Two 15GP22s At TheBay
 

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

Terry Cheek

http://cgi.ebay.com/ws/eBayISAPI.dll...E:B:SS:US:1123
http://cgi.ebay.com/ws/eBayISAPI.dll...E: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?

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

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?

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

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'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?

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

:D

-Ian

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

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.

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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 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.

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."

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!

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

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

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

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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.

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.

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

John

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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