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Electrolux FGMO205KBA, Service Manual

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Electrolux FGMO205KBA Service Manual Download Page 31

   

Section 3 Troubleshooting and Testing

3-13

Procedure 

Letter

M

Component Test

TESTING METHOD FOR AH SENSOR AND/OR CONTROL UNIT

To determine if the sensor is defective, the simplest method is to replace it with a new replacement
sensor.
1.   Disconnect the power supply cord, and then remove outer case.
2.   Open the door and block it open.
3.   Discharge high voltage capacitor.
4.   Remove the AH sensor.
5.   Install the new AH sensor.
6.   Reconnect all leads removed from components during testing.
7.   Re-install the outer case (cabinet).
8.   Reconnect the power supply cord after the outer case is installed.
9.   Reconnect the oven to the power supply and check the sensor cook operation as follows:
9-1.  Fill approximately 200 milliliters (7.2 oz) of tap water in a 1000 milliliter measuring cup.
9-2.  Place the container on the center of tray in the oven cavity.
9-3.  Close the door.
9-4.  Press STOP/CLEAR, then touch timer/on-off pad once, the POWER LEVEL pad twice and touch
 

  the START/ENTER pad once. Touch the NUMBER pad (1) once and the NUMBER pad (4) once.

9-5.  The control panel is in automatic Sensor operation.
9-6.  The oven turns off automatically, and the time for detecting moisture will be displayed.
If new sensor dose not operate properly, the problem is with the control unit, and refer to 
explanation in checking the control unit.

CHECKING CONTROL UNIT

1.   Disconnect the power supply cord, and then remove outer case.
2.   Open the door and block it open.
3.   Discharge high voltage capacitor.
4.   Disconnect the sensor connector that is mounted to control panel.
5.   Then connect the dummy resistor circuit (see next page) to the sensor connector of control 

panel.

6.   Disconnect the leads to the primary of the power transformer.
7.   Ensure that these leads remain isolated from other components and oven chassis by using 

insulation tape.

8.   After that procedure, re-connect the power supply cord.
9.   Check the sensor cook operation proceed as follows:
9-1. Press STOP/CLEAR, then touch TIMER/ON-OFF pad once, the POWER LEVEL pad twice and 

touch the START/ENTER pad once. Touch the NUMBER pad (1) once and the NUMBER pad (4) 
once.

9-2. The control panel is in the sensor cooking operation.
9-3. After approximately 25 seconds, push plunger of select switch for more than 3 seconds. This    

 condition is same as judgement by AH sensor.

9-4. After approximately 3 seconds, the display shows “ X X . X X “ which is the time for detecting  

 moisture.

If the above is not the case, the control unit is probably defective.
If the above is proper, the AH sensor is probably defective.

Continued on next page.

Summary of Contents for FGMO205KBA

Page 1: ...All About Servicing MICROWAVE OVENS With Electronic Controls Publication 5995557609 Part 316439603 January 2009 Electrolux Major Appliances North America 250 Bobby Jones Expwy Augusta GA 30907 ...

Page 2: ......

Page 3: ... operation 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...

Page 4: ...ions 2 4 Door Open Mechanism 2 4 Door Sensing And Primary Interlock Switch 2 4 Monitor Switch 2 4 Turntable Motor 2 5 Cooling Fan Motor 2 5 Cavity Temperature Fuse 2 5 Monitor Fuse 2 5 Magnetron Temperature Fuse 2 5 Humidity Sensor Circuit 2 6 Section 3 Troubleshooting and Testing Warnings and Cautions 3 1 Troubleshooting Guide Chart 3 2 Test Procedures 3 3 Section 4 Component Teardown Warnings an...

Page 5: ...osure by themselves or when they are damaged loosened or removed Section 1 Basic Information 1 3 WARNING This service manual is intended for use by persons having electrical and mechanical training and a level of knowledge of these subjects generally considered acceptable in the appliance repair trade Electrolux home products cannot be responsible nor assume any liability for injury or damage of a...

Page 6: ...emission 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 a...

Page 7: ...open 3 Discharge high voltage capacitor 4 Reconnect leads to the primary of the inverter unit 5 Reinstall the outer case cabinet 6 Reconnect the power supply cord after the outer case is installed 7 Run the oven and check all functions After repairing 1 Reconnect all leads removed from components during testing 2 Reinstall the outer case cabinet 3 Reconnect the power supply cord after the outer ca...

Page 8: ...ty The 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 ...

Page 9: ...d accurately 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 fast...

Page 10: ...t 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 Add 30 sec pad Sensor cooking pads Number selection pads Power Level pad Timer ...

Page 11: ...rd and plug must be connected to a separate 120 Volt AC 60 Hz 15 Amp or more 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 obliga...

Page 12: ...ntable on the turntable support securely The turntable will rotate clockwise or counterclockwise Only remove for cleaning 9 Ventilation openings rear 10 Microwave oven light It will light when microwave oven is operating or door is open 11 Waveguide cover DO NOT REMOVE 12 Auto Touch control panel 13 Time display 99 minutes 99 seconds 14 Serial plate 15 Menu Label Oven Diagram 1 7 3 10 9 8 2 5 4 12...

Page 13: ...e 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 the monitor switch door sensing switch primary interlock switch relay RY1 and secondary interlock relay are activated with the following result...

Page 14: ...Section 2 Operation 2 2 Figure 2 1 Oven Off Condition Figure 2 2 Oven ON Cooking Condition ...

Page 15: ...without figuring time power level or quantity When the oven senses enough steam from the food it relays the information to its microprocessor which will calculate the remaining cooking time and power level needed for best results When food is cooked water vapor is developed The sensor senses the vapor and its resistance increases gradually When the resistance reaches the value set according to the...

Page 16: ...s Door Sensing Switch Monitor Switch Switch Lever Primary Interlock Switch Latch Heads Door COOKING SEQUENCE 1 Operate the oven in sensor cooking mode by referring to the operation manual 2 The coil of shut off relays RY1 and RY3 are energized the oven lamp turntable motor and cooling fan motor are turned on but the power transformer is not turned on 3 After about 32 seconds the relay RY2 is energ...

Page 17: ...r is opened the monitor switch contact close to the ON condition due to their being normally closed At this time the secondary interlock relay RY2 and primary interlock switch are in the OFF condition contacts open due to their being normally open contact switches The contacts of relay RY1 are in the ON condition contacts close 2 As the door goes to a closed position the monitor switch contacts ar...

Page 18: ...put voltage of the absolute humidity circuit to allow the LSI to control sensor cooking of the unit When the unit is set in sensor cooking mode 16 seconds clearing cycle occurs then the detector circuit starts to function and the LSI observes the initial voltage available at its AN1 terminal With this voltage given switches SW1 to SW5 in the LSI are turned on in such a way as to change the resista...

Page 19: ...fuse If the monitor fuse is replaced the monitor switch must also be replaced CAUTION Whenever troubleshooting is performed with the power supply cord disconnected It may in some cases be necessary to connect the power supply cord after the outer case has been removed in this event 1 Disconnect the power supply cord and then remove outer case 2 Open the door and block it open 3 To discharge high v...

Page 20: ...Section 3 Troubleshooting and Testing 3 2 ...

Page 21: ... measuring cup with 16 oz 453 cc of tap water and measure the temperature of the water with a thermometer or thermocouple temperature tester Stir the thermometer or thermocouple through the water until the temperature stabilizes Record the temperature of the water 2 Place the cup of water in the oven Operate oven at 100 POWER selecting more than 60 seconds cook time Allow the water to heat for 60 ...

Page 22: ... 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 d...

Page 23: ...icate a closed circuit unless the temperature of the cavity temperature fuse reaches approximately 302 F 150 C An open cavity temperature fuse indicates overheating of the oven exchange cavity temperature fuse and check inside of oven cavity and for improper setting of cooking time or operation of control unit Check for restricted air flow through the vent holes of the oven cavity especially the c...

Page 24: ...OM and normally open NO terminal of the switch The meter should indicate an open circuit with the door open and a closed circuit with the door closed If improper operation is indicated replace the door sensing switch 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 ...

Page 25: ...g the monitor switch reconnect wire lead to monitor switch COM terminal and check continuity of monitor circuit 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 TOUCH CONTROL PANEL ASSEMBLY TEST The touch control panel consists of circuits includ...

Page 26: ... light up or they continue to light up e Wrong figure appears f A certain group of indicators do not light up g The figure of all digits flicker 3 Other possible problems caused by defective control unit a Buzzer does not sound or continues to sound b Clock does not operate properly c Cooking is not possible 4 If the Key unit or the Control unit is defective a Disconnect the power supply cord and ...

Page 27: ...ntrol unit circuit check the circuit between the pins of the key unit that correspond to the STOP CLEAR pad When the pad is pressed the ohmmeter should indicate short circuit When the pad is released the ohmmeter should indicate open circuit If incorrect readings are obtained the key unit is faulty and must be replaced About the other pads the above method may be used 5 Reconnect all leads removed...

Page 28: ...voltmeter during the microwave cooking operation DC voltage indicated Defective relay DC voltage not indicated Check diode which is connected to the relay coil If diode is good control unit is defective 8 Disconnect the power supply cord and then remove outer case 9 Open the door and block it open 10 Discharge high voltage capacitor See Warnings and Instructions on page 3 1 11 Reconnect all leads ...

Page 29: ... high voltage capacitor 4 Disconnect the leads to the primary of the power transformer Ensure that these leads remain isolated from other components and oven chassis by using insulation tape 5 After that procedure re connect the power supply cord 6 Follow the troubleshooting guide given below for repair 7 Disconnect the power supply cord and then remove outer case 8 Open the door and block it open...

Page 30: ... not detected the vapor of the food ERROR will appear and the oven will shut off WATER LOAD COOKING TEST Make sure the oven has been plugged in at least two minutes before checking sensor cook operation The cabinet should be installed and screws tightened 1 Fill approximately 200 milliliters 7 2 oz of tap water in a 1000 milliliter measuring cup 2 Place the container on the center of tray in the o...

Page 31: ... displayed If new sensor dose not operate properly the problem is with the control unit and refer to explanation in checking the control unit CHECKING CONTROL UNIT 1 Disconnect the power supply cord and then remove outer case 2 Open the door and block it open 3 Discharge high voltage capacitor 4 Disconnect the sensor connector that is mounted to control panel 5 Then connect the dummy resistor circ...

Page 32: ...ock it open 3 Discharge high voltage capacitor 4 Disconnect the leads to the primary of the power transformer 5 Using an ohm meter check between the terminals as described in the following table If incorrect readings are obtained replace the noise filter 6 Reconnect all leads removed from components during testing 7 Re install the outer case cabinet 8 Reconnect the power supply cord after the oute...

Page 33: ...n 2 If the wave guide or oven cavity are not intact 3 If the door is not closed 4 If the outer case cabinet is not fitted WARNING Disconnect oven from power supply before removing outer case Discharge high voltage capacitor before touching any oven components or wiring after removing outer case CAUTION To prevent an electric shock take the following precautions 1 Before wiring A Disconnect the pow...

Page 34: ...power supply cord and then remove outer case 2 Open the door and block it open 3 Discharge high voltage capacitor 4 Disconnect wire leads primary and high voltage from power transformer and the filament leads from the magnetron and capacitor terminals 5 Remove two 2 screws holding transformer to bottom plate 6 Remove transformer from bottom plate RE INSTALL 1 Rest transformer on the bottom plate w...

Page 35: ...onnect the power supply cord and then remove outer case 2 Open the door and block it open 3 Discharge high voltage capacitor 4 Disconnect wire leads from magnetron 5 Remove the two 2 screws holding the chassis support to the magnetron and the oven cavity front flange 6 Slide the magnetron duct slightly so that the two 2 screws at left hand side of the magnetron appear 7 Carefully remove the four 4...

Page 36: ... turntable support from oven cavity 3 Lay the oven on its backside Remove the turntable motor cover by snipping off the material in four corners 4 Where the corners have been snipped off bend corner areas flat No sharp edges must be evident after removal of the turntable motor cover 5 Disconnect wire leads from turntable motor See Positive lock connector removal 6 Remove one 1 screw holding turnta...

Page 37: ...l of the microwave oven and the precautions you must take when doing so To perform the servicing power to the touch control panel is available either from the power line of the oven itself or from an external power source 4 Disconnect the leads to the primary of the power transformer 5 Ensure that these leads remain isolated from other components and oven chassis by using insulation tape 6 After t...

Page 38: ...ed be careful that abnormal voltage due to static electricity etc is not applied to the input or output terminals 4 Attach connectors electrolytic capacitors etc to PWB making sure that all connections are tight 5 Be sure to use specified components where high precision is required Control Panel Assembly Removal 1 Disconnect the power supply cord and remove outer case 2 Open the door and block it ...

Page 39: ...e capacitor that is the connecting lead of the high voltage rectifier against the chassis with the use of an insulated screwdriver NOTE Make sure that any pieces do not enter the gap between the rotor and the stator of the fan motor as the rotor is easy to be shaven by pliers and metal pieces may be produced Do not touch the pliers to the coil of the fan motor because the coil may be cut or damage...

Page 40: ...ivated with the door closed 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 NOTE To discharge the high voltage capacitor wait for 60 seconds and then short circuit the connection of the high voltage ca...

Page 41: ...ment REMOVAL 1 Disconnect the power supply cord 2 Push the open button and open the door slightly 3 Insert a putty knife thickness of about 0 5mm into the gap between the choke cover and door frame as shown in Figure 4 7 to free engaging parts 4 Pry the choke cover by inserting a putty knife as shown Figure 4 7 5 Release choke cover from door panel 6 Now choke cover is free 7 Release two 2 pins of...

Page 42: ...er to Microwave Measurement Procedure Figure 4 8 Door Components Note When carrying out any repair to the door do not bend or wrap the slit choke tabs on the door panel assembly to prevent microwave leakage After any service to the door 1 Make sure that door sensing switch and secondary interlock switch are operating properly Refer to section 3 Test Procedures 2 An approved microwave survey meter ...

Page 43: ...Section 5 Wiring Diagrams 5 1 Wiring Schematic Oven OFF Condition ...

Page 44: ...Section 5 Wiring Diagrams 5 2 Wiring Diagram ...

Page 45: ...Section 6 Parts List 6 1 Control Panel And Door Parts ...

Page 46: ...Section 6 Parts List 6 2 ...

Page 47: ...Section 6 Parts List 6 3 Oven And Cabinet Parts ...

Page 48: ...Section 6 Parts List 6 4 Packing And Accessories ...

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