Is it a PSP 3000?
A noticeable scan line problem is apparent in these consoles when something fast moving is on the screen. Sony said these are problems with the screen and not the console itself, so they will not fix them. ever.
Lots of info can be found by typing “Scan line problem psp 3000″ in Google.

These lines could be a result in dead pixels in the screen. Anything can cause them but i’m not sure how to get rid of them.

Test