Here's the high voltage power card. The capacitors were all at 0.0V, and their in-circuit capacitances were all within spec. Even tho it's been sitting for unknown decades, I think this card is probably safe to power up. The little bar isn't electrically connected to anything. I think it's just to help put the card in the slot.
And heres the low voltage power card. It is visually similar, so I wont bother with alt text. It has an aluminum plate to dissipate heat from some silicon components, and is also model 1201. It's slot has some pins next to it labelled +120, -8, and +8. They're not connected to anything, so I guess they're test points.
It has 1 big sprague cap which seems good, and 3 of obscure brands which all measure a little high. 2 of them are only rated for 16V and the other is rated for 200V. This is also in-circuit, so the measurements can rightly be questioned, but I think I'll keep an eye on them and what those 8V testpoints measure
Next are the circuits for each individual display. It looks like they use a lot of ceramic caps. Some of the non-ceramic capacitors I might be worried about look similar to one I measured in the high voltage card, and it was dead-nuts on, so I think they're probably fine. There's some orange-drop caps, and on one card, they're blue instead of orange. There's no obvious signs of service or repair, so I think the color change would just indicate a change to a new order of capacitors at the factory. There's some small diodes, which given the age wouldn't surprise me if they need replacement, but they're hard to access, and everything else seems pretty good, so I think I'll plug it in and see what happens.
And we have life! One tube doesn't show a line like the others, but I see a dot appear on it when I turn everything off, so it might just need some adjustment
Ive never seen a crt running from above/behind before, and wow it looks cool. It feels weird to just see some little green lines floating there
The testpoints measure 115VDC and +7.4VDC. I didnt measure the middle cuz it's a little awkward to reach, and I don't want to short anything. 7.4 seems a little too low for me, but I'll keep checking it and see if it changes as the caps get reformed with use
I hooked up a signal generator, and we can see a sine wave in the first display!
Used a little usb oscilloscope for my phone to set my signal generator to as close to 9V peak to peak and 2.5kHz as I could. Now to adjust the first display to match
The trimmer knob is close to one end, but I think I got it all set right.
TommyTorty10