Service Information
!WARNING
To avoid risk of electrical shock, personal injury, or death, disconnect power to oven and discharge capacitor before servicing, unless testing requires power.
Proper Handling of Magnetron Tubes
!CAUTION
A magnetron tube, like a radio or television tube must be handled with a reasonable amount of care. When handling a tube, always handle by the housing only. Use caution not to touch or strike the ceramic portion at the top. The carton used to ship service replacement tubes is reusable.
Magnetron Failure Modes
Magnetron failures that have been identified are generally grouped into categories shown below.
1.Shorted
Air - This is a case where the tube has had the vacuum envelope destroyed and air has entered the tube. This will cause internal arcing and high secondary current if high voltage is applied.
R.F. Capacitors - May short to chassis. This condition will also cause loss of high voltage.
2.Open Heater (Filament) - Can be determined by a ohmmeter when transformer leads are disconnected. Resistance is normally less than one ohm; filament does not short internally. Any tube removed should be checked since usage tends to make the filament more fragile. Later handling and shipping may open the filament and thereby mask the true failure mode when checked at the factory.
3.Low Power - Caused by “wearout” of the emission characteristics of the directly heated cathode. Symptoms are: (1) tube current will take longer to get to operating point than a new tube (normally about 2 - 3 seconds), (2) tube current does not get high enough to cause the tube to oscillate with normal line voltage, (3) oven produces low power into a load,
4.Physical Damage - Caused by mishandling of magnetron tube.
Output
Antenna 
Ceramic
Fins
Anode
Block
Magnet
Terminals/R.F. Capacitors |
Not Replaceable |
Serial Number
©2006 Maytag Services | 16026795 | 17 |
