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  #1  
Old 04-09-2010, 04:07 PM
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bandersen bandersen is offline
RCA 741PCS
 
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Protelgram 3NP4 + optics

Cool stuff. Anyone have a working example ?

http://cgi.ebay.com/Protelgram-Proje...130381735019QQ
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  #2  
Old 04-09-2010, 05:58 PM
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I have a complete but unrestored one.
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  #3  
Old 04-09-2010, 06:23 PM
pearsonk pearsonk is offline
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Many sets used this system in late '40s, into early 50's. There was a 3-projector color system.
I have a restored Scott 6T11 and a Duo-Vue which projects a nice pic
on a wall - think its a 3x4 foot pic.
The corrector lens determines final pic size/distance from projector.
.......................
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Old 04-09-2010, 07:32 PM
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The one I have is a Duo View, it has to be wired up to an existing TV to work.
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Old 04-09-2010, 09:54 PM
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My Fada projection set

...using the Protelgram system. The optics are so touchy to set! And the focus is critical. You can focus on the front or the back of the plastic fresnel lens and it will actually tint the picture if you are on the wrong side. And it is only about 1/16th inch thick. Those physics of light are beyond me.

And there are some oil-filled electrolytics! Be carefull. I am suspect as to what the oil is.

This set is a 630 jeeped up with Jones connectors to guide the video to the Protelgram unit.
Attached Images
File Type: jpg fada 009.jpg (80.4 KB, 52 views)
File Type: jpg fada 010.jpg (91.1 KB, 53 views)
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Last edited by Dave A; 04-09-2010 at 09:57 PM. Reason: text
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  #6  
Old 04-09-2010, 10:00 PM
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OK even if I were interested, that annoying a$$ music is enough to never go back to that seller's page. <puke>
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  #7  
Old 04-09-2010, 10:46 PM
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bandersen bandersen is offline
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Quote:
Originally Posted by Dave A View Post
...using the Protelgram system. The optics are so touchy to set! And the focus is critical. You can focus on the front or the back of the plastic fresnel lens and it will actually tint the picture if you are on the wrong side. And it is only about 1/16th inch thick. Those physics of light are beyond me.

And there are some oil-filled electrolytics! Be carefull. I am suspect as to what the oil is.

This set is a 630 jeeped up with Jones connectors to guide the video to the Protelgram unit.
Impressive! What do you think of the picture when everything is just right ?
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Old 04-09-2010, 11:33 PM
pearsonk pearsonk is offline
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The oil filled part is the HV trippler. It is used to keep the tubes
cool I think. I have rebuilt one, forgot the tube #, they are wired in. refilled with mineral oil.
Dave's picture is very good for one of these, especially in the bright light.
The concave mirrors cost me about $80 to resilver............
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Old 04-10-2010, 08:35 PM
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banderson,

For what it is, I am impressed. But this set has more problems with the 630 chassis than the Protelgram. It barely makes a full raster and is very h-sync touchy...and all recapped and restored. It may be a case of it wants a hot signal. It is bright but remember the picture is 3" blown up to 18" or so. Very 8mm film like. And it is only bright if you are spot-on centered on the lens. Lean to the left for your beer and things go dark.

I grabbed some test pattern stills on the net and burned them to a dvd and used them to fine adjust and finally got it right.

It was a wonder in 1949 and still is but nothing like the RCA projections of the era. I had one that was beyond sharp. Chroma-crawl and all.

See all of you in Ohio with my little Indextron vs. KV-5100 face-off.
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Old 04-11-2010, 11:37 AM
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Quote:
Originally Posted by Dave A View Post
My Fada projection set ...using the Protelgram system.
Nice looking set! (And a nice looking picture despite the issues you describe.)
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