I have an Amana Convection Oven. I actually don't know how old it is. It came with our place. The oven sometimes does not come on, on all modes (bake, broil, and all Convection). Sometimes when I turn it on, it simply turns off before it starts heating. Other times it works fine. If it does begin heating (temp switches to 170) it works fine. When it switches off, it stays at the temperature selected and never does the switch to 170.