This might be a long shot, so I'm a little scared... but is there anyone out there with expertise on the old Atari plasma displays? Here's a video showing what my Airborne Avengers just started doing (it was fully working when I got it):

I have. The board seems to look fine. I noticed the left edge contacts are pretty dirty and if I press in certain spots, I can get various segments to light up. I am going to clean up these contacts and see where that gets me.

My biggest concern is getting the the vertical line of digits that are completely out to work. Hopefully that is also a connector since I saw this fully working not more than a few days ago...

Could you elaborate on that? Are there any particularly safe, effective methods?

I was planning on using contact cleaner + microfiber cloth.

Fixed it. I tried using a q-tip, but mine was so dirty I actually had to use a magic eraser to get the dirt/corrosion off. I also had to bend the retaining clips on the display board downward to grip the display better, but luckily no pcb issues...

Here's a follow up video: