I got hold of an Admiral model C1617(?). I have just sent the 15GP22 tube off to a rebuilder, Video Display Corp. They tell me that they can do one of three things: rebuild the guns in it, replace the guns with newer type guns, or remake new guns like the originals. They have a shop that builds new guns.
I have after taking steps to go through the circuitry, have replaced one bad electrolytic, four bad tubulars, and a gassy horizontal output tube. The set now seems ok in all circuits, with full voltage, and no CRT hooked up.
Is the CTC2 schematic I got from your site as close as it gets? It is a 1954 Admiral. The schematic is very close, but not the same. One thing I noticed right off, is the use of cold gas regulator for the HV shunt regulator in my set. The RCA schematic shows a far better 6BD4 vacuum tube regulator. Also it looks like the set is using an in-chassis power supply. My set has very heavy
separate power supply
, using three 5U4s.
You can see the difference in my main chassis. Notice the gas regulator that sits
just to the right
of the fly-back cage. I need to test it when I can get ahold of a probe. The filaments went out of my tube just after the high voltage came up. I think it was going to happen any way. The tube was full of air, and it probably ionized into a short.
My tube made it today to Video Display, They will check it over and we will talk price next week. I will learn the price to tool up for a cathode and filaments and the price for re-spraying the cathode plus filament replacement. I will let you know of the outcome.
[This is an edited version of e-mail Bruce sent to collectors known to this site. --Pete] I know that we all are interested in rebuilding 15GP22 and 15HP22 tubes. I have a 15GP22 at Video Display for research. It is my interest to develop a way to repair or rebuild this tube. I just got off the phone with Bob. He is their electron gun engineer. Video Display is able to manufacture complete electron guns for replacement.
I am hoping to find someone who has a tube that is broken, or for some reason, will never be rebuilt. We need the guns from this tube to use for examination. If anyone knows of a source for a gun, please let me know. I have decided to do a hard search for a dud gun for a month. If at that time I have not found one, I will let Bob cut the neck off my tube for research.
It is a challenge to see if this can be pulled off, but it is fun also. I will be keeping you all posted as to what I learn.
I would also be interested in learning of other collectors in the same predicament some of us are in. Please, if you know someone, let me know who they [or you] are. [I'll forward e-mail on the subject to Bruce. --Pete]
Today I received a stem from The Fredericks Company. It is a 15G stem. It was made years ago, and was located after a search. Fredericks can make this stem for us. The ones they will make will use Sylvania #40 pins instead of the nickle wires in this stem. I am still waiting on an estimate of cost from them for this.
I have sent the stem to Global for John B.'s examination and approval. In a phone convo today, Mr. B. said he would get back with us soon. He seems positive about doing this tube miracle.
For those who are not up to speed, Global will rebuild the guns, and Hawkeye will do the installation of the rebuilt gun to the dud tube.