Exactly the same thing is happening on my N810. After a few hours of use it starts flickering (vertical line). It stopped doing that at some point, but then again after several hours of use, it flickers (one thick vertical line).

Not sure if I should try returning the unit back to CompUSA (I got it 2-3 weeks ago), since the vertical line flickering may not show up when once they get device back.

Or maybe I can do something about it, on my end. Don't know what. Connection, what does that mean? Open it up, and fix loosen connectors?