if you listen to Jim Rome his trackball wouldnt go up, someone suggested cleaning it and it worked out great (I think he hasnt mentioned it again anyways) so I say all that to say this, generally as others have stated a good scrubbing will work, but make sure you do it PROPERLY, you dont want to hurt the berry that is for sure!
I think if you clean it and it's still not working, it might be an internal phone problem, not the trackball.
A couple weeks ago, I had a problem where my trackball all of a sudden couldn't scroll up anymore. After about a half hour, it started working again. Very weird. I didn't try to clean it or anything. Maybe you should call t-mobile if it still doesn't work after cleaning it.
I think if you clean it and it's still not working, it might be an internal phone problem, not the trackball.
Most trackball problems ARE in fact related to the trackball hardware itself, not an internal phone problem. The way that dirt and grime builds on on the tiny wheels is the same as the way it used to build up on the wheels inside ball mice many years ago. The buildup and responsiveness is very unpredictable and can come and go. Cleaning often goes a long way but I like to replace mine every so often, this also keeps the ball white, rather than black and grimy. I ordered mine from blackberrytrackballs.com but I've seen them online from places in china too.
Its easy to replace, you just pop out the clip w/ an eyeglass screwdriver, put the new one in and pop in the new clip.
The WORST thing about this problem is that the carriers are helpless. They really should educate their store reps on fixing this to eliminate unnecessary calls and warranty repairs.
