Prototype set is here

[old_coot88]

Originally Posted by Kevin Kuehn

This is really, really exciting.

Roger that. This thing's got a Lost Ark mystique about it, in spades. oc

[Komet]

Nick... Amazing set!

[Eric H]

Interesting thing about this chassis is it may not have ever worked, at least not in the fashion we have come to expect from a Color TV.
You may get green people and orange skies for all we know, maybe it won't produce any kind of stable colors at all.

[David Roper]

Maybe red apples, green grapes and blue bananas.

[jeyurkon]

Throwing in my two cents; I'd restore it the way you plan on doing it, if the CRT is actually good. If it were bad, I'd have to think hard before having the CRT rebuilt. As Eric said, we don't know how functional the chassis ever was. But, it would be fun to find out.

John

[miniman82]

IT WORKS!!!!






Bob and Pete stopped by today with a CTC-2 chassis, wooden CRT truck, extension cables, CRT testers (to read all the guns at one time), and of course a Wiz of Oz DVD in tow. One more test of the tube with Bob's Beltron proved that all 3 guns were indeed working perfectly, so we set about powering it in a real world situation with Pete's CTC-2. The CRT was placed in the truck, cleaned, yoke and purity assemblies installed, and Bob's anode extension wire attached. We connected my DVD player to the CTC-2 using Pete's composite input mod box, and powered the chassis through my RCA Isotap variable isolation transformer set to 115 VAC.

We threw the switch, HV spooled up, and got a bright full raster! There were a few hiccups getting an actual picture to appear which were mainly my fault for powering the DVD player incorrectly, but in the end we were able to get something on the screen. Something was amiss with the Merrill though, as it was only powering one gun at a time and so we were not able to do any convergence or get a color picture. Just proving the tube still works was a monumental success for the comminuty, and so we called it a day.

Enjoy the pictures!

Setting up the CRT for testing.



Historic first light!



Initial images being displayed. It's supposed to be the yellow brick road, but degaussing, purity, and convergence all still need to be done before anything decent appears on this tube.

[ceebee23]

Actually it all poses a question ..if it was an experimental chassis... one designed to have changes and additions made as RCA made changes to its dot sequential system.... just which version do you restore the set to match?

But this whole exercise is one of the most exciting on this forum ever!

[jr_tech]

What incredible news!

Congratulations!
jr

[Mal Fuller]

As far as convergence & purity are concerned, are you sure that the CTC-2 chassis and this developmental CRT are fully compatible with each other?

[miniman82]

Originally Posted by Mal Fuller

As far as convergence & purity are concerned, are you sure that the CTC-2 chassis and this developmental CRT are fully compatible with each other?

Yes, if they were not we would not have had a decent monochrome picture on the screen. The electron gun is almost identical to a 15GP22, the pins are all the same. At this point we were not able to get color because of a chassis fault, and even if the chassis was 100% the tube needed to be degaussed and we didn't have the degausser. Therefore, we could not do any of the setup operations which would be required for proper display. A project for another day.

[Eric H]

RCA may have dropped the ball by going with the leak prone 15G, this design seems more robust.
I wonder what their reasons were, perhaps we'll find out.

[ohohyodafarted]

Originally Posted by Mal Fuller

As far as convergence & purity are concerned, are you sure that the CTC-2 chassis and this developmental CRT are fully compatible with each other?

It's Pete Deksnis here at Bob and Tamy's house for an overnight visit. Mal, it's a good question and I believe based only on physical shape, the two are not compatible. As to adjustments for purity are concerned, no, I wasn't about to shift that CT-100 yoke back and forth along the neck with 20 kV 1/2-in. from my hand. I did rotate the purity coil and it did affect the picture somewhat, but this was not the time for perfection... too many variables at play.

My CTC2 had been powered up for the first time yesterday since breaking down the RACS 15GP22 rebuild demo at ETF on May 1; since then it traveled over 1500 miles in the back of my Yaris, so I was very glad to see the HV still working (including the ozone if you were there seeing and smelling it operating at ETF!) and only the green channel not operational.

Glad to have been able to inspect the proto chassis up close; still many, many questions to resolve. Nick and Bob found a socket for a crystal, but there's no positive indication that it is for 3.579595 mc.

What a great opportunity we few had to participate in and witnesss such an historic event.

Pete

[TubeType]

Fantastic work Nick, Pete, and Bob! I'm really glad you guys were able to get to "First-Light 2011" in such a short period of time.

[miniman82]

Originally Posted by Pete

it's a good question and I believe based only on physical shape, the two are not compatible.

Correct. I was speaking more to the electrical compatability between the 2, and they seem to be a perfect match. Bob noted that the gun was almost identical to a production 15GP22 one, only a few added supports differ between them.

[Mal Fuller]

Wouldn't it be nice if you could lay hands on the engineering notes for your prototype? Delay line questions, burst frequency, convergence supply specifications, how and if high voltage is regulated, what tubes go where, the list seems endless.
It looks as if this thread could last a while. That's perfectly fine by me.