Tom, I know that I am late to the party. I did see the pictures that you posted a few days ago. Just wanted to say how wonderful it looks. I must admit that I only recently became aware of the 15GP22 CRT thanks to this forum and the Antique Radio Forum. I will admit to having never seen a real 15" color set (vintage that is).

Very Nice!

I just had an idea. I improved my 7JP4 with the grid-cathode short remover
of my Sencore. Maybe my 15GP22 arcs are not caused by gas ... I never saw
a purple glow. I'm going to try that short remover on every single pair of
electrodes in the gun, including ones between different guns (excluding
heater-cathode). It can't hurt. I'll first check it with a 2kV supply set to
current limit at say 50uA. That should catch gas.

Sure sounds like it's worth trying. If we can stave off the death of one more 15GP22, that would be very nice. Let us know how it goes!