thanks for the suggestions.
CN2 voltages to the sound card are 4.95, -15.15, 11.45
Both at the power supply and at the sound card.

I think the sound card is ok as when the ribbon cable was the other way around, it was playing the end game sound.

Does anyone know a way to check the output sound signals from the CPU board?

Or diagnoise and elliminate areas that are working ok?

Thanks,
Rich.