CT-100 eBay

[Eric H]

Same guy in Oregon that had the 5 earlier

http://cgi.ebay.com/RCA-CTC100-THE-R...QQcmdZViewItem

"The rare one" Nah, there's at least a hunnerd of em...

[Sandy G]

Too bad the CRT's toast...What the hell am I getting exercised over a CT-100 ? I can't drop $3500-4000 on a TV...

[Charlie]

Originally Posted by Sandy G

What the hell am I getting exercised over a CT-100 ? I can't drop $3500-4000 on a TV...

While this is usually the case for most of us, it's still exciting to learn there's a few of them floating around out there, and to know that only individuals interested in preserving them will be bidding.

Sooo... drool all you want... even if you don't bid!

[Phil Nelson]

That's about a 3.5 hour one-way drive from me.

No fibbin', guys, what's a fair price for this thing minus CRT?

And what are the chances (and cost) of getting a replacement CRT?

Regards,

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

[kx250rider]

Originally Posted by Phil Nelson

And what are the chances (and cost) of getting a replacement CRT?

'fraid not... Never seen one for sale that was any good. Not to be negative, but if you buy that set, pay what you think is fair without hope of a CRT forthcoming.

Charles

[Kamakiri]

Yep, it's just a display piece at this point. I gave up hope on getting one for mine after a few years.

[Pete Deksnis]

is number 114 on the Living CT-100 list. It is a moderately late production unit and so would be configured with all known production changes such as the boost B+ mod. These sets have typically been won for $3000+. An NIB 15GP22 seems to pop up every two or so years. More good used CRTs than that are found installed in newly discovered sets. Too bad this one is a dud.

[Phil Nelson]

Well, $3K for a display piece doesn't sound terribly interesting.

I asked the seller about the CRT and got this reply:

'It has an open filament and before that it was up to air.'

I gather these are not rebuildable, since nobody has mentioned rebuilding a dud . . . ?

[Steve McVoy]

There is an ongoing project at Hawkeye to rebuild the tubes. Progress has been made, but we don't have one done yet.

[Phil Nelson]

Just out of curiosity, what makes these especially difficult to rebuild?

[Bobby Brady]

It is very comforting to see anothger set on it's way to safety!
I hope one of you guys gets it.
If I had the money to spare I would want it even as a display piece but I would spend a lot of time getting a new tube produced!
It must be possible to get some person to make a glass mold and recreate it from scratch. It must be posssible to do that or somehow repair the existing ones. I guess one big problem is metal corrosion. Apparently the cone of the CRT is metal. I never saw one but I can imagine. Foriegn company's have and still do take finished products and copy them with apparent ease. Seems like we could get all the users of those 15" CRT's to comibine efforts to get it done.
I guess that is what you guys are doing!
I hope so!

[andy]

---

[John Folsom]

There have been a number of discussions here at AK and elsewhere about rebuilding the 15GP22 CRT. There is an active effort under way to attempt this. This effort has been under way for YEARS, with small incremental progress followed by long periods with no progress. But now we are close....

There are a number of issues involved in attempting to rebuild a 15G. Here is an over-simplified overview.

First, you have to find a rebuilder who will even consider attempting it.

Then you need a stem. This is the piece of glass which the wires pass through, and which has the hollow evacuation tube. 15G stems have not been produced for probably 40+ years. We have had a limited number of stems custom-made to the original 15GP22 specifications.

Next there are issues with the heating and cooling cycles used to process the tube during evacuation. When new, the 15Gs were processed at a lower temperature than is normal for modern CRT manufacture, and the heat-up/cool-down times were much longer. We are having custom oven controlcams made to allow us to use a 6 hour cycle time, instead of the usual 3 hour cycle time to process the CRT.

Then there are issues with the equipment used to hold the CRT during processing, including special thermal shields to protect the stem during processing, and assorted pieces used to hold the CRT in the lathe while the old gun is removed and the new one is welded in place. Some custom made pieces are being fabricated to support this.

Then there are issues with the gun itself. No 15G guns exit. So when a CRT is processed for rebuilding, a "good" gun must be ready to install once the "bad" gun is removed. The CRT cannot remain exposed to air for a long time (at least rebuilders do not want them to do so). The "bad" gun is then sent off to have its filaments and cathodes cut out and new ones installed, transforming it into a "good" gun. Of course, the gun was never designed to have this done, so some percentage of guns will be broken during the process. This will be one of many on-going problems to solve.

Then once a CRT is processed, there is some considerable debate about whether the enormous frit (glass to metal) seals at the 15G ultor will survive the thermal stresses.

And then there is the issue of the "leaker" tubes. Most candidate 15G CRTs have some air in them due to leaks. It is unknown if the leaks can be plugged, and if they can, if the exposure to air will make the CRT unusable.

Most of these issues have been addressed, at least to the point that, with any luck, we are with several months of our first attempt to rebuild a non-leaker 15G CRT. We will keep you posted..... !

[kx250rider]

Originally Posted by Phil Nelson

Just out of curiosity, what makes these especially difficult to rebuild?

BIG thread here:

http://audiokarma.org/forums/showthr...ebuilt+15gp22s

Charles

[Tony V]

I know this is a dumb question but thought i would ask anyway. Is there a possibilty to use one of the newer roundie tubes to hook up to the CTC100 chassis if for nothing else to bench test it during a restoration? I know it wouldnt be original as far as mounting in a set but would be useful to restore the chassis just in case the original tubes eventually can be rebuilt. I know for myself if i was able to spend that kind of money to have to have a 15gp22 rebuilt i definately wouldnt want to use it for testing purposes until the chassis was restored completely so there wouldnt be a risk of damaging such a rare tube. I know the deflection angle and convergence set-up is different but was wondering if there was a way to make some kind of jig with something like the more conventional roundie tubes to test this chassis when doing a restoration and if not then why? I've read alot of what you guys have posted on this set and i dont think this question has been asked yet. Just curious...
Thanks,
Tony