Prototype set is here

[cwmoser]

Do you have any information about where this TV has been over the last 60 years?

Carl

[Steve McVoy]

I really doubt if the set was used over the years. The only evidence of that is the tube date codes, which is tenuous. I don't see any other components that look newer than 1952 ish.

Congratulations on having what appears to be a working tube.

[Aussie Bloke]

Congratulations on buying this ultra rare prototype colour TV set, I am glad to see it has gone to a good home and to someone of these forums!!! Best of luck getting this set crankin again and I look forward to seeing your progress along the way!

[Kamakiri]

I may have missed it, but what's the story of how you got this set in the first place? Inquiring minds want to know

[miniman82]

Originally Posted by Kamakiri

I may have missed it, but what's the story of how you got this set in the first place? Inquiring minds want to know

It was at auction, on Ebay. I would like to know how Harry Poster got a hold of it though, he never did tell anyone unless I missed it.

[Steve McVoy]

Harry told me he got the set from a picker, and and it probably came from the Camden area, but he didn't know anything else about it.

[Phil Nelson]

Originally Posted by Steve McVoy

Harry told me he got the set from a picker

That reminds me of visiting a well known radio dealer years ago. His place was packed with amazing items. I finally broke down and asked, "Where do you find all this stuff?" He shrugged and replied, "People bring things to me."

Phil Nelson

[JBL_1]

Looks to me like there is one newer yellow electrolytic soldered under the chassis.
I'm a big fan of getting rid of all the leaky paper caps. But I have also had very good
luck with electrolyics in cans from the pre-wars up thru the mid 50's. I just reform them with a very low charge current and they are not leaky. It is not like they are in a place to cause a lot of damage when they short. My TRK-120 has all of it's original electrolytics and it works fine.. I thought Harry told me he got it from a picker from the Lancaster area.. I'll have to go back and check my emails.

[Mal Fuller]

I've been back tonight snooping again through your excellent and detailed photos of your chassis. I found it very interesting that the rear apron red, green and blue screen controls (presumably) have plastic color keyed shafts. That seems almost prophetic in such an early prototype.
For a chassis this seminal, I'd have expected three generic pots, identical in every way, both physically and electrically.

[Steve D.]

Originally Posted by JBL_1

Looks to me like there is one newer yellow electrolytic soldered under the chassis.
I'm a big fan of getting rid of all the leaky paper caps. But I have also had very good
luck with electrolyics in cans from the pre-wars up thru the mid 50's. I just reform them with a very low charge current and they are not leaky. It is not like they are in a place to cause a lot of damage when they short. My TRK-120 has all of it's original electrolytics and it works fine.. I thought Harry told me he got it from a picker from the Lancaster area.. I'll have to go back and check my emails.

I also remember the Lancaster area being mentioned in an early post or e-mail on this.

-Steve D.

[Penthode]

Originally Posted by JBL_1

Looks to me like there is one newer yellow electrolytic soldered under the chassis.
I'm a big fan of getting rid of all the leaky paper caps. But I have also had very good
luck with electrolyics in cans from the pre-wars up thru the mid 50's. I just reform them with a very low charge current and they are not leaky. It is not like they are in a place to cause a lot of damage when they short. My TRK-120 has all of it's original electrolytics and it works fine.. I thought Harry told me he got it from a picker from the Lancaster area.. I'll have to go back and check my emails.

I am glad to see someone else saving the early dry electrolytics. I reform them as well and have little problem with them.

I have also had good luck with early-mid 1930's wet electrolytics. If the electrolyte has not leaked (due to perished rubber seals) I have been able to reform and use these as well. My old Scott radio has a wet electroytic from1935 and it maintains the 20ufd with vitually no leakage. The reforming took about four days incrementally increasing the voltage across the wet electrolytic until the full rated voltage was reached. As the capacitor reforms, the leakage current drops and the wet electolytic leakage remains constant at about 50uA at full voltage.

The post WWII dry electrolytics reform pretty fast but I still give each a couple of days to ensure the leakage is below 100uA and remains there.

Terry

[tubesrule]

Thanks Pete. That is certainly different than what I expected. The burst is down in the sync rather than riding at the black level. I still need to find out how they phased the burst and components.

Darryl

[earlyfilm]

Originally Posted by tubesrule

Thanks Pete. That is certainly different than what I expected. The burst is down in the sync rather than riding at the black level. I still need to find out how they phased the burst and components.

Darryl

Darryl,

I have an article from p338-343 in the March 1953 Proceedings of the I.R.E. where they describe how they generate a CPA NTSC color bar test pattern if that would help. They describe how these signals were used in the late 1951 and 52 tests. The color sync was 3.89 Mc

I could email it to you if you think it would help. The files are a little too big to post here.

James.

[tubesrule]

Originally Posted by earlyfilm

Darryl,

I have an article from p338-343 in the March 1953 Proceedings of the I.R.E. where they describe how they generate a CPA NTSC color bar test pattern if that would help. They describe how these signals were used in the late 1951 and 52 tests. The color sync was 3.89 Mc

I could email it to you if you think it would help. The files are a little too big to post here.

James.

Definitely! That sounds like it might contain enough information to fully implement CPA.

Thanks James

PM sent

[Pete Deksnis]

Originally Posted by tubesrule

Thanks Pete. That is certainly different than what I expected. The burst is down in the sync rather than riding at the black level.
Darryl

Here's something from Loughlin published by IEEE in 1984; it seems to explain the odd burst.

Pete