Originally Posted by DarknessOfDeath
Or I could just say that Beast was able to come up with a back up in order for Prof X to use Cerebro again at the mansion... or something like that. I mean come on, Beast is smart
Heck, even Jean was able to fix Cerebro in X1...those two are smart.
Since it was never definitely stated that it was working or not after X2, you can do whatever you want depending on the needs of your story. Either it was fixed, or it's waiting to be fixed, or it is out of action without Magneto to help put all the panels back in place..