i had the same problem. Sleep timer was set at never. I even went into the HDMI setting and put that timer on never. still it timed out every 10 seconds. i had the same thing happen a couple months ago on a different but same tablet and I did so much that i forgot what i did the first time. go figure. Now I am here to say that more than likely its a timer set in an app you have downloaded. which one? Who knows. Start with your cleaner app. I did it the easy way.. I factory reset it and chose not to forward any apps over from my other device. Boom!!! Now it works perfectly. Now I will go download a cleaner and see what happens...then move on from there. Im glad its over cause that can make a person really irritated. Good luck.