PS2 Surround Sound Problem

[Niku-Sama]

ok kinda odd, today i noticed my PS2 stopped outputting in surround sound. my Reciver (the Sony STR-DE698) shows it as reciving a 40Khz signal from the PS2 but its not showing as able to decode any thing.

i have it hooked up through optical and it used to decode to surround sound and my dvd player is being decoded.

how do i get my PS2 back to outputting in 5.1 again?

[Kid Ice]

Check your system options.

Also, I thought you had to use the optical to get surround sound but I might be mistaken on that. EDIT Doh that's what you said, never mind

[Slate]

Try removing the cable from the PS2 then reinserting it.

[Niku-Sama]

tried that, still nothing, i did shoot a e-mail to playstation.com's support but still no word.