WOW .. this is going to be the most amazing thread... this is real history .... I sure hope you can get the set to come alive... this really is what all this is about. Good luck and congratulations!

Congratulations on getting to delivered. It should be an exciting project.

The space marked Delay doesn't look like it is in the video section?

Nick,

Great photos. Glad everything arrived in good order. My money is still on this being an RCA prototype. Look forward to what ever you guys discover.

-Steve D.

Glad it all got there in good shape Nick. Especially that rare proto CRT. Hard to tell what the getter looks like from the photo, but you could check for continuity on the filiments before I get there on Saturday.

I will bring the Sencor and the B&K along with the adapter for the 20Pin bi-decal base.

From the photo I can tell the gun assembly is definately of the 15GP22 type with electrostatic convergence cup. It has some centering wings that are spot welded to the cup that are not present on a 15G gun but other than that, the gun is a 15G gun.

In the event the crt is a leaker, You could send it to France to be leak sealed with frit glass and re-gunned. John and I will be sending our first 4 15G tubes over there sometime in august. We have special cartons and a crate being built. Each round trip shipment to France and back will contain 4 tubes.

Good for you Nick. Will enjoy watching your progress. That is quite the set.
Greg

Congratulations for your acquiring this unique set, Nick. I notice the convergence pin on the CRT socket looks like new, so it must not have had much use, though the 1958 1B3 is interesting.

Bob-

I am happy to hear that the RACS 15GP22 rebuild project is moving beyond the one-off stage and into true production.

One of the things that Harry Poster told me was that he suspected that the previous owner (not a TV person) had plugged tubes in sockets just to sell the set.

Bob, one of the photos from Harry showed the filaments glowing, so the filament has continuity and the tube isn't fully air.

The chassis seems to show signs of a normal life and maintenance period during your set's first years in some kind of service. Sprague and Mallory single-section electrolytics and the 1B3 date coded 1958, all suggest a period of "normal" use.
Having no apparent delay line along with a chassis area earmarked "delay" is another unsolved mystery.
I gather reading twixt the lines that this set recently came from Harry Poster. He sure has had some rare merchandise through the years.

The adventure begins! Have you determined at all if this could be a dot-sequential prototype rather than early NTSC?

You know, a luminance delay line can also be a network of peaking coils and resistors in a can, or a long thin shielded wire wrapped around a non-inductive core with an active frequency compensation circuit. Until cheap glass delay lines were developed there were several methods of delaying a broadband signal. - Of course the delay might have been removed.. :sigh: I gather this set does not use IQ demodulation otherwise it would need TWO delays.

This is kinda like findin' Gottlieb Daimler's heretofore unknown SECOND prototype of his 1886 car under a tarp in a dry barn somewhere...

I think you might be right....

:banana::banana::banana::banana::banana:


Took a little time to wake up, but all 3 guns read at the top of the good scale after sitting for 5 minutes and the life test ain't bad either. Anyone wanna hear how the variac powerup of the chassis went? :scratch2:

You guys are getting all the fun! Don't keep us in suspense...

You're got to be kidding, this tube tested good!! :thmbsp::thmbsp:
Can it be plugged into a working CT-100 chassis to see if it works.