Hello again. I've spent a lot of time ensuring that this set is in exactly the same condition as when I acquired it. Also checked the values of 20 original ceramic caps and replaced one disk that showed more than twice the specified capacitance and one with possibly overworked leads. Also repaired and reinstalled the original horizontal size pot. Other than replacing defective parts and upgrading parts to comply with advice from this forum, the set is exactly the same as when I bought it.
Now, to address one issue at a time, please consider V15, 6SL7, Balanced Vertical Output. I have inconsistent voltage readings going back to when I first started working on the set. Now, rather than trying to describe my difficulty in reading the voltage, here's a quick video of the multimeter on one plate and one grid.
Adm 17T12 9015 V15 Jitters by
H Boyars, on Flickr
I checked it with another meter and with another tube, but both grids, both plates, and one cathode still give the same result. What might cause this phenomenon?
Here's a link to the 17T1 schematic:
https://flic.kr/p/2mv3Wrm