http://www.videokarma.org/attachment.php?attachmentid=204916&stc=1&d=1664814703

Anyone know what the prefix letters stand for on this 15GP22 serial number?
L=Lancaster ?
B= ?

Leaky Bulb :)

There you go ;-)
Is this one the six thousandth, four hundredth, thirty sixth example ?
How many were made ?

Leaky Bulb :)

You beat me to it. :D

Leaky Bulb :)

You beat me to it. :D

I'm glad I'm in good company, when I saw the "LB" my first thought was "Leaks Badly" ;)

I'm glad I'm in good company, when I saw the "LB" my first thought was "Leaks Badly" ;)

My thought for "LB" was "Lousy Bondings" :D

LB likely bad. :D

One would think that they started with serial number 0001, but I find it hard to imagine that they made over 6,400 of these tubes. Maybe they did when you count all of the CRTs made for other manufacturers. After all, they did make 4,400 CT-100s. It's also possible that they assigned a serial number before the tube was tested. That would mean a lot of rejects used up a serial number.

I like Tom C's definition of "LB."

One would think that they started with serial number 0001, but I find it hard to imagine that they made over 6,400 of these tubes. Maybe they did when you count all of the CRTs made for other manufacturers. After all, they did make 4,400 CT-100s. It's also possible that they assigned a serial number before the tube was tested. That would mean a lot of rejects used up a serial number.

I like Tom C's definition of "LB."

My assumption, RCA likely assigned prefex’s to prototypes, and production 15GP22’s ? Trying to find out. Sometimes you see the chassis serial number incorrectly pasted to the CRT.

RCA did sell to other manufacturers, explaining the high number and some manufacturers built their own based on RCA specs. A mystery.

I can’t imagine who’d have the resources besides RCA to build that tube, even under license.

I can’t imagine who’d have the resources besides RCA to build that tube, even under license.

Philco, Westinghouse, General Electric.

CBS didn't just make 15GP22. They one upped RCA and figured out how to deposit phosphor onto the inside of the face of the envelope (without reducing the ability to obtain good purity and convergence) and came out with a 19" version of the 15GP22 the IIRC 19VP22... Motorola, CBS, Westinghouse and others actually made sets with the 19V.
RCA was so ticked off their $6M invest in CRT tech was obsolete that they bought the patent from CBS them came out with the 21AXP22 to obsolete the CBS tube... During the time the 19V was the best tube on the market RCA refused to modify the CT-100 (it would have only been cabinet modifications) to use the 19V and because of that waiting and customer frustration with their current product being essentially obsolete. They had to basically hack together the 21CT55 to take the 21AXP22 as a stop gap till the CTC-4 was ready.

CBS didn't just make 15GP22. They one upped RCA and figured out how to deposit phosphor onto the inside of the face of the envelope (without reducing the ability to obtain good purity and convergence) and came out with a 19" version of the 15GP22 the IIRC 19VP22... Motorola, CBS, Westinghouse and others actually made sets with the 19V.
RCA was so ticked off their $6M invest in CRT tech was obsolete that they bought the patent from CBS them came out with the 21AXP22 to obsolete the CBS tube... During the time the 19V was the best tube on the market RCA refused to modify the CT-100 (it would have only been cabinet modifications) to use the 19V and because of that waiting and customer frustration with their current product being essentially obsolete. They had to basically hack together the 21CT55 to take the 21AXP22 as a stop gap till the CTC-4 was ready.

Yes. Woe was RCA to accept someone’s else’s technology. Here is a photo of the upcoming RCA 19 inch Color TV, courtesy the Estate of Ed Reitan which had to be scuttled because of the CBS Hytron.

https://visions4netjournal.com/wp-content/uploads/2022/10/A48EFB14-1D55-40D3-BB47-32D87A43040D.jpeg

Just curious. Those of you with working 15GP22 sets, how often do your fire them up and watch them. Spats bear on YouTube was the last one I watched the rebuilding process.

Just curious. Those of you with working 15GP22 sets, how often do your fire them up and watch them. Spats bear on YouTube was the last one I watched the rebuilding process.

When friends, family or a guest that expresses interest come over. Otherwise once every two months or so. My set has survived 3 years after restoration, crossed fingers.

I watched his video, fun. YouTube deleted some of my videos, even though they have brief broadcast clips. Others okay and they put ads on. Would love to see more 15GP22 videos.

Just curious. Those of you with working 15GP22 sets, how often do your fire them up and watch them. Spats bear on YouTube was the last one I watched the rebuilding process.

I watch mine every month or so, for typically the length of a baseball or football game, or occasionally the end of a golf tournament.

Doug McDonald

My CT-100 gets run roughly monthly....I was watching it once a week for a while, but it's developed intermittent color sync about 15min after warmup (varies with line voltage) that I want to fix.

I'd like to find another 1KVA voltage regulating line isolation transformer for the CT-100...My 21CT55 runs VERY happily on one, and they'd probably share it were they not in different rooms.

Didn’t RCA have to license a Zenith patent for the AX’s convergence, too?

I watch mine usually every month or two, more when I show it to amazed visitors. Interestingly though, it too has developed the exact same intermittent issue, where it looses color sync once in a while.