is this as bad as I fear it is
 

I got home with my new rebuilt 24AEP4 (I have a set that uses one), and checked condition of the neck, and saw this scary trace of white just inside the plastic neck cap, which I didn't remember seeing when I first saw the tube
I know that white on the inside of a tube is a sign it has gone to air- but other tubes I've seen that have gone to air are full of white

I also mention that this tube was perfectly snug in its box, with no "wiggle room" at all. Nothing could have possibly struck the neck

Please tell me that this little bit of white could be normal.

That may just be the type of glue that was used to fix the plug to the glass. Pull out the tube and see if the black shiny getter is there as that would turn white if it went to air. Never seen a tube go white that high unless it's glue.

I agree. Probably used superglue to hold the base on, and it left a haze on the glass.

Why did the tube come back from a rebuild with a yoke installed?

Thanks! At least there's hope.

I guess the only way to know for sure would be to set the CRT in the horizontal position and put 6V on the fil.

Don't know. I got it at the auction at the convention. It looked especially convenient as the yoke looks exactly like the one on my Emerson 1224 - the plastic (or black-plastic-like substance) on that yoke is decomposing).

YOO-HOO! It scratches off - so it's only with the rest of the world that had already gone to air about 2,300,000,000 years ago.

Good buddy,thats g00d to hear!!