MICROWAVE OVEN SERVICE MANUAL
Contents
1. 1 Setting time does not count down when touching START pad o Check continuity of secondary switch with door closed No continuit Defective Replace secondary switch secondary switch Continuity p Replace fan motor Check continuity of secondary Defective P C B Replace P C B switch with assembly assembly door closed Connection then Continuity Loose connection tightly 2 Fan motor or u Defective fan Replace fan gt oven lamp do Check fan motor D No continuity HOOF not turn on Check oven lamp 32 No continuity vei an TROUBLE 4 Oven seems be operation but little heat is produced in oven load CONDITION CHECK RESULT CAUSE REMEDY Output is low _ Check the Lower than 90 of Decrease in power Suggest customer power source rating voltage source voltage contact local voltage with load electric power el Normal utility co or qualified electrician Disconnect the wire leads from Abnormal Defective P C B Replace P C B relay 2 and check assembly assembly on and off time with multitester Abnormal Measure the Abnormal Defective Replace Abnormal output magnetron magnetron NOTE Simple test of power output conducted by heating one liter water for one min i2. SCHEMATIC DIAGRAM YON UL WLL E wick m 7 punoJB sisseuo 0 y JO jeuiuJe N3349 N9 yov yg abeyon eAneDoeu ay Ag Jojoede d38 de TE W8 uBiu ebieyosid ONIDIAYIS 390438 Avo ox xis 39V1710A 1n vH 30 31loVvdvo 13 YSLOSANNOOAC SNDINHOSL NOLLN3AH3 LNI LNVAV FOILON LNOHLIM 39NVHO jj uepepnue esse OL LOAFENS 39 LINDYIO E nn _ ue e JOA JojesuepuoxysBunuuedsuoou ONMNLHOW Qq3N3dO SI HOOQ ALON x NHOLIOVdVO A H Ol 3ISNINH AALLWNYALIV NOYLINOVIAN mn no JaOIaAH AaVOg LIn Wl TOULNOD H3MOd di to Y0193108d LINDUII YAWYOASNVEL ADVLIOA HOIH EJE S INO N9 20 HOLIMS AHVOIONOOIS HM yg NP J HM 18 A QS 18 ZAV TAM 0 Xgl 3SION 18 o o 9 ZHOS NOEZ OV S 90 d Q T H3MOd LNdNI T 9 9 asn4 SE xg Y Ng Ng oTo Ng Nd O N a HOLIMS AYVINIlHd IVISONY3H1 WVAOVIG JL VAWSHOS 4 3 CIRCUIT DESCRIPTION GENERAL DETAI
3. Make sure the wire leads correct position e 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 5 16 EXPLODED VIEW INTRODUCTION OVEN CAVITY PARTS INTERIOR PARTS BASE PLATE PARTS LATCH BOARD PARTS CONTROL PANEL PARTS DOOR PARTS 6 2 CONTROL PANEL PARTS 6 3 OVEN CAVITY PARTS 6 4 LATCH BOARD PARTS TA 0 0 Y 2 6 5 INTERIOR PARTS BASE PLATE PARTS 6 7
4. approx 190mm height approx 90mm e Glass thermometer 100 C or 212 F 1 deg scale MEASURING MICROWAVE ENERGY LEAKAGE e 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 e 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 bcm 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 JV M ELE EL Probe scanning speed Less than 2 5 cm sec 1in sec 222220222222 gt CN NON NN NN UN N 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 opecial care should be taken in measuring the following parts Circled area of below Fig Around the magnetron The waveguide WARNING AVOID CONTACTING ANY HIGH VOLTAGE PARTS Magnetron H V Transformer H V Capacitor H V Cable Ass y H V Circuit Protector MEASUREMENT WITH A FULLY ASSEMBLED OVEN After all components including the outer case are fully
5. assembled measure for microwave 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 removedless 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 e 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 y
6. cloth MICROWAVE LEAKAGE TEST 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 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 f 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 4 mW cm Always start measuring of an unknown field to assure safety for operating personnel from radiation leakage 5 1 NECESSARY MEASURING INSTRUMENTS e TESTER VOLTS DC AC Ohmmeter Microwave survey meter Holaday HI 1500 1501 Narda 8100 8200 e Inch scale e 600 cc non conductive material beaker glass or plastic inside diameter approx 8 5 cm 3 2 in e Cylindrical and made of borosilicate glass vessel max thickness 3 mm outside diameter
7. is too low Sparks occurring Using metallic ware and allowing it to touch the oven wall ypy Use the microwave oven at adequate line voltage This may not be a defect It is possible that the food should be cooked for a longer time period Do not use metallic ware for cooking except where noted in the cooking guide Ceramic ware trimmed in gold or silver powder is used ox Uneven cooking Inconsistent intensity of microwave by their characteristics Turntable drags or makes noise IExcessive weight on tray or improperly balanced 5 11 Do not use any type of cookware with metallic trimming 1 Wrap the thinner part with aluminum foil 2 Use plastic wrap or lid 3 Stir once or twice while cooking soup cocoa or milk etc Distribute food evenly Cook smaller portions and or use lighter weight cookware TROUBLE 1 Oven lamp does not turn on when the timer knob is pushed with door closed Incomplete segments e Segment missing e Partial segment missing Digit flickering NOTE Slight flickering is normal Colon does not turn on or blink A distinct change in the brightness of one or more numbers in display One or more digits in the display are not lighting Display indicates a number different from one touched for example key in 5 and 3 appears in the display Specif
8. motor cover The turntable base cover is easily removed by pinching the six parts with a wire cutting 5 Disconnect the leadwire from the turntable motor terminals 6 Remove the screw securing the turntable motor to the oven cavity ASS Y 7 After repairing the motor rotate the removed turntable motor cover 8 Fit the turntable motor cover s projecting part to the base plate slit 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 Motor K 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 SUB ASS Y and take off the PCB SUB ASS Y 5 6 L 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 2 MOUNTING OF THE PRIMARY MONITOR SECONDARY SWITCHES TO THE LATCH BOARD ADJUSTMENT DIRECTION PRIMARY SWITCH MONITOR SWITCH SECONDARY SWITCH 3 INSTALLATION AND ADJUSTMENT OF THE LATCH BOARD TO THE OVEN ASSEMBLY Mount the latch board to the oven assembly e Adjust
9. survey meter Microwave energy must be below the limit of 5 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 Hemove Hinge Plate Hemove Door Assembly AS E 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 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 guide ASS Y to the oven cavity and remove the high voltage diode earth screw 4 Remove the screw of the capacitor bracket 5 Remove the two screws holding the fan motor ASS Y to the suction guide ASS Y G HIGH VOLTAGE CAPACITOR AND DIODE REMOVAL 1 Discharge the high voltage capacitor 2 Disconnect the leadwire from fan motor noise filter 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
10. the latch board in the arrow direction so that oven door will not have any play in it when the door is closed e Tighten the mounting screw Check for play in the door by pushing the door release button Door movement should be les than 0 5 mm 1 64 inch Don t push the door release button while making adjustment Make sure that the latch moves smoothly after adjustment are completed and that the screws are tight Make sure the primary monitor and secondary switches operate properly by following the continuity test procedure FIG 1 CAUTION CHECK THE CORRECT POSITION MAGNETRON pid PRIMARY CIRCUIT PROTECTOR 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 to 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
11. the screw holding the high voltage capacitor bracket H V b Capacitor be d e 4 22 c Transformer H V H AIR DUCT ASSEMBLY REMOVAL 1 Disconnect the leadwire from lamp 2 Remove the mounting screw to Latch Board I MAGNETRON REMOVAL 1 Disconnect the leadwire from the high voltage transformer and high voltage capacitor 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 waveguide 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 Dome Waveguide Bracket Magnetron Gasket Magnetron 5 9 J REMOVING THE TURNTABLE MOTOR 1 Remove the turntable 2 Remove the Rotating Ring 3 Lay the unit down on its back 4 Remove the turntable
12. ECT POSITION e WHEN REMOVING THE WIRE LEADS FROM THE PARTS BE SURE TO GRASP THE CONNECTOR NOT THE WIRES 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 2 Be careful of the high voltage circuit 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 circuitry on the digital programmer circuit since static electric discharge may damage this control panel Always touch yourself ground while working on this panel to discharge any static charge built up in your body CONDITION CAUSE REMEDY Microwave oven does not work Inserting many plug into one plug outlet and using them at the same time causes overloading Avoid using other electrical appliances when you use the microwave oven Microwave oven plug is not inserted tightly Insert microwave oven plug securely Output power is too low Low AC input voltage Food temperature
13. K Website http biz lgservice com LG MICROWAVE OVEN MODEL MS 2384B CAUTION BEFORE SERVICING THE UNIT READ THE SAFETY PRECAUTIONS IN THIS MANUAL June 2004 P NO 3828 553871 Printed in Korea 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 th
14. LS e 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 e The micom controller memorizes the function 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 e Turntable rotates PRIMARY SWITCH O O FUSE XQ MONITOR SWITCH XX CO SECONDARY l RELATA TT SWITCH l The fan motor rotates and cools the magnetron by blowing the air coming from the intake on the baseplate e The air is also directed into the oven to exhaust the vapor in the oven through the upper plate e Cooking time starts counting down 3 2 volts AC is generated from the filament winding of the high voltage transformer This 3 2 volts is applied to the magnetron to heat the magnetron filament through two noise preventing choke coils 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 chargin
15. Single phase 3 wire grounded Microwave 1250W Power Output 850 Watts full microwave power IEC 60705 Microwave Frequency 2450 MHz Magnetron 2M167B M47J1 Timer 0 99 Min Outside Dimensions 507 W x 283 H x 435 D mm Cavity Dimensions 331 W x 203 H x 360 D mm Net Weight 14 0 kg approx Shipping weight 16 0 kg approx Control Complement Microwave Power for Variable Cooking Power level MAA ERN Full power throughout the cooking time MED Al Alison cas approx 80 of Full power MEDIUM a een approx 60 of Full power DEFRO Treaa approx 40 of Full power 1 2 approx 20 of Full power Name plate Location Back Side i Accessories Owner s manual Glass tray Rotating ring This microwave oven is designed for household use only It is not recommended for commercial purposes 1 1 CAUTIONS Unlike other appliances the microwave oven is high voltage and high current equipment MICROWAVE RADIATION Personnel should not be exposed to the microwave energy which may radiate from the magnetron or other microwave generating device if it is improperly used or connection Though it is free from danger in ordinary use extreme care should be taken during repair DO NOT operate on a 2 wire extension cord during repair and use All input and output microwave connections waveguide flange and gasket
16. agnetron gasket in the correct position and be sure that the gasket is in good condition HIGH VOLTAGE CAPACITOR HIGH VOLTAGE DIODE NOTE Some inexpensive meters may indicate infinite resistance in both direction Measure the resistance Ohm meter scale Rx1000 e Terminal to terminal Measure the resistance Ohm meter scale Rx1000 e Terminal to case Measure the continuity Forward Ohm meter scale Rx10000 Measure the continuity Reverse Ohm meter scale Rx10000 5 9 Normal Momentarily indicates several ohms and then gradually returns to infinite Normal Normal Continuity Abnormal Normal Abnormal Continuity COMPONENTS TEST PROCEDURE RESULTS RELAY 2 Check for continuity of relay 2 with an POWER ohm meter LEVEL v dii n Remove wire leads from relay 2 and operate the unit 20 40 60 80 100 6 sec 10 sec 14 sec 18 sec 22 16 12 sec 8 sec 4 sec 0 sec Transformer Measure the resistance Ohm meter scale R x 100 FAN MOTOR Wire leads removed Normal 350 450 Abnormal or several TURNTABLE Measure the resistance MOTOR Ohm meter scale R x 1000 Wire leads removed Normal Approx 16 K Abnormal several NOTE MICROWAVE LEAKAGE TEST MUST ALWAYS BE PERFORMED WHEN THE UNIT IS SERVICED FOR ANY REASON e MAKE SURE THE WIRE LEADS ARE IN THE CORR
17. ating 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 e Stirring devices and measuring instruments are selected in order to minimize addition or removal of heat WATER LOAD E gt TURNTABLE DISASSEMBLY AND ADJUSTMENT A OUTER CASE REMOVAL 1 Disconnect the power supply cord from the outlet 2 Remove the screws from the rear and along side edges 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 earth terminal CAUTION DISCHARGE THE HIGH VOLTAGE CAPACITOR BEFORE SERVICING refer to page 2 1 C CONTROL PANEL ASSEMBLY 1 Disconnect the leadwire from the PCB SUB ASS Y 2 Remove the screws for the earth and securing the control panel 3 Lift control panel ASS Y from the oven by the tab unhooked D DOOR GROSS ASSEMBLY REMOVAL 1 Open the door 2 Remove the choke cover cap 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
18. ch e Y AUTO DEFROST Used to select the auto defrost le 2 BP en STOP CLEAR Used to stop over and clear all oa entries except time of day DIAL START QUICK START One tap allows over to begin functioning OPERATING SEQUENCE The following is a description of component functions during oven operation 1 SETTING THE CLOCK ELEM Set the minutes ra Clock NOTE 1 You can set 12 hour clock or 24 hour clock optionally 2 Clock will operate as long as power is applied to the oven 2 CANCEL FUNCTION Touch the pad whenever you need to cancel an entry or a function currently in use The display will either return to the last item entered or to the clock 3 CHILD LOCK This oven has a CHILD LOCK feature e TO SET CHILD LOCK e Touch the pad e Touch STOP pad L appear in the display e TO CANCEL CHILD LOCK e Touch the pad e Touch STOP pad gt L disappears 4 QUICK START Stop Start Quick start 5 MICROWAVE COOKING Power 3 amp Time gt Start 6 AUTO WEIGHT DEFROST Auto Defrost Weight kg Start Quick Start 7 AUTO COOK Auto Cook Weight kg gt Start Quick Start 8 SPECIAL COOK gt a Cook 0 Weight kg T Start Quick Start
19. 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 necessary to do this continuity test before operating the oven COMPONENTS TEST PROCEDURE RESULTS SWITCHES Check for continuity of the Wire leads removed switch with an Ohm meter Primary Switch Mon
20. crowave 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 The wires in this mains lead are colored in accordance with the following code Earth Neutral Live Green and yellow Blue Brown As the colors of the wires in the mains lead of this appliance may not correspond with the colored markings identifying the terminals in your plug proceed as follows The wire which is colored green and yellow must be connected to the terminal in the plug which is marked with the letter E or by the earth symbol C or colored green or green and yellow The wire which is colored blue must be connected to the terminal in the plug which is marked with the letter N or colored black The wire which is colored brown must be connected to the terminal in the plug which is marked with the letter L or colored red OPERATING INSTRUCTIONS FEATURES Oven Front Plate Window Door Screen Door Seal Control Panel Safety Door Lock System GLASS TRAY ROTATING RING CONTROL PANEL POWER Used to select the desired microwave power level for cooking grill and combi CLOCK Used to set the time of day SPECIAL COOK QUICK DEFROST Used to select the quick defrost 5 AUTO REHEAT Used to select the auto reheat xxr AUTO COOK Used to cook the foods listed by one i tou
21. e microwave oven and clean inside it with a soft damp cloth Check for damage such as misaligned door damage around the door or dents inside the cavity or on the exterior Put the oven on a counter table or shelf that is strong enough to hold the oven and the food and utensils you put in it The control panel side of the oven is the heavy side Use care when handling Do not block the vent and the air intake openings Blocking vent or air intake openings can cause damage to the oven and poor cooking results Make sure the microwave oven legs are in place to ensure proper air flow The oven should not be installed in any area where heat and steam are generated because they may damage the electronic or mechanical parts of the unit Do not install the oven next to a conventional surface unit or above a conventional wall oven Use microwave oven in an ambient temperature less than 104 F 40 C Place the microwave oven on a sturdy and flat surface at least 10 cm 4 inches from the wall Place the microwave oven as far away as possible from TV RADIO COMPUTER etc to prevent interference Do not touch the front glass during or after cooking of the Grill and Combination mode This glass is very hot during heater operating Do not operate the oven at microwave and combination mode with Grill rack placed in the cavity when the oven is empty 10cm 3 1 EARTHING INSTRUCTIONS This mi
22. ear have the electromagnetic energy leakage monitor checked for calibration by its manufacturer 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 x 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 190 mm The oven and the empty vessel are at ambient temperature prior to the start of the test e 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 e The time T for the temperature of the water to rise by a value AT 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 P in watts is calculated from the following formula 4187 X AT 0 55 X T2 To XM T e T Temperature after heating e To Temperature after bown M Weight of bowl is measured while the microwave generator is oper
23. f available 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 m Defective PCB Replace PCB Disconnect the No continuity oscillation assembly assembly wire leads from relay 2 and check continuity gt Continuity of relay2 Operate the unit Defective circuit Replace circuit Abnormal protector protector Normal Check high vol ABRA Defective high Replace high tage transformer voltage voltage transformer transformer Tema Check high vol T Defective high Replace high tage capacitor voltage capacitor voltage capacitor Normal Check high vol Defective high Replace high tage diode voltage diode voltage diode Normal Check Abnormal Defective Replace magnetron magnetron magnetron Check circuit protector E 5 15 TROUBLE 5 No microwave oscillation even though oven lamp and fan motor run Display operates properly CONDITION CHECK RESULT CAUSE REMEDY Output is full power Disconnect the Abnormal Defective PCB Replace PCB when you set lower wire leads from assembly assembly power level relay 2 and check continuity relay 2 Operate the unit NOTE
24. g 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 4 4 power of microwave oven as POWER LEVEL refer to page 1 1 WHEN THE DOOR IS OPENED DURING COOKING Both the primary switch and relay 2 are cut off primary winding voltage of the high voltage transformer e 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 secondary switch is closed The cooking time stops counting down Relay stops functioning As the door is opened if the contact of primary switch and relay 2 and or secondary switch fails to open the fuse opens due to the large current surge caused by the monitor switch activation which in turn stops magnetron oscillation PRIMARY SWITCH FUSE MONITOR SECONDARY 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 e Phillips screwdriver e Flat blade screwdriver e Wrench size 5mm e Nutdriver size 5mm e Adjustable wrench e Soldering iron e Solder e Vinyl insulation tape e Polishing
25. ic numbers for example 7 or 9 will not display when key pad is touched Display does not count down with time blinking or up with clock operation Display obviously jumps in time while counting down Display counts down too fast while cooking Each indicator light does not turn on after setting 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 CONDITION CHECK RESULT CAUSE REMEDY 1 No input can be Check the conn Continuit MER Defective PCB Replace PCB programmed ection between y assembly assembly membrane key assembly and Re 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 number or figure different from one touched Loose Replace PCB Still have trouble connection 4 Random programming when touching other pads Display is fixed at some figure and can not accept any input 5 12 TROUBLE 2 Oven does not operate at all Display window does not display any figures and no input is accepted CONDITION CHECK RESULT CAUSE 1 Fuse blows Check continuity of monitor sw
26. is manual before the oven is released to the owner E A microwave leakage check to verify compliance with the Federal Performance Standard 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 CONTENTS Page SAFETY PRECAUTION Siena ias Inside front cover SPECIE IC ATION cR D E m Lm 1 1 a dec esu mr s ee oe 2 1 INSTALLATIONS CA RU RE IER IN M DN TUI RU II VERE 3 1 OPERATING INSTRUCTIONS see 4 1 EEATUBES en ee emer re 4 1 eoe Br er zT C TT T t PETENS 4 1 OPERATING SEQUENCE aa odo 4 2 SCHEMATIC DAGBA nm ee 4 3 DESCRIPTION se ge 4 4 SERVICE INFORMATION nen 5 1 TOOLS AND MEASURING INSTRUMENTO ae 5 1 MEROWAVELEAKAGE TES nu m 5 1 MEASUREMENT OF MICROWAVE POWER OUTPUT 5 3 D SASSEMBLY AND ADJUSTMEN ia 5 3 INTERLOCK CONTINUITY TES Tiara 5 7 COMPONENT TEST PROCEDURE re u 5 8 TROUBLE SHOOTING Are 5 12 EXPLODED VIEW EC LITT T ITIITIIQIICCIQIC TT 6 1 REPLACEMENT PARTS idas 7 1 SPECIFICATIONS MODEL MS 2384B Power Requirement 230 Volts AC 50 Hz
27. itch with door closed Check continuity of primary switch with door opened 7 Malfunction of the Continuity monitor switch No continuity Heplace fuse Continuity 3 gt No continuity Shorted contact at the primary switch Disconnect one side of the wire lead connected from transformer to the high voltage capacitor and operate the unit AN A Defective high voltage capacitor Fuse blows again Defective high volt age transformer NOTE All these switches must be replaced at the same time Refer to page 5 6 5 7 2 Fuse does not blow Check continuity of magnetron thermostat Check continuity of power supply cord No continuity gt Continuity No continuity gt 9 13 Defective mag netron thermostat Defective power supply cord REMEDY Replace primary and monitor switches Replace primary and monitor switches Replace high voltage capacitor Replace high volt age transformer Replace power Replace mag o netron thermostat supply cord 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
28. itor Switch Secondary Switch NOTE After checking for the continuity of switches make sure that are connected correctly 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 HIGH VOLTAGE TRANSFORMER Wire leads removed TEST PROCEDURE RESULTS FILAMENT WINDING TERMINAL SECONDARY TERMINAL PRIMARY TERMINAL 1 Measure the resistance Ohm meter scale Rx1 and Rx100 Primary winding Approx 2 5 Q Secondary winding Approx 110 Q e Filament winding Less than 0 4 Q 2 Measure the resistance Ohm meter scale Rx1000 Primary winding to ground e Filament winding to ground MAGNETRON Wire leads removed 1 Measure the resistance Ohm meter scale Rx1 Normal Less than 1 Q e Filament terminal 2 Measure the resistance Ohm meter scale Rx1000 Normal e Filament to chassis COMPONENTS TEST PROCEDURE Antenna Gasket Filament RESULTS NOTE When testing the magnetron be sure to install the m
29. must be secure e NEVER TOUCH any oven components or wiring during operation e BEFORE TOUCHING any parts of the oven always remove the power plug from the outlet never operate the device without a microwave energy absorbing load attached Never look into an open waveguide or antenna while the device is energized For about 30 seconds after the oven stops an electric charge remains in the high voltage capacitor When replacing or checking you must discharge the high voltage capacitor by shorting across the two terminals with an insulated screwdriver Proper 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 e Remove your watches whenever working close to or replacing the Magnetron NEVER operate the oven with no load NEVER injure the door seal and front plate of the oven cavity e NEVER put iron tools on the magnetron NEVER put anything into the latch hole and the interlock switches area 2 1 ANTENNA FILAMENT TERMINALS MAGNETRON CHASSIS GROUND MAGNETRON THE OVEN IS TO BE SERVICED ONLY BY PROPERLY QUALIFIED SERVICE PERSONNEL INSTALLATIONS BEFORE YOU BEGIN READ THE FOLLOWING INSTRUCTIONS COMPLETELY AND CAREFULLY INSTALLING 1 Empty th
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