PSP-3000 screen problem
“On some occasions, scan lines may appear on scenes where brightness changes drastically, due to the hardware features of the new LCD device on PSP-3000. Installed with this new LCD device, PSP-3000 offers more natural and vibrant colors on its screen, but the scan lines have come out to be more visible as a result of improving response time to alleviate the afterimages on PSP-3000,”
Sony Computer Entertainment of America (SCEA) has issued an official response.

The image on the PSP-3000 has interlaced vertical and horizontal black lines which will annoy many. Sony has undno plans at this time to fix this issue:
But though that screen displays some of the most lucious strawberries known to man, new PSP-3000 owners are reporting that it doesn’t fare quite so well with games. When rendering games like Disgaea, official PlayStation Forum users report, the screen seems to display interlacing artifacts.