It's easy to get used to the convenience of just popping leftovers in the microwave for a quick re-heat. But it can be worrying if your microwave begins to make a strange clicking noise. It's a common problem, with a variety of causes – here are some of the most likely reasons for a crackling microwave.
Firstly, please note that microwaves should only be repaired by qualified, competent engineers. They operate using high voltages which must be discharged from the capacitor before they are worked on.
Magnetron Tube
If your microwave is loud, noisy or making unusual crackling buzzing sounds, it could be a result of a defective magnetron tube. The magnetron tube uses high voltage, high current DC power that generates the microwave frequency, which cooks the food, and is meant to be nearly silent.
If it's burnt out or damaged, it can emit a high-pitched, growling or clicking sound. It's not generally dangerous to use the microwave if it starts making these noises. However, it is a warning that the magnetron is on its last legs and needs replacing as soon as possible.
Wave Guide
The wave guide is designed to protect the magnetron whilst ensuring that the micro waves that cook the food are distributed evenly and efficiently. It is usually found on the inside wall of the microwave with the magnetron located behind. If the wave guide is showing any signs of wear or damage it could be causing the unusual sounds such as crackling, clicking or buzzing.
Diode
The Diode is a high voltage component allowing an electrical current to pass one way. If the diode is faulty it can cause a crackling noise.
Fan Motor
A noisy or clicking microwave could also be an indication that the stirrer motor has worn out. The stirrer is a metal blade that slowly turns around to deflect microwave energy to a random pattern inside the microwave itself. As it nears the end of its life, it starts to make unusual grinding and clicking noises. Without the stirrer, the microwave won't heat food evenly, so it should be replaced.
Turntable
A noisy microwave could also be a sign that the turntable motor or turntable rollers are wearing out – a common problem with microwaves, which is easy to replace.
