NN-T990SA Panasonic Microwave Stopped Heating

Question

Well this sure stinks. For the last week the microwave has been making this high pitch squeeling noise for about ten seconds before it made its usual heating hum. The other morning it stopped making that noise and no hum anymore either. The fan runs, the turntable turns the timer times but it won't heat. Also the timer when set for one minute goes for exactly 22 seconds after starting and then the machine completely shuts down. Any thoughts would be appreciated.