Played around with this set a little tonight.
The CRT still checks really good, the short popped up just for a moment and now is gone.
Pulled the HV cage off and the 6BG6 had a white getter and in fact was broken around the bottom near the base. Installed a new one and I have some HV at the top of the 1B3 but nothing coming out the bottom.
I suspect the B+ is low from bad capacitors and it's just not generating enough HV to fire the heater in the 1B3.
Something else I noticed, while I had the CRT connected to the tester and in the "Emissions" position, there was a purple glow inside the neck under the Ion trap. This was the "Good" "surface of the glass glow" and not the "Gassy inside the elements type of glow"
It didn't do this when the set was turned on so I would guess the tube was not being driven by the video circuits?
Eric