Anyone ever fix a PS2 DISC READ ERROR???

[ProjectNaked]

A friend gave me 3 PS2's that all have the dreaded "DISC READ ERROR" theY will not play dvd disc but will play games on cd's...Sold 1 as-is on ebay but would like to fix the other 2. I just finished adjusting the white level wheel a few click at a time but no progress - about to adjust the laser voltage. Any advise, (other than buy a new one )

[Fap]

Happend to mine.. there is a site about how to fix it. Google it, tthere are exact directions about what to do. You need to open it and shit. But yeah it's all there

Edit: found it for you:
http://arstechnica.com/articles/paedia/hardware/ps2.ars