See if you have any working boards that use the AY*whatever* sound chips that Tron uses... odds are against both of them being bad, but you never know.
I had an issue with my board where I was getting no audio, but I was also getting a sound board error on boot, ended up being bad RAM.
What's good about Tron is if NONE of the sound works... that usually tells you something about the issue. Since everything is done in pairs (2 chips, each covering half the channels) and the sound amp board having two amps on it (each speaker)... it would require a dual fault, and that's very unlikely to happen. So, it's usually something like a loose wire (had the shielded wire go out and screwed up my sound once) or a bad connector or a cold joint.
As with pretty much ANY MCR board problem... I'd start by replacing the ribbon cables, then going from there.