Our Kitchen Aid Superba Convection Oven won't heat. The stovetop works, the broiler works, but when setting the oven, it stays on "LOW" and will not increase in temperature. We replaced the oven ignitor and that wasn't it. I've read it could be the thermal fuse, but based on the diagram of parts for our oven, there isn't a part called "thermal fuse". There is a "thermo-disc" and it is in the control panel area. Is this it? Any help would be most appreciated. Thanksgiving turkey and pies depend on the oven getting fixed!!!