belling microwave oven will not heat after swithing on with no food in?

Hi Brian, sorry to say that there is a better than fair chance that you have damaged the Magnetron, that's the thing that makes the Microwaves, by running the machine whilst empty. Briefly, a microwave oven uses radio waves to "cook" food, unfortunately radio devices suffer from a self destruct mode by virtue of their mode of operation if they are not run into a load. Simply put run a radio/tv transmitter without an ariel (antenna) connected, thus giving it a "load" to work into, or a Microwave oven without food in it (a load) the device, simply put, eats itself. Ergo, no go. Now it is possible that you have been lucky and merely blown the sacrificial cavity fire fuse, or any one of several other non connected causes, but odds on, the first is most likely. get a technician to check it out, not a job for the layman. This is potentially lethal area to be playing with, even unplugged ! Any further help find me via microwave-repairs.co.uk
kindest regards

patrick
July 2009