Hi @mmusk818 hope you have fixed your N64 by now. And hello everyone arriving here by searching “n64 no audio”. I found this thread (again) after searching online for the solution that worked for me and since I saw it nowhere I wanted to share it with you guys.
I also had audio issues with my childhood N64 a while ago and I tried all these suggestions here but none of them worked until I got the sound fixed just last week all thanks to a Brazilian YouTube video that came out July of this year.
Basically I ended removing the rightmost chip (with the control ports facing you) U2, and bridged contacts 3-7 and 8-12(they are numbered on the board). And it frigging worked! (sorry for the quality and lack of photos, in the excitement I forgot to take photos of the wires I soldered, perhaps for the best)
I had no issues with my N64. The chip I removed is stated to be an amp but I noticed no sound quality or volume loss. Apparently that chip is there only to close those two paths.
Alternatively it might be a problem with the capacitors C25, C26 or C142. So replacing them might work too. Check them for shorts.
If ripping off a chip from your n64 seems too scary/drastic (please don’t literally rip it off, desolder it) then soldering a wire between U2’s contact 7 and the capacitor directly above it (C142, the one between caps C25 C26 and the U2 chip) can do the trick (for me it didn’t).
Hope it helps, dunno if posting a YouTube video or referring to is allowed so let me know if I can and you want the link. Would love to give the guy from the video the due credit.