I used this very helpful site when doing service mode adjustments to my 32" Sony Wega.

This is a general guide:

http://209.145.176.7/~090/awh/how2adj.html#5

...and from another part of the site, here is a list of codes for the Sony XBRs, but they were pretty much all the same for my Wega.

http://209.145.176.7/~090/awh/sonyadj.html

Good luck! BTW i would follow the advice on the site about writing down the initial settings before you adjust them. I found that even adjusting one at a time it's easy to lose track.