I had funny lines aswell.
I think I had a minor case of them because:
- they only occured int the OS(lock screen, home screen, apps were fine(apart from some keyboards))
- only in the horizontal pixels in the lines with text in them were darker
- int went away after two days (pretty much non-stop on the power-line)
for that you need to take a look at the power and sensor cable (guide is on here as well). Either replace it or if you know what you are doing modify it.
I got the home button out, cleaned the rim and put it back in.
Works every time now, it only worked when I removed the dock cable in the correct angle before.