Microwave Oven Service Manual
Contents
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6. RFS18G 4 2 Cooking Displays Shows when power is connected to oven Open and close door to clear READY shows when oven control will accept entries Appears after oven door is opened and closed 33 33 shows heating time When more than 1 heating stage is programmed total time for all stages displays COOK shows when oven is operating 20 indicates the microwave power level used If power level does not show oven is heating at 100 power Indicates programming mode See Programming section of manual for programming procedure Indicates programming user options mode See User Options section of manual for programming procedure 4 3 Operation To avoid fire do not dry newspapers or clothes in microwave oven Interrupting Operation Open oven door to interrupt operation Oven fan continues to operate Close door and press START pad to resume oven operation Press STOP RESET pad to interrupt operation Display continues to show countdown time Press START pad to resume oven operation and countdown timing Canceling Mistakes If oven is operating press STOP RESET pad once to stop oven then again to clear display If oven door is open and time shows in display close oven door and press STOP RESET pad to clear display Operating Preprogrammed Pads Oven has 10 20 preprogrammed number pads Instructions
7. e 1 22k fp voraz s 8 ie A Eo o gs 4 1 ase 58855 2335 H 8 8 9 338 ea 5 3355838385 5069095 Eeprom 58553892923 as PROGRAMMING Adaa Ag Atos CONNECTOR SSPSZRSZZEZSEaR CN2 2mm 0 0 MONITOR SW POWER 208 208 230 DOOR SWITCH 5 1 MAGNETRON 11 a 7 1 NOTE 1 The unit of ELECTROLYTIC CAPACITOR is uF iV 2 The unit of CERAMIC CAPACITOR Is pi 3 The unit of RESISTOR is ohm and K 1000 M K K 4 The transistor in the hidden circle line is transistor ex 220 25 220luF 25 V ex 223P 22 10 pF with built in bias resistor PRINTED CIRCUIT BOARD 68701 99 1 2339 2004 07 15 Q
8. INSTALLATIONS BEFORE YOU BEGIN READ THE FOLLOWING INSTRUCTIONS COMPLETELY AND CAREFULLY INSTALLING GROUNDING INSTRUCTIONS 1 Empty the microwave oven and clean inside it with a For personal safety this appliance must be fully soft damp cloth Check for damage such as grounded at all times misaligned door damage around the door or dents inside the cavity or on the exterior In the event of an electrical short circuit grounding reduces the risk of electrical shock 2 Put the oven on a counter table or shelf that is strong The plug must be plugged into an outlet that is properly enough to hold the oven and the food and utensils you installed and grounded put in it The control panel side of the oven is the heavy side Use care when handling 3 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 WARNING Improper use of the grounding plug can result in a risk of electric shock Do not under any circumstances cut or remove the third ground prong from the power cord plug 4 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 5 Use m
9. Measure the resistance Ohm meter scale Rx1000 e Primary winding to ground Filament winding to ground 208V 220 240 V Approx 0 8 1 0 0 9 1 1 ohm Approx 70 80 ohm 70 80 ohm Less than 1 ohm Normal Infinite Normal Infinite MAGNETRON Wire leads removed Measure the resistance Ohm meter scale Rx1 Filament terminal Measure the resistance Ohm meter scale Rx1000 e Filament to chassis 5 8 Normal Less than 1 ohm Normal Infinite COMPONENTS TEST PROCEDURE RESULTS Antenna Chassis N Filament 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 e 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 N 5 9 Normal Infinite Abnormal Continuity COMPONENTS TEST PROCEDURE RESULTS 208V RELAY 4 R
10. 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 Door Wire leads removed switch with an Ohm meter open Primary Switch lt N Monitor Switch Secondary Switch EN 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 WINDING SECONDARY TERMINAL PRIMARY TERMINAL 1 Measure the resistance Ohm meter scale Rx1 and Rx100 e Primary winding Secondary winding Filament winding
11. high voltage capacitor by shorting across the two terminals with an insulated screwdriver e Remove your watches whenever working close to or replacing the Magnetron DO NOT touch any parts of the control panel circuit A resulting static electric discharge may damage this P C B NEVER operate the oven with no load NEVER injure the door seal and front plate of the oven cavity NEVER put iron tools on the magnetron NEVER put anything into the latch hole and the interlock switches area 2 1 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 All input and output microwave connections waveguide flange and gasket must be secure never operate the device without a microwave energy absorbing load attached Never look into an open waveguide or antenna while the device is energized 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 ANTENNA Gasket COOLING FIN FILAMENT MAGNETRON TERMINALS CHASSIS GROUND MAGNETRON THE OVEN IS TO BE SERVICED ONLY BY PROPERLY QUALIFIED SERVICE PERSONNEL
12. minutes 30 seconds press 2 3 and 0 pads 4 Press desired power level pad to change power level If a power level pad is not pressed oven defaults to 100 power For example pressing MEDIUM 50 pad sets oven to 50 power Display shows current power level if other than 100 percent power 5 Press START pad Oven operates and time counts down 6 Oven stops heating and oven signal sounds when heating timing elapses PROGRAMMING Preprogrammed Number Pads Oven has 10 preprogrammed number pads Follow instructions below to program heating times and power levels for customized cooking 1 Open oven door If door is closed STOP RESET pad is pressed before finishing programming sequence oven exits programming mode 2 Press and hold pad 1 for approximately 5 seconds After 5 seconds signal sounds Display shows PROGRAM indicating program mode 3 Press desired number pad Display shows heating time COOK LEVEL and power level if other than 100 percent power 4 Press number pads to enter desired cooking time For example to heat for 2 minutes 30 seconds press 2 3 and O pads 5 Press desired power level pad to change power level If a power level pad is not pressed oven defaults to 100 power For example pressing MEDIUM 50 pad sets oven to 50 power Display shows current power level if other than 100 power 6 Press START pad to save new heating time and power l
13. 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 F MAGNETRON REMOVAL 1 Disconnect the leadwire from the magnetron 2 Remove the duct ASS Y 3 Carefully remove the mounting screws holding the magnetron and the waveguide 4 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 w
14. 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 REMEDY Microwave oven gt Inserting many plugs into one gt Avoid using other electrical does not work outlet and using them at the appliances when you use the same time microwave oven blown fuse or breaker Microwave oven plug is not Insert microwave oven plug inserted tightly securely Output power is too low Low AC input voltage gt Use the microwave oven at adequate line voltage Food temperature is too low This may not be a defect It is possible that the food should be cooked for a longer time period Sparks occur Using metallic ware and p Do not use metallic ware for allowing it to touch the oven cooking except that noted in wall the cooking guide Ceramic ware trimmed in Do not use any type of gold or silver powder is used cookware with metallic trimming Uneven cooking _ Inconsistent intensity of gt 1
15. to I servicing the oven if the oven is operative prior to Pour 275 15 of 20 5 C 68 9 F water in a beaker servicing which is graduated to 600 cc and place the beaker The service personnel should inform the on the center of the turntable manufacturer importer or assembler of any Set the energy leakage monitor to 2 450 MHz and certified oven unit found to have a microwave use it following the manufacturer s recommended emission level in excess of 5 mW cm and should test procedure to assure correct result repair any unit found to have excessive emission levels When measuring the leakage always use the 2 inch 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 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 personnel should probe perpendicular to the surface being measured Tell the user not to operate the oven Contact the manufacturer and CDRH Move probe along shaded area Center for Devices and Radiological Health 2222 immediately Probe scanning speed NOTE Address on CDRH Less than 2 5 cm sec Office of Compliance HFZ 312 1in sec Center for Devices and Radiological Healthe 1390 Pic
16. CAUTION BEFORE SERVICING THE UNIT READ THE SAFETY PRECAUTIONS IN THIS MANUAL Amana Microwave Oven Service Manual RFS18G RFS18MPS 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 nat 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 before the oven is released to the owner E A microwave lea
17. ELAY 6 220 20V RELAY RELAY 5 Check for continuity of relay 3 an ohm meter Remove wire leads from relay 2 and operate the unit EA 3 sec 4 sec 5 sec 6 sec 7 sec 8 sec 9 sec 10 sec 11 sec 12 sec BLOWER MOTOR Wire leads removed Measure the resistance Ohm meter scale R x 100 Normal Approx 208V 28 31 ohm 220 240V 31 35 ohm Abnormal Infinite or several K ohm STIRRER MOTOR Wire leads removed Measure the resistance Ohm meter scale R x 1 Normal Approx 12 14 kohm Abnormal Infinite or several ohm NOTE A MICROWAVE LEAKAGE TEST MUST ALWAYS BE PERFORMED WHEN THE UNIT IS SERVICED FOR ANY REASON e MAKE SURE THE WIRE LEADS ARE IN THE CORRECT POSITION WHEN REMOVING THE WIRE LEADS FROM THE PARTS SURE TO GRASP THE CONNECTOR NOT THE WIRES 5 10 TROUBLE SHOOTING WHEN YOU GET A COMPLAINT FROM YOUR CUSTOMER EVALUATE COMPLAINT CAREFULLY 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
18. I Len BTM STIRRER 230V tap 5 MOTOR H I q 2 iai 208V 46 T I wH BK I 8 GN inf 2 I SECONDARY STIRRER INTERLOCK CN1 SWITCH MOTOR I TOP INTERLOCK I MONITOR SWITCH TAB8 I RD V S RELAY2 RY 4 1 208 so BL BK 0 NO H TOP MAGNETRON SEE HV CIRCUIT BL BTM INTERLOCK MONITOR SWITCH NC 1 DOOR IS OPENED 2 WIRE COLOR BTM MAGNETRON SEE HV CIRCUIT TOP PRIMARY INTERLOCK BK SWITCH O BN SYMBOL BN WH BK BL YL PK RD GN GREEN HV CIRCUIT 2 PLACES r 1 CIRCUIT PROTECTOR l EA boo CHOKE FILTER MAGNETRON H V DIODE 4 7 WH BTM MGT 145 60 C 293 140 F BTM PRIMARY INTERLOCK SWITCH 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 IMPORTANT FOR PROTECTION FROM MICROWAVE RADIATION FIRE ELECTRICAL SHOCK AND IMPORTANT SAFETY NOTE THE SHADED AREAS ON THIS SCHEMATIC DIAGRAM INCORPORATE SPECIAL FEATURES NOTICE SINCE THIS IS BASIC SCHEMATIC DIAGRAM VALUES OF COMPONENTS AND SOME PARTIAL CONNECTIONS ARE SUBJECT TO CHANGE FOR IMPROVEMENT CIRCUIT DESCRIPTION GENERAL DETAILS The low voltage transformer supplies the necessary voltage to the mico
19. IMARY 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 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
20. TERLOCK 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 3 INSTALLATION AND ADJUSTMENT OF THE LATCH BOARD TO THE OVEN ASSEMBLY e Mount the latch b oard 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 ADJUSTMENT DIRECTION MONITOR SWITCH PRIMARY SWITCH SECONDARY SWITCH INTERLOCK CONTINUITY TEST WARNING FOR CONTINUED PROTECTION AGAINST EXCESSIVE RADIATION EMISSION REPLACE ONLY WITH IDENTICAL REPLACEMENT PARTS TYPE NO SZM V 16 FD 63 OR V 16 3C 25 FOR PRIMARY SWITCH TYPE NO SZM V 16 FD 62 OR V 16 2C 25 FOR MONITOR SWITCH TYPE NO SZM V 16 FD 63 OR V 16 3C 25 FOR SECONDARY SWITCH A PR
21. Use plastic wrap or lid microwave by their 2 Stir once or twice while characteristics cooking soup cocoa or milk etc gt Display CALL SERVICE This may be cause incomplete connect to H V transformer 5 11 TROUBLE 1 The following visual conditions indicate a probable defective control circuit 1 Incomplete segments Segment missing Partial segment missing Digit flickering NOTE Slight flickering is normal programming when touching other pads 5 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 Defec
22. age transformer This 3 3 volts is applied to the magnetron to heat the magnetron filament through two noise preventing choke coils 4 8 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 3 and relay 5 208V relay 4 amp relay 6 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 3 is 12 WHEN THE DOOR IS OPENED DURING COOKING Between the btm primary switch and relay 5 208V relay 6 and top primary switch and relay 3 208V relay 4 cut off the primary winding voltage of the high voltage transformer ON OFF of relay 3 relay 5 208V relay 4 and relay 5 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 top primary switch and relay 3 208V relay 4 and the btm primary switch and relay 5 208V relay 6 and or secondary
23. are written for factory programmed ovens Ovens that are reprogrammed can respond differently than described below 1 Open oven door place food in oven and close oven door If pad is not pressed in 30 seconds open and close oven door again 2 Press desired number pad Oven operates and time counts down 3 Oven stops heating and oven signal sounds when heating timing elapses Operating QTY 2X Pads 1 Press ee Pad 2 Press desired number pad Example press ES ESP 18 sec Preprogrammed Times and Cook Level All preprogrammed pads arrive set at full power Option Single Digit Option Double Digit Heating Times Heating Times Heating Times 10 sec _ 10 sec 20 sec 20 sec 20 sec 40 sec 30 sec 30 sec 1 min 45 sec 45 sec 1 30 min 1 min 1 min 2 min 1 30 min 1 30 min 3 min 2 min 2 min 4 min 3 min 3 min 6 min 4 min 4 min 8 min 2 3 4 5 6 7 8 9 0 5 min 5 min 10 min Manual Time Entry Manual Time Entry feature allows the operator to enter time and power levels and heat without changing the preprogrammed pads 1 Open oven door place food in oven and close door Display shows READY If pad is not pressed 30 seconds open and close oven door again 2 Press TIME ENTRY pad Display shows 00 00 3 Press number pads to enter desired cooking time For example to heat for 2
24. aveguide and the magnetron Magnetron G REMOVING THE BOTTOM STIRRER FAN MOTOR 1 Lay the unit down on its back 2 Remove the screw securing the base cover 3 Disconnect the leadwire from the stirrer fan motor terminals 4 Remove the screw securing the stirrer fan motor to the oven cavity ASS Y 5 After repairing the motor replace the removed base cover NOTE 1 Remove the wire lead from the stirrer fan motor VERY CAREFULLY 2 Be sure to grasp the connector not the wires when removing 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 I BLOWER MOTOR ASSEMBLY REMOVAL 1 Discharge the leadwire from blower motor 2 Remove the two screws holding the blower motor bracket to the upper plate 3 Remove the screw holding the blower motor bracket to the back cover 4 Romove the screw holding the high voltage capacitor bracket 5 Remove the screw holding the duct Ass y J HIGH VOLTAGE CAPACITOR AND DIODE REMOVAL 1 Discharge the high voltage capacitor 2 Disconnect the leadwire from high voltage capacitor 3 Remove the screw holding the high voltage diode earth screw 4 Remove the screw holding the high voltage capacitor bracket Blower Motor ASS Y 5 6 K IN
25. card Drive Rockville MD 20850 The service personnel should check all surface and 7 X N 4 vent openings for microwave leakage ys A e Check for microwave leakage after every servicing The power density of the microwave radiation leakage 1 7 emitted by the microwave oven should not exceed 4 mW cm Always start measuring of an unknown field KS 2 v to assure safety for operating personnel from radiation leakage 5 1 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 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 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
26. cm sq 5 2 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 electromagnetic energy leakage monitor checked for calibration by its manufacturer MEASUREMENT 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 glas
27. emove 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 RMOVAL 1 Open the door 2 Remove the screw for securing the control panel 3 Disconnect the leadwire from RELAY of the PCB SUB ASS Y 4 Disconnect the leadwire from connector CN1 of the PCB SUB ASS Y 5 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 securing Remove choke cover 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 SUB ASS and take off the PCB SUB ASS Y PCB Sub Asm Control Panel Remove door E DOOR MAIN 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 Door seal plate NOTE 1 After replacing the door be sure to check that the primary switch
28. evel in oven memory Repeat step 3 6 to program additional pads 7 Press STOP RESET pad or close oven door to exit programming mode 4 5 Multiple Heating Stages Follow instructions below to program oven to perform 3 consecutive heating cycles without interruption 1 Open oven door If door is closed or STOP RESET pad is pressed before finishing programming sequence oven exits programming mode 2 Press pad 1 for approximately 5 seconds After 5 seconds signal sounds 3 Press desired number pad Display shows heating time and preprogrammed number 4 Press number pads to enter desired cooking time For example to heat for 2 minutes 30 seconds 5 Press desired power level pad to change power level If a power level pad is not pressed oven defaults to 100 power For example pressing MEDIUM 50 pad sets oven to 50 power Display shows current power level if other than 100 percent power 6 Press TIME ENTRY pad Display briefly shows STAGE 2 Then cook time and power level for stage show in display Repeat steps 5 6 to create additional stages 7 Press START pad to save new heating time and power level in oven memory 8 Press STOP RESET pad or close oven door to exit programming mode User Options 4 Press START pad to advance to next option Follow the instructions below to customized the See table for options microwave oven s operation End of cycle signal 5 Press numbe
29. icrowave oven in an ambient temperature less than 104 F 40 C 6 Place the microwave oven as far away as possible from TV RADIO COMPUTER etc to prevent interference 7 Place the microwave oven on a stardy and flat surface A Allow at least 11 2 inches 3 81 centimeters of clearance around top and sides of equipment Proper air flow around equipment cools electrical components With restricted air flow oven may not operate properly and life of electrical parts is reduced B Allow at least 3 inches from door front to edge of countertop to avoid accidental tipping of oven 3 1 ENSURE PROPER GROUND EXISTS BEFORE USE OPERATING INSTRUCTIONS FEATURES Window Door Screen Electronic Control Safety Door Lock System CONTROL PANEL RFS18MPS Display Some items in display can be seen but will not glow COOK Pads TIME ENTRY Use to enter heating time without changing preprogrammed number pads Pads 1 0 Use to begin heating with preprogrammed times and power levels or to enter times for Manual Time Entry cooking HOLD 0 Use to select power level Oven can heat at DEFROST 20 full or reduced power If oven power level is MEDUIM 50 set to 0 oven does not heat for MED HI 70 programmed time If no power level is selected oven operates at 100 power STOP RESET Use to exit progra
30. ingle phase 3 wire grounded Power Output 1 800 Watts full microwave power IEC60705 Microwave Frequency 2 450 MHz Magnetron 2M246 Timer 0 60 min Outside Dimensions 21 3 4 W x 1414 H x 17 7 8 0 Cavity Dimensions 1474 W x 8718 H x 16 3 3 D Net Weight 64 lbs approx Shipping weight 71 lbs approx Control Complement Touch Control System Clock 00 60 Microwave Power for Variable Cooking Power level Full power throughout the cooking time 70 Med High 50 Med Low 20 Low approx 70 of Full power approx 50 of Full power approx 20 of Full power Nameplate Location Back side Y Accessories Time chart This microwave oven is designed for commercial use only It is not recommended for buelt in Installation 1 1 CAUTIONS Unlike other appliances the microwave oven is high voltage and high current equipment Though it is free from danger in ordinary use extreme care should be taken during repair DO NOT operate on 2 wire extension cord during repair and use NEVER TOUCH any oven components or wiring during operation BEFORE TOUCHING any parts of the oven always remove the power plug from the outlet 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
31. inuity sister does not count of secondary secondary switch secondary switch down when switch with touching START door closed gt Continuity pad gt Check the con Continuity Defective PCB Replace PCB nection between assembly assembly CN1 connector gt s No continuity Loose connection gt Camba hem assembly tightly 2 Blower motor Check blower motor gt Abnormal Defective blower motor Replace blower motor or oven lamp do not turn on Check oven lamp Abnormal Defective oven lamp Replace oven lamp Normal TROUBLE 4 Oven seems to be operating but little heat is produced in oven load CONDITION CHECK RESULT CAUSE REMEDY Lower than 90 of Decrease in power Suggest customer gt EN rating voltage source voltage contact local Fo with load electric power L Normal utility co or qualified electrician p Disconnect the Abnormal Defective PCB gt Replace PCB wire leads from assembly assembly relay 3 5 or relay 4 6 and check on and off time Normal 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 microwave osci
32. inuity m Malfunction of 8 of secondary secondary switch secondary switch with switches and door opened L No continuity RELAY RY3 5 or RY4 6 of P C B Assembly Disconnect one Defective high volt Replace high volt side of the wire Fuge blows again age transformer age transformer lead connected from transformer to the high voltage gt Normal capacitor and operate the unit Measure to gt Normal Set is good condition resistance high defective fuse only voltage capacitor page 59 Defective hi i gh Replace high Abnommal voltage capacitor voltage capacitor NOTE All these switches must be replaced at the same time Refer to page 5 7 5 8 2 Fuse does not blow cord Check continuity gt No continuity Defective Replace of thermostat thermostat thermostat gt Continuity Check continuity _ No continuity Defective power Replace power of power supply supply cord supply 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 Check continuity No cont
33. kage check to verify compliance with the Federal Performance Standard should be performed on each oven prior to release to the owner CONTENTS Page SAFETY PRECAUTIONS Inside front cover SPECIFICATIONS 1 1 CAUTIONS 2 1 INSTALLATIONS nene nene renos 3 1 OPERATING INSTRUCTIONS 4 1 4 2 CONTROL 4 2 COOKING DISPLAYS 4 3 OPERATION 4 4 4 SCHEMATIC DIAGRAM 4 7 CIRCUIT DESCRIPTION 4 8 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 5 7 COMPONENT TEST PROCEDURE 5 8 TROUBLE SHOOTING anna 5 11 EXPLODED VIEW ee 6 1 SCHEMATIC DIAGRAM P C B nee 7 1 CIRCUIT BOARD en eee 7 2 SPECIFICATIONS DESCRIPTION RFS18G RFS18MPS Power Requirement 208 220 240 Volts AC 60 Hz 2 800 Watts 13 A S
34. llation even though oven lamp and blower motor run Display operates properly CONDITION CHECK RESULT CAUSE REMEDY No microwave oscillation Disconnect the x Defective PCB Replace PCB wire leads from Ball assembly assembly relay 3 5 or relay 4 6 and check a continuity of relay 3 5 gt Continuity or relay 4 6 Operate the unit Check high vol Defective high Replace high tage transformer voltage voltage transformer transformer Normal i Check high vol Defective high Replace high tage capacitor voltage capacitor voltage capacitor Normal gt Check high vol gt Abn rm l ee Defective high Replace high tage diode voltage diode voltage diode 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 3 5 or relay 4 6 and check continuit
35. m 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 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 top primary switch and relay 3 208V relay 4 and the btm primary switch and realy 5 208V relay 6 Stirrer fan rotates BTM PRIMARY INTERLOCK FUSE SWITCH 097 FUSE 00 TOP PRIMARY INTERLOCK SWITCH TOP INTERLOCK TOP MONITOR TRANSFORMER G MONITOR SWITCH SWITCH BIM BTM H V INTERLOCK u TRANSFORMER l J pa SECONDARY 7 Y INTERLOCK RELAY 3 RELAY 5 SWITCH MICOM CONTROLLER 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 volt
36. mming mode and stop cooking during cooking cycle START Use to start Manual Time Entry program or restart interrupted cooking cycle Use to advance to next user option Use to save times and power levels when programming pads QTY2x Use to automatically increase the programmed time for double quantities OPERATING INSTRUCTIONS FEATURES Window Door Screen Electronic Control Safety Door Lock System Display Some items in display can be seen but will not glow COOK x Pads TIME ENTRY Use to enter heating time without changing preprogrammed number pads Pads 1 0 Use to begin heating with preprogrammed times and power levels or to enter times for Manual Time Entry cooking DIAL Use to enter times for Manual Time Entry cooking POWER Use to select power level Oven can heat at LEVEL full or reduced power If oven power level is set to 0 oven does not heat for programmed time If no power level is selected oven operates at 100 power STOP RESET Use to exit programming mode and stop cooking during cooking cycle START Use to start Manual Time Entry program or restart interrupted cooking cycle Use to advance to next user option Use to save times and power levels when programming pads QTY2x Use to automatically increase the programmed time for double quantities
37. or is opened keyboard disabled 5 OP 50 Prevents adding heating time while oven is heating Add Time During OP 51 Allows heating time to be changed while oven is heating when a memory pad Heating is pressed 6 OP 60 Allows oven to resume heating time countdown after door is opened during Reset Door Open cycle OP 61 Cancels heating time count down after door is opened during cycle 7 OP 70 Allows 60 minutes of heating time some models some models OP 71 Allows 10 minutes of heating time Maximum Heating Time 8 OP 80 Allows use of preprogrammed pads only Manual Operation OP 81 Allows use of manual time entry and preprogrammed pads 9 OP 90 Allows 10 0 9 preprogrammed pads some models OP 91 Allows 100 00 99 preprogrammed pads Double Digit Operation 0 OP 00 Do not display message Clean Filter Message OP 01 Display message for 24 hours every 7 days OP 02 Display message for 24 hours every 30 days OP 03 Display message for 24 hours every 90 days SCHEMATIC DIAGRAM MAIN PCB I TAB1 CURRENT AC 208 220 240V 60Hz SINGLE PHASE ONLY NOISE FILTER ASSEMBLY WH BK GN ela TRANSFORMER 8 Lai TAB2 WH OVEN TCO 110 0 C TOP MGT 230 32 F ed 145 60 C 293 140 F AUTO 1 VOLTAGE S DETECTION 5 S POWER q BLOWER TRANSFORMER g J we MOTOR O 208 RY7 3 I BK 4 o RY1
38. r pad 0 1 3 to change option maximum heating time and other options can be 6 Press START pad to save changes changed to meeting your cooking needs Repeat steps 4 6 to change additional options 1 Open oven door 7 Press STOP RESET pad or close oven door to exit If door is closed or STOP RESET pad is pressed programming mode before finishing programming sequence oven exits programming mode 2 Press and hold pad 2 for approximately 5 seconds After 5 seconds signal sounds Display shows OPTION 3 Press number pad that matches desired option OP represents optional program mode first number represents option number and second number represents functions currently selected for option Optional Program Pad Option Indicator Number Selected Numbered Pads Display Options Factory Settings in Bold 1 OP 10 3 second beep End of Cycle Beep OP 11 Continuous beep until door is opened OP 12 5 beep bursts until door is opened 2 OP 20 Eliminates beep Speaker Volume OP 21 Sets volume to low OP 22 Sets volume to medium OP 23 Sets volume to high 3 OP 30 Prevents beep when pad is pressed Key Beep OP 31 Allows beep when pad is pressed 4 OP 40 15 seconds after oven door is opened keyboard disabled Keyboard Enable OP 41 30 seconds after oven door is opened keyboard disabled Window OP 42 1 minute after oven door is opened keyboard disabled OP 43 2 minutes after oven do
39. s 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 1 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 ceramic plate which is in the lowest position and the microwave power switched on 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 in watts is calculated from the following formula 4187 x 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 CERAMIC PLATE AS 7 gt WATER LOAD DISASSEMBLY AND ADJUSTMENT A OUTER CASE REMOVAL 1 Disconnect the power supply cord from the outlet 2 R
40. 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 BTM PRIMARY INTERLOCK FUSE SWITCH 0 6 FUSE 0 06 m TOP PRIMARY INTERLOCK SWITCH O INTERLOCK TOP H V INTERLOCK BTM H V MONITOR TRANSFORMER MONITOR TRANSFORMER SWITCH SWITCH Q SECONDARY INTERLOCK RELAY 3 RELAY 5 SWITCH MICOM CONTROLLER SERVICE INFORMATION TOOLS AND MEASURING INSTRUMENTS NECESSARY TOOLS NECESSARY MEASURING INSTRUMENTS Tools normally used for TV servicing are sufficient TESTER VOLTS DC AC Ohmmeter Standard tools are listed below e Microwave survey meter Diagonal pliers Holaday HI 1500 Long nose pliers HI 1501 Phillips screwdriver Narda 8100 Flat blade screwdriver 8200 e Wrench size 5mm Inch scale e Nutdriver size 5mm 600 cc non conductive material beaker glass or plastic Adjustable wrench Soldering iron Solder Vinyl insulation tape e Polishing cloth inside diameter approx 8 5 cm 31 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 MICROWAVE LEAKAGE TEST CAUTIONS MEASURING MICROWAVE ENERGY LEAKAGE Be sure to check microwave leakage prior
41. tive PCB Replace PCB programmed ection between assembly assembly membrane key assembly and roa Loose Connect them PCB assembly Seine connection tightly 2 Some inputs Replace key gt gt Everything works Defective key Replace key cannot be membrane as specified membrane membrane programmed assembly and assembly assembly check operation 3 Display shows a gt Still have trouble gt Defective PCB Replace PCB number or figure assembly assembly different from one touched 4 Random TROUBLE 2 Oven does not operate at all Display window does not display any figures and no input is accepted CONDITION CHECK RESULT CAUSE REMEDY inui a Malfunction of the Replace fuse 1 Fuse blows Check continuity Continuity i of monitor i monitor switch switch with switches and door closed L No continuity RELAY RY3 5 or RY4 6 Replace fuse of P C B Assembly ae Replace fuse gt continuity Continuity Shorted contact at gt primary monitor of primary i i secondary switch with the primary switch Switches and door opened a RELAY RY3 5 or No continuity RY4 6 of P C B Assembly mui Replace fuse gt continuity y Cont
42. y relay 3 5 or relay 4 6 Operate the unit I Abnormal Defective PCB assembly Replace PCB assembly 5 15 EXPLODED VIEW INTRODUCTION MODEL RFS18G OVEN CAVITY PARTS INTERIOR PARTS BASE PLATE PARTS LATCH BOARD PARTS DOOR PARTS CONTROL PANEL PARTS 6 1 EXPLODED VIEW INTRODUCTION MODEL RFS18MPS OVEN CAVITY PARTS INTERIOR PARTS BASE PLATE PARTS LATCH BOARD PARTS DOOR PARTS CONTROL PANEL PARTS EV DOOR PARTS MODEL RFS18G RFS18MPS 6 3 CONTROL PANEL PARTS MODEL RFS18G CONTROL PANEL PARTS MODEL RFS18MPS EV OVEN CAVITY PARTS MODEL RFS18G RFS18MPS 6 6 LATCH BOARD PARTS MODEL RFS18G RFS18MPS EV INTERIOR PARTS MODEL RFS18G RFS18MPS 6 8 EV BASE PLATE PARTS MODEL RFS18G RFS18MPS SCHEMATIC DIAGRAM OF P C B
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