Hi Everyone,  Apologies if this is a n00b question but:
Certain games like Battlezone, Tron, Star Trek: Strategic Operations Simulator,  Star wars,  Space War, Lunar Lander, seem to load properly, but then cannot be played. They just sit their in demo mode.
I can't seem to "insert coin" on most of the games. On Star Trek I can hit right-shift to trigger the insert-coin event, but then can't start the game no matter what key I press.  Same is true using an xTension controller.
Other games work perfectly.  Joust, Pac Man, Donkey Kong, Defender, etc, all work.
I am running the latest version of Recallbox on a Raspberry Pi 3.  LibRetro and AdvanceMame are also installed too.  I've tried 2 different keyboards and the Xtension controller Emulator Edition.  No luck, no fun! 
Any help is appreciated.  Thanks!
Mark