This JAMMA cabinet had gone pop almost two years ago, time to diagnose why. On applying power the primary fault was quickly identified – high voltage fireworks were literally shooting out the top of the flyback! You can see the burn marks on the picture, but there is probably a hairline crack as well.
So, remove old flyback, install new one… and it worked! Great to find the fault hadn’t taken out anything else on the board. Usually this would be a good time to install a cap kit, but it seems the previous owner must have done this at some point, as all the caps looked new. (Disclaimer, do not attempt to remove or even touch the flyback or tube if you don’t understand how to safely discharge a CRT. Very high voltages can be present even with power off).
Apart from some screen burn in, picture quality is great for a 33 year old monitor!