Was able to rule out the monitor using a very hacky hack to get some signal directly to a separate VGA. I didn't know how to deal with the grayscale, so I just sent it to green -- and you can see the same pattern shown. So its something on the logic board. I guess I'll proceed with ordering some caps, and see if that fixes anything (but I doubt it)
You'll probably be able to reach Rob Blessin at nextcomputers.org, but if not, I was able to get help from him three years ago at the email address on this site: https://www.blackholeinc.com/specials/contact.shtml and he was very knowledgeable.