Okie well try this.
Make sure there is NO pressure on the battery door. NONE wat so ever. Then go into somewhere dark and type. If the backlight starts acting up (or whenever it does) put pressure on the battery door.
If the problem seems to stop or get better, u have a bug that I had with me 8300 and ya gotta send it in
If ur ATT they'll send ya a new one, then u send urs in
This is what happened to me and a new curve was only way to fix it seems
Just see if u have my problem, I'd ya do, there's the solution