NES audio good ground location

[Drakon]

okay I honestly don't expect anyone to have a solution for this for one reason.  I need to find a good point on the nes pcb to attach audio ground.  I'll even take the audio signal anywhere off of the pcb if it fixes my problem.  The reason why I doubt anyone can help me with this is because this's a problem on my RGB modded nes.  The rgb picture looks fan-diddly-tastic when the audio ground isn't wired up.  As soon as I wire audio ground into the audio rca jack the picture isn't quite perfect anymore.  If I leave audio ground disconnect I do get sound but it comes with a humming noise.  I was wondering if there's a point on the nes pcb where I can attach audio ground that won't have any effect whatsoever on the picture.  The rgb ppu is extremely sensitive and it needs a seperate ground from the rest of the system to pump out an awesome rgb picture.  I wired up the audio with a ground seperate from the ppu ground but strangely enough it's still effecting the picture.  So I need to find a better ground point from the nes pcb and hopefully that will fix this...

*edit* I found a good spot