Have had this game for several years, nothing has recently been done to it and this issue just arose.

At full volume when starting a game "let the game begin" is either at max volume or very very faint. Seems to be very random.. sometimes its loud then pressing for a 2nd player 'deal me in' is faint, other times several of the call outs are loud then it goes to barely audible.

There is no music at all

In test all sounds work but faint and no music works.

What I have done so far:

Reseated all connections
Replaced the ribbon cable with known good cable
Swapped out MPU
Swapped the PS board

On the sound board:

Swapped the 68B09E mpu from U4
Swapped the YM2151 sound from U16
Swapped the YM301 d/a conv from U19

What next? sound board is clean, nobody has ever worked on it.

'faint' sound makes me want to blame the TDA2002s but then why no music at all? I see two on the board. Does anyone know if music and speech go through different ones?

I have schematics, logic probe, meter, soldering station and desoldering station so willing to try anything