Reviving this thread because...
Someone sold me a working 21AXP22A! A GE-branded rebuild NOS in the box, measures in the middle green on all three guns on the RCA tester.
Here are the first pix after a day and a half of removing the "temporary" makeshift mount and 21FBP22 glass tube and reinstalling the metal tube support hardware. Plus about 40 minutes of roughing it in.
The SAMS bias set up procedure just doesn't seem to work right on this set. couldn't get any red at all until turning up the screen setting. Also, supposed to start with 130 volts red K-G, but can get 110 max. I will try the RCA procedure, which is somewhat different.
This set is still weak on luma drive, even with AGC cranked, so maybe I have to do something in the IF (replace tubes?). Replacing video outputs never cured it.
Images look much brighter in these shots than they really are.
003 by
old_tv_nut, on Flickr
First rough convergence with 21AXP22A by
old_tv_nut, on Flickr