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-   Early Color Television (http://www.videokarma.org/forumdisplay.php?f=36)
-   -   Prototype set is here (http://www.videokarma.org/showthread.php?t=251369)

Aussie Bloke 06-16-2011 07:04 AM

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!!! :D Best of luck getting this set crankin again and I look forward to seeing your progress along the way!

Kamakiri 06-16-2011 08:53 AM

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 06-16-2011 09:23 AM

Quote:

Originally Posted by Kamakiri (Post 3006253)
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.

miniman82 06-16-2011 09:32 AM

Quote:

Originally Posted by Eric H (Post 3006231)
I think the next question is not if this set can be made operational but IF it should be. If it's an RCA Prototype it truly is a signifigant piece of history, replacing capacitors and other components would seriously compromise it's historical value IMO.


Here's my take:

It is a museum worthy piece, therefore it belongs in a museum. For that reason, I am considering placing it at the ETF once I am done with it.

I have always been of the mind that if the set actually works, no one is going to care what's 'under the hood', since 9 times out of 10 it would not have worked on original capacitors anyway. No one walks into the ETF and says about the Model 5: "you know that thing would be much better non-functioning and with original caps". I don't think so. It's a much better thing to see it in operation, it blows away any thought of keeping it original once you see something on screen.

Lastly, I may not have to change anything in the first place. The chassis has what appear to be aerospace grade metal-film capacitors, so it may not need total replacement of the caps. They are not prone to leakage and breakdown like wax/PIOs are, so we'll see if they are any good. The lytics will be restuffed, but thankfully they are all mounted on wafers and secured to the chassis with screws. They will be easy to do.

Pete Deksnis 06-16-2011 10:36 AM

Quote:

Originally Posted by MelodyMaster (Post 3006242)
But it appears that the set has been used over the years http://www.videokarma.org/showpost.p...8&postcount=24 So it was either built as 3.579 quadrature, or has been modified to be NTSC-compatible.

I use the popular version of Occam's Razor: Don't allow an unproven variable to screw up a comfortable conclusion.:D

As Steve McVoy indicated, there are competing reasons for a post-1952 tube to be in this set. Also, as been stated earlier in this thread, there is not a scintilla of visible evidence that the CRT socket had 4-or-so kV on the convergence element (pin 13) for an extended period.

Still, there are no final conclusions. Perhaps this chassis will turn out to be from Hazeltine Corp.; they were located in the same general area as RCA Labs and where Harry Poster now has his business.

The quest goes on...

Pete

Steve McVoy 06-16-2011 11:55 AM

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.

TubeType 06-16-2011 01:06 PM

Quote:

Originally Posted by miniman82 (Post 3006257)
Here's my take:

It is a museum worthy piece, therefore it belongs in a museum. For that reason, I am considering placing it at the ETF once I am done with it.

I have always been of the mind that if the set actually works, no one is going to care what's 'under the hood', since 9 times out of 10 it would not have worked on original capacitors anyway. No one walks into the ETF and says about the Model 5: "you know that thing would be much better non-functioning and with original caps". I don't think so. It's a much better thing to see it in operation, it blows away any thought of keeping it original once you see something on screen.

Lastly, I may not have to change anything in the first place. The chassis has what appear to be aerospace grade metal-film capacitors, so it may not need total replacement of the caps. They are not prone to leakage and breakdown like wax/PIOs are, so we'll see if they are any good. The lytics will be restuffed, but thankfully they are all mounted on wafers and secured to the chassis with screws. They will be easy to do.

Hi Nick,
Congratulations! I agree with your statements one-hundred percent.
Also, once you have an operational platform, Pete might consider performing comparitive colorimetry measurements on your CRT.

JBL_1 06-16-2011 06:43 PM

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 06-16-2011 06:53 PM

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. 06-16-2011 07:00 PM

Quote:

Originally Posted by JBL_1 (Post 3006279)
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.

Steve McVoy 06-16-2011 07:09 PM

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

Steve D. 06-16-2011 07:15 PM

Quote:

Originally Posted by Steve McVoy (Post 3006282)
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 06-16-2011 08:39 PM

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 06-16-2011 09:00 PM

1 Attachment(s)
Several requests have been received for me to label the back panel controls, so here it is!

Zenith6S321 06-16-2011 09:38 PM

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?


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