So, after finding out that the dead blaser was a typical problem, i decided to order one from eBay and do it myself.
After a few tries, I managed to put all the pieces in the right place, and the PS3 was actually loading blu-rays and games.
I then started closing the drive, first the black plastic box, then the metal part, and trying after every stage, to make sure it was still reading. At some point it stopped reading. I've been trying to fix it since then, but I wasn't able to.
What happens is that the disk is not sucked in, or even detected (no blue light or beep). The mechanism is working perfectly (if I force a CD in I can eject it), so I think it could be a problem with the optical sensor or the wires. Although all seems wired perfectly. Any tips on how to solve this?