Microwave oven has become very noisy

Question

This microwave is several years old and has recently become very noisy when operating. When the microwave is running it makes a very loud gravelly noise. I notice that when the oven is on high it makes the noise all the time, but on medium it goes off every so often, and on low it goes off even more often, so it sounds to me like the energy producing component. Can this be fixed? The turntable is not affected. Cooking takes place normally