I recently picked up a strong testing 17BJP4 CRT as a backup for my Setchell Carlson P65 portable. Is anyone here familiar with Channel Master date markings? November 20, 1973?

It's nice how they have all the numbers that this tube subs for printed on the label.

Sure looks like it. Channel Master made decent tubes. Usually a step above the local independent rebuilders in quality and longevity, and at a reasonable price.

Dennis, Thanks for confirming. This CRT was found in a really beat up Setchell Carlson P62. The P62 must date from around 1957. I find it very interesting that someone bothered to put a new CRT in that TV set in 1973.

I don't, that was considered a commercial or institutional set and many of them were kept going for schools etc. far beyond what you would expect for a normal customer. They didn't get a lot of use under those conditions and it was easier to get repairs authorized than replacement of the set.

Even so, if someone owned the set and really liked it, they could have spent $70-$80 to put in a rebuilt CRT and replace a handful of the old paper caps in the early 70's.

We still had a few elderly customers in the shop who were having sets from the early 50's rebuilt as their main living room TV. I suspect these people never watched much TV though and figured the sets were not worn out in the 70's. Several of our customers purchased their first color set in the mid-late 70's trading in old black and white consoles.

Well then I guess I'm not the only one that torments his family by keeping outdated electronics.

So were these Channel Masters always rebuilt CRT's?

I don't recall ever having seen a "new" Channel Master CRT. There was some speculation at the time among dealers that they may have purchased some "seconds" from RCA or another one of the major brand name rebuilders, which would have been limited to cosmetic flaws like a bubble in the glass or the neck being a bit too lumpy where the new gun assembly was joined to it. No way I know of to prove or disprove that. I would expect that 95% or more were tubes that Channel Master rebuilt themselves at a facility they owned or held under contract. By that time, there was no call for new black and white CRT's other than for new production of TV's or computer monitors. Even if you had a brand new TV a week old and the CRT failed, usually all you could get from the distributor would have been a rebuilt. The exception was the little 5" or 7" sets, the cost of the new CRT was so low that it didn't make any sense to offer rebuilts.

I had a 'new' Channel Master 21FBP22A that had a single dot matrix missing on the screen. Unless I mentioned it, nobody ever noticed where it was. I think this might have been one of the 'second' tubes mentioned previously.

The labeling was green. Label stated all new glass, and new electron gun. It lasted almost 19 years in my CTC-10C before I got a VDC rebuilt tube in Atlanta. That tube is 26 years old now, and looking fine, too.

Channel Master black and white CRTs were as good as any, but their Bonded color tubes often used a clear, non-tinted (cheaper) safety glass that detracted from the tube's performance in normal room light conditions. These "white-faced" tubes were so unsatisfactory that I refused to take delivery of them.
A 25AP22/25XP22 is supposed to have a 65% light transmission safety glass.

As far as Channel Master crt's when I worked for Warren Radio Co we sold many. As I remember to b/w were optima/plus, colour jugs were, colour-lux, colour-king, and chroma-king. But that was 40 years ago. dave