Whirlpool 721.663398 manual Condition, Check, Result

Page 27

(TROUBLE 1) The following visual conditions indicate a probable defective control circuit.

1.Incomplete segments.

Segment missing.

Partial segment missing.

Digit flickering (NOTE: Slight flickering is normal.)

2.Colon does not turn on or blink.

3.A distinct change in the brightness of one or more numbers in display.

4.One or more digits in the display are not lighting.

5.Display indicates a number different from one touched, for example, key in 5 and 3 appears in the display.

6.Specific numbers (for example 7 or 9) will not display when key pad is touched.

7.Display does not count down with time blinking or up with clock operation.

8.Display obviously jumps in time while counting down.

9.Display counts down too fast while cooking.

10.Each indicator light does not turn on after setting cooking cycle.

11.Display time of day does not reappear when cooking is finished.

CONDITION

1.No input can be programmed.

2.Some inputs cannot be programmed.

3.Display shows a number or figure different from one touched.

4.Random programming when touching other pads.

5.Display is fixed at some figure and can not accept any input.

CHECK

Check the conn- ection between membrane key assembly and PCB assembly.

Replace key membrane assembly and check operation.

RESULT

Continuity

No continuity

Everything works as specified.

Still have trouble.

CAUSE

Defective PCB assembly.

Loose connection.

Defective key membrane assembly.

Defective PCB assembly.

REMEDY

Replace PCB assembly.

Connect them tightly.

Replace key membrane assembly.

Replace PCB assembly.

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Contents Division Basic Field Manual For Microwave Oven Page Foreword Test the Latch and Switch Sequence Adjustment ProceduresCheck the Door Latch and Switch Closing Adjust the Latch and Switch ClosingLatch Latch Board Trial Operation Precautions on InstallationFeatures and Specifications General Precautions in USESwitch Table SpecificationsSchematic Diagram Overall Circuit Diagram Matrix Circuit for Touch KEY Board Operating Procedures A. Oven Control Panel Easy USE Table Equipment Procedure for Measuring Microwave Energy LeakageMeasuring Microwave Energy Leakage Measurement with the Outer Case RemovedPower Output Measurement Measurement with a Fully Assembled OvenRecord Keeping and Notification After Measurement Important Notes Disassembly InstructionsDoor Assembly / Removal Magnetron Removal FAN Motor Assembly / Removal High Voltage Transformer Removal Removing SensorHigh Voltage Capacitor and Diode Removal Interlock Mechanism Interlock SystemComponents Test Procedure Results Primary Interlock Switch TestSecondary Interlock Switch Test Monitor Switch TestMagnetron Test and Checkout PROCEDURES, and TroubleshootingTest Procedures Components Filament Winding Primary TerminalHigh Voltage CapacitorDiode FAN Motor PowerRelay LevelCheckout Procedures Checkout Procedures for Fuse BlowingProblems Causes YES Good Checkout Procedures for Relay Problem a Problem BPage Condition Cause Remedy Trouble ShootingCondition CheckResult Fuse blows Condition Check Result Cause RemedyCondition Check Result Cause Remedy Check Result Exploded View Door Parts Controller Parts Oven Cavity Parts Latch Board Parts Interior Parts Base Plate Parts Sensor Parts No MFL30502909