So my Counterforce has been pretty much rock solid for the past 4 years. Ground mods were done, some connectors replaced....basic sys 80 stuff. Well, tonight I go to turn it on, and it's mostly dead. All backbox lights are on, even the controlled ones, no lights on the playfield (although they do blink when first turned on), and weirdly, the credit display shows a little "c". This could be a glitch, or it could be trying to tell me something, not sure. Power supply voltages are good, and +5v is going to the MPU. Almost seems like the MPU is locked up or something, but I am at a loss. Anyone seen anything like this before?

Thanks guys, I hope to get back into it this evening.

No, I didn't. I actually took a closer look at my MPU board, and noticed the acid damage that had always been there was looking worse. I never cleaned it, as I figured if it was still working, don't mess with it. I decided to order a Swemmer board to replace it, and installed that last week. Now it is doing other weird things, ha. Most of the time when I power it on, I get nothing but blank displays, and GI lights with some playfield insert lights. Rarely, I will power it on, and it works fine. I left it on this evening for a couple hours, and played probably 10 games or so without issue. Turned it off, and could not get it to boot again.

I have checked the +5v going to the MPU, and it was around 5.03. I did turn it up a bit to 5.10, but that did not help. In conversations with Keith @ K's Arcade, he seemed to think it may be a driver board/harness issue, so I decided to order a Niwumpf board, and use the IDE harness instead of the stock one. Got that in today, but still getting the same issue.

At this point, I am thinking it is possibly connector related, even though my connectors look good, far as I can see. I did replace some a couple years back, but those were for the displays, and one for the sound. I have the System 80 repair guide from Gottlieb, but looking through it, I really can't see any particular connector that would be suspect here.