[PhilcoPhan1936]

Well, I worked on it today. Checked a few things under the chassis. Nothing odd or dead or open, so I pulled tubes and started testing.
The 6F6G output tested low: 1200/2000. I got lucky and found one that tested 1800/2000, so in it went.
The 6J5G 2nd Det/AVC tested low as well: 2000/2600. Again, found a replacement that tested 3700/2600, so in it went.
The 6A8G, 6K5G and 5Y4G checked out ok.
That left the 6K7G. I went to remove the shield, and the tube popped. The shield was too tight on it, and it broke.
I managed to get the shield off, but the tube bit a finger in trying to unplug it from the base. I guess it was a vampire tube and needed some blood.
So I have no idea what it tested at.
I punched the tube into Radio Museum, and found it was used in a Philco 37-61B Late Tombstone I have that sits on a shelf for later restoration.
I pulled it, and It tested strong at 1550/1450, so in it went.

Turned the radio on, and it's back to life!

So I guess it just needed some blood.
Or a replacement 6K7 or 6J5 tube.

Will put it back together tonight, and dive back into a Zenith repair job.