Prototype set is here

[Pete Deksnis]

Originally Posted by John Folsom

Pete, Great photos and commentary. Almost as good as being there!

After seeing the photo of the number stamped on the rim of Nick's prototype CRT, I closely examined my two down-to-air metal bell prototype CRTs and discovered numbers on their rims I had never noticed before. One had D76, the other had D111. Both of my tubes have 14 pin stems and bases, which I believe places them somewhere earlier in the prototype tube progression. By March of 1953, RCA had provided 477 tricolor CRT samples to 177 companies.

I speculate that these rim numbers may represent a serialization of the metal bells used to assemble the tubes.

I went back to my original photograph and checked for what I thought at the time were four integers. The first and fourth were lighter than the others and so I projected that they were hand stamped. Upon closer inspection, the first character could well be a 'D' with 205 following. If that is correct, and when he can find the time (Nick is young guy, not retired like us!), Nick might be able to confirm or deny my supposition. If so, this 20-pin prototype would fall right along the timeline.

Pete