There is but I haven't tried it yet.....too darn busy fooling around with other stuff in my little life....haha
There's a socketed sound chip called "AY"-something (I'm nowhere near a slot machine at the moment lol)
Some boards I'm afraid to say, have an embedded chip in that location....cant do it with those unless you can un-solder the chip and install a socket.
If you got a computer programmer whiz kid that's in college, ask him to remove the socketed chip and reprogram it.
I'm pretty sure it's just a few bytes that need to be turned off in the data of that chip.
Save the original file in case he screws it up....lol
Gunna need a re-programmable eeprom-type of chip the same size to do all the trial and error.
I just never got around to it....I actually kinda like the sounds of an ol' S+.....except for that bloody bell tho!!!
If you can tell me what SP chip you're using....I might be able to scrounge up a PSR and see if there's any settings to make it do what you want besides that dipswitch setting.