I too would love to do a vector mame on an old vector color monitor. As Kevin said, the signal input is totally different, and most x/y monitors are not compatible with each other. They have different specs and run at different speeds. It's a little spendy, but probably worth it, but i think you could solve those problems by using a Zektor Vector Generator. I'm still saving up for one (and a color vector monitor, hehe). It was designed for use with mame and displaying true vector graphics on original vector monitors. They even have a pic of it running a vector arcade board on those old Vectrex home gaming systems. It's a tiny screen, but a lot cheaper than your standard vector arcade monitor. I think their webiste is zektor.com. The card was also mentioned in the Project Arcade book too.