Electrolux FMV156DBE service manual Operation, Description of Operating Sequence

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FMV156DBE

FMV156DSE

FMV156DQE

FMV156DCF

OPERATION

DESCRIPTION OF OPERATING SEQUENCE

The following is a description of component functions dur- ing oven operation.

OFF CONDITION

Closing the door activates the door sensing switch and secondary interlock switch. (In this condition, the monitor switch contacts are opened.)

When oven is plugged in, 120 volts A.C. is supplied to the control unit. (Figure O-1).

1.The display will show "WELCOME, PRESS CLEAR AND PRESS CLOCK".

To set any program or set the clock, you must first touch the STOP/CLEAR pad. The display will clear, and " : " will appear .

COOKING CONDITION

Program desired cooking time touching the NUMBER pads. When the START pad is touched, the following operations occur:

1.The contacts of relays are closed and components connected to the relays are turned on as follows.

(For details, refer to Figure O-2)

RELAY

CONNECTED COMPONENTS

RY1

Oven lamp / Fan motor / Stirrer motor

RY2

Power transformer

RY3

Turntable motor

RY4

Hood fan motor

2.120 volts A.C. is supplied to the primary winding of the power transformer and is converted to about 3.3 volts A.C. output on the filament winding, and approximately 2000 volts A.C. on the high voltage winding.

3.The filament winding 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 channelled through the waveguide into the cavity feed- box, 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, monitor switch, door sensing switch, primary interlock switch, and secondary interlock relay are activated with the following results. The circuits to the stirrer motor, the cooling fan motor, the turntable motor, and the high voltage components are de-energized, and the digital read-out displays the time still remaining in the cook cycle when the door was opened.

7.The monitor switch is electrically monitoring the

of the primary interlock switch, and door sensing switch is mechanically associated with the door so that it will function in the following sequence.

(1)When the door opens from a closed position, the secondary interlock relay, door sensing switch, and primary interlock switch open their contacts, and then the monitor switch contacts close.

(2)When the door is closed from the open position,

the

monitor switch contacts open first. Then the

contacts

of the primary interlock switch and door

sensing

switch close. And contacts of

the relay (RY1) open.

If the primary interlock switch and secondary interlock relay (RY2) fail with the contacts closed when the door is opened, the closing of the monitor switch contacts will form a short circuit through the monitor fuse, primary interlock switch, relay (RY1) and secondary interlock relay (RY2), causing the monitor fuse to blow.

POWER LEVEL P-0 TO P-90 COOKING

When Variable Cooking Power is programmed, the 120 volts A.C. 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(P-HI)

32 sec.

0 sec.

(100% power)

 

 

Power 9(P-90)

30 sec.

2 sec.

(approx. 90% power)

 

Power 8(P-80)

26 sec.

6 sec.

(approx. 80% power)

 

Power 7(P-70)

24 sec.

8 sec.

(approx. 70% power)

 

Power 6(P-60)

22 sec.

0 sec.

(approx. 60% power)

 

Power 5(P-50)

18 sec.

4 sec.

(approx. 50% power)

 

Power 4(P-40)

16 sec.

6 sec.

(approx. 40% power)

 

Power 3(P-30)

12 sec.

20 sec.

(approx. 30% power)

 

Power 2(P-20)

8 sec.

24 sec.

(approx. 20% power)

 

Power 1(P-10)

6 sec.

26 sec.

(approx. 10% power)

 

Power 0(P-0)

0 sec.

32 sec.

(0% power)

 

 

Note: The ON/OFF time ratio does not correspond with the percentage of microwave power, because approx. 2 seconds are needed for heating of the magnetron

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Contents Over the Range Microwave Oven Models Table of ContentsBefore Servicing Dont Touch Before Servicing When the testing is completedMicrowave Measurement Procedure RequirementsLeakage test Electrolux General Information Product SpecificationOven Diagram Control Panel Description of Operating Sequence OperationVertical Venting Horizontal VentingRE-CIRCULATION Inside Venting Figure O-1. Oven Schematic-Off Condition Functions Description and Function of ComponentsTroubleshooting Guide CK = Check / RE = Replace Procedure Component Test Letter Magnetron Assembly Test Microwave Output PowerPower Transformer Test Magnetron Temperature Fuse Test High Voltage Capacitor TestCavity Thermal CUT-OUT Test TEMPERATURE, Replace Temperature Fuse Procedure Component Test LetterPrimary Interlock Switch Test Door Sensing SwitchSecondary Interlock Relay RY2 Monitor Switch TestProcedure Hood Thermal CUT-OUT TestHood FAN Motor Test Before testing Relay Test KEY Unit TestDefrost Center Test Foil Pattern on the Printed Wiring Board Test1ST Stage 2ND Stage Level TimeOccurrence Cause or Correction RemovalSteps Occurrence Cause or Correction Measuring Point Indication of OHM-METER Procedure Component Test Letter Noise Filter TestTouch Control Panel Assembly Description of LSILSI OUT Oven lamp, fan motor and turntable motor driving signal Signal to sound buzzer 2.0 kHzSignal coming from touch key Signal similar to P46Hood lamp driving signal Key strobe signalHood motor driving signal Segment data signalServicing Other PrecautionsShapes of Electronic Components Servicing of Touch Control PanelHood Exhaust Louver Removal Component Replacement and Adjustment ProcedureRe-install Power Transformer RemovalPictorial Diagram Hood FAN Motor RemovalHigh Voltage Rectifier and High Voltage Capacitor Removal Magnetron RemovalHood FAN Thermal CUT-OUT Removal Thermal CUT-OUT Cavity RemovalInstallation Cooling FAN Motor RemovalSide View Control Panel ASSEMBLY, Control Unit and KEY Unit Removal Positive Lock Connector NO-CASE Type RemovalPositive lock connector Turntable MotorControl Unit and KEY Unit Removal Key unit locationDoor Assembly RE-INSTALL Door Replacementdoor Assembly RemovalDoor Frame Assembly Door DisassemblyChoke Cover Latch SPRING, Latch Head and Door PanelPictorial DiagramFigure S-2. Power Unit Circuit LSI Unit Circuit Figure S-4. Printed Wiring Board Electric Parts Parts ListCabinet Parts Control Panel PartsDoor Parts MiscellaneousSCREWS,NUTS, Washers and Other Oven and Cabinet Parts Control Panel Parts Door Parts Miscellaneous Non-replaceable items Packing and AccessoriesFMV156DBE FMV156DSE FMV156DQE FMV156DCF FMV156DBE FMV156DSE FMV156DQE FMV156DCF FMV156DBE FMV156DSE FMV156DQE FMV156DCF
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