Mega Drive high pitched whine

[Xaranar]

Last MD thread, I swear. So as the subject suggests, my MD2 produces a constant, high pitched whine sound through the audio output. I have the Mega Amp audio mod installed, and switching it to filtered mode reduces the whine somewhat, but it is most audible when completely unfiltered. I have replaced all of the caps on the system, so I know it's not that, anyone have any ideas?

[rama]

No ideas, just keywords you can Google and try solutions for:
Signal integrity, capacitive coupling, power bypass capacitors, copper foil shielding

It's a broad field and it would help a lot if you posted some pictures along with your question.

[Strider77]

It's what happens with the mega amp in Megadrive 2 consoles. I saw a video with the guy behind those and he listed that as something he doesn't like about the MD2.

[Syntax]

I'll confirm if it's an amp issue today as I have electrical interference on screen that looks like A.C..