Is this malfunction covered under warranty?
you can set the function you want, it will start then suddenly stop no sound at all. It seems to be a major part. I have had it a little over a year, to soon to break down.
sounds like a thermal cutoff or high voltage section shutdown. Most have only a 1 year warranty, some have an extended warranty on the magnetron itself, but that failure is usually accompanied by a noticeable loud humm before shutdown. Panasonic Customer Service is likely best option for coverage consideration