My gut says that there are some issues with using the 801 in an 805 mostly because the input voltage is listed as +25V on the 801 and its listed as +40V on the 805 but if it is mostly working then maybe its not as big of a
. either way there is a regulator there and maybe that is doing the job.
You were absolutely right...
I downloaded the two manuals last night and compared. The output voltages of the two boards are identical with the exception of the anode which is 14KV for the 801 and 12KV for the 805. But further reading states that's nominal and can go 2KV either way so I'm not sweating that too much. And the input range for the 801 HV board is 23-38Volts, and the 805 is 31-42Volts. So IF the input is still 40V (which I bet it's a little degraded over the years) it doesn't appear it's pushing it too far beyond it's "normal" range. Especially for a game that stays on for a couple hours a day at the very most.
If you know how, can you please direct me on where to read and adjust the 90V on the HV board (I.E. where to put my meter leads, and should everything be hooked up and running when taking/adjusting the voltages?)? The link you provided for the Voltage Doubler replacement states you may have to check and adjust if necessary the 90V after replacing the doubler.
Thanks!