For the version of minigun I mean are you using the mini din 8 pin version or the mini din 9 pin version? The 8 pin version doesn't require any components in the AV cable. The 9 pin version does.
What is the manufacturer and model of the TV? We need to know what csync level it is expecting.
There are two different A/V connectors standard that the minigun uses. Your board will have either an eight or nine pin mini DIN A/V connector. You can buy a premade cable for either one.
The CPS1 multi is available and plays all CPS1.5 games, including Cadillacs and Dinosaurs. Converting CPS1.5 games to CPS2 doesn't make much sense any more.