Laser Recalibration

[nwong]

How does one perform this task or where does one send it in to get done (somewhere in So. Cal. preferred)? When I first chipped my PS2 with Neo4, all DVD-Rs played fine. Games and movies played excellent. But for some strange reason, today when I tried to play one of my backup DVD-rs, it gave me the red screen to Insert Valid Game Disc. After several attempts, it finally played, but does this mean the laser is bad or needs replacing? DVD-r movies play fine, but I'm afraid they will eventually fail. Any help? Thanks!