I'm still fairly new to owning my first pin, which happens to be Hollywood Heat, but I know enough that I can say that when "The Heat is On" sticks on the screen it means it hasn't detected all the balls as being ready, though I think it can also be caused if certain switches are sticking closed. Make sure all switches (except the slam switch) are not closed prior to starting and make sure the switches in the ball trough and the drain switch are functioning properly and adjust/clean as necessary. I think the trough switches may normally be closed when balls are on them, but I still don't know enough about the machine to know if that's the case or not. (Thus I'll be learning some of this along with you.)