Prototype set is here

[old_tv_nut]

The adventure begins! Have you determined at all if this could be a dot-sequential prototype rather than early NTSC?

[Pete Deksnis]

Originally Posted by old_tv_nut

The adventure begins! Have you determined at all if this could be a dot-sequential prototype rather than early NTSC?

I wondered that too. Based upon a reading of Wentworth and Fink plus the preponderance of 1952 tubes, I don't see now how it could be a dot sequential set using three-state communitator circuitry. However, I couldn't resolve one way or the other their flirtation with phase alternation in that time period. So, it probably uses equaband quadrature circuitry for chroma, bypassed luma (of course), in 1952 perhaps a nonstandard color subcarrier frequency, and maybe PAL-like circuits.

My two cents.

Pete

[MelodyMaster]

Originally Posted by Pete Deksnis

I wondered that too. Based upon a reading of Wentworth and Fink plus the preponderance of 1952 tubes, I don't see now how it could be a dot sequential set using three-state communitator circuitry. However, I couldn't resolve one way or the other their flirtation with phase alternation in that time period. So, it probably uses equaband quadrature circuitry for chroma, bypassed luma (of course), in 1952 perhaps a nonstandard color subcarrier frequency, and maybe PAL-like circuits.

My two cents.

Pete

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.

[Pete Deksnis]

Originally Posted by MelodyMaster

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.

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