Prototype set is here

[Penthode]

If this prototype dates from 1950-51, how far along was it's development?

Has anyone identified whether this is a set still running on the dot sequential principle or whether the design had progressed to the constant luminance principle with interleaved chroma?

Is there any schematic information with this set? It would be very interesting to reverse engineer this set to find out what the design comprises of.

Note: seems I missed an earlier part of this thread. I see from Ed's post that progress had moved to CPA and possibly later to the early '53 NTSC development closer to the final standard.

It will be interesting to see what the reverse engineering reveals.