21AXP22A Replacement in CTC-5

[miniman82]

You need the metal CRT support ring from a CTC-7, which will also have the edge purity hairpin magnets on it. Then instead of trying to keep the stock yoke, you might try using one from a later chassis like a 9 or a 10. Those clamp to the neck of the tube, and it would be a simple thing to crush a useless octal tube to repin it's socket for use with the yoke.

I tried using a glass tube in my CTC-4, but the yoke support was too close to the anode connection of the 21FJP22 I was using and it arced over.