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 Post subject: RCA Laboratory Research Bulletins?
PostPosted: Jul Fri 10, 2020 9:43 pm 
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Within the One Electron website archives there is an RCA laboratory bulletins index covering 1946 to 1956. I'm specifically interested in a Bulletin from 1949 titled "A Direct-Drive Deflection and High Voltage System for Television Receivers, LB-789" http://www.one-electron.com/Archives/RC ... 6-1956.pdf
The Electron One website has these bulletins online covering the years of 1955 to 1957, but the earlier one's appear to be lost to time. Does anyone here know of a location where these can be viewed? I'm very curious to read the inside story surrounding the development of that method used in the 1950 RCA televisions and later licensed to other manufactures. Thank you for any insight!


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 Post subject: Re: RCA Laboratory Research Bulletins?
PostPosted: Jul Sat 11, 2020 1:34 am 
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David Sarnoff Library probably has them.......contact them - they may hold a digital copy, or have a photocopy service.

davidsarnoff.org

They had some info on the RCA color demonstrator Nick W. has, IIRC.

EDIT:

email: info@davidsarnoff.org

phone: 609-451-0047.

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"Capacitor Cosmetologist since 1979"
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 Post subject: Re: RCA Laboratory Research Bulletins?
PostPosted: Jul Sat 11, 2020 1:49 am 
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The Hagley Museum in Wilmington, DE houses the RCA archives.

https://findingaids.hagley.org/xtf/search?keyword=rca

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"One of the advantages of being disorderly is that one is constantly making exciting discoveries." A. A. Milne


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 Post subject: Re: RCA Laboratory Research Bulletins?
PostPosted: Jul Sat 11, 2020 2:34 am 
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Sarnoff had them at one time :wink: :roll:

These technical reports and a similar number from the Sarnoff Corporation were donated to Hagley in 2009, along with the rest of the archival collections of the David Sarnoff Library.
Access Restrictions

Collection is open for research.

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Brian
"Capacitor Cosmetologist since 1979"
USN Retired 1984-2006 (Avionics/Cal)


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 Post subject: Re: RCA Laboratory Research Bulletins?
PostPosted: Jul Sat 11, 2020 6:21 am 
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Thank you guys for the suggestions. I had found those two websites but could not conclude who had what so got frustrated and gave up. Now I've finally found the LB bulletins storage location at Hagley. So I'll put in my request and wait to hear back. If I need to go there I'm out of luck.


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 Post subject: Re: RCA Laboratory Research Bulletins?
PostPosted: Jul Thu 16, 2020 9:56 pm 
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I received the scan of the RCA Bulletin I requested from the Hagley Museum. I was pleasantly surprise at how fast that happened. I thought a few here could be interested in this somewhat mysterious development so I've attached the PDF files below. In my opinion there's nothing more fascinating than reading an explanation of a circuits operation from the individuals that developed it.


Attachments:
Direct Drive 1.pdf [995.07 KiB]
Downloaded 27 times
Direct Drive 2.pdf [1.45 MiB]
Downloaded 19 times
Direct Drive 3.pdf [1.39 MiB]
Downloaded 21 times
Direct Drive 4.pdf [1.5 MiB]
Downloaded 19 times


Last edited by Kevin Kuehn on Jul Fri 17, 2020 3:54 am, edited 1 time in total.
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 Post subject: Re: RCA Laboratory Research Bulletins?
PostPosted: Jul Thu 16, 2020 11:58 pm 
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Thanks for posting those.

As you can see (ignoring their linearity control) they ended up with nearly the same result as a standard format circuit shown in figure 9 of this article:

http://worldphaco.com/uploads/TELEVISIO ... ODE_OR.pdf

Except for the fact they simply eliminated(deleted) the winding on the LOPT core that was in parallel with the yoke, so they then could define it as series or direct drive, rather than shunt or parallel drive. Ultimately this became the topology used in transistor sets where the yoke was no longer shunted across a winding on the LOPT but appeared connected from the transistor's collector (or a tap nearby) via the S correction capacitor to either ground or B+ as the capacitor also isolated the DC component from the yoke and because the internal Z of the power supply is low, the connection could be made to ground or B+.


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