I just change the housing on my BB. I bought my BB used and the previous housing was gross, I couldn't tell if the trackball was dark colored or if it was filthy! Anyhoo, I changed the trackball as well and immediately found out that it does not scroll perfectly, it seems to be slipping (not under my thumb, but slipping from the rollers that detect moment), so I couldn't scroll vertically properly, but horizontal was great. So I switched the trackball for the old one, and that worked great, but the ball itself was just gross. So, I opened both of the trackball assemblies and switched the balls, now neither one of them scrolls properly. I have tried cleaning the ball (old and new) and the movement rollers. I even cleaned the sensors on the board.
I don't mind buying a new trackball, but I want it to work. With these trackballs I can scroll great in one direction, but for the other direction I have to scroll twice, and sometimes the cursor moves in the opposite direction. So if vertical scrolling is messed up, then when I scroll up, the cursor will jiggle around a move a bit lower on the screen and vice versa.
There is a contact point under your track ball. The contact point is probably now defective and needs to be replaced. (If your carrier will even provide that service). If you can get another contact point and replace it, it should be fine.
Posted from my CrackBerry at wapforums.crackberry.com
I bought my housing from eBay, I paid C$26 for complete housing and opening tools. By the time I was done changing it, the only thing old in my blackberry was the motherboard and LCD. But the housing was really cheap. I couldn't use the keypad that came with it because the caps and the sym keys were permanently pressed!! And the mute key is hard to press, it does work, but a bit tricky to press.
The trackball does look a little off centered to me. I'll poke and jiggle with it to see if I can get it going.
