Hi guys! I'm new here

We picked up a mostly working Whirlwind for the lounge at work. It needs some maintenance and at least a few new bulbs. The biggest issue is the display is completely dark. Had the top open and checked + reseated all the cables to the display board, no change. They all look ok, ribbon cable has no apparent damage.

I'm completely new to pinballs (other than playing some many years ago), though I have experience with electronics and computers (also retro).

The previous owner said the display works sometimes, but flickers.

Before I dive into the machine probing around (minding high voltages, of course) I wanted to ask if there are any classic issues on these I should check for.
High voltage caps? Grounds?

Other future-proofing tips specific for these machines? (Batteries are corroded, at least needs a change - looks like no board damage from a brief inspection)