Thanks guy's I'm almost sorted
Put my new ROM in today and it plays all the right sounds. It doesn't lock up and it sounds heaps better.
Only trouble is one of the sounds once triggered seems to play continuously.
I guess I'll have to look at all the sound lines/chips replacing them till i find the problem.
I'm sure the new ROM is not to blame for this
Isn't it always the way fix one problem and that just leads you to the next?

Again thanks for everyone's help on this

cheers
Wally