I'm actually a technician and I repair computers, smart phones, tablets, iPads, consoles, etc.
I have an iPad 4 here from a customer. I'm stumped seeking some help. The digitizer is acting very funny. It has a mind of its own. Sometimes, the ipad could be sitting on a desk and it will randomly open things or on the screen keyboard will press letter son its own. The bottom of the digitizer will also not respond at all. The top will. I can manage to power it off sometimes. From my knowledge, these problems are usually due to a bad digitizer. So I replaced it with a brand new one and it's doing the exact same thing. No change at all.
So I factory restored and updated it. It's not running iOS 7. Same thing. As a matter of fact, I can't even complete the setup because where it asks you to slide on the bottom to begin, it will not respond to my touch. So now I'm stuck. Could it be coincidence I got a lemon of a new screen? I repair ipads and do digitizer replacements all the time and I've never seen it happen like that.
I'm at a loss. When the restore and update was done it was done through iTunes. I'm not sure if it's some software setting and even after it was restored and updated it just restored that setting?? The user was reporting the issue before the iOS upgrade, obviously so it isn't that.
If it's not the digitizer itself, what other piece of hardware or section on the logic board could cause this?