The Space Station I have currently has an LED display installed that works.
The HV display was included (originally from a Big Guns), but had been replaced with the LED. The previous owner says "one day I turned it on and it just wasn't working. My tech guy replaced it with the LED one".
So I have no idea what the actual state of the HV display is.
I started off looking at the HV side of the power supply. The fuse blew immediately even with no load. I pulled one leg of each passive comment and found Q1 and Q3 were faulty and ZR2 and ZR4 have strange readings. (Details https://www.aussiearcade.com/showthread.php?t=91312 )
I replaced every component on the HV side of the power supply and it now starts without blowing the fuse and I see 100v and -100v on pins 4 and 3 as expected.
Now, before I plug in the HV display board, is there anything I should check?