Arty,

Just spit balling here. I had the same problem on my Genesis. The 5VDC was adjusted high, 5.62 volts under load. I didn't think this was much of an issue, but as soon as I adjusted the voltage down to 5 volts under load, the sound started working instantly. I'd start there, and see if the 5 volts is high. Good luck,

Postmaster

I adjusted the voltage with the pot. on the power board, right below J2. I would turn machine off, adj, then turn on and check. I only adjusted the voltage with the game off, in case I got a little out of control with my fingers lo.