Prototype set is here

[Steve McVoy]

My mistake. Lancaster is what Harry said, but he wasn't certain.

[Steve D.]

Originally Posted by Steve McVoy

My mistake. Lancaster is what Harry said, but he wasn't certain.

Steve,

Either city would work. RCA had plants in both Lancaster, Pa. and Camden, N.J.

-Steve D.

[Mal Fuller]

Working under a blank check from Sarnoff, engineers developed the tri-color, shadow mask prototypes and finally the 15GP22 in Lancaster I believe. I once owned a wonderful RCA booklet about RCA's tri-color CRT development project. I lent it on request to the late Rudolphus (?) Swan, a retired engineer from Sylvania's tube division who, despite repeated requests, never would returned it.

[miniman82]

Several requests have been received for me to label the back panel controls, so here it is!

[Zenith6S321]

Since there does not seem to be any main power transformer or power rectifiers present, is the 7 pin male plug on the lower left chassis back panel where a separate power chassis plugs in?

[miniman82]

That reminds me: I'm gonna need like 30 tube shields! lol

[Electronic M]

I've got a box of maybe ten or fifteen assorted 7 and 9 pin tube shields your welcome to.
I've also got an old power supply from a corespondence course that you can have if it will help.

Tom C.

[Username1]

Hey my dad took that same course! I remember playing with that PS when I was a kid!
Its no good for that tv, its going to need to be more current and they'll have to figure out what different voltages are needed too. That PS is for single tube circuits.

Most likely they are going to have to come close to matching the specs on the PS for the ct-100's that some of those guys already have access to, or possibly a model 5, something like that. This tv should have a lot of very similar circuits to what later became the production version of this set.

Anyway it should be fun for these guys, and for us to read about. Thanks guys!

[Steve McVoy]

Harry offered the set to the museum before he put it on Ebay. I tried to get him to donate it and take a tax deduction, but he declined.

[Penthode]

If this prototype dates from 1950-51, how far along was it's development?

Has anyone identified whether this is a set still running on the dot sequential principle or whether the design had progressed to the constant luminance principle with interleaved chroma?

Is there any schematic information with this set? It would be very interesting to reverse engineer this set to find out what the design comprises of.

Note: seems I missed an earlier part of this thread. I see from Ed's post that progress had moved to CPA and possibly later to the early '53 NTSC development closer to the final standard.

It will be interesting to see what the reverse engineering reveals.

[miniman82]

It's an idea I've tossed around a few times, trust me. I don't have a CTC-2 chassis though, only CTC-2B.

[Pete Deksnis]

Originally Posted by miniman82

It's an idea I've tossed around a few times, trust me. I don't have a CTC-2 chassis though, only CTC-2B.

Okay, let's work this out. I just got back from Detroit area where I picked up Bob's 1948 Moto; are you two still getting together tomorrow? (just tried calling Bob. no answer). I can probably stuff my CTC2 and the Moto in the Yaris. I for one am itching to see that tube light up w/Dorothy. What say you?

Pete

[Dave A]

If the Italians can restore DaVinci's Last Supper fresco in Milan and justify it, this box o' bulbs can get the same. Go for it. The intellectual and historic end result is seeing the intent and accuracy of the artists work...not how it got there. Think of the glowing phosphors as the canvas of the fresco and the restored, tinted plaster as the chassis.

I think intent on the part of the inventors/designers applies here. Just think of how many changes they made to this particular chassis to get what they wanted. It was not a one and done effort. And there is no hope of picking one particular version of this set. They were all failures until it worked. It was an ongoing process to get the CRT to glow in color and that should be the same here and stop at that point.

[miniman82]

Originally Posted by Dave A

If the Italians can restore DaVinci's Last Supper fresco in Milan and justify it, this box o' bulbs can get the same. Go for it. The intellectual and historic end result is seeing the intent and accuracy of the artists work...not how it got there. Think of the glowing phosphors as the canvas of the fresco and the restored, tinted plaster as the chassis.

I for one have to agree, especially since I have seen said fresco in person

If this is going to happen, Pete and Bob will stop by on Sat and we'll see what the result is. My hope is that we will all see what RCA had in store for the viewing public back in 1952-ish!

I think intent on the part of the inventors/designers applies here. Just think of how many changes they made to this particular chassis to get what they wanted. It was not a one and done effort. And there is no hope of picking one particular version of this set. They were all failures until it worked. It was an ongoing process to get the CRT to glow in color, and that should be the same here and stop at that point.

Agreed, though there should be one caveat: the developmental chassis was an experiment in what was to be, insomuchas color chassis go. Let's not make any assumtions on what was TO COME, based on what we already know. That would be a mistake. Every evolutionary step beyond what I currently own is still a grand mystery. Nothing is written in stone. That said, I eagerly await the results of a developmental CRT powered by a production CTC-2 chassis. Much fanfare waiting in the wings!

[Kevin Kuehn]

This is really, really exciting.