Yup. Thank you again for the infinikey. So I've tried all the tricks multiple times, no luck. The volume controls in the test menu work perfectly fine. The board simply doesn't seem to produce any audio. I've tried both mono and stereo sound settings, no luck on either.
I've begun looking around the board for anything that looks... suspicious. Broken traces, faulty pins, etc... Nothing seems out of the ordinary. The sound roms themselves seem fine, no bent pins, went in smoothly. I tried cleaning up and reflowing one of the ICs that looked suspicious and coroded, no change in behavior. For reference it was the IC LS04. Beyond that, I don't see anything wrong. There's some poor looking traces, but any that I've found I've tested with my multi-meter. All that I've tried seem good.