I have a fat ps2 and I have changed the laser to another one. It's better than it was but it doesn't seem to read the burned games properly. I'm going to guess it's the media (maxell). I took it apart and what seems to be happening is the laser moves into the inside of the disk and you can see it shaking like it can't read it and it starts clicking. If it gets past that part it usually seems fine reading the rest of the disc but every time the laser moves back to that spot it starts...
Fat PS2 Not Reading Burned Games Properly
Fat PS2 Not Reading Burned Games Properly