sounds like he gave you some CPS2 boards. Are they bare PCBs, or did they happen to come in a some shells? A-boards are relatively useless without a companion "B" board, that contains the actual game. Think of the A boards you have as a games console and the companion B boards as the cartridges.
System 16 CPS2 page
If you're trying to actually play them, you're gonna have a good little chunk of parts/equipment that you'll still have to buy. Be it a supergun, proper hardware to run the game on a modern monitor, an older more technical monitor instead, and some method of controlling the game.
They're JAMMA standard games, so I would start your search on properly wiring JAMMA games. Since it sounds like you're experienced in do-it-yourself electronics work, I would check out the
MiniGun Supergun, an open source "all in one" method of running most JAMMA games at home. You'll still need some other equipment to run controls, and also some equipment depending on what monitor you intend to use, but I cant recommend that supergun enough if you're good with your hands/soldering and you have some knowledge on the JAMMA standard.
Welcome to the arcade hobby I suppose- be it by choice or not! lol...also if you choose to not hang on to those boards, maybe let me know
Edit: Your new post popped up right after I hit submit...oh well, still leaving this up for the links
lol