Electrolux EW27MO55HSA Technical & Service Manual Download Page 1

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Publication #5995532487 P/N 316439272 April 2009

Technical Service Manual

Microwave Oven

Models

EW27MO55HSA
EW30MO55HSA

Summary of Contents for EW27MO55HSA

Page 1: ...Publication 5995532487 P N 316439272 April 2009 Technical Service Manual Microwave Oven Models EW27MO55HSA EW30MO55HSA ...

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Page 3: ...ation of any safety device 5 Use ONLY REPLACEMENT PARTS CATALOGED FOR THIS APPLIANCE Substitutions may defeat compliance with Safety Standards Set For Home Appliances 6 GROUNDING The standard color coding for safety ground wires is GREEN or GREEN with YELLOW STRIPES Ground leads are not to be used as current carrying conductors It is EXTREMELY important that the service technician reestablish all ...

Page 4: ...iptions 2 4 Door Sensing and Primary Interlock Switch 2 4 Monitor Switch 2 4 Third Door Switch 2 4 Magnetron Thermal Switch Cut Out 2 5 Oven Thermal Cut Out 2 5 Humidity Sensor Circuit 2 5 Section 3 Troubleshooting and Testing Warnings and Cautions 3 1 Troubleshooting Guide Chart 3 2 Test Procedures 3 3 Section 4 Component Teardown Warnings and Cautions 4 1 Outer Case Removal 4 2 Magnetron Removal...

Page 5: ...NO OTHER VISIBLE DAMAGE WITH THE OVEN SERVICING AND REPAIR WORK MUST BE CARRIED OUT ONLY BY TRAINED SERVICE PERSONNEL CERTAIN INITIAL PARTS ARE INTENTIONALLY NOT GROUNDED AND PRESENT A RISK OF ELECTRICAL SHOCK ONLY DURING SERVICING SERVICE PERSONNEL DO NOT CONTACT THE FOLLOWING PARTS WHILE THE APPLIANCE IS ENERGIZED INVERTER UNIT THAT INCLUDES HIGH VOLTAGE CAPACITOR HIGH VOLTAGE POWER TRANSFORMER ...

Page 6: ...ion check as per the Microwave Measurement Procedure outlined in this service manual If microwave emissions level is in excess of the specified limit contact ELECTROLUX HOME PRODUCTS INC immediately If the unit operates with the door open service person should 1 Tell the user not to operate the oven 2 Contact Electrolux HOME PRODUCTS INC and Food and Drug Administration s Center for Devices and Ra...

Page 7: ...r case is installed 4 Run the oven and check all functions Microwave ovens should not be run empty To test for the presence of microwave energy within a cavity place a cup of cold water on the oven turntable close the door and set the power to HIGH and then set the microwave timer for two 2 minutes When the two minutes has elapsed timer at zero carefully check that the water is now hot If the wate...

Page 8: ...e water container shall be a low form of 600 ml 20 oz beaker with an inside diameter of approx 8 5 cm 3 1 2 in and made of an electrically nonconductive material such as glass or plastic The placing of this standard load in the oven is important not only to protect the oven but also to insure that any leakage is measured accurately 4 Set the cooking control on Full Power Cooking Mode 5 Close the d...

Page 9: ...ately 4 Set the cooking control on Full Power Cooking Mode 5 Close the door and select a cook cycle of several minutes If the water begins to boil before the survey is completed replace it with 275 ml of cool water C Leakage test with enclosure installed 1 Grasp probe of survey instrument and hold it perpendicular to gap between door and the body of the oven 2 Move the probe slowly not faster than...

Page 10: ...rowave Power for Variable Cooking Repetition Rate P HI Full power throughout the cooking time P 90 approx 90 of Full Power P 80 approx 80 of Full Power P 70 approx 70 of Full Power P 60 approx 60 of Full Power P 50 approx 50 of Full Power P 40 approx 40 of Full Power P 30 approx 30 of Full Power P 20 approx 20 of Full Power P 10 approx 10 of Full Power P 0 No power throughout the cooking time Auto...

Page 11: ...e dedicated line using a grounded receptacle When installing this appliance observe all applicable codes and ordinances A short power supply cord is provided to reduce risks of becoming entangled in or tripping over a longer cord Where a two pronged wall receptacle is encountered it is the personal responsibility and obligation of the customer to contact a qualified electrician and have it replace...

Page 12: ...shaft 10 Menu label 11 Oven light It will light when oven is operating or door is open 12 Waveguide cover DO NOT REMOVE 13 Time display 99 minutes 99 seconds 14 Popcorn Bacon Tray 15 Removable turntable Place the turntable on the turntable support securely The turntable will rotate clockwise or counterclockwise Only remove for cleaning 16 Removable turntable support Carefully place the turntable s...

Page 13: ...ity feedbox and then into the cavity where the food is placed to be cooked 5 Upon completion of the cooking time the power transformer oven lamp etc are turned off and the generation of microwave energy is stopped The oven will revert to the OFF condition 6 When the door is opened during a cook cycle third door switch monitor switch door sensing switch the secondary interlock relay and the primary...

Page 14: ...E POWER SUPPLY CORD CIRCUITS SUBJECT TO CHANGE WITHOUT NOTICE RY3 RY3 RY2 B5 B6 B4 B3 B2 B1 B8 B10 SCHEMATIC NOTE CONDITION OF OVEN 1 DOOR CLOSED 2 COOKING TIME PROGRAMMED 3 START PAD TOUCHED A1 A3 A7 A9 L V TRANSFORMER CONTROL UNIT SWITCH 3RD DOOR DM FM OL CM TURNTABLE MOTOR CONVECTION MOTOR TTM OVEN LAMP FAN MOTOR DAMPER MOTOR PNK PPL BRN ORG RED PNK MONITOR SWITCH FUSE 20A 60Hz 120V 0 0033 F AC...

Page 15: ...g When Variable Cooking Power is programmed the 120 volts AC is supplied to the power transformer intermittently through the contacts of relay RY2 which is operated by the control unit within an interval second time base Microwave power operation is as follows Vari Mode ON TIME OFF TIME Power 10 High 100 Power 32 sec 0 sec Power9 P 90 Approx 90 30 sec 2 sec Power8 P 80 Approx 80 26 sec 6 sec Power...

Page 16: ... latch hook It is activated the contacts opened by the lower latch head while the door is closed The switch is intended to render the oven inoperative by means of blowing the monitor fuse when the contacts of the relay RY1 and primary interlock switch fail to open when the door is opened Functions 1 When the door is opened the monitor switch contacts close to the ON condition due to their being no...

Page 17: ...stration One thermistor is housed in the closed vessel filled with dry air while another in the open vessel Each sensor is provided with the protective cover made of metal mesh to be protected from the external airflow 2 Operational Principle of Absolute Humidity Sensor The figure below shows the basic structure of an absolute humidity sensor A bridge circuit is formed by two thermistors and two r...

Page 18: ... proceeds the food is heated to generate moisture by which the resistance balance of the bridge circuit is deviated to increase the voltage available at AN6 terminal of the LSI Then the LSI observes that voltage at AN6 terminal and compares it with its initial value and when the comparison rate reaches the preset value fixed for each menu to be cooked the LSI causes the unit to stop sensor cooking...

Page 19: ...Open the door and block it open 3 To discharge high voltage capacitor wait for 60 seconds and then short circuit the connection of the high voltage capacitor that is the connecting lead of the high voltage rectifier against the chassis with the use of an insulated screwdriver 4 Reconnect the leads to the primary of the power transformer 5 Reinstall the outer case cabinet 6 Reconnect the power supp...

Page 20: ... into wall receptacle ENJOY does not appear in display when power cord is first plugged into wall receptacle Display does not operate properly when STOP CLEAR pad is touched The time of day should appear on the display with beep sound Oven lamp does not light with door opened Oven lamp does not light in cook cycle It lights when door is opened Cooking cycle runs 1 minute then shuts down Oven lamp ...

Page 21: ... temperature stabilizes Record the temperature of the water 2 Place the cup of water in the oven Operate oven at POWER HI HIGH selecting more than 60 seconds cook time Allow the water to heat for 60 seconds measuring with a stop watch second hand of a watch or the digital read out countdown 3 Remove the cup from the oven and again measure the temperature making sure to stir the thermometer or ther...

Page 22: ... power supply cord and then remove outer case 2 Open the door and block it open 3 Discharge high voltage capacitor See Warnings and Instructions on page 3 1 4 Isolate the rectifier from the circuit Using the highest ohm scale of the meter read the resistance across the terminals and observe reverse the leads to the rectifier terminals and observe meter reading If a short is indicated in both direc...

Page 23: ...remove outer case 2 Open the door and block it open 3 Discharge high voltage capacitor See Warnings and Instructions on page 3 1 4 Isolate the switch and connect the ohmmeter to the common COM and normally open NO terminal of the switch The meter should indicated an open circuit with the door open and a closed circuit with the door closed If improper operation is indicated replace the switch 5 Rec...

Page 24: ...ons on page 3 1 4 Before performing this test make sure that the secondary interlock relay and the primary interlock switch are operating properly according to the above Test Procedure Disconnect the wire lead from the monitor switch NC terminal Check the monitor switch operation by using the ohmmeter as follows When the door is open the meter should indicate a closed circuit When the monitor swit...

Page 25: ... thermal cut out indicates overheating of the oven cavity 5 Reconnect all leads removed from components during testing 6 Reinstall the outer case cabinet 7 Reconnect the power supply cord after the outer case is installed 8 Run the oven and check all functions NOISE FILTER TEST 1 Disconnect power supply cord and remove outer case 2 Open the door and block it open 3 Discharge high voltage capacitor...

Page 26: ... Unit The following symptoms indicate a defective control unit Replace the control unit 2 1 In connection with pads a When touching the pads a certain group of pads do not produce a signal b When touching the pads no pads produce a signal 2 2 In connection with indicators a At a certain digit all or some segments do not light up b At a certain digit brightness is low c Only one indicator does not ...

Page 27: ...s good control unit is defective 8 If any abnormal condition is detected replace the control unit 9 Disconnect the power supply cord and then remove outer case 10 Open the door and block it open 11 Discharge high voltage capacitor See Warnings and Instructions on page 3 1 12 Reconnect all leads removed from components during testing 13 Re install the outer case cabinet 14 Reconnect the power suppl...

Page 28: ...r given of by the spray and turn off before food is properly cooked 8 After the oven is started on sensor cooking condition if the sensor has not detected the vapor of the food within 30 minutes ERROR will appear and the oven will shut off WATER LOAD COOKING TEST WARNING The oven should be fully assembled before following procedure Make sure the oven has been plugged in at least two minutes before...

Page 29: ...after the water is boiling bubbling If new sensor dose not operate properly the problem is with the control unit 2 CHECKING CONTROL UNIT 1 Disconnect the power supply cord and then remove outer case 2 Discharge high voltage capacitor 3 Disconnect the wire leads from the cook relay 4 Disconnect the sensor connector that is mounted to lower portion of control panel 5 Then connect the dummy resistor ...

Page 30: ...Troubleshooting and Testing 3 12 Notes ...

Page 31: ...igh voltage capacitor before touching any oven components or wiring after removing outer case AVOID POSSIBLE EXPOSURE TO MICROWAVE ENERGY PLEASE FOLLOW INSTRUCTIONS BELOW BEFORE OPERATING THE OVEN 1 Disconnect the power supply cord 2 Make sure that a definite click can be heard when the microwave oven door is unlatched Hold the door in a closed position with one hand then push the door open button...

Page 32: ...emove outer case 2 Discharge high voltage capacitor 3 Disconnect filament leads of transformer from the magnetron and capacitor 4 Disconnect high voltage lead of capacitor from the transformer 5 Disconnect wire leads from transformer 6 Remove two 2 screws holding the transformer to the base cabinet RE INSTALL 1 Rest the transformer on the base cabinet with its primary terminals toward rear cabinet...

Page 33: ...rewdriver To discharge the high voltage capacitor wait for 60 seconds and then short circuit the connection of the high voltage capacitor that is the connecting lead of the high voltage rectifier against the chassis with the use of an insulated screwdriver Turntable Motor Coupling Removal 1 Disconnect the power supply cord 2 Remove the turntable tray and the turntable support out of the oven cavit...

Page 34: ...fan motor to fan duct with the two 2 screws 2 Install the fan blade to the fan motor shaft according to the following procedure 1 Hold the center of the bracket which supports the shaft of the fan motor on the flat table 2 Apply the screw lock tight into the hole for shaft of the fan blade 3 Install the fan blade to the shaft of fan motor by pushing the fan blade with a small light weight ball pee...

Page 35: ...nt REMOVAL 1 Disconnect the oven power supply cord and remove outer case 2 Open the door and block it open 3 Discharge high voltage capacitor 4 Disconnect the wire leads from the switch 5 Remove the one 1 screw holding the latch hook right or left to the oven cavity front plate and release the latch hook right or left 6 Keep pushing the stopper tub holding the switch to the latch hook right or lef...

Page 36: ...sed with the door closed 6 Secure the screws firmly 7 Check all of the switches operation If any switch has not activated with the door closed loosen the screws and adjust the position of the latch hook right and the latch hook left After adjustment check the following 1 In and out play of door remains less than 0 5mm when in the latched position First check upper position of latch hook pushing an...

Page 37: ...Hinge Left Oven Hinge Right Door Cam Right Figure 4 5 Door Replacement and Adjustment Door Cam Left Door Assembly Oven Hinge Left Oven Hinge Right Door Cam Right Left Door Cam Pin Right Door Cam Pin Left Door Hinge Pin Right Door Hinge Pin Figure 4 6 Door Assembly Components To discharge the high voltage capacitor wait for 60 seconds and then short circuit the connection of the high voltage capaci...

Page 38: ...h an approved microwave survey meter Refer to Microwave Measurement Procedure Door Disassembly 1 Disconnect the power supply cord and remove outer case 2 Open the door and block it open 3 Discharge high voltage capacitor 4 Remove the door assembly referring to Door Replacement 5 Place the door assembly on a soft cloth with latch heads facing up NOTE As the engaging part of choke cover and door fra...

Page 39: ...anel 21 Now the door panel is free Control Assembly And CPU Unit Removal CONTROL PANEL ASSEMBLY 1 Disconnect the oven power supply cord and remove outer case 2 Open the oven door and block it open 3 Discharge the high voltage capacitor 4 Disconnect the 9 pin 14 pin harness from the connectors CN D and CN N on the power unit 5 Remove the four 4 screws holding the control panel assembly to the oven ...

Page 40: ...Component Teardown 4 10 Notes ...

Page 41: ...MATIC DIAGRAM DOOR CLOSED COOK OFF CONDITION SECONDARY PRIMARY INTERLOCK SWITCH RY1 MAGNETRON RY2 INTERLOCK RELAY RY2 RY3 RY4 RY5 RY6 RY1 A5 RY1 0 94 TRANSFORMER POWER CAPACITOR DAMPER SWITCH THER MISTOR E1 E2 E3 E4 E5 F3 AH SENSOR F2 F1 DOOR SENSING SWITCH WIRE COLOR CODES ARE APPLICABLE TO PRIMARY CIRCUIT ONLY AND NOT APPLICABLE TO LOW VOLTAGE CIRCUIT AND SECONDARY CIRCUIT NOTE 1 2 3 H V RECTIFI...

Page 42: ... E D THERMISTOR 1 2 RED RED RED RED BLK BLK WHT WHT GRN MAGNETRON RED HIGH VOLTAGE COMPONENTS HIGH VOLTAGE CAPACITOR POWER TRANSFORMER P P L BRN ORG RY4 RY5 RY1 COM RY1 N O RY2 COM ORG RY2 N O RY3 COM RED PNK RY3 N O BRN BRN RED GRY PNK W H T BLK RED GRY G R Y G R Y O R G NOTE Hot ORG wire must be connected to the power transformer terminal nearest to the transformer mounting screw DOOR SENSING SW...

Page 43: ...Outer case cabinet Base plate Foot Rear plate Capacitor holder Oven hinge L Oven hinge R Latch hook R Latch hook L Door cam L Door cam R Turntable motor cover Front cover Duct B Duct C 1 1 4 1 1 1 1 1 1 1 1 1 1 1 1 CABINET PARTS 32 33 34 35 36 37 38 Touch control assy Display unit Control panel angle Grounding spring PSU harness Screw Screw 1 1 1 1 1 8 4 CONTROL PANEL PARTS 39 40 41 42 43 44 45 46...

Page 44: ...0 2 DOOR PARTS 76 77 78 79 80 81 82 83 84 85 86 Main wire harness High voltage wire B Grounding wire Cooling fan motor Monitor caution label NHW caution label Operation manual User caution BIK label GND caution label Installation instructions Menu label 1 1 1 1 1 1 1 1 1 1 1 WIRING LABELS 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 Screw Screw Screw Screw Screw Special screw Screw Screw Screw S...

Page 45: ... 23 22 66 26 106 96 18 14 15 46 43 52 96 3 2 90 10 97 90 67 100 64 105 101 91 47 41 40 39 25 4 102 2 92 99 106 16 98 6 45 7 96 8 95 104 42 48 5 87 94 20 94 94 1 51 55 92 103 24 4 4 56 13 11 21 88 12 57 49 99 90 50 109 110 84 83 80 82 86 79 90 54 44 Oven And Cabinet Parts ...

Page 46: ...Parts List 6 4 89 89 29 30 89 89 31 90 90 90 17 90 63 90 61 60 61 63 90 59 90 91 62 58 90 91 107 108 Cabinet And Frame Parts ...

Page 47: ...Parts List 6 5 CONTROL PANEL PARTS DOOR PARTS MISCELLANEOUS 68 73 75 72 69 74 74 73 75 71 70 32 35 33 37 34 38 36 Actual wire harness may be different than illustration 78 77 76 Control And Door Parts ...

Page 48: ...INSTALLATION MANUAL 81 OPERATION MANUAL 40 TURNTABLE SUPPORT TRAY PAD DOOR PROTECTION SHEET PLASTIC BAG Not replaceable items PACKING CASE BOTTOM BASE PAD TOP BASE PAD TOP CROSS SUPPORT VERTICAL CORNER POST PALLET Packing and Accessories ...

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