Here are two 15GP22s I found for auction at TheBay.
Happy Holidays,

Terry Cheek

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250527056091&ssPageName=ADME:B:SS:US:1123
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250527058486&ssPageName=ADME:B:SS:US:1123

I am dying to here the comants on these.

FRAUD! FRAUD! FAKE!

Nah, I'm just kiddin! :D

It's interesting he mentioned it looks as if someone has rebuilt one of them. Wow... if that's correct, I wonder how many years back that was done?!

I'll make one comment

"my CRT tester will not test this CRT"

If I had a $2000-$3000 CRT I'd find a tester that would test it, won't most of the B&K's do it if you use some alligator clips?

He's in N.J. I'm sure someone here would be happy to go test it for them?

It's interesting he mentioned it looks as if someone has rebuilt one of them. Wow... if that's correct, I wonder how many years back that was done?!

I really wonder about that "rebuild"... look at the label on the tube... looks original factory to me. Did somebody carefully remove the label, rebuild the tube, then put the label back on the tube? Perhaps it was just a factory "re-neck" ? :scratch2:

I have never seen a listing for that gun type in any of the Superior Electronics catalogs that I have been able to find.

jr

I'll make one comment

"my CRT tester will not test this CRT"

If I had a $2000-$3000 CRT I'd find a tester that would test it, won't most of the B&K's do it if you use some alligator clips?

He's in N.J. I'm sure someone here would be happy to go test it for them?

The Sencore CR-70 will test a 15GP using the universal test adapter it comes with. That's what I have and that's what I have tested my 15GP22s with.

Gilbert

Perhaps this would have been the grandfather of all RCA Colorama tubes! :yes:

I have a 15GP22 adaptor I made for my Beltron. I am near the seller and sent a note asking to visit to check the tubes. Stand by.

Question about testing a CRT in unknown condition:

If a CRT has gone to air, but nobody has powered the filament since before the vacuum was lost, could such a CRT be restored to operation by re-evacuating the tube, without have to do a total rebuild (assuming any leak would be extremely slow or could be found and closed)?

I say this, because I wonder if a test of an unknown CRT should start with a very low voltage continuity test of the filament, then, if there is any conductivity, doing some type of test for any presence of air in the tube.

Rather than just hooking up the tester, which would destroy the gun of the tube if in fact the tube had gone to air?

Question about testing a CRT in unknown condition:

If a CRT has gone to air, but nobody has powered the filament since before the vacuum was lost, could such a CRT be restored to operation by re-evacuating the tube, without have to do a total rebuild (assuming any leak would be extremely slow or could be found and closed)?


My understanding of it is no, once the cathode has been activated exposure to air destroys it.

I'm sure someone who really knows the answer to this will chime in. :yes:

Testing an unknown CRT is certainly a common scenario. Perhaps one of the sages could tell us all what the potential risks might be.

Phil Nelson

I'm not too surprised, as I've seen a good share of 15GP22s on eBay. I sold 4 or 5 of them myself, in various states of condition. I've seen rebuilt ones, but likely rebuilt in the 50s. In fact, these two tubes may have come from me. I sold two of them to a collector Back East about 10 years ago, and one was a rebuilt.

Charles

I say this, because I wonder if a test of an unknown CRT should start with a very low voltage continuity test of the filament, then, if there is any conductivity, doing some type of test for any presence of air in the tube.

Rather than just hooking up the tester, which would destroy the gun of the tube if in fact the tube had gone to air?

When I first powered up my 22EP22 after sitting for 15+ years, I did just that, and brought the heater voltage up slowly. I did NOT want to see a flash from the heater that would indicate that I had destroyed the tube! :no:

I was fortunate, the heaters appeared to power up normally. Had they not, I really had no game plan, and I doubt that the tube could have been saved anyway... Perhaps long term low voltage on the heaters would "pump" the tube somewhat... perhaps the getters could be "re-flashed"... but at least the heaters would be intact for further experiments.

jr

During the activation of the cathode BaCO3 is dissociated to BaO. Subsequent heating at a higher temperature then reduces some of the BaO to Ba with the help of a reducing agent like Si. When the tube goes up to air the Ba oxidizes back to BaO or BaO2. Mostly BaO I believe. There are other alkali's involved too, but Barium is the major one.

You would need to reactivate it, but the reducing agent should have been mostly used up during the first activation.

There would a significant expense in trying it, with no way of knowing the status of the cathode before hand. I don't think it would be worth it. If I spent that much I'd want to know that I had a fresh gun in the end.

John

I really wonder about that "rebuild"... look at the label on the tube... looks original factory to me. Did somebody carefully remove the label, rebuild the tube, then put the label back on the tube? Perhaps it was just a factory "re-neck" ? :scratch2:
jr

I've seen the tubes. The one with the weld on the neck definitely looks like a old rebuild. Or a "re-neck" but what's a re-neck? This is the second one I've seen like that. Untested unless Dave A or someone gets over there, but I can vouch that they're absolutely for real and lookin' good.

--Dave Sica

I've seen the tubes. The one with the weld on the neck definitely looks like a old rebuild. Or a "re-neck" but what's a re-neck? This is the second one I've seen like that. Untested unless Dave A or someone gets over there, but I can vouch that they're absolutely for real and lookin' good.

--Dave Sica

What I am calling a "re-neck" is something that occurs at the factory. For example, something goes wrong after the gun is sealed to the funnel, say a broken stem or a poorly annealed seal that cracks, or a defect is discovered in the gun... something like that. It is very easy at that point to simply remove the gun, seal on a new section of glass neck tubing and insert a new gun/stem assembly for a second try. If the labels on the tube look factory original, but the tube has an extra neck weld, I usually assume that it is a factory rework rather than a "rebuild".

jr

I'm firing up my time machine. My 1968 Allied catalog has 15GP22 "Colorama" tubes for like $135. Anyone want to chip in on a bulk buy?

I'm firing up my time machine. My 1968 Allied catalog has 15GP22 "Colorama" tubes for like $135. Anyone want to chip in on a bulk buy?

Hmm. Only problem with this plan is that there isn't a whole lot of room in a DeLorean...

:D

-Ian

Testing an unknown CRT is certainly a common scenario. Perhaps one of the sages could tell us all what the potential risks might be.
So, what is the layman's answer to this question? If you fire up an unknown CRT on a tester, are you risking anything for a future rebuild? Or do you just go ahead on the theory that the damage (if any) has already been done?

Phil Nelson

Hmm. Only problem with this plan is that there isn't a whole lot of room in a DeLorean...

:D

-Ian

Maybe pack them well and ship them by the US Postal Service. Might be just arriving. I'll have to watch for the mail man.

---

So, what is the layman's answer to this question? If you fire up an unknown CRT on a tester, are you risking anything for a future rebuild? Or do you just go ahead on the theory that the damage (if any) has already been done?

Phil Nelson

If you fire up a gassy CRT at full heater voltage, it is very likely that the heater will quickly burn out. Since the heater and cathode are replaced during a rebuild, it is unlikely that a future rebuild would be adversely affected by doing so.

However, once the heater is burned out, a rebuild would be the ONLY option. No possibility of a rework (however slim) would exist. I guess that I would prefer to leave as many options open for as long as possible. Perhaps an attempt to seal the leaks followed by a getter re-flash and cathode re-activation could still rescue the tube, as long as the heaters remain intact. However, this is very unlikely and perhaps a waste of time and money, but at least the option remains open. If I had access to an RF generator and a getter "wand", I would try a getter re-flash in a New York Nanosecond... not much to loose!

jr

I'm firing up my time machine. My 1968 Allied catalog has 15GP22 "Colorama" tubes for like $135. Anyone want to chip in on a bulk buy?


I have no need for a 15GP22.

It does occur to me, however, that since you'll only be carrying a load of 15Gs on the return trip, you'll have extra space during the departure.

We can make a deal. How much to send me one-way? :-)

I have a 21F_P22, Channel Master rebuild, that worked fine c.1995. About 5 years ago I awoke it from a long nap using a tester and noticed the filaments were very, very dim. Puzzled, I initially blamed it on the tester. Then I watched the filaments die one by one.

I'm not really worried that what I did was bad. Certainly the crt has air in it; finding/repairing the leak, and dealing with the air? Not an option, really. I just stuck it upstairs in my "dud" pile.

I have a 15GP22 adaptor I made for my Beltron. I am near the seller and sent a note asking to visit to check the tubes. Stand by.

Did you test it? Today I found a note on #250527056091:

"Thanks to another Ebayer I was contacted by a very nice person who took the time to drive too my house and test this CRT. This person came in and tested The CRT with his custom made adapter for the CRT. As you can see this 15GP22 passed with Flying colors all three guns tested good. The CRT passed the ten second test. The Blew gun started to drop emission at 12 seconds after cutting power the green followed at 14 and the red gun at 15. Needless to say this is one good 15GP22."

Did you test it? Today I found a note on #250527056091:I did the actual test as I was much closer to the seller's location. A homemade adapter makes the Beltron think it's testing a 21AXP22.

Pete

Wow... in most cases, you wouldn't expect an unknown 15G to pop up on ebay and test with such good results!

What is the make-up of this adapter? It sounds like there's a little more involved than simply getting the pins correct.

Pete, was there anything else interesting about the tube? For instance, the guy mentioned the neck weld... do you think it was actually rebuilt? Was there a date code on it?

Of course, none of that really matters considering those test results... it could be pink with purple dots.... someone is still going to want that tube!

What is the make-up of this adapter? It sounds like there's a little more involved than simply getting the pins correct.I guess editorial flair souped up the basic nature of the adapter: just port the three G1, three cathodes, and filament over to a 20-pin Cinch connector.

Pete

the neck weld... do you think it was actually rebuilt? Was there a date code on it?

There's no doubt in my mind that it is a factory rework weld. Date code is a bit hard to confirm via my photos, but it appears to be the 43rd week of '54, with only the '3' in question.

Pete

simply applying HV to the CRT while the socket pins are grounded will tell you if it's very gassy.
What would you look for to tell if it's gassy? Glowing fog or other light show in the neck? Sorry to be so dense, but I haven't tried any of these experiments -- or had a gassy CRT, for that matter.

Phil

---

Seller updated one of the auctions. Looks like someone was able to visit the seller and test the CRT's One of them is good with great emission! The other has gone to air. If the buyer of the So cal set wins the good CRT we might have another living CT-100 soon!

I wrote the seller tonight to ask their reason for pulling the gassy tube off eBay. Everything has value ... even a dud gone to air.

I'm firing up my time machine. My 1968 Allied catalog has 15GP22 "Colorama" tubes for like $135. Anyone want to chip in on a bulk buy?


Instead...I think I would like to go back and take a couple of empty semi's with me, to two dates...about 1970, and maybe 1948....both around new york, though I could drive around. One of the semis would contain a minivan, that might NOT make the 'return trip".

Then, for about a month each time, I would 'curb shop" with my van and put my finds n the trucks. IMAGINE--what I could find around 1970, in the NY area--a LOT of CTC-5,7, 9 and so on rca tv sets, maybe a few CT-100's and 21ct55's, etc, along with TONS of nice Hi-fi gear. I would load the semis to the gunwales and "bring it all home".

Then,I would take two other semis to 1948 or so..same area...THIS time--prewar sets and nice radios of ALL types. Once again, about a month and back home.

I wrote the seller tonight to ask their reason for pulling the gassy tube off eBay. Everything has value ... even a dud gone to air.

Hopefully he just wants to relist it to give people a chance to rebid knowing the true status.

John

---

I was able to chat with the seller today. My understanding from our conversation was that once the ebayer p**u did a bid retraction the bid price fell back to the opening bid of $9.99. The seller said he didn't want to give away the tube - so he canceled the auction. The seller then asked me to make an offer. I suggested he relist with a higher minimum bid. Hopefully, something he's comfortable with. I'll give it another day, but so far he's not gotten back to me about my offer.

Well, he probably wants to wait and see what the good tube sells for. Perfectly understandable; but to those of us who collect and restore old TV sets there's a big value difference between a good 15GP22 and one that's gone to air. I suppose time will tell what that different may be if the seller ever decides to relist the dud.

US $2.050,00

Wowh!

Ok now that I am the winning bidder I will tell some more of the story.


Pete Deksnis is the person who went over and tested the tube, and he told me that it is VERY good.

So it looks like I will be getting one oif my two CT100's up and running with a new crt berfore very long.

Pete is going to go over and pick the tube up for me. I am not sure when I will have it in my possession. Maybe not till the next ETF convention.

Bob Galanter

Wow... an NOS 15G... that's gotta give you goosebumps!

Is your CT100 ready for the tube... plug-and-play? Or will you need to do some chassis work first?

The chassis is rebuilt and opperational. I have a 15GP22 under vacuum, but one of the guns has a dead filiment. The chassis was tested with that tube.


My under vacuum, two color tube will be rebuilt on the next trip that John Folsom and I are going to make to Hawkeye. We will be rebuilding 2 under vacuum duds on our next trip. One is mine and one is John's. We are planning the trip for sometime in December if all goes according to plans.

But before I even think of puting my first CT100 together, I need to do some refinishing work on the cabinet. It will probably be well into the first quarter or even the second quarter of next year before I find the time to do the work on my set. I am so involved with the 15GP22 project and our future attempts to seal and rebuild the leaker tubes that there is not much time do do my own sets right now. After we put the 15GP22 rebuild project to bed, I will have more time for personal projects.

Bob

Congratulations with the acquisition Bob! It's a double bonus with the money going to a good cause.

John

but to those of us who collect and restore old TV sets there's a big value difference between a good 15GP22 and one that's gone to air.
You got that right Tom. I don't think a leaker will ever be worth more than about $300, even if John Folsom and I are able to develope a workable method to seal the leakers.

The bottom line is; rebuilding a 15GP22 ( one that is still under vacuum ) is going to cost more than what I just paid for this NOS tube.

And, if we are successful, rebuilding a leaker will be even more expensive than rebuilding a tube still under vacuum, due to the extra work that will most likely be involved.

Bottom line is.... 15GP22 tubes that are under vacuum and fully functional, will be getting more and more expensive as time goes by because the cost to rebuild these tubes will greater than the today's current market price of a known good tube.

Bob

For an animal such as this, you can't expect it to be anything less than expensive. If you're hard core, you'll do what you can to get these things... put up your house, children, wife, land... whatever you can to obtain one of these.

As Bob points out, they will get more and more expensive as time passes. So, if times get hard and you're stuck between a rock and a TV set, you can always get your investment back and more. Of course, you don't want to have to go that route, but, you're certainly not going to lose... at least... not in our lifetime.

Just imagine. If we knew the back story up front, even more money could have been raised for the Sarnoff project.

Deleted:

I've also been spending time at Sarnoff with Alex to help get ready for the move. I can assure you that Alex's intentions are good and after the dust has settled one of us might very well make a presentation at the next Early Television Convention about the whole thing. I have some photos of this tube and other items that may leave you speechless. The collection will continue to be available to the public and the archives will continue to be available to researchers, but there is a ton of work yet to be done packing up and a very costly move to the new locations to be made (and paid for!) Anyone near Princeton NJ who could spare a day or two would be welcome to come by and help with the packing.

--Dave Sica

Just curious ... does any know what happened to the dud 15GP22 CRT? The seller had it for sale and then cancelled his listing on eBay?

Just curious ... does any know what happened to the dud 15GP22 CRT? The seller had it for sale and then cancelled his listing on eBay?I saw it three days ago at the seller's location, so it's still around; current plans are to preserve the tube as a museum display piece. Probably in the historic Marconi site here on the Jersey shore.

Pete

I saw it three days ago at the seller's location, so it's still around; current plans are to preserve the tube as a museum display piece. Probably in the historic Marconi site here on the Jersey shore.

Pete

Seems like a waste, since it's still under partial vacuum it would make a good candidate to try resealing on?

I saw it three days ago at the seller's location, so it's still around; current plans are to preserve the tube as a museum display piece. Probably in the historic Marconi site here on the Jersey shore.

Pete

Maybe that could be true. But ....something seems odd. :scratch2: Yes, behind the Marconi Hotel there is the Radio Technology Museum... but I've never know the museum to have any TV exhibits. Sure seems like a possible waste to give away the CRT when there are collectors dedicated to preserving the technology with the best means possible.

Sure seems like a possible waste to give away the CRT when there are collectors dedicated to preserving the technology with the best means possible.I'm not unsympathetic to your point Tom; yesterday when I called the seller to get the info in my post, it was pointed out to him that $300 was the average price for a 15G dud. His response was what you read. Even though it's only about 6 or 7 miles from where I live, I have never been to the site, and so got myself invited there today for a personal and behind-the-scenes tour to see firsthand how the volunteers are turning a history-rich former army base into a -- hopefully -- first-class museum. John, the seller, noted that the Marconi Hotel you mentioned is in a state of dilapidated disrepair. It should be an interesting couple of hours. I'll take my camera.

Pete

Wow, what a great place :thmbsp: It's a site dripping with history... from its Marconi beginnings to its Camp Evans days, you can spend hours as a visitor or years as a volunteer and not get your fill. Didn't get a site tour, as John had family show up, but Steve Goulart showed me much of what the volunteers have accomplished on a shoestring budget, including a small display area of vintageTV, which could use some NTSC color representation as well... we'll see.

Go visit InfoAge in Wall, NJ if you can.

Pete