Playchoice Games; How do you start them?

[Alpha17X]

I've got a few playchoice games on my cabinet,  like dr mario, for example.  and they appear to load fine, but I can't get them to start.  you put in 'quarters' and it adds time, and tells you to make selection but I can't seem to actually start the game  I've tried everything from pressing 1 button at a time, to just mashing them randomly to see if anything happens.  I double checked and all of my controls map to a function, nothing is left blank.   Is there a magic trick to getting a playchoice game to start?  If anyone knows the secret, I'd love go hear it.

[romshark]

Playchoice had extra buttons for selecting games. So when you put in money, it's waiting for you to select a game. So the button you need is the dash (-). For reference, equal (=) resets the loaded game (not the whole Playchoice board, so any time remaining is kept), and zero (0) selects the game (although MAME can only load one game at a time, I think).

[Alpha17X]

Thanks a lot