What causes magnetron failure?

The most common cause of an overheating magnetron is when too much energy is reflected back into the device. This can happen when you run your microwave empty (something you should never do), or if the turntable has been removed.

Humming. A loud humming noise from your microwave is often a sign of a faulty or worn-out diode. The diode is responsible for converting AC to DC to supply the magnetron with power. If a defective diode is to blame for your microwave making noise, the microwave won’t generate heat.

magnetron, diode vacuum tube consisting of a cylindrical (straight wire) cathode and a coaxial anode, between which a dc (direct current) potential creates an electric field. A magnetic field is applied longitudinally by an external magnet. Connected to a resonant line, it can act as an oscillator.

The magnetron remains in use in some radar systems, but has become much more common as a low-cost source for microwave ovens. In this form, over one billion magnetrons are in use today.

There are three types of magnetrons: Negative resistance type. Cyclotron frequency type. Travelling wave or Cavity type.

There is no difference between a 650, 700, 750 and 1000W microwave magnetron wise, they all use the same size magnetron, the same transformer and rectifier and the only difference is the high voltage capacitor, which controls the current in the magnetron.

No matter how new your microwave or if there’s only one problem, if the magnetron is out then you might as well replace the entire appliance. The magnetron is the heart of a microwave that actually makes the micro-waves. Replacing it is about equal to the cost of buying a whole new microwave, sometimes even greater.

A noisy humming or vibrating noise can mean you need the magnetron tube replaced. An abnormal clicking sound can also be a sign of a bad magnetron. A grinding or groaning sound can signify a problem with the turntable roller guide or turntable drive motor. Grinding can also mean there’s a problem with the stirrer motor.

Although the average life of a magnetron tube is 22 years, a number of factors can cause that number to diminish and for the microwave oven to lose power more quickly.

You can change the frequency of a magnetron over a small range by changing the match of the output line. This is called frequency pulling and the data may be shown in the performance data by a Reike diagram which shows power, efficiency and frequency as a function of output match on a Smith Chart.

The microwave oven uses a magnetron to generate microwave energy. The microwave energy travels through a waveguide and is distributed into a metal cavity where the food is cooked. The waves are absorbed by the food and excite water molecules in the food. This heat then transfers throughout the food cooking it.

A combi oven or combi microwave is a combination of an oven and microwave. So you only need one device in your kitchen for baking, grilling, and heating.