http://cgi.ebay.com/RCA-First-Production-1954-Color-TV-CT-100_W0QQitemZ170467244645QQcmdZViewItemQQptZLH_Def aultDomain_0?hash=item27b0a3ba65


not affiliated,
jr

Hmm, maybe someone should send the seller a link to that $750 set?

Is that a brightner wired into the CRT heater? So even if it's still under vacuum you can assume it's shot anyway.

I think we are going to see alot more CT-100s in the future. Folks that own these sets may be worried about the CRTs going to air and might believe that there is no hope for rebuilding it. Therefore to them it is nothing more than a risk to them and they're looking to rid themselves of it.

My .02 for what its worth.

I think we are going to see alot more CT-100s in the future. Folks that own these sets may be worried about the CRTs going to air and might believe that there is no hope for rebuilding it. Therefore to them it is nothing more than a risk to them and they're looking to rid themselves of it.

My .02 for what its worth.Thats exactly why I only have a actual picture of one, What would I do with it once it sucked air? I would have broken even for the price to say I had one I think it got a good home now do I shell out 5 grand for this one? LOL

I also beleive that more collectors will start to unload their CT 100 sets.
With ZERO chance of CRT replacement/rebuilds, and the astronomical failure rate of the 15GP22, they become less and less attractive to even the most dedicated of collectors.

With the market flooding, I put in the opening bid, but reserve not met. North Hills (a polite new name for the not-so-great neighborhood in Los Angeles formerly known as Sepuveda), is close enough to our place in Moorpark, CA that I could go get it easily if I won.

Charles

There is not "zero" chance of rebuilding the tubes. In fact, RACS is making excellent progress. There will be a presentation at this year's Early Television Convention about the progress.

I don't believe there will be a flood of CT-100 sales. People collect old TV sets whether they work or not.

Perhaps not "ZERO" chance, but "pretty freaking small".

I wonder when the last sucessful rebuild happened???

Probably when RCA was pulling unsucessful "new" tubes off of the line and "rebuilding" them.

OK, I'll shut up now.

I don't believe there will be a flood of CT-100 sales. People collect old TV sets whether they work or not.

I agree with this statement. All of a sudden people are badmouthing the CT-100. It is a VERY collectible television even if it does not function due to a bad CRT. Bet you guys wouldn't turn down a pre-war set with a bad CRT.

Everyone has a set or two that does not function. So what? They look nice on display even if not functional. Just my thoughts.

Gilbert

I wonder when the last sucessful rebuild happened???



Technically about six months ago, true it went to air later but it still proved it was at least possible to re gun one.

Charles:

I have an adaptor to test the CRT. If you want to go look at the set in person you can borrow it if you'd like. Also, don't forget to get the serial numbers if you go.

Steve

I agree with this statement. All of a sudden people are badmouthing the CT-100. It is a VERY collectible television even if it does not function due to a bad CRT. Bet you guys wouldn't turn down a pre-war set with a bad CRT.

Everyone has a set or two that does not function. So what? They look nice on display even if not functional. Just my thoughts.

Gilbert
The particular one I was looking at would have been a great buy, but I think it deserved a better home than to just sit collecting dust with me and being of no functional use to me and it's not my era of TV. I think this is much like collecting cars some guys are Corvette collectors and some guys are charger collectors, I dont think you can get much money out of either in this economy.
I have a Charger myself:D

Technically about six months ago, true it went to air later but it still proved it was at least possible to re gun one.

Did the Hawkeye rebuild go to air? I had not heard what happened after it was successfully rebuilt and tested.

Did the Hawkeye rebuild go to air? I had not heard what happened after it was successfully rebuilt and tested.

Yes, it went gassy at least.

Here's the thread:

http://www.videokarma.org/showthread.php?t=247317

I'm in no way badmouthing the CT-100 as a collectible TV; CRT intact or compromised. I'm just pointing out that the market is flooding at the moment, and the final price will probably the best you'll get for the time being. When there's a lull, and no CT-100s are for sale for awhile, there are newbie TV collectors with good bankrolls, and the price skyrockets when one finally shows up on the market.

Charles

I also beleive that more collectors will start to unload their CT 100 sets.
With ZERO chance of CRT replacement/rebuilds, and the astronomical failure rate of the 15GP22, they become less and less attractive to even the most dedicated of collectors.

I'm quite happy to be the new caretaker of a CT-100 even with a bad CRT. Yes, it's all beat up, but it will (someday) be refinished to become a decent "display only" piece for our museum. I know I'd never own one of the $10,000 ones, or even if they came down to half that. But I got this one at a "couldn't pass it up" price. And I hear that it may even be the lowest serial number CTC-2 known, to boot!

(Not currently being stored in a particularly ritzy setting. :))

http://videokarma.org/attachment.php?attachmentid=166735&stc=1&d=1270526471 http://videokarma.org/attachment.php?attachmentid=166736&stc=1&d=1270526471 http://videokarma.org/attachment.php?attachmentid=166737&stc=1&d=1270526471

.

Nice find! :banana::banana::banana: Is that a Ctc-4 mask on top?

Ok, my head is spinning... within the last week or two *5* previously unknown CT-100s have surfaced?

1. The eBay $755 BIN set.
2. The eBay set that started this thread (aprox. $1200 Reserve not met now)
3. A set at Constantine tv.
4. A set found in an alley.
5. This bathroom set.

jr

You've a better chance of finding a chicken that will squeeze out two double-yoke eggs in sequence than you will have finding another $750 BIN restorable CT-100... the guy screwed up, as we all realize.

In spite of the current economy, a restorable Merrill is worth in the neighborhood of 2K, a good 15GP22 is worth in the neighborhood of 2K, and a dud 15GP22 is worth in the neighborhood of 0.2K.

Pete

I'm quite happy to be the new caretaker of a CT-100 even with a bad CRT. Yes, it's all beat up, but it will (someday) be refinished to become a decent "display only" piece for our museum. I know I'd never own one of the $10,000 ones, or even if they came down to half that. But I got this one at a "couldn't pass it up" price. And I hear that it may even be the lowest serial number CTC-2 known, to boot!
.

The CRT is bad? The getters look shiny?

The CRT is bad? The getters look shiny?

Well, I didn't test it myself, but since I got it from Pete Deksnis, I'm going to take his word for it that its toast. Pete also corrected me that it is this CRT that sports the lowest known date code, and while the chassis is also early, it was probably made on the second day of production.

Pete didn't want to move ALL of his CT-100s when he emigrated from New Jersey recently and he made me an offer I couldn't refuse to ensure that THE SET (his original CT-100, the story of which had been chronicled in detail on his now extinguished website) would be preserved and displayed at the New Jersey Antique Radio Club's Radio Technology Museum (http://rtm.ar88.net/) at Infoage.

http://cgi.ebay.com/RCA-First-Production-1954-Color-TV-CT-100_W0QQitemZ170467244645QQcmdZViewItemQQptZLH_Def aultDomain_0?hash=item27b0a3ba65


not affiliated,
jr

"I Am Not Not Affiliated With This Auction"

Current bid is at $1700. The reserve has been met and the $5000 BIN has been lifted.

The seller reports, the chassis S/N appears to be B8000316 and the cabinet S/N is 538; the getters are shiny and there is filament continuity.

"I Am Not Not Affiliated With This Auction"

Current bid is at $1700. The reserve has been met and the $5000 BIN has been lifted.

The seller reports, the chassis S/N appears to be B8000316 and the cabinet S/N is 538; the getters are shiny and there is filament continuity.

I would not place bets that the tube is good. In two of the photos you can see a milky white residue around the getters. That is a very bad sign. The tube that John and I rebuilt went gassy and the getters are still nice and silver with NOT any sign of milky white residue. This tube is most likely under partial vacuum, but probably gassy. And in any event the seller disclosed that somebody had wired a makeshift brightner in the filiment circuit and that is sure sign that the crt is toast.

Well, I didn't test it myself, but since I got it from Pete Deksnis, I'm going to take his word for it that its toast. Pete also corrected me that it is this CRT that sports the lowest known date code, and while the chassis is also early, it was probably made on the second day of production.


And lest we forget, that second day of production probably looked something like this...

- Kevin

I would not place bets that the tube is good. In two of the photos you can see a milky white residue around the getters. That is a very bad sign. The tube that John and I rebuilt went gassy and the getters are still nice and silver with NOT any sign of milky white residue. This tube is most likely under partial vacuum, but probably gassy. And in any event the seller disclosed that somebody had wired a makeshift brightner in the filiment circuit and that is sure sign that the crt is toast.

Bob,
I couldn't agree with you more.
Also, it would be best for any potential bidder/buyer to arrange for an exhaustive crt check by a qualified person and to make the sale contingent upon the crt test results.

I would not place bets that the tube is good. In two of the photos you can see a milky white residue around the getters. That is a very bad sign. The tube that John and I rebuilt went gassy and the getters are still nice and silver with NOT any sign of milky white residue. This tube is most likely under partial vacuum, but probably gassy. And in any event the seller disclosed that somebody had wired a makeshift brightner in the filiment circuit and that is sure sign that the crt is toast.

I 100% agree with your observation... even though some "silver" is seen in the center of the getter flashes, the other side of the getter is likely to be white and "used up". I suspect that if the tube is powered up with a tube checker the heaters will quickly burn out from excess current, if they are not blown already. :tears:

jr

I 100% agree with your observation... even though some "silver" is seen in the center of the getter flashes, the other side of the getter is likely to be white and "used up". I suspect that if the tube is powered up with a tube checker the heaters will quickly burn out from excess current, if they are not blown already. :tears:

jr

Jr,
I'd recommend testing the crt for gas (air), with an HV source, before connecting a tester.

Jr,
I'd recommend testing the crt for gas (air), with an HV source, before connecting a tester.

Why? To protect the tester? Once the CRT is up to air I don't think there's anything left to protect.

John

Pete didn't want to move ALL of his CT-100s when he emigrated from New Jersey recently and he made me an offer I couldn't refuse to ensure that THE SET (his original CT-100, the story of which had been chronicled in detail on his now extinguished website) would be preserved and displayed at the New Jersey Antique Radio Club's Radio Technology Museum (http://rtm.ar88.net/) at Infoage.

I didn't know Pete's site was down, that's sad, it was an enjoyable site. Some of it is archived at archive.org (http://web.archive.org/web/20080504162745/home.att.net/~pldexnis/restoretv.html)...

I liked Pete's site too...... :tears:

Why? To protect the tester? Once the CRT is up to air I don't think there's anything left to protect.

John

I think that there might be a couple of reasons to proceed with caution.

1. Liability... I really would not want to be the person operating the CRT checker, if that test blows the heaters, unless the owner of the tube fully understands the the possibility that the test might "finish off" the tube.:no:

2. If the heaters blow it is indeed "game over" for the tube (except for rebuild). If they are intact, there still might be a very slim possibility to save it... Perhaps Scotty can re-flash the getters? :scratch2:

just my 2cents (or less) worth,
jr

I think that there might be a couple of reasons to proceed with caution.

1. Liability... I really would not want to be the person operating the CRT checker, if that test blows the heaters, unless the owner of the tube fully understands the the possibility that the test might "finish off" the tube.:no:

2. If the heaters blow it is indeed "game over" for the tube (except for rebuild). If they are intact, there still might be a very slim possibility to save it... Perhaps Scotty can re-flash the getters? :scratch2:

just my 2cents (or less) worth,
jr

The issue of dealing with an irate seller who thinks you just blew his 15GP22 is certainly a worry. A noisy hand held Tesla coil might have him wondering too.

As far as "game over" or not... I'm skipping definition of terms because I know you're very knowledgeable technically.

The getter flash probably has a capacity of a few hundred liter-microns before it is used up. If the getter flash is gone you've probably had that much air enter. It's less effective for nitrogen, the few hundred liter-micron figure is for oxygen. You probably have at least a few hundred liter-microns of air to deal with once you find a gassy 15GP22.

I'm not sure how the getter in the 15GP22 is made, but it's probably a large ring at the end of the gun. The ring could be a channel or a tube. If it's a tube then it has a thin wall that bursts when it's heated and the barium evaporates out. If it's a channel, then it's probably a stable barium alloy like BaAl4, that reacts exothermically with a nickel support once above 800C and quickly reaches higher temperatures evaporating the barium. Nickel powder is also added to BaAl4 powder, but I don't think this technology existed then.

Any barium left to flash will be minimal and you have a lot of gas to deal with.

The cathodes will be deactivated. During the activation barium oxide is reduced to barium forming a thin layer of barium metal on the barium oxide. Any metallic barium will have turned to an oxide if the tube was gassy. It is reduced either by silicon that was added to it or by the nickel cathode base metal. The nickel will have formed some nickel oxide and might prevent another reduction of the barium oxide.

I have a bunch of 6J6's that have air in them. I've thought about adding a pump-out and see if I can reactivate the cathodes. I suspect it won't work, but it would be fun to try. Finding the time is hard though.

John

John said:

"I'm not sure how the getter in the 15GP22 is made, but it's probably a large ring at the end of the gun. The ring could be a channel or a tube. If it's a tube then it has a thin wall that bursts when it's heated and the barium evaporates out. If it's a channel, then it's probably a stable barium alloy like BaAl4, that reacts exothermically with a nickel support once above 800C and quickly reaches higher temperatures evaporating the barium."

In the case of the 15GP22... The getters appear to be the "stirrup" style mounted in the neck... looks like there are 6. IIRC, not all getters were exothermic.

"Any barium left to flash will be minimal and you have a lot of gas to deal with."

I 100% agree with this. But if the tube were mine and I had an RF generator, and a getter "wand" I would try it.

"I have a bunch of 6J6's that have air in them. I've thought about adding a pump-out and see if I can reactivate the cathodes. I suspect it won't work, but it would be fun to try."

Back in my old "poor starving young engineer" days, I kept an old CTC-4 going by re-flashing and re-activating the 6CB5 HO tubes several times (darn things were expensive and I had access to an "engineering tube lab")... your experiment sounds like fun :yes:

jr

Why? To protect the tester? Once the CRT is up to air I don't think there's anything left to protect.

John

No John, it's to protect my rear from the CT-100 owner who's trying to get me to bid on his priceless vintage set.
I don't want to watch the expression on his face when I destroy his crt's filament.
I can't run that fast, anymore.

John said:

"
"Any barium left to flash will be minimal and you have a lot of gas to deal with."

I 100% agree with this. But if the tube were mine and I had an RF generator, and a getter "wand" I would try it.

jr

I would too. I just wouldn't have my hopes up. On the other hand, I have seen a number of vacuum tubes where it looked like they barely flashed the getter and there might be much left.

Your comments about the 6CB5 are encouraging. I'll have to try it. I can evacuate the 6J6 without needing to bother with the getter and I can RF heat the elements to outgas them.

No John, it's to protect my rear from the CT-100 owner who's trying to get me to bid on his priceless vintage set.
I don't want to watch the expression on his face when I destroy his crt's filament.
I can't run that fast, anymore.

I guess it would depend on whether the seller would understand well enough what you were doing. The value of the set would be greatly enhanced with a good 15GP22 and I would hope they would let me test it and understand if the result was a briefly glowling filament. Otherwise I'd be reluctant to pay top dollar not knowing if it was good or not.

The Tesla coil vacuum tester that I have would probably scare them if they had never seen one before.

Of course since I'm not actively searching for one, it's easy for me to say. Maybe I'd be of a different opinion if I were about to make an offer for one.

John

Isn't there a small copper tube nipple under or around the Black pin base?
If the filaments are good and then the base carefully removed; couldn't one vacuum pump the tube back down to around 1 X 10-5 or 1 X 10-6 ,and after applying VAC-U-Seal over the leak paths while still pumping (of course) . But then again you would only tap into this tube nipple if you knew the tube had already gone to air.

Isn't there a small copper tube nipple under or around the Black pin base?
If the filaments are good and then the base carefully removed; couldn't one vacuum pump the tube back down to around 1 X 10-5 or 1 X 10-6 ,and after applying VAC-U-Seal over the leak paths while still pumping (of course) . But then again you would only tap into this tube nipple if you knew the tube had already gone to air.

Unfortunately, not all of the air can be removed with a vacuum system alone.
You can read more about the process by searching this forum for "15GP22".

Isn't there a small copper tube nipple under or around the Black pin base?
If the filaments are good and then the base carefully removed; couldn't one vacuum pump the tube back down to around 1 X 10-5 or 1 X 10-6 ,and after applying VAC-U-Seal over the leak paths while still pumping (of course) . But then again you would only tap into this tube nipple if you knew the tube had already gone to air.

If I understood John and Bob correctly, most of them haven't gone completely up to air, but are gassy. I think you could tap into the line without breaking the residual vacumm and reach the pressure range you mention.

You need much better vacuum than this for long life. If rebuilding options were available I'd rather go that route if I had one that didn't work, rather than expending resources on a repair that wouldn't last long.

John

If I understood John and Bob correctly, most of them haven't gone completely up to air, but are gassy. I think you could tap into the line without breaking the residual vacumm and reach the pressure range you mention.

You need much better vacuum than this for long life. If rebuilding options were available I'd rather go that route if I had one that didn't work, rather than expending resources on a repair that wouldn't last long.

John

I wonder if a small turbomolecular pump would fit in the base of a CT-100, I think they are good for 10-8 or so. :scratch2:

jr

I wonder if a small turbomolecular pump would fit in the base of a CT-100, I think they are good for 10-8 or so. :scratch2:

jr

Or an ion pump so you wouldn't have to deal with the sound of the backing pump. :D

I think some of the high power klystrons basically have an ion-pump built into them.

John

http://cgi.ebay.com/RCA-First-Production-1954-Color-TV-CT-100_W0QQitemZ170467244645QQcmdZViewItemQQptZLH_Def aultDomain_0?hash=item27b0a3ba65


not affiliated,
jr

I see it went for $2,290. A bit more than I would have guessed.

John

Turbo - Vacuum pump it once then seal the nipple (AGAIN) , there Wouldn't be a constant running noise because; the 'General David' sucked it out once in 1954, Just re - SUCK back down to 1 X 10-8 again and RESEAL with VAC - U - SUCK
"SEAL" AND - IT - MIGHT Last another 50 Y E A R S !!!!!!:banana::banana::banana:

This is, in theory, and I emphasize "in theory" something that might possibly work. However, the real problem would be in tapping into the old stub of the pinchoff in the base, connecting up to it for the pump down, and then somehow sealing the pinchoff without losing the vacuum.

IN the real world, when a tube is pumped down, it is done through a 4 inch length of glass tubing that sticks out the base of the tube where the wires exit. That 4" long tube is connected to the vacuum pumping system. After the tube has been properly evacuated, an electric heating element that was placed around the glass tube, right up next to where the wires exit, is turned on. IT heats the glass tubing up to the melting temperature, and the vacuum inside the tubing causes the molten glass to colaps, thus sealing the tube. the remanant of the 4 inch long glass tube is snapped off right where the tubing made the "pinch off" seal.

I personally cant see how you would tap into and then seal off a crt in the method you propose. It would be easier to just re-gun teh thing and do a conventional rebuild, and that way you have a real rebuilt crt with NEW emission to boot.

The issue if rebuilding the 15GP22 is going to be solved. You just have to have faith. "So let it be written...so let it be done"

I had an idea on how to fix it, though I must admit I think more like a machinist than the electrician I really am. Sometimes that can be a good thing, though I have yet to lay hands on a 15GP22.

Seems to me the welded seal is the problem for many of the tubes, so why not get rid of it entirely? I mean, if there's a metal rim embedded into the glass, could you not just trim it back flush with the glass, then mate the 2 glass parts of the CRT together the same way neck glass is attached?

One other thing that I wonder about, is why if the metal part was leaking would you attempt to fix the leak by any other process but welding? I mean really, if 1954 welders could do the entire tube rim with a TIG torch, what's stopping those with rim leaks from sealing up a little pinhole? Is it really that difficult, or do tube people really not think that way RCA did back then?

To me, even difficult problems usually have very simple solutions...

I had an idea on how to fix it, though I must admit I think more like a machinist than the electrician I really am. Sometimes that can be a good thing, though I have yet to lay hands on a 15GP22.

Seems to me the welded seal is the problem for many of the tubes, so why not get rid of it entirely? I mean, if there's a metal rim embedded into the glass, could you not just trim it back flush with the glass, then mate the 2 glass parts of the CRT together the same way neck glass is attached?

One other thing that I wonder about, is why if the metal part was leaking would you attempt to fix the leak by any other process but welding? I mean really, if 1954 welders could do the entire tube rim with a TIG torch, what's stopping those with rim leaks from sealing up a little pinhole? Is it really that difficult, or do tube people really not think that way RCA did back then?

To me, even difficult problems usually have very simple solutions...

The welded seal is also the Ultor HV connection, so you can't just eliminate it.

John and Bob, and Jerome, have done a lot of research. Probably your other questions will be answered at the ETF convention.

John

I think the problem is the heat from a welder would cause the glass to break, but I don't know if the two halves were joined after the glass was attached to the metal flanges or after?

I had an idea on how to fix it, though I must admit I think more like a machinist than the electrician I really am. Sometimes that can be a good thing, though I have yet to lay hands on a 15GP22.

Seems to me the welded seal is the problem for many of the tubes, so why not get rid of it entirely? I mean, if there's a metal rim embedded into the glass, could you not just trim it back flush with the glass, then mate the 2 glass parts of the CRT together the same way neck glass is attached?

One other thing that I wonder about, is why if the metal part was leaking would you attempt to fix the leak by any other process but welding? I mean really, if 1954 welders could do the entire tube rim with a TIG torch, what's stopping those with rim leaks from sealing up a little pinhole? Is it really that difficult, or do tube people really not think that way RCA did back then?

To me, even difficult problems usually have very simple solutions...


And yes, you need to "lay your hands" on a 15G in order to appreciate the complexity of the issues involved. It has taken John and I more than 2 years of constant trial and error discoveries, to figure out where the problems are and how best to resolve them. It may look simple on the surface, but take my word for it, the issues are very complex indeed.

We will also have two 15G's on display at the ETF convention that were broken during our experiments. One tube has the entire glass rear section removed so you can get up close and personal with the shadow mask, and the other tube has the entire front cover glass and the decorative mask removed, so you can get up close and personal with the phosphor dot plate.

I am presently interviewing local welders to find someone with the talent to weld leaks that we have found in the Kovar TIG weld which fastens the two halves of the Kovar ultor flange. But only a small percentage of the 15G leaks occur at the weld line. Most leaks occur in the glass to Kovar bond or in two other Kovar to Kovar bonds, which I will explain in more detail in my presentation at the ETF convention.

Be there or Be square!

I think the problem is the heat from a welder would cause the glass to break, but I don't know if the two halves were joined after the glass was attached to the metal flanges or after?

Eric,

The glass components were likely made by someone like Corning, and the Kovar ultor rings were fused to the glass at the the glass factory. The front and rear sections were delivered to RCA as a completed sub component, with the Kovar ultor rings already attached to the glass.

Due to the way the Kovar ultor ring is fabricated, there is not enough heat transfer from the weld to the glass to cause breakage. In fact the mechanical design of the Kovar ultor ring was designed the way it was, specifically to take into account the prevention of heat transfer to the glass.

There is also mention in literature pertaining to the general design of Kovar components for crt's, that in some cases, copper heat sink rings could be employed to prevent heat migration. We however, have no evidence one way or the other if copper heat sink rings were used at RCA in the welding process. In the only photo of the welding process at RCA, there does not appear to be the use of copper heat sinks.

We will also have two 15G's on display at the ETF convention that were broken during our experiments. One tube has the entire glass rear section removed so you can get up close and personal with the shadow mask, and the other tube has the entire front cover glass and the decorative mask removed, so you can get up close and personal with the phosphor dot plate.



I really do hope lots of up close pictures will be posted on the web, since I will not be able to make it. This is something I'd love to get involved in, since I'm good at solving complicated problems.