[Tomcomm]

Bob and John, so sorry about the final demise of the heroic 15GP22 rebuild project, bummer! At least now you can hopefully get back to your 21CT55 restorations? My operational 21CT55 needs company so we can compare screen shots.
I once had an engineering prototype 15in color CRT that RCA supplied to a member of the NTSC development team supporting the FCC color TV standard hearings in NY. I believe it was Hazeltine. I got it from an RCA engineer in 1963 who built a chassis for it from parts of the special component kit RCA was selling for the production 15GP22. I traded a cherry 3in Pilot T37 with case and magnifier for the 15G... proto, CRT mounting board and partially complete chassis sometime in 1963. I recall the CRT had a shadow mask/dot screen assembly that was put together with a bunch of tiny nuts a & bolts but I don’t recall if it had a metal or glass cone. It was definitely a handmade, possibly a one of a kind engineering item. I still have the documentation that came with the RCA kit. I attempted to fire up the CRT and chassis to see if anything worked. With no B++ or HV applied, all filaments lit-up. When I activated the B++ there was a flash in the gun assembly and the HV fuse blew. Disaster, the red filament was dead, After the required OH SHT ! I knew the project was over so I put everything back on the shelf. A couple of years later I trashed everything. Even dead, the prototype 15GP22 would be a museum display today, but in mid ’60s how was I to know? At least I still have the 21CT55 I got about the same time…..Tom