Ok, So I've had my Acer A500 for quite some time now. Couple years in fact. Anyway a few months after getting it I noticed that I couldn't change the display brightness whatsoever. Also the autobrightness did nothing even tho I had tested the sensor and it came out fine. Now I don't know if this problem existed before I rooted and installed a custom rom, however no matter the rom the brightness still will not adjust. I have even taken the tablet apart and made sure the cable to the screen was seated well. I'm wondering if anyone might know if this is a hardware issue what may be causing it? or if it may be a driver/software problem.
xda-developers