Well after a lot of mucking around I found that the keywiz loader program was the issue. Im using a ps2 keywiz from groovy game gear, and sunrise credit board for my coin mech interface. The keywiz does not have F1 as a standard keyset, so I was loading a custom set on boot up. Although the loader program appears to close it must not have been releasing control to videobox. I found that F1 is a standard keyset using their "shazam" feature. In short I earthed the Shazam contact, uninstalled the keywiz loader program. Now the keywiz operates on standard preloaded keyset.. not requiring the loader program and everything is working a treat!