Well, I've learned that apparently you can't test a 1B3 tube's filaments with an ohmmeter, and apparently my tube tester also cannot test a 1B3 tube so entirely possible that my diagnosis could have been inaccurate.
I went back and did a few more checks and found a few more out of tolerance resistors and one that was open and decided to give it another try. This time, HV did come up briefly but it started arcing after a few seconds. I took the HV cage apart again, even coated the leads of the new caps with corona dope, quadruple checked everything put it back and same thing.
https://youtu.be/mxDbkEfzzWA
The camera doesn't pick it up very well but the buzzing is accompanied by blue-ish flashes in the HV tube. From what I've read, blue means the tube is gassy, but everything was working fine before.
Ideas?
Thanks!
FK