OTR MICROWAVE/ CONVECTION OVEN
Contents
1. ELEMENT The 1400 watt convection heating element is located under the circulation pulley cover and the top plate The heating element heats the air that is distributed into the oven cavity by the convection fan It operates on 120 VAC and is controlled by the convection ther mistor and the heater relay on the micro computer board During a convection or combination cooking cycle the heater cycles on and off to maintain the programmed cav ity temperature The heating element sur rounds the convection fan blade and is not visible through the oven cavity UNCLIP ELEMENT CONVECTION HEATING VIEWED FROM UNDER TOP PLATE CIRCULATION PULLEY COVER SENSOR COVER YELLOW TESTING 1 Set the ohmmeter to the R x 1 scale 2 Measure across the heating ele ment terminals You should measure between 40 and 90 2 O 68 F Le CONVECTION HEATING WIRES ELEMENT 5 Blower Motor Removes smoke and odors from the kitchen cooking area through outside venting or recirculation Circulation Motor Circulates heated air inside the oven dur ing convection cooking Tower Motor Circulates air through the electrical section of the oven during microwave and convection cooking to cool it Fan Motor Cools the magnetron and circulates air through the oven d2. MICROWAVE CONVECTION OVEN JOB AID Part No 4321501 FORWARD This Job Aid will introduce the technician to the Whirlpool OTR Convection Microwave Oven This Job Aid is a reference guide for he experienced tech nician It is not designed as a replacement to basic training This Job Aid does not replace the Service Manual or the Use and Care Guide It is de signed to be used in conjunction with these manuals OBJECTIVE The objective of this Job Aid is to have the experienced appliance techni cian become familiar with the operation and service of the Whirlpool OTR Convection Microwave Oven It is designed as reference material and is not a replacement for basic training WHIRLPOOL CORPORATION assumes no responsibility for any repair made on our products by anyone other than Authorized Factory Ser vice Technicians Copyright 1994 Whirlpool Corporation Table of Contents Important safely InstrUctlofis eoe e oe AS is Page iv Models M EE Page 1 Mounting Bracket roe HU D tota eda te E PRU 2 Blower Motor Mounting POSITIONS da cta Page 3 Th Gas erect coeds Page 4 The Convection TOTES TOR surdi herbe ro Ee Se Nie a ue Page 5 The Thermal Ait casas ane Page 6 The Blower Motor Capacitor x eee pe esteem
3. 15 THINGS KNOW COMBINATION BAKE The combination bake temperature range is 150 F to 4507 The combination bake time will be limited to a maximum of 199 minutes 99 seconds Access To The Preheat Feature After the cook time is entered the COMBI NATION BAKE keypad must be pressed again within 2 seconds if a preheat is de sired Preheat When the START enter keypad is pressed the PREHEAT and TEMP display will light and LO F will be displayed until the oven temperature reaches 1007 After this point is reached the display will actively show the oven temperature 5 increments until the preheat set temperature is reached At that time the end of preheat signal will sound and the oven temperature will be maintained for 30 minutes or until the food is placed in the oven and the START enter keypad is pressed If the START enter keypad is not pressed within 30 minutes of the end of preheat sig nal the feature will be terminated The combination bake cycle will utilize 10 microwave power but will not be added until the preheat temperature is reached if programmed REMOVING THE CONTROL PANEL CONTROL PANEL MTG SCREW COMBINATION ROAST The combination roast temperature range is 150 F to 450 F The combination roast time will be limited to a maximum of 199 minutes and 99 seconds Access To The Preheat Feature After the cook time is entered the COMBI NATI
4. The safety lock feature disables the front panel controls to prevent small children from using the microwave oven However the fan and the cooktop light will still be operational To deactivate the front panel controls 1 Touch and hold numeric keypad 3 You will hear three tones followed a few mo ments later by two more tones You will then see a lock on the display 2 Release the keypad and the front panel controls will be deactivated NOTE The exhaust fan and night light func tions will still operate To reactivate the front panel controls 1 Touch and hold numeric keypad 3 until you hear two tones and see the lock on the display disappear 2 Release the numeric keypad and the front panel controls will be reactivated TIMED FAN The timed fan feature provides a method for controlling the hood fan speed It also allows the fan to be time limited with the use of the TIMER keypad To set the fan operat ing time the fan must first be running After pressing the HIGH or LOW keypad press the TIMER keypad twice within 3 seconds The first press will light the ENTER and TIMER display and T ME will be displayed The second press will cause T ME to be cleared from the display and FAN to be dis played in its place The display will remain the same Pressing the TIMER SET keypad will toggle between the FAN and displays When a numeric keypad is pressed the dis play will be cleared and t
5. l 1 RD RELAY 2 I LIGHT LIGHT RD Eno e oO RD WH LOW VOLTAGE TRANSFORMER SECONDARY INTERLOCK 1000 RELAY 1 RELAY 5 RELAY 6 RELAY 3 RELAY 4 RELAY 7 SWITCH MOTOR CAPACITOR WH LT BASE THERMAL PROTECTOR 133 104 F RELAY 8 TEMP THERMISTOR PROBE SENSOR CONTROL MODULE w PK RD BL BR YL BK 1 2 3 4 5 6 8 8 PIN CONNECTOR PK BL BR PK BL E 1 2 3 LI l 4 PIN CONNECTOR 4 1 3 PIN CONNECTOR HEATER MONITOR SWITCH YE MAGNETRON HIGH VOLTAGE PRIMARY HIGH VOLTAGE TRANSFORMER INTERLOCK CAPACITOR SWITCH 1 DOOR i 4 Q 1 E 2 WH NOTES 1 The door is open 2 The following color abbreviations are used BK Black BR Brown RD Red YL Yellow GN Green BL Blue PK Pink WH White 17 STRIP CIRCUITS 1 UNIT IS PLUGGED IN CLOCK IS WORKING L1 N MICROCOMPUTER BOARD a t eoo A LINE LOW VO
6. NO C INTERLOCK D SWITCH TOWER RELAY 8 o 0 110 E BR W RD BR YL SYNCHRONOUS MOTOR RELAY 2 ia Wd YL 0 6 VOLTAGE u SYSTEM 20 9 15 L1 N CAVITY MAGNETRON MICROCOMPUTER THERMAL THERMAL BOARD PROTECTOR PROTECTOR ISA EINE LOW VOLTAGE FUSE E HD TRANSFORMER W o es BK 5 5 AAAA AAT OVEN LIGHT SWITCH RELAY 1 BL BK 0 0 3 NO O SECONDARY INTERLOCK BL SWITCH TOWER MOTOR RELAY 7 bk a RD 09 oK Q BR O CIRCULATION MOTOR CONVECTION W is RELAY 9 HEATER p YL OO O 21 Heater cycling is controlled by the convection thermistor SKILLS CHECK In the convection mode the bake temperature range is between 150 F and 450 F How does the OTR microwave convection oven maintain the selected temperature List all of the motors used in the OTR microwave convection oven and give a brief description of their functions Which motor s is are used during the microwave cook function of the OTR microwave convection oven The cooktop light operates on either HIGH or LOW How do the lighting circuits provide the two light intensities 22 5 At what temperature does the blowe
7. D M PROTECTOR PROTECTOR w 5 BL RD AZ RELAY 5 m 6 COOKTOP LIGHT IS ON LOW L1 N MICROCOMPUTER BOARD 15A LINE 1 USE LOW VOLTAGE o5 i 4 CAVITY MAGNETRON a AO AA THERMAL THERMAL H XS eG P COOKTOP LIGHTS PROTECTOR PROTECTOR NN p W E yl 4 BL 5 w RELAY 6 NIGHT LIGHT DIODE J WHEN RELAY 6 CLOSES THE AC SIGNAL SEE WAVEFORM 1 PASSES THROUGH IT TO THE NIGHT LIGHT DIODE THE DIODE ACTION ALLOWS ONLY THE POSITIVE HALF OF THE SIGNAL TO PASS THROUGH IT SEE WAVEFORM 2 TO THE COOKTOP LIGHTS AND REDUCES THE BRIGHTNESS DURING NIGHT LIGHT OPERATION 19 7 OVEN IS OFF COOKTOP TEMPERATURE IS ABOVE 133 F BLOWER MOTOR IS ON LOW L1 N MICROCOMPUTER J 3 LOW VOLTAGE T BK RD TRANSFORMER 1 w O BK oo lt o AAA A AUi CAVITY MAGNETRON CAPACITOR THERMAL THERMAL R Y PROTECTOR PROTECTOR RELAY 4 BL YL 4 BASE BLOWER THERMAL MOTOR PROTECTOR LOW L1 N CAVITY MAGNETRON MICROCOMPUTER THERMAL THERMAL BOARD PROTECTOR PROTECTOR 7 15A LINE LOW VOLTAGE FUSE TRANSFORMER w Ko 0 o 4 1 7 FS PY OVEN LIGHT OVEN LIGHT RELAY 1 SWITCH Bit w 0 3 O SECONDARY
8. The error code will remain in the display until the OFF CANCEL keypad is pressed 12 HIDDEN FEATURES DISABLING ENABLING THE AUDIBLE SIGNALS 1 Touch and hold numeric keypad 1 for four seconds When the time has elapsed you will hear two beeps which signals that the programming tone and the of cycle reminder signals are disabled OR 2 Touchandhold numeric keypad 2 When the time has elapsed you will hear two beeps which indicates that all of the sig nals except the end of timer are dis abled 3 To turn the audible signals back on re peat the step that disabled it NOTE Two tones will sound when the au dible signals are turned on or off THE DEMONSTRATION FEATURE NOTE You can only use the demonstration feature after the OTR Microwave Convection Oven is first plugged in Once a command pad has been touched the feature cannot be used unless the unit is unplugged and plugged back in again To set the oven so that it will demonstrate its functions without turning the oven on 1 Open the oven door 2 Touch and hold the AUTO START key pad You will hear three tones followed a few moments later by two more tones 3 Release the AUTO START keypad 4 Close the oven door and the demonstra tion feature will begin To stop the dem onstration feature touch the OFF CAN CEL keypad otherwise it will continue to run THE SAFETY LOCK FEATURE POSSIBLE CUSTOMER COMPLAINT
9. beads sche sero ed Page 8 The Convection Heating Element sse eene nnne Page 9 er 10 Changing The Synchronous Motor la Page 11 Error CodeS mc Page 12 Hidden Features s eee A e eda Page 13 TOMOS TO KNOW cis S haqa A 16 Wiring 17 cj kde cse HER Page 18 DKS CIS CK e Page 22 IMPORTANT SAFETY INSTRUCTIONS WARNING TO SERVICE TECHNICIANS To avoid possible exposure to microwave radiation or energy visually check the oven for damage to the door and door seal before operating any oven Use a microwave survey meter to check the amount of leakage before servicing In the event the R F leakage exceeds 4 mW cm at 5 cm appropriate repair must be made before continuing to service the unit Check interlock function by operating the door latch The oven cook cycle should cut off before the door can be opened The door and latching assembly contains the radio frequency energy within the oven The door is protected by three safety interlock switches Do not attempt to defeat them UNDER NO CIRCUMSTANCES SHOULD YOU TRY TO
10. the bracket e A 1 2 lag bolt in a wall stud using one the holes along the top or bottom of the bracket e Spacers to mount on the back wall as shown below o 0 0 0 00 O O O O O O H 14 u N spacers B 2 BLOWER MOTOR MOUNTING POSITIONS Recirculating ROUTE THE CABLE THROUGH USE THESE TWO THE NOTCH AND TO THE LEFT MOUNTING HOLES of gt Venting ROUTE THE CABLE THROUGH USE THESE TWO THE NOTCH AND TO THE LEFT MOUNTING HOLES AS SHOWN AN FRONT Top Venting USE THESE MOUNTING HOLES Va gt Z Lg A ROUTE THE CABLE THROUGH THE NOTCH AND TO THE LEFT NOTE ALL MICROWAVE OVENS ARE SHIPPED WITH AS SHOWN THE BLOWER MOTOR IN THE TOP VENTING POSI TION 245 THE GAS SENSOR The gas sensor is used during the Sensor Cook operation of the oven It is located above the oven and is mounted on the left side of the sensor cover The sensor con sists of two circuits housed on a small mi crocomputer board that is supplied with a current to keep it heated The sensor heat SENSOR COVER TAB LIFT TO RELEASE conductivity will vary depending upon the humidity of the oven Changing humidity con ditions due to the cooking process within the oven cavity causes a difference in potential bet
11. CTOR Il protector SINGLE PHASE ONLY E 1 302 140 F T 293 140 F L FUSE x ue BK RELAY 9 YL O RELAY 2 LIGHT COOKTOP ro Z 3 i LOW VOLTAGE TRANSFORMER SECONDARY INTERLOCK SWITCH Q O E MP yL WH THERMAL PROTECTOR 133 104 F WH O O O RELAY 5 BL CIRCULATION MOTOR RELAY 6 F M i BK BR RD RELAY 3 i WH peje a ee Ev pee eee SYNCH MOTOR RELAY 7 P RD BR N C C MONITOR SWITCH PEA HEATER YL O O YL RD 0000000000000 HIGH VOLTAGE O PRIMARY HIGH VOLTAGE TRANSFORMER INTERLOCK CAPACITOR SENSOR Z Temp SWITCH THERMISTOR PROBE DOOR THE BLOWER MOTOR CAPACITOR The blower motor capacitor is located directly capacitor helps to maintain a constant volt behind the control panel It is in use any time age to the blower motor so that it runs more the blower vent motor is operating The efficiently Non convection models may have this capacitor mounted in another location TESTING 1 Set the ohmmeter to the R x 10K scale BLOWER MOTOR CAPACITOR Ma 2 Measure across the capacitor ter minals The ohmmeter should indicate several ohms then gradually re turn to infinity
12. LTAGE BK BK _ RD TRANSFORMER W O O O 14 CAVITY MAGNETRON THERMAL THERMAL PROTECTOR PROTECTOR 1 1 2 DOOR IS OPEN OVEN LIGHT IS MICROCOMPUTER BOARD DT due LET T 71 LOW VOLTAGE TRANSFORMER L1 14 T s r OVEN LIGHT 15A LINE OVEN LIGHT FUSE SWITCH BK BK BK 21 5 RD gt BK THERMAL THERMAL PROTECTOR PROTECTOR 3 BLOWER MOTOR IS ON LOW L1 N MICROCOMPUTER BOARD SE LOW VOLTAGE BK RD 1 TRANSFORMER w o o PK c 6O O 4 WII CAVITY MAGNETRON THERMAL THERMAL PROTECTOR PROTECTOR RELAY 4 CAPACITOR RHHY RELAY 3 Uv BLOWER MOTOR LOW 18 4 BLOWER MOTOR IS ON HIGH L1 N MICROCOMPUTER BOARD pea LOW VOLTAGE BK BK RD i TRANSFORMER f o ro OF 0 OQ 4 1 CAVITY MAGNETRON INS CAPACITOR THERMAL THERMAL R Y PROTECTOR PROTECTOR RELAY 4 BL BK BLOWER MOTOR HIGH 55 5 COOKTOP LIGHT IS ON HIGH L1 N MICROCOMPUTER BOARD 15A LINE TUSE LOW VOLTAGE BK RD TRANSFORMER w BS get PK c ees 4 CAVITY MAGNETRON THERMAL CET
13. Micro wave Convection Oven will shut down operation All key pads except OFF CANCEL will cause an invalid data entry signal if pressed before the problem is corrected or cleared If a cooking operation is attempted before the problem is corrected the failure code will be redisplayed and the operation will once more be shut down This im plies for example that after a temperature probe fail ure occurs and the error code is cleared all other operations not utilizing the temperature probe will still function The 2 amp 4 display code may be cleared so that the clock is visible and the minute timer may be used Both of these operations will continue uninterrupted in the background if a failure occurs while either is active The failure code is cleared by pressing the OFF CANCEL key pad The following error codes will be displayed when the as sociated failure mode has occurred F1 Sensor Error will occur if no change in re sistance is detected by the microcomputer board over time F2 Keyboard Error will occur if a keypad is pressed or shorted for 15 seconds F3 Thermistor Error will occur if the oven cavity tem perature fails to change F4 Temperature Probe Error will occur if the inter nal temperature of the food does not change 888 88 Will be displayed after power has been interrupted An audible signal should sound when a failure code ap pears on the display
14. NOT attempt to operate the oven with the door open since open door operation can result in harmful exposure to microwave energy It is important not to defeat or tamper with the safety interlocks DO NOT place any object between the oven front face and the door or allow soil or cleaner residue to accumulate on sealing surfaces DO NOT operate the oven if it is damaged It is particularly important that the oven door close properly and that there is no damage to the 1 Door bent 2 Hinges and Latches broken or loosened 3 Door Seals and Sealing Surfaces DO NOT operate the microwave oven if the door window is broken The microwave oven should be checked for microwave leakage by qualified service personnel after a repair is made The oven should not be adjusted or repaired by anyone except properly qualified service personnel DO NOT operate the microwave oven with the outer cabinet removed A CAUTION High voltages are present during the cook cycle Extreme caution should be observed at all times Abrasive cleansers steel wool pads gritty wash cloths etc can damage the control panel and the interior and exterior oven surfaces Use a sponge with mild detergent or paper towels with spray glass cleaner Apply spray glass cleaner to paper towel Do not spray directly on oven Before touching any oven component or wir ing always unplug the oven from its power source and discharge the capacitor by using a 20 000 o
15. ON ROAST keypad must be pressed again within 2 seconds if a preheat is de sired Preheat When the START enter keypad is pressed the PREHEAT and TEMP display will light and LO F will be displayed until the oven temperature reaches 1507 After this point is reached the display will actively show the oven temperature 5 increments until the preheat set temperature is reached At that time the end of preheat signal will sound and the oven temperature will be maintained for 30 minutes or until the food is placed in the oven and the START enter keypad is pressed If the START enter keypad is not pressed within 30 minutes of the end of preheat sig nal the feature will be terminated The combination roast cycle will utilize 20 microwave power but will not be added until the preheat temperature is reached if programmed THE TEMPERATURE PROBE The temperature probe will be inoperative during the broil operation but may be grammed for all other convection and com bination features SERVICE MANUALS OTR Microwave Convection Oven LIT4321659 OTR Microwave Oven Conventional 11714321620 16 WIRING DIAGRAM MAGNETRON CAVITY THERMAL THERMAL AC 120V 60 HZ PROTECTOR PROTECTOR SINGLE PHASE ONLY S02 140F 293 140F 5 BK E s 1 RELAY 9 YL RD
16. OPERATE THE OVEN WITH THE DOOR OPEN Proper operation of microwave ovens requires that the magnetron be properly assembled to the waveguide and cavity Never operate the magnetron unless it is properly installed Be sure the seal is not damaged and is assembled around the magnetron dome properly when installing the magnetron Routine service safety procedures should be exercised at all times Untrained personnel should not attempt service without a thorough review of test procedures and safety information contained in this manual 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 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 the microwave power for any service test or inspection within the microwave generating components check the magnetron wave guide or transmission line and cavity for proper alignment d Any defective or misadjusted components in the interlock monitor door seal and microwave generation and transmission system shall be repaired or adjusted by pr
17. he number entered will be shown in the display to the far right TIMED LIGHT The timed light feature provides a method for controlling the vent hood light It also al lows the light to be time limited with the use of the TIMER keypad To set the light oper ating time the light must first be turned on After pressing the NIGHT LITE or LITE key pad press the TIMER keypad twice within 3 seconds The first press will light the ENTER and TIMER display and T ME will be displayed The second press will cause T ME to be cleared from the display and L GHT to be displayed in its place The display will remain the same Pressing the TIMER SET keypad will toggle between the L GHT and TIMER displays When a numeric keypad is pressed the dis play will be cleared and the number entered will be shown in the display to the far right 14 TOUCH PANEL TEST COMPONENT Touch the keyboard see below FPC CONNECTOR TOP TEST PROCEDURE Measure the resistance between the terminal pins of the keypad shown below that you wish to check For example To measure the PROBE TEMP keypad refer to the illustration and 1 Find the first terminal number along the top bar pin 4 2 Find the second terminal num ber in the side bar pin 8 3 Set the ohmmeter to the H x 1 scale a With the keypad not de pressed touch the ohmmeter leads between pins 4 and 8 on the ends of the FPC con necto
18. hm discharge resistor or use an insu lated plastic handle screwdriver to short across the capacitor terminals Check that the unit is grounded before trouble shooting Be careful of the high voltage circuits Discharge any static charge from your body by touching ground before handling any part of the circuitry on the control board Electrostatic dis charge may damage the control circuit Do not touch oven components or wiring dur ing operation Attach meter leads with alligator clips when making operational tests For continued protection against radiation emis sion replace only with these types of switches Primary Interlock Switch SZM V16 FA 63 or VP 533A OF Secondary Interlock Switch SZM V01 FA 32 Interlock Monitor Switch SZM VI6 FA 62 or VP 532A OF Oven Lamp Switch SZM V6 FA 31 or VP 331A OD It is neither necessary nor advisable to attempt measurement of high voltage Attaching the adaptor ground terminal to the wall receptacle cover screw does not ground the appliance unless the cover screw is metal and not insulated and the wall receptacle is grounded through the house wiring AWARNING Disconnect the oven from electrical supply be fore servicing Failure to do so could result in electrical shock or death Improper use of the grounding plug can result risk of electrical shock Do not under any circumstance cut or remove the third ground prong from the power cord plug Fire Electr
19. ical Shock Excessive Exposure to Microwave Energy Personal Injury amp Product Damage Hazard Do not block the rear air intake openings or exhaust vents Allow a few inches of space at the back of the oven where intake openings and exhaust vents are located Blocking the air intake openings and exhaust vents can cause damage to the oven and poor cooking results Make sure the microwave oven legs are in place to ensure proper airflow Do not install the oven next to or over a heat Source a cooktop or range Do not install oven in any area where exces sive heat and steam are generated This could cause fire electrical shock excessive exposure to microwave energy other personal injury or damage to the outside of the cabinet V MODELS AFFECTED 1994 amp 1995 PRODUCTION Brand Whirlpool Roper KitchenAid Estate Features Base Model MH6110XBB Q MHE11RDB Q TMWH110DB Q Probe MH7110XBB Q KHMS105B Sensor MH7115XBB Q BL WH AL KHMC107B Convection MH9115XBB Q BL WH AL MOUNTING BRACKET USE A MOLLY BOLT AT THESE FOUR CORNER LOCATIONS OPENINGS FOR REAR VENTING LOCATE A SUPPORT STUD BEHIND THESE HOLES The mounting bracket for the OTR Microwave Convection Oven should be installed as shown in the Installation Instructions These instructions include installing Molly bolts in each of the four corners of
20. ing a ther mistor 9 WHITE WIRES CAUTION WHEN REPLACING THE THERMISTOR DO NOT CUT AND SPLICE THE WHITE WIRES OR AN IMPROPER SIGNAL WILL BE SENT FROM THE THERMISTOR TO THE MICROCOMPUTER BOARD CONVECTION THERMISTOR CIRCULATION PULLEY COVER THE THERMAL PROTECTORS There are three thermal protectors in the OTR Microwave Convection Oven They are the magnetron thermal protector the cavity thermal protector and the base thermal pro tector The magnetron and cavity thermal protectors are located inside the high volt age section of the oven These two thermal protectors are normally closed and will open at a set temperature to disable the oven Both of these protectors are resettable Magnetron Thermal Protector Cavity Thermal Protector Base Thermal Protector CAVITY THERMAL PROTECTOR Q Opens 302 F 150 C Opens 293 F 145 C Closes O 133 F 56 C MAGNETRON lt gt MAGNETRON THERMAL PROTECTOR The base thermal protector is located directly behind the control panel It is a normally open protector that when closed activates the blower motor at a low speed see the wiring diagram on the next page POSSIBLE CUSTOMER COMPLAINT The unit turns on by itself Resets 140 F 60 C Resets 140 F 60 C Resets 104 F 40 C MAGNETRON THERMAL THERMAL AC 120V 60 HZ PROTE
21. ocedures described in the Basic Service Manuals for the specific microwave oven being serviced before the oven is released to the owner e A microwave leakage check to verify compliance with Federal Performance Standards should be performed on each oven prior to release to the owner f Do not attempt to operate the oven if the door glass is broken Whirlpool microwave ovens have a monitoring system designed to assure proper operation of the safety interlock systems The interlock monitor switch will immediately cause the oven fuse to blow if the door is opened and the primary door interlock switch and or the secondary interlock switch contacts fail in a closed position CAUTION REPLACE BLOWN FUSE WITH 15 AMPERE CLASS H FUSE ONLY Test the upper and lower door interlock switches cook relay and interlock monitor switch middle switch for proper operation as described in the component test procedures before replacing the blown oven fuse DO NOT ATTEMPT TO REPAIR STICKING CONTACTS OF ANY INTERLOCK SWITCH SAFETY SWITCH OR COOK LATCH RELAY REPLACE THE SWITCHES AND RELAY Any indication of sticking contacts during component tests requires replacement of that component to assure reliability of the safety interlock system IF THE FUSE IS BLOWN THE MONITOR PRIMARY AND SECONDARY INTERLOCK SWITCHES MUST BE REPLACED BE SURE THEY ARE PROPERLY CONNECTED Precautions to Avoid Possible Exposure to Excessive Microwave Energy DO
22. r b Press the PROBE TEMP keypad RESULT Normal Readings KEYPAD NOT PRESSED Indi cates more than 1 MO resis tance Normal Readings KEYPAD PRESSED Indicates less than 400 Q resistance Abnormal Readings KEYPAD NOT PRESSED Indi cates continuity zero resis tance Abnormal Readings KEYPAD PRESSED Indicates infinite resistance CONVENTIONAL MICROWAVE CONVECTION MICROWAVE TOUCH PANEL MATRIX TOUCH PANEL MATRIX 1 2 3 4 5 6 7 1 2 3 4 5 6 7 87 MA emen ue Qo 6 Loo Gr MA eme Qo 6 Loo 8 e e e e 8 e 4 e e no AG QUO o momo 7 1 comemos FAN 7 4 9 7 7 7 9 7 7 7 A X LOW PLATE 8 2 E LOW NC warm 8 2 101 e e e e e e ho e e e e NC d on NO unue d 9 3 Pour Mes NO unue d 9 3 H1 47 PA 47 EA ga 11 P a 47 e P 47 P a T wc Sime cancer 4 5 MAU T adt cance 4 5 2 e e 2 no IE 5 JE LORI 13 e e e 13 e
23. r motor turn on automatically At what temperature does the blower motor turn off automatically 6 How does the microwave energy enter the oven cavity and how is it distributed 7 How much microwave power is used during COMBINATION BAKE How much microwave power is used during COMBINATION ROAST 8 When using the safety lock feature all keypads are disabled except the 9 What relay on the microcomputer board is used to energize the circulation motor 10 What error code will be displayed if the gas sensor is not working properly 23 NOTES 24 10 SKILLS CHECK ANSWERS The thermistor cycles the convection heating element on and off to regulate the temperature Blower Motor Removes smoke and odors from the kitchen cooking area through outside venting or recirculation of the air Circulation Motor Circulates heated air inside the oven during convection cooking Tower Motor Circulates air through the electrical section of the oven during micro wave and convection cooking to cool it Fan Motor Cools the magnetron and circulates air through the oven during micro wave cooking Synchronous Motor Distributes microwave energy into the oven during microwave cooking Tower fan amp synchronous motors A diode in the night light circuit cuts the AC voltage reducing the light intensity On at 133 F amp Off at 104 F Microwave energy enters the bottom of the oven cavity and is distribu
24. ted by a rotating distribution plate 10 for Bake amp 20 for Roast Exhaust fan high amp low amp Cooktop light Night Lite amp Lite pad 3 Relay 7 F1 25 MAGNETRON CAVITY THERMAL THERMAL AC 120V 60 HZ PROTECTOR PROTECTOR SINGLE PHASE ONLY 302 140 F 293 140 F RELAY 9 d RELAY 2 COOKTOP COOKTOP l LIGHT LIGHT CLP WH c cC WH LOW VOLTAGE TRANSFORMER VIGET LIGHT SWITCH SECONDARY C O LA BK INTERLOCK D 2 BE Q SWITCH N C H N A ot TOWER MOTOR x HE i RELAY 1 Eg RELAY 5 Sono H 112 sh Bb OO NIGHT BLOWER RELAY 6 nen MOTOR DIODE 6 l RELAY 3 EN YL 7 O E BASE I THERMAL H PROTECTOR l BK 133 104 F RELAY 7 T BR MONITOR I RELAY 8 puts SWITCH 1 GR BL PK HIGH VOLTAGE PRIMARY HIGH VOLTAGE TRANSFORMER INTERLOCK CAPACITOR SENSOR 4 SWITCH THERMISTOR PROBE DOOR P
25. uring microwave cooking Synchronous Motor Distributes microwave energy into the oven during microwave cooking MOTOR CIRCULATION MOTOR CONVECTION ONLY TOWER MOTOR B N SYNCHRONOUS MOTOR MICROWAVE COOKING ONLY FAN MOTOR 10 CHANGING THE SYNCHRONOUS MOTOR To remove the synchronous motor 3 Lift the distribution plate off the motor shaft 1 Remove the baseplate from the oven 4 Remove the synchronous motor from the 2 Openthe oven door and pry up the bottom panel of the oven cavity inset 1 bottom of the oven inset 2 DISTRIBUTION PLATE NOTE TOP oD BOTTOM PANEL MOTOR OF OVEN SHAFT INSET 1 PRY UP EDGE OF BOTTOM PANEL WITH A PUTTY KNIFE INSET 2 BOTTOM OVEN YELLOW WIRE SYNCHRONOUS MOTOR ie e SCREWS BROWN WIRE 11 ERROR CODES Missing Probe or Invalid Probe PROBE If the temperature probe is not plugged for an opera tion that requires its use or if it is plugged in and the se lected operation does not allow its use a probe error will be displayed when the START enter keypad is pressed Heating Or Control System Component Failure F2 F 3 Fy EJEETHH Whenever any of the critical components in the heating or control system encounter a failure mode the OTR
26. ween these two circuits This difference is monitored by the microcomputer during cooking allowing the microcomputer to de termine the proper cook time NOTE Always verify that the sensor cover is not obstructed proper air flow is passing over the sensor and that the fan motor is working properly before replacing the gas sensor TESTING 1 Set the ohmmeter to the R x 1 scale 2 Remove the 3 pin connector from the control circuit board and mea sure the resistance between the a Red amp white wire terminals You should measure 20 2 68 F b White amp yellow wire terminals You should measure infinity CONTROL PANEL MTG SCREW THE CONVECTION THERMISTOR The convection thermistor is located under the circulation pulley cover and is used dur ing the convection operation of the oven When the temperature increases the resis tance of the thermistor decreases The ther mistor resistance is monitored by the micro computer As the oven temperature rises and TESTING 1 Set the ohmmeter to the R x 10K scale 2 Remove the 6 pin connector from the control circuit board and mea sure across terminals 5 amp 6 You should measure 155 to 350 O 68 F falls the thermistor signal going back to the microcomputer causes the heater relay to open and close and cycles the heating ele ment on and off NOTE Verify that the heating element is working correctly before replac
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