Prototype set is here

[cbenham]

Originally Posted by miniman82

Tom C. found the plug I need for the filament string in this chassis, I hope to have it in my possession by the end of the coming week. Now, if only I could source a backshell for the other plug...

What's the diameter of the connector? I may have a shell for it.

Cliff

[miniman82]

Originally Posted by cbenham

What's the diameter of the connector? I may have a shell for it.

I get 1 3/8" for outer diameter, not sure what the shell size should be. Steve McVoy sent one from a regular octal connector, it was too small.

[cbenham]

Originally Posted by miniman82

I get 1 3/8" for outer diameter, not sure what the shell size should be. Steve McVoy sent one from a regular octal connector, it was too small.

I misjudged what is in the picture entirely. Thought it was a small two pin 1/2 inch diameter Cinch-Jones connector, not something 1-3/8 inches diameter.

I'll look some more but I doubt there's anything like that in my parts boxes.

Cliff

[miniman82]

Originally Posted by cbenham

I misjudged what is in the picture entirely. Thought it was a small two pin 1/2 inch diameter Cinch-Jones connector, not something 1-3/8 inches diameter.

The small one is coming with a backshell, it's just not shown in the picture. What I said was "Now, if only I could source a backshell for the other plug...", referring to the large 7-pin round one. No one seems to have one, so I may end up trying to make my own.

[Penthode]

Has anyone considered construction of the CPA encoder? I wonder if an existing encoder chip can be modified for the purpose.

Ideally, it would be interesting to create as envisioned, a truly NTSC-CPA signal. Y', Cb', Cr', is available from many consumer devices and this would simplify the construction of the quadrature modulation and luma adder.

The R-Y axis would have to be inverted each field and the CPA sync would have to include the flag to properly correlate and signal the color field.

Any thoughts? It may be interesting to have an "official" competition to see who comes up with the best design. Maybe the prize could be, say, an RCA CTC-11 or something like that?

[tubesrule]

Originally Posted by Penthode

Has anyone considered construction of the CPA encoder? I wonder if an existing encoder chip can be modified for the purpose.

Ideally, it would be interesting to create as envisioned, a truly NTSC-CPA signal. Y', Cb', Cr', is available from many consumer devices and this would simplify the construction of the quadrature modulation and luma adder.

The R-Y axis would have to be inverted each field and the CPA sync would have to include the flag to properly correlate and signal the color field.

Any thoughts? It may be interesting to have an "official" competition to see who comes up with the best design. Maybe the prize could be, say, an RCA CTC-11 or something like that?

We were discussing this offline, and I thought had mentioned it on the thread, but perhaps not. If Nick decides to restore the set to CPA specs, I'll write the algorithms for my SCRF converters to generate the correct signal. Since the entire signal is generated in firmware, nearly any conceivable format can be realized. I have done other one-off or low volume versions like the British 405 NTSC, 405 SECAM and of course CBS field sequential color.

Darryl

[miniman82]

Originally Posted by tubesrule

We were discussing this offline, and I thought had mentioned it on the thread, but perhaps not. If Nick decides to restore the set to CPA specs, I'll write the algorithms for my SCRF converters to generate the correct signal.

I think it was only a topic via the email conversations. In any event, I still need to figure out which standard the set uses. To that end, I figured that getting the thing to actually run is the best way to do it. My brother is taking far too long to get the schematics in order, and I already have the horizontal section half ass working. Nevermind the fact that the schematics are causing their own set of issues, as far as being easily interpreted over the internet. Since the horizontal section is the heart of any receiver, it's a logical starting point. Once I have stable high voltage and sweep, I can hook up one of the CRT's and see if an NTSC signal does anything. I have a strong suspicion that it was modified at some point to use the later standard, but began life as a CPA platform- a test bed of sorts.

If it does turn out to be CPA, Darryl will definitely be getting a call from me. Rest assured, I will not stop until I am able to get some sort of picture out of this thing- hopefully a color one.

[Penthode]

Originally Posted by tubesrule

We were discussing this offline, and I thought had mentioned it on the thread, but perhaps not. If Nick decides to restore the set to CPA specs, I'll write the algorithms for my SCRF converters to generate the correct signal. Since the entire signal is generated in firmware, nearly any conceivable format can be realized. I have done other one-off or low volume versions like the British 405 NTSC, 405 SECAM and of course CBS field sequential color.

Darryl

I suppose I can visualize an algorithm to rescale and interpolate at baseband spatially or temporally for example the CBS field sequential system, it blows my mind to think you would be able to accurately realize in firmware the correct relationship between the the baseband luma and properly interleaved chroma!

I thought an FPGA implementation would be a bit over the top in this case. I suppose I am old school still thinking of a firmly hardware based implementation. For component 525 video, no rescaling would be required and fairly basic hardware following early 50's guidelines (but in solid state) would have been most appropriate.