be sure that the gasket is in good condition HIGH VOLTAGE CAPACITOR Measure the resistance Ohm meter scale Rx1000 Terminal to terminal Normal Momentarily indicates several ohms and then gradually returns to infinite Measure the resistance Ohm meter scale Rx1000 Terminal to case Normal Infinite HIGH VOLTAGE DIODE NOTE Some inexpensive meters may indicate infinite resistance in both direction Measure the continuity Forward Ohm meter scale Rx10000 Normal Continuity Abnormal Infinite Measure the continuity Reverse Ohm meter scale Rx10000 5 9 Normal Infinite Abnormal Continuity COMPONENTS TEST PROCEDURE RESULTS RELAY 2 Check for continuity of relay 2 with an ohm meter Remove wire leads from relay 2 and operate the unit Relay 2 DEIN E 4 sec 6 sec 8 sec 10 sec 12 sec 14 sec 16 sec 18 sec 20 sec 22 sec FAN MOTOR Wire leads removed Measure the resistance Ohm meter scale R x 1 Normal A Approx 85 100 ohm B Approx 10 25
14. 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 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 1in sec MEASUREMENT WITH OUTER CASE REMOVED When you replace the magnetron measure for microwave energy leakage before the outer case is installed and after all necessary components are replaced or adjusted Special care should be taken in measuring the following parts Circled area of Fig below Around the magnetron The waveguide WARNING AVOID CONTACTING ANY HIGH VOLTAGE PARTS MEASUREMENT WITH A FULLY ASSEMBLED OVEN After all components including the outer case are fully assembled measure for microwa
15. UB ASS and take off the PCB SUB ASS Y Control Panel PCB Sub Asm Key Membrane Door Open Button Release Lever E DOOR MAIN ASSEMBLY REMOVAL 1 Open the door 2 Remove the choke cover very carefully with a flat blade screwdriver CAUTION Be careful not to damage door seal plate by screwdriver 3 Lift up 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 parallel to the chassis Also adjust so the door has no play between the inner door surface and oven frame assembly If the door assembly is not mounted properly microwaves may leak from the clearance between the door and the oven 5 4 Remove choke cover Remove door F AIR DUCT ASSEMBLY REMOVAL 1 Disconnect the leadwire from the lamp 2 Remove the mounting screw to the magnetron G MAGNETRON REMOVAL 1 Disconnect the leadwire from the magnetron 2 Carefully remove the mounting screws holding the magnetron and the waveguide 3 Remove the magnetron ASS Y until the tube is clear from the waveg
16. apkins towels and plastics should not be used microwave oven 2 Paper napkins towels plates cups cartons and cardboard can Note be used in the microwave oven Do not use recycled paper e Care should be taken when removing utensils or the glass products since they may contain impurities which may cause turntable as they may become hot during cooking sparks and or fires when used in cooking Consult your e Only use a thermometer that is designed or recommended for cookbook for correct use of these products use in the microwave oven Ensure the turntable is in place when you operate the oven 11 3 1 What s the microwave 1 2 1 History of dielectric heating In 1945 Dr Spencer working for RAYTHEON Co in the U S A found out a pieces of chocolate in his pocket melting suddenly by the electric wave ultra high frequency wave using for radar on his experiment for radar then began research in heating matters by the electric wave So far experiments for heating foods by the electric wave has been developed into the household telephone as well as microwave oven etc The heating method for microwave is to give an electric wave to the food and make the food itself generate heat It is different from that of the past which was to give heat to the food and make the temperature rise So since the microwave oven does not give any heat to the food we do not need appliances like the gas oven Not only the microwave oven i
17. ated by the secondary winding creating an approximate total voltage of negative 4000 Volts D C The negative 4000 Volts DC causes the magnetron to conduct current and to oscillate at 2450 MHz The first half cycle and the second half cycle become one complete cycle repeated input power frequency times per second 17 4 4 Microwave generation system_Magnetron 1 2 GASKET FILAMENT CATHODE ANODE MAGNET FERRITE FILTER CASE FILTER ELECTRONS ANODE ANTENNA OUTPUT MAGNET MAGNETIC CIRCUIT VANE FILAMENT TERMINALS FEED THROUGH CAPACITOR The magnetron is the energy source for the microwave oven The magnetron is a vacuum tube of special construction It is basically a diode with addition of a magnetic field It consists of a small coiled heating element filament made of tungsten which readily emits electrons when heated This element serves as the cathode negative element within the tube The anode positive element of the tube consists of a thick walled copper cylinder with vertical vanes extending inward which surround but do not touch the cathode To complete the magnetron and make it operate distinctly different from other vacuum tubes two permanent magnets are mounted over each end of the tube 18 4 4 Microwave generation system_Magnetron 2 2 2 450 MHz ANTENNA ELECTRONS PERMANENT ANODE MAGNET TESTING MAGNETRON TUBE In order to create an electro
18. before the oven is released to the owner E A microwave leakage check should be performed on each oven prior to release to the owner CAUTION MICROWAVE RADIATION DO NOT BECOME EXPOSED TO RADIATION FROM THE MICROWAVE GENERATOR OR OTHER PARTS CONDUCTING MICROWAVE ENERGY 2 1 Function amp Type 1 2 1 How a Microwave Oven Works The microwave oven is one of the great inventions of the 20th century millions of homes in world have one Microwave ovens are popular because they cook food incredibly quickly They are also extremely efficient in their use of electricity because a microwave oven heats only the food nothing else A microwave oven uses microwaves to heat food Microwaves are radio waves In the case of microwave ovens the commonly used radio wave frequency is roughly 2 500 megahertz 2 5 gigahertz Radio waves in this frequency range have an interesting property they are absorbed by water fats and sugars When they are absorbed they are converted directly into atomic motion heat Microwaves in this frequency range have another interesting property they are not absorbed by most plastics glass or ceramics Metal reflects microwaves which is why metal pans do not work well in a microwave oven 2 Type of Microwave Oven 1 MICROWAVE COOKING solo model Using the energy of microwaves only food is cooked quickly without altering its colour and shape Microwaves generated by a magnetron enter the
19. cessary to do this continuity test before operating the oven COMPONENTS TEST PROCEDURE RESULTS SWITCHES Check for continuity of the Door Wire leads removed switch with an Ohm meter open Primary Switch A Monitor Switch Secondary Switch ER NOTE After checking for the continuity of switches make sure that they are connected correctly 5 7 COMPONENT TEST PROCEDURE CAUTIONS 1 DISCONNECT THE POWER SUPPLY CORD FROM THE OUTLET WHENEVER REMOVING THE OUTER CASE FROM THE UNIT PROCEED WITH THE TEST ONLY AFTER DISCHARGING THE HIGH VOLTAGE CAPACITOR AND REMOVING THE WIRE LEADS FROM THE PRIMARY WINDING OF THE HIGH VOLTAGE TRANSFORMER SEE PAGE 2 1 2 ALL OPERATIONAL CHECKS WITH MICROWAVE ENERGY MUST BE DONE WITH A LOAD 1 LITER OF WATER IN CONTAINER IN THE OVEN COMPONENTS TEST PROCEDURE RESULTS HIGH VOLTAGE TRANSFORMER Wire leads removed FILAMENT 0 WINDINGO PRIMARY O TERMINAL 1 Measure the resistance Ohm meter scale Rx1 and Rx100 Primary winding Approx 0 2 0 4 ohm Secondary winding Approx 60 90 ohm Filament winding Less than 1 ohm 2 Measure the resistance Ohm meter scale Rx1000 Primary winding to ground Normal Infinite Filament winding to ground Normal Infinite MAGNETRON Wire leads removed 1 Measure the resistance Ohm meter scale Rx1 Normal Less than 1
20. ction you set The time you set appears in the display window Each indicator light turns on to indicate that the stage has been set WHEN TOUCHING THE START PAD The coil of the relay is energized by the micom controller Power input is supplied to the high voltage transformer through the fuse to the primary switch and relay 2 Turntable rotates PRIMARYO FUSE SWITCH O a 7 MONITORO TRANS D SWITCH FORMER SECONDARYO 9 5 SWITCH 00 CONTROLLER A high voltage of approximately 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 average output power of microwave oven as POWER LEVEL refer to page 1 1 One complete cycle of relay 2 is 22 seconds WHEN THE DOOR IS OPENED DURING COOKING Both the primary switch and relay 2 cut off the primary winding voltage of the high voltage transformer ON OFF of relay 2 is coupled electrically with opening and closing of the secondary switch When the door is opened the secondary switch is opened and when the door is closed the secon
21. dary switch is closed The cooking time stops counting down Relay stops functioning As the door is opened if the contact of primary switch and relay2 and or secondary switch fail to open the fuse opens due to the large current surge caused by the monitor switch activation which in turn stops magnetron oscillation PRIMARYO FUSE SWITCH MONITORO The fan motor rotates and cools the magnetron by blowing the air coming from the intake on the base plate The air is also directed into the oven to exhaust the vapor in the oven through the upper plate Cooking time starts counting down 3 3 volts AC is generated from the filament winding of the high voltage transformer This 3 3 volts is applied to the magnetron to heat the magnetron filament through two noise preventing choke coils 4 4 FORMER SWITCH _ SECONDARYO MICOM CONTROLLER RELAY 2 SERVICE INFORMATION TOOLS AND MEASURING INSTRUMENTS 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 e Wrench size 5mm Nutdriver size 5mm Adjustable wrench Soldering iron Solder Vinyl insulation tape Polishing cloth MICROWAVE LEAKAGE TEST CAUTIONS Be sure to check microwave leakage prior to servicing the o
22. ey are suitable for use 3 Plastic dishes cups freezer bags and plastic wraps may be in the microwave oven used in the microwave oven Follow the manufacturer s The following chart summaries the proper use of cooking utensils instructions or the information given in the cookbook when in your oven using plastics in the microwave oven 4 Metal utensils and utensils with metallic trim should not be Cooking utensils Microwave used in the microwave oven For more information on the Heat resistant glass glass ceramic yes proper use of metal in your oven please read the introduction Ceramic china yes section in the cookbook If the use of aluminum foil skewers Do not use china or utensils containing metal in the oven is specified in the with gold or recipe allow at least 2 5cm clearance between the metal silver trim object and the interior oven wall If arcing sparks occurs Metal cookware no yes remove immediately Non heat resistant glass no no Microwave plastic yes no Note Plastic wrap yes no Consult your cookbook individual recipes and charts for correct Paper cup plates towels yes no use of cooking containers products and other useful information Straw wicker and wood no no Grill Microwave 1 Heat resistant glassware ceramic and metal cookware can 1 Most glass glass ceramic and heat resistant glassware utensils be used are excellent Those with metal trim should not be used in a 2 Paper n
23. http www LGEservice com GoldStar E mail Techsupport LGEservice com MICROWAVE OVEN MODEL MA 2005ST CAUTION BEFORE SERVICING THE UNIT READ THE SAFETY PRECAUTIONS IN THIS MANUAL _ 5 SAFETY PRECAUTIONS This device is to be serviced only by properly qualified service personnel Consult the service manual for proper service procedures to assure continued safety operation and for precautions to be taken to avoid possible exposure to excessive microwave energy PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY A Do not operate or allow the oven to be operated with the door open B Make the following safety checks on all ovens to be serviced before activating the magnetron 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 transmission line and cavity for proper alignment integrity and connections D Any defective or misadjusted components in the interlock monitor door seal and microwave generation and transmission systems shall be repaired replaced or adjusted by procedures described in this manual
24. i tage capacitor voltage capacitor voltage capacitor Normal Check high vol Defective high Replace high tage diode voltage diode voltage diode gt Normal Check Abnormal Defective Replace magnetron magnetron magnetron 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 Output is full power when you set lower power level Disconnect the wire leads from relay 2 and check continuity relay 2 Operate the unit gt Abnormal Defective PCB assembly Replace PCB assembly 5 15 EXPLODED VIEW INTRODUCTION OVEN CAVITY PARTS INTERIOR PARTS BASE PLATE PARTS LATCH BOARD PARTS DOOR PARTS CONTROL PANEL PARTS 6 1 DOOR PARTS 6 2 CONTROLLER PARTS 6 3 OVEN CAVITY PARTS 6 4 LATCH BOARD PARTS 6 5 INTERIOR PARTS 6 6 BASE PLATE PARTS 6 7 d 3 4 E 8 88 882528828888 8282 32 888
25. imes per second The friction among molecules of food occurs repeatedly It then causes the frictional heat and the temperature of the food rises 12 3 1 What s the microwave 2 2 3 The safety of microwave oven Since the microwave oven can t make the native fire like gas you have no use for worrying about the fire Because it doesn t become hot like the ordinary electric range It has been used in the dinner car of the trains etc Microwave oven has the shielded structure strictly with metal case not to leak electric wave at once not only using but on opening the door Because it uses the electric wave the x ray is never emitted The UHF wave generally called microwave is like the electric wave of the TV or the radio and is used for the wireless communication the radar and the UHF medical instruments using 2450 MHz like that of the microwave oven etc 4 Definition of electric wave An electric wave is the electron wave of the frequency from 10 KHz to 3 000 000 MHz Wave length of 2450 MHZ 300000 Km _ 20 122m 12 2 cm f 245000 KHz A Wave Length Where c The Velocity of Light f Frequency The division from the sound frequency to the light frequency 20Hz 3Hz 30 Hz 300 KHz MHz 30 MHz 300 MHz GHz 30 GHz 300 GHz 20 KHz 30 KHz 300 KHz 3 MKHz 30 MHz 300 MHz 3GHz GHz 300 GHz 1018 Hz SOUND LF MF HF VHF ULF SHF EHF LIGHT WAVE FREQ
26. n flow from cathode to anode the cathode must be heated and a potential difference must exist between the two This is accomplished by heating the cathode with 3 4 to 3 5 V AC from the filament winding of the high voltage transformer and applying a negative 4000 V DC from the voltage doubler circuit to the cathode Originally the electrons would travel in a straight line from the cathode to the anode However with the addition of a permanent magnet surrounding the anode creating a magnetic field the electrons travel an orbital path between the cathode and anode As the electrons approach the anode their orbital path takes them past small resonant cavities that are part of the anode The passing notion of the electrons induces electron current to oscillate in the resonant cavities at the very high frequency or 2 450 MHz This RF Radio frequency energy is then transferred to the antenna Disconnect power remove the wrapper and discharge the capacitor Remove the two leads from the magnetron terminals Connect the ohmmeter between one terminal of the magnetron and the outer case of the magnetron If the onmmeter reads infinity go to below If the reads less than infinity the magnetron is shorted Connect ohmmeter across the terminals of the magnetron ohmmeter should read less than one ohm meter if the ohmmeter reads over one ohm or infinity the tube is defective 19 5 1 Multiwave s
27. netic energy leakage monitor checked for calibration by its manufacturer SPECIAL TIP This oven used the button head screws Button Head Torx style 2 When you remove the screws use the tamper resistant Torx driver having a pin in head MEASUREMENT OF MICROWAVE POWER OUTPUT Microwave power output measurement is made with the microwave oven supplied at its rated voltage and operated at its maximum microwave power setting with a load of 1000 5 g of potable water The water is contained in a cylindrical borosilicate glass vessel having a maximum material thickness of 3 mm and an outside diameter of approximately 190mm The oven and 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 for the temperature of the water to rise by a value A T of 10 2 K is measured where T is the time in seconds and AT is the temperature rise The initial and final water temperatures are selected so that the maximum difference between the final water temperature and the ambient temperature is 5 K The microwave power output in watts is calculated from the following formula 4187 x
28. o the common intervals When the button is released slowly the COM and normally open NO terminals of the latches should activate the switches with an switch The meter should indicate a open circuit in audible click the door open condition When the door is closed If the latches do not activate the switches when meter should indicate an closed circuit When the the door is closed the switches should be a secondary switch operation is abnormal make the adjusted in accordance with the adjustment necessary adjustment or replace the switch only procedure Disconnect the wire lead from the with the same type of switch primary switch Connect the ohmmeter leads to the common COM and normally open NO C MONITOR SWITCH TEST terminal of the switch The meter should indicate an open circuit in the door open condition When the door is closed the meter should indicate a closed circuit When the primary switch operation is abnormal make the necessary adjustment or replace the switch only with the same type of switch 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 should indicate an open circuit When the monitor switch operation is abnormal replace with the same type of switch NOTE After repairing the door or the interlock system it is ne
29. on t have to worry about safety The heater moves back to it s position automatically after grilling Your food is more evenly grilled and delicious when Auto Moving Heater Conventional Heater e Sheath Heater LG s Auto Moving Heater Ye One touch Grilling amp Oven Cookie gt Heater 45 Pizza Frozen pizza Chicken piece gt Heater 90 e When grilling heater goes down automatically R amp D e Quartz Heater 22 MODEL SPECIFICATIONS DESCRIPTION MA 2005ST Power Requirement 120 Volts AC 60 Hz 1 550 Watts 13 6 A Single phase 3 wire grounded Power Output 1 150 Watts full microwave power IEC705 Microwave Frequency 2 450 MHz Magnetron 2M246 2M248J Timer 0 99 min 99 sec Outside Dimensions 23778 W 139 16 x 1813 16 D Cavity Dimensions 171 16 W x1013 16 x 185 16 D Net Weight 42 lbs approx Shipping weight 46 Ibs approx Control Complement Touch Control System Clock 1 00 12 59 Microwave Power for Variable Cooking Power level Full power throughout the cooking time approx 90 of Full power 8 Reheat 6 Medium 4 Defrost 2 Simmer approx 80 approx 70 approx 60 approx 50 approx 40 approx 30 approx 20 approx 10 Nameplate Location Back Side Accesso
30. ot 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 REMEDY Avoid using other electrical appliances when you use the microwave oven Insert microwave oven plug securely Use the microwave oven at adequate line voltage Sparks occur This may not be a defect It is possible that the food should be cooked for a longer time period Using metallic ware and allowing it to touch the oven wall Do not use metallic ware for cooking except that noted in the cooking guide Ceramic ware trimmed in gold or silver powder is used Uneven cooking Inconsistent intensity of microwave by their characteristics 5 11 Do not use any type of cookware with metallic trimming 1 Use plastic wrap or lid 2 Stir once or twice while cooking soup cocoa or milk etc TROUBLE 1 The following visual conditions indicate a probable defective control circuit Incomplete segments Segment missing Partial segment missing Digit flickering NOTE Slight flickering is normal
31. oven and cook the food evenly on a rotating turntable Power control can be adjusted in 11 steps which can enable a variety of goods to cook at a suitable power for the best results 2 1 Function amp Type 2 2 2 GRILL COOKING This is a method of cooking with radiant heat from the grill heater on the top of the oven This is a traditional way of cooking which quickly seals and browns food evenly The temperature inside the oven is fixed at 180 C which is ideal grilling temperature for this oven 3 CONVECTION COOKING This is a method of cooking with hot air from the convection heater situated at the rear of the oven This method allows food to be browned evenly without losing any of the juices Air heated by the heater is circulated in the oven by a fan This enables the efficient heating and cooking of food The temperature inside the oven can be controlled according to the type and weight of food being cooked Circulation Motor Convection Rack Grill Heater 4 COMBINATION COOKING Using a combination of microwaves hot air and radiant heat this solid state control can cook alternately according to the cycles programmed This efficient method of cooking fully utilizes the advantages of all three functions giving quick results with a traditional appearance to your cooking Circulation Motor Convection Rack 2 2 Installation amp Utensils 1 2 1 Installation 1 Unpack your oven and place it on a flat level
32. r HIGH VOLTAGE TRANSFORMER 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 J FAN MOTOR ASSEMBLY REMOVAL 1 Discharge the high voltage capacitor 2 Disconnect the leadwire from fan motor and high voltage capacitor 3 Remove the two screws holding the the suction guide ASS Y to the oven cavity and remove the high voltage diode earth screw 4 Remove the two screws holding the fan motor ASS Y to the suction guide ASS Y K HIGH VOLTAGE CAPACITOR AND DIODE REMOVAL 1 Discharge the high voltage capacitor 2 Disconnect the leadwire from fan motor and high voltage capacitor 3 Remove the screw holding the suction guide ASS Y to the oven cavity and remove the high voltage diode earth screw 4 Remove the screw holding the high voltage capacitor bracket Fan Motor ASS Y Es gt PS 5 6 L INTERLOCK SYSTEM 1 INTERLOCK 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 ADJUSTMENTO O DIRECTION O SECONDARYO SWITCH MONITORO SWITCH
33. ries Owner s manual amp cooking guide Glass turntable Rotating ring This microwave oven is designed for household use only It is not recommended for commercial purposes OPERATING INSTRUCTIONS FEATURES Oven Front Plate Window Door Screen Door Seal E Display Window SS Control Panel Door Open Button Safety Door Lock System Turntable Rotating Ring CONTROL PANEL 1 DISPLAY WINDOW 2 ONE TOUCH CONTROL This menu has been pre programmed to cook food automatically by one touch 3 AUTO DEFROST This feature provides you with the best defrosting method for frozen foods 4 CUSTOM COOK This feature allows you to set and execute a frequently used single stage program 5 NUMBER These used to set for time of day cooking time power level or defrost weight Cerco Eu Beverage 6 MORE LESS All of the one touch cook and TIMED COOK Pizza Food Frozen gt can be adjusted to cook food for a longer or shorter time Plate Entree MORE Pressing MORE will add 10 seconds to the Baked Casserole cooking time Vegetable Goods LESS Pressing LESS will subtract 10 seconds of 3 Aulo D Custom 8 cooking time etrost Cook Set 7 STOP CLEAR It used to stop oven and clear all entries except time of day 9 8 CUSTOM SET You can select sound on off clock on off scroll speed Ibs kg choice language choice demo on off mode 10 9 TIME You can se
34. surface 5 Fill a microwave safe container 2 Place your oven in the level location of tour choice with more with 300 ml 1 2 pint of water than 85cm height but make sure there is at least 30cm of space Place on the GLASS TRAY and on the top and 10cm at the rear for proper ventilation The front close the oven door of the oven should be at least 8cm from edge of the surface to prevent tipping An exhaust outlet is located on top of side of the oven Blocking the outlet can damage your oven Press the START button six times to set 3 minutes of cooking time You 3 will hear a BEEP each time you O press the button Your oven will start before you have finished the sixth press don t worry this is normal 7 The DISPLAY will count down from 3 Plug your oven into a standard household socket Make sure 3 minutes When it reaches 0 it will your oven is the only appliance connected to the socket If your sound three BEEPS Open the oven Se oven does not operate properly unplug it from the electrical door and test the temperature of the socket and then plug it back in water If your oven is operating the Ca water should be warm Be careful 4 Open your oven door by pressing the DOOR HANDLE Place when removing the container it the ROLLER REST inside the oven and place the GLASS may be hot TRAY on top 10 2 2 Installation amp Utensils 2 2 2 COOKING UTENSILS Utensils should be checked to ensure that th
35. t generates heat all around the apparatus and the foods are well done with short time If you heat something for long time all of it will be burnt and can t be eaten 14 4 1 Construction of microwave oven Cavity Cabinet locking in microwave and holding food Door Gate coming in and out food It has window and seal structure Control and SS operating state DOOR PARTS Controller supervise of oven OVEN CAVITY PARTS INTERIOR PARTS BASE PLATE PARTS LATCH BOARD PARTS CONTROL PANEL PARTS Magnetron Inject microwave to oven 4 2 How does the microwave oven operate After plugging your oven into a standard household socket press start button or turn the timer And then switches primary secondary timer close the circuit Eventually the input power will be applied to turntable motor timer motor fan motor oven lamp and high voltage transformer A high voltage of 2 100 volts AC is generated in the second winging of H V Transformer And the voltage is doubled by H V Capacitor amp H V Diode The 4Kv DC voltage is applied to filament of magnetron then magnetron start to produce microwave This microwave is injected to cavity THERMAL CUT OUT HIGH VOLTAGE OVEN ey lt TIMER POWER CONTROL Ac RELAY TRANSFORMER BN BN Mo RD r 1
36. t the desired cook time 10 POWER You can select the desired power level for cooking 11 TIMER You can use the timer function of your oven for purpose other than cooking 13 12 CLOCK It is used to set the time of day 13 EZ ON You can extend cooking time in multiples of 1 minute by repeatedly touching this pad during cooking 14 START This feature allows oven to begin functioning 2 One Touch Control 11 12 14 OPERATING SEQUENCE The following is a description of component functions during oven operation 1 SETTING THE CLOCK STOP CLEAR gt CLOCK NUMBER CLOCK ex To set 4 30 touch number key 4 3 and 0 NOTE 1 This is a 12 hour clock 2 Clock will operate as long as power is applied to the oven 2 CANCEL FUNCTION Touch the STOP CLEAR pad whenever you need to cancel an entry or a function currently in use The display will return either to the last item entered or to the clock 3 EZ ON STOP CLEAR gt EZon 4 ONE TOUCH COOKING STOP CLEAR POPCORN NOTE Heat only 1 package at a time 5 TIME COOKING STOP CLEAR gt gt TIME NUMBER POWER gt NUMBER START 6 MULTI STAGE COOKING 1ST STAGE STOP CLEAR
37. tself but utensil don t get hot either when heat is provided the utensil will gradually got hot by thermal conduction however the temperature of the surface and the inside of the fond get hot simultaneously and the food is well done rapidly 2 The principle of dielectric heating The microwave oven has a vacuum tube called magnetron M G T it injects the electric wave of 2450MHz The vibrations of two billion four hundred and fifty million per second are given to the oven This electric wave is called the microwave The wireless electric wave having not more than 1 m of the wave length is using for the radio telephone and broad casting of T V and radar a radio locator It is similar to an electric wave and its wave length is short The length of the electric wave having frequency of 2450MHz is 12 2cm The characteristics of this microwave is as follows 1 When it touches the metal it is reflected and changed direction 2 It passes through ceramics porcelain glass etc plastics and paper 3 If it is touches the food or the wood having water in humidity it is absorbed and generates heat The Microwave oven cook food using these characteristics Generally the food whether it is large or small has humidity So if you put this food in the microwave oven and it gets the electric wave so the energy of it is absorbed in the food since it set up a vibration of the molecules with a frequency two billion four hundred and fifty million t
38. uide NOTE 1 When removing the magnetron make sure its dome does not hit any adjacent parts or it may be damaged 2 When replacing the magnetron be sure to install the magnetron gasket in the correct position and be sure that the gasket is in good condition 3 After replacing the magnetron check for microwave leakage with a survey meter around the magnetron Microwave energy must be below the limit of 5 mW cm With a 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 Waveguide Bracket MagnetronO Gasket Magnetron 5 5 H REMOVING THE TURNTABLE MOTOR 1 Remove the turntable and rotating ring Lay the unit down on its back Remove the turntable motor cover The turntable base cover is easily removed by pinching the eight parts with a wire cutting 4 Disconnect the leadwire from the turntable motor terminals 5 Remove the screw securing the turntable motor to the oven cavity ASS Y 6 After repairing the motor rotate the removed turntable motor cover 7 Fit the turntable motor cover s projecting part to the base plate slit 2 3 NOTE 1 Remove the wire lead from the turntable motor VERY CAREFULLY 2 Be sure to grasp the connector not the wires when removing Turntable Moto
39. ve energy leakage around the door viewing window the exhaust opening and air inlet openings Microwave energy leakage must not exceed the values prescribed below NOTE Leakage with the outer case removed less than 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 NOTES WHEN MEASURING Do not exceed meter full scale deflection 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 along the oven surface this may possibly cause probe damage RECORD KEEPING AND NOTIFICATION AFTER MEASUREMENT After adjustment and repair of any microwave energy interruption or microwave energy blocking device record the measured values for future reference Also enter the information on the service invoice The microwave energy leakage should not be more than 4 mW cm sq after determining that all parts are in good condition functioning properly and genuine replacement parts which are listed in this manual have been used At least once a year have the electromag
40. ven 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 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 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 e Inch scale 600 cc non conductive material beaker glass or plastic inside diameter approx 8 5 cm 31
41. ystem What is Multi Wave The multi Wave system heats food more evenly than convectional microwave ovens Conventional Multi Wave SINGLE WAVE MULTIWAVE rn Plate of food 1 2 Glass of milk NO COLD SPOTS 2 Bie UNIFORM COOKING 5 2 Infrared sensor What s the infrared sensor You may be annoyed when you defrost or reheat food with microwave oven If you reheat soup the result is superficial The surface is hot but inside of the soup is still cold You have to set the clock and push Start again The cooking time is much longer than you expected LG microwave oven reduce cooking time Our revolutionary Infrared sensor makes it 3 times faster than the ordinary microwave Infrared eye tracks the exact temperature of food and regulates the power of the microwave so that the temperature reaches you actually set We prepared the temperature LED bar and dial for your precise control and convenience Infrared sensor means fast and real hot result Power Output Finish Finish Save 40 24 5 3 Auto moving heater What s does move automatically Conventional microwave oven with grill has a heater on the ceiling of cooking room Whether you cook a pizza or chicken the position of heater is unmovable We changed the old way LG heater is moving when you choose grill the heater goes down The angle of heater varies as to each menu You d
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