To learn how to troubleshoot magnetron, we need to learn how magnetron works. The primary function of a magnetron is to generate microwaves. The underlying physics of the magnetron is quite complex. It uses a strong external magnetic field to direct the flow of electrons within a resonant circular cavity, producing power levels from tens to hundreds of watts at frequencies around 2.45 GHz. To test a magnetron, we can check for continuity. The resistance between the terminals should be less than 1 ohm, and the insulation resistance between the terminals and the housing should be infinite.

It is possible to detect a faulty magnetron when it starts producing loud humming noises. A magnetron that has a short between the filament (cathode and anode) is likely to create a loud hum when the cooking cycle begins. Additionally, evidence of arcing, such as burned spots around the ventilation holes in the base or a burnt odor, typically indicates a malfunctioning magnetron. Melting or other damage to the antenna may result from arcing caused by issues in the oven cavity or waveguide, especially if we use the microwave while empty.