I've been teaching robotics with the Lego Mindstorms NXT system for several years now. I have core of four NXT units I use with up to eight student and I have two other NXTs in need of repair. The NXTs are tough but they are not tough enough to be dropped several times. One of my NXT works but the screen doesn't light up. I found this repair procedure that I'm going to try to revive it.