Those voltages are way out of spec. What kind of power supply board are you using, original or aftermarket? If aftermarket what brand? Looks like the display is toast, it's outgassing and has some column connections that have failed. The flashing may be a separate logic failure altogether.

Can you get a photo of the power supply? Regardless I would replace the power supply with an X-Pin XP-DE5047 from xpinpinball.com. The only replacement display is from PinLED at pinled.com but I think X-Pin is currently working on a replacement. You can email Brett from the website and ask.

You can have it repaired if you want to go that route but I would suggest new for the sake of modernization and efficiency. Brett will be happy to help if you have any issues. You can probably re-use that old board in a game that has an LCD or LED replacement display installed. These do not need high voltage. Or if you decide to upgrade this display to LED you might be able to keep your existing power supply if there aren't any other issues and the PinLED display doesn't use high voltage to power it.