Incidentally, do you happen to have documentation on what the LED codes for Racing Jam mean? MAME goes through a bunch of numbers and then stops on "50" when it dies.
I don't but I am happy to help in any way I can to get this driver doing something interesting.
I have to get a test setup made for these so I can tell you what it's doing when it halts on this error which might give you some insight as to what they mean.
If you need to know anything else let me know.