[Arakon]

remove the chip carefully, then check the points and area around them with a magnifying glass for solder drops and bridges.
if you find nothing, check the cable to the cd drive.. make sure it's plugged in properly and not damaged.

if that fails, open the top of the ps2 and remove the top case of the cd/dvd drive (4 very small screws, make sure you don't lose them). then turn on the ps with it open and watch if the laser lense flashes red on power up (do NOT look straight into it from above!) for a moment, and if it moves at all. if not, the laser unit might have gotten damaged.