I have a weird issue on my Samsung Galaxy Ace S5830 with baseband s5830XXKPP (bought in Mexico), whenever I'm doing anything (playing a game, using a web browser, etc), after a certain time (like a minute or so), the screen turns off, but whatever app I was using at the time stays there (sometimes I have to lock and unlock the phone to see whatever is on the screen again, and some other times, after blacking out it shows again, but brighter), it's really annoying and I'm not sure what happened (I recently upgraded from 2.3.4 to 2.3.6 and I didn't have that problem before). My brightness is set to the minimum and I've set the Screen timeout to 10 minutes. Does anybody know why this happens and how to fix it?
Ok, I found out the reason for this problem is the band differences on the 3G:
S5830: HSDPA 900 / 2100 S5830B: HSDPA 850 / 2100 S5830L: HSDPA 850 / 1900
And the incompatibility with the current firmware I had (I updated to CyanogenMod 7.2.0 and still had the same issue), so for a quick fix, I went to:
Settings > Wireless & networks > Mobile networks > Use only 2G networks
And that took care of the issue, however, for a full solution, flashing a latin (like the Brazilian one) with a Modem file like the kp7 or kpl should take care of the problem.