If your microwave works, has power and timer runs but there is no heating, the most common problem MIGHT be a broken fuse, the second fuse that some microwaves don"t have but most of them have it. I didnt replace mine, I only add an additional wire, the tickest I found. That is not so safe but untill I will buy a new one works just fine.
Be carefull when working with electricity, DON'T TURN ON YOUR MICROWAVE UNTIL YOU PUT THE COVER BACK ON.
