Sega Manx TT: wrong sound at times

[ids]

Having a sound issue on an original Manx TT Twin (not Mame) ... on one of the bikes, where there should be a tire screeching sound, there is instead what sounds like a woman speaking Japanese.  I've done all the tests in the service menu, they all pass just fine.  I have also gone through all the sounds effects within the service menu and located the specific ones that are incorrect.

Solution?  New rom(s)?

(This is the unit I am referring to, fwiw: http://www.arcade-museum.com/game_detail.php?game_id=8616)

Many thanks in advance!