Twenty-eighth operational CT-100 screen shots...

[Pete Deksnis]

Simplistically, a 15GP22 is a dud for one of only two reasons: no vacuum and no or low emission. (Maybe that makes three?)

Anyway, the process to rebuild a no/low emission 15GP22 electron gun assembly is perfected and in place. Ditto the manufacturer of glass stems. Basically, rebuilding the gun means replacing the old filament and cathode with new ones.

Recently (the last year or more) effort was extended to connect a stem to an old, dud 15GP22 neck. This has been done although I'm not certain the technique is as reliable as, say, the rebuilding of the electron gun. But the process has been successfully demonstrated.

What's being done now? The archives have yielded a bit of vintage 15GP22 data covering the baking temperature and slew rate of that baking heat. They are different from what is done today. Finding a way to reproduce the vintage procedure is the present challenge.

As to the phosphor in air question, no one seems certain although the current thinking is that since the 15GP22 is aluminized, the phosphors may be protected from the air.