Positronium

Sorry to drag up an old thread too, but I'm trying to modify my SONY MZ-N505 and I can't find the needed chip on the player. Do someone know which one it is, and how to make that modification on the N505 ? It would be great I've been looking for something like that for many years, I hope it works. Is it the only way to have a digital output on a portable player ? USB doesn't work ? Thank you.