[rxfeng]

Hi all - hopefully someone out there has had/heard of this problem and resolved it!

About two days ago my 8100 (OS 4.2, T-Mobile, had since Feb-07) went nuts and started firing the trackball/enter key function on its own. It was just sitting on a table when it first happened. The issue is so that, for example, if left on the Messages icon, it would rapidly move through the menu tree, saving dozens of drafts of the most recent message. If it happens during a call, the phone mutes and unmutes repeatedly. The issue comes and goes, and persists for about 5-10 minutes at a time before abating, and comes back at random.

Tried the following fixes, none of which worked:
- Cold reboot (removing the battery)
- Removing and cleaning the trackball assembly
- Wipe and reinstall OS and apps

It might be worth it to note that while I was cleaning the trackball the issue persisted while the trackball cavity was exposed, so I'm pretty sure it's not something wedged in there.

Any advice? The phone is out of warranty so I want to do whatever I can to fix it!! Thanks everyone.

[paulbblc]

From the sounds of it, it could be a bad connection on the board where the trackball sensors are. You may want to find a wireless phone repair shop in your area to see if they can pin down the issue.

[rxfeng]

Thanks for the tip! In general would you recommend a carrier's store (in my case a T-Mobile storefront) or a specialty mobile phone repair shop?

Either way I'll report back the findings.

[paulbblc]

Not sure if many carrier stores will repair it at the store, they'd have to ship it away I would imagine. If you can find a specialty store they may be able to do it within a matter of minutes/hours depending on the issue.

[rxfeng]

Just thought I'd post an update...

I took the phone over to a wireless repair shop by my office (run by AT&T) and, after describing the problem, was told that it did sound like an issue with the board, which they don't touch. On to the next...

After reading some of the other threads here I gave the folks at BBrepairshop.com a call and the CSR over there told me that they've dealt with this issue before and that the copper contact point on the board that interfaces with the trackball assembly most likely needed a replacement.

As I was mulling it over I removed the trackball assembly again and hit the guts with some canned air, cleaned it out with isopropyl and, just for the hell of it, poked at the copper contact a bit with a paperclip. I put the trackball back in and the problem vanished. 8 hours later the phone is still running normal.

I'll be 100% confident if it doesn't come back after a few days, but it's good to know that BBrepairshop has a last resort fix.