The original tube was a 17GP4 It has been replaced with a 20CP4 along with the required focus magnet.Kinda looks homebrew from the rear. It is a RCA 20CP4. The hole was cut wider for the crt on the sides and there is a single piece of 1" thick board supporting it at the front. Anyhow it works.
I made the mistake of firing it up again to see if I could get a signal through it with a digital converter box.One of the filters started to let go
and I quickly pulled the plug.It won't get turned on again until it gets the recap treatment.