GE microwave - works intermittently

Model JES 1451DS1WW. Purchased April, 2014. The microwave turns shuts down after 20 or 30 seconds of heating something up. There is also a funny smell coming from it.....like burning wires or circuitry. My factory warranty will cover it but I am curious as to what the problem may be. Also the light sometimes doesnt come on when you open the door. Not to mention the door button stays in most of the time when you push it. My old Ge lasted about 14 years. It still worked when I retired it. Got rid of it because the paint was peeling in the turn table area. Just looked nasty. They sure don't make appliances to last like they used to.