When my Arena display was dead (and everything else was working), it ended up just being dirty edge connectors on the MPU (I think specifically A1J2?) and pins on the associated connectors. Regardless, I unplugged them all, cleaned all the edges and connectors, and the display hasn't given me a single problem since. Re-pinning them where possible is always a plus, but try a good cleaning to see if you get some life.

Basic start on 80B's in my mind: Remove battery, clean any corrosion and replace anything damaged by, Ground mods, then clean all connectors/edges. Of course fuses, etc and the basics as well, but you said you did that normal stuff.

Keep us posted!

If you have some pics, it wouldn't hurt to post them so we can take a look at what you've got going on.

Just to rewind the clock a little, can you break down what happens overall with the machine. I think when I read this previously, I was under the impression that the game worked and just the display was out. Sounds like you've never actually hooked everything up to give it a try though. I have worked on several 80b games, all with various problems, but I don't think I ever tested it piecemeal like the way you're describing. Is there a reason you're not just testing it all hooked up? I might have missed that above, if so I apologize.