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Troubleshooting and Testing

 

3-4

Procedure 

Letter

B

C

Component Test

POWER TRANSFORMER TEST

1.   Disconnect the 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.   Disconnect the primary input terminals and measure the resistance of the transformer with an 

ohmmeter. Check for continuity of the coils with an ohmmeter. On R x 1 scale, the resistance of 
the primary coil should be less than 1 ohm and the resistance of the high voltage coil should be 
approximately 84.4 ohms; the resistance of filament coil should be less than 1 ohm.

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.

 

HIGH VOLTAGE RECTIFIER TEST

1.   Disconnect the 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 directions, or if an infinite resistance is 

 

read in both directions, the rectifier is probably defective and should be replaced.

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.

NOTE:

  Be sure to use an ohmmeter that will supply a forward bias voltage of more than 6.3 volts.

DO NOT TOUCH THE COMPONENTS OF THE POWER TRANSFORMER WHILE POWER 
TRANSFORMER IS ENERGIZED.  IT IS DANGEROUS BECAUSE THIS HAS HIGH VOLTAGE 
COMPONENTS.  (HIGH VOLTAGES ARE PRESENT AT THE HIGH VOLTAGE TERMINAL, SO 
DO NOT ATTEMPT TO MEASURE THE FILAMENT AND HIGH VOLTAGE.)

Summary of Contents for E30MO75HPS - 1.5 cu. Ft. Drop-Down Door Microwave

Page 1: ...Publication 5995532800 P N 316439273 April 2009 BRUSH DIRECTION Technical Service Manual Microwave Oven Models E30MO75HSS E30MO75HPS ...

Page 2: ......

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: ... 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 Reheat pad Add 30 sec pad Popcorn pad Auto Defro...

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: ...n 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 support in the center of th...

Page 13: ...nding voltage heats the magnetron filament and the H V winding voltage is sent to a voltage doubler circuit 4 The microwave energy produced by the magnetron is channeled through the waveguide into the cavity 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 ...

Page 14: ...UPPLY 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 AC125V 0 00...

Page 15: ... occur A The heater relay is de energized by the control unit temperature circuit and thermistor opening the circuit to the heating element B The oven will continue to function for 30 minutes turning heater on and off as needed to maintain the selected preheat temperature The oven will shut down completely after 30 minutes CONVECTION COOKING CONDITION When the preheat temperature is reached a beep...

Page 16: ...emperature the following operations occur A The power supply voltage is alternated to the heating element and power transformer B The heating element operates through the heater relay RY3 contacts and the power transformer operates through the primary interlock relay RY2 contacts C These are operated by the control unit to supply alternately within a 32 second time base convection heat and microwa...

Page 17: ... desired Sensor setting 3 Touch START pad The coil of shut off relay RY1 RY6 is energized the oven lamp and cooling fan motor are turned on but the power transformer is not turned on 4 After about 16 seconds the cook relay RY2 is energized The power transformer is turned on microwave energy is produced and first stage is started The 16 seconds is the cooling time required to remove any vapor from ...

Page 18: ...revious voltage measured the LSI judges it as a fire in the oven cavity and switches off the relays to the power transformer fan motor and convection motor The LSI also stops counting down and closes the damper door so that no fresh air will enter the oven cavity OPERATION Please refer to the timing diagrams below 1 The thermistor operates within a 32 seconds time base and it is energized for thre...

Page 19: ...owing 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 normally closed At this time the door sensing and primary interlock and third door switches are in the OFF condition contacts open due to their being normally open con...

Page 20: ...C HEATING ELEMENT The heating element is located at the left side of the oven cavity It is intended to heat air driven by the convection fan The heated air is kept in the oven and force circulated and reheated by the heating element Humidity Sensor Circuit 1 Structure of Absolute Humidity Sensor The absolute humidity sensor includes two thermistors as shown in the illustration One thermistor is ho...

Page 21: ...ZA495DR CONVECTION COOKING SYSTEM This oven is designed with a hot air heating system where food is not directly heated by the heating element but is heated by forced circulation of the hot air produced by the heating element The air heated by the heating element is circulated through the convection passage provided on the outer casing of theoven cavity by means of the convection fan which is driv...

Page 22: ...ven is microwave cooking Damper is in the open position 3 When oven is convection cooking A Damper motor is energized by touching the convection temperature and START pads B When damper is in the closed position damper switch is OFF its signal is sensed by the control unit and shut off relay RY4 is de energized C The damper is held in the closed position during the convection cooking operation D A...

Page 23: ...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 supply cord a...

Page 24: ...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 light when door is opened Cooking cycle runs 1 minute then shuts down Oven lamp light but turntable motor does not operate Turntable motor operates normally but cooling fan motor does not operate Oven does not go into a cook cycle when START pad is touche...

Page 25: ... 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 26: ... 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 27: ...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 28: ...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 29: ...ut out An open 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 MAGNETRON THERMAL CUT OUT on the waveguide 1 Disconnect the power supply cord and then remove outer case 2 Open the door and ...

Page 30: ...ings and Instructions on page 3 1 4 Make sure the heating element is fully cooled and test as follows a Disconnect wire leads and measure the resistance with an ohmmeter On the R x 1 scale the resistance between the heating element terminals should be approximately 10 2 b Disconnect wire leads and measure the insulation resistance with 500V 100M insulation resistance meter The insulation resistanc...

Page 31: ...When switch actuator is pushed by the damper motor cam the meter should be indicated a closed circuit B When power cord is plugged into the wall receptacle the damper motor operates and damper cam will start to rotate When the switch actuator is released the meter should be indicating an open circuit If improper operation is indicated replace the damper switch 5 Reconnect all leads removed from co...

Page 32: ... number pad two figures or more are displayed C When touching the pads sometimes a pad produces no signal 2 Control Unit The following symptoms indicate a defective control unit Replace the control unit A 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 B In connection with indicators a At a certain d...

Page 33: ...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 supply cord after th...

Page 34: ...ing solvents near the oven while using Sensor settings The sensor will detect vapor 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 foll...

Page 35: ...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 36: ... remove 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 cabin...

Page 37: ...crewdriver 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 cavi...

Page 38: ...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 39: ...connect wire leads from the convection motor Remove the convection fan belt 5 Remove two 2 screws holding the convection motor mounting angle to the heater duct and base cabinet 6 Take out the convection motor assembly from the unit The convection motor assembly is now free 7 Remove two 2 screws and nuts holding the motor to mounting angle 8 Remove pulley from the motor shaft Convection motor is n...

Page 40: ...the chassis with the use of an insulated screwdriver Heater Unit Assembly Removal THERMISTOR 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 wire leads from H V capacitor and re move four 4 screws holding rear cabinet to bottom plate and three 3 screws holding to heater unit assembly and two 2 s...

Page 41: ...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 42: ...Hinge Left Oven Hinge Right Door Cam Right Figure 4 6 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 7 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 43: ...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 44: ...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 45: ...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 1 NOTE 2 3 H V RECTIFI...

Page 46: ... 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 47: ...EF NO DESCRIPTION Q TY 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 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 35 36 37 38 39 40 41 Touch control assy Display unit Control panel angle Grounding spring PSU harness S...

Page 48: ...ing Convection motor mounting plate Pulley Convection fan belt Damper duct cushion 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 55 56 57 58 59 60 61 62 63 64 65 65 66 67 54 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 68 REF NO DESCRIPTION Q TY 91 92 93 94 95 96 97 98 Door frame assembly Door panel Choke cover Latch head R Latch head L Latch head s...

Page 49: ...2 115 122 136 16 121 6 48 7 119 8 118 134 45 51 5 110 117 23 117 117 1 54 58 115 133 27 4 4 59 13 11 24 111 12 139 140 107 106 103 105 109 102 11 6 9 52 122 53 11 3 57 47 TO OVEN BASE PLATE 12 6 75 71 77 12 5 89 79 14 1 12 9 13 1 13 0 76 12 9 17 13 0 12 5 12 8 12 8 88 19 87 74 12 9 73 13 1 x3 72 78 8 12 9 56 83 12 6 82 6 18 12 9 80 90 11 3 12 7 81 84 60 142 Oven And Cabinet Parts ...

Page 50: ...Parts List 6 4 112 112 32 33 112 112 34 90 90 90 20 90 66 90 65 63 63 66 90 62 90 90 65 61 90 90 137 138 Cabinet And Frame Parts ...

Page 51: ...Parts List 6 5 CONTROL PANEL PARTS MISCELLANEOUS 35 38 36 40 37 41 DOOR PARTS 91 96 98 95 92 97 97 96 98 94 93 39 Actual wire harness may be different than illustration 101 100 99 Control And Door Parts ...

Page 52: ...INSTALLATION MANUAL 104 OPERATION MANUAL 43 TURNTABLE SUPPORT TRAY PAD Not replaceable items 86 HIGH RACK 85 LOW RACK DOOR PROTECTION SHEET PLASTIC BAG PACKING CASE BOTTOM BASE PAD TOP BASE PAD TOP CROSS SUPPORT VERTICAL CORNER POST PALLET Packing and Accessories ...

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