Gilfillan Prototype Set

[miniman82]

Originally Posted by ChrisW6ATV

Very nice-looking set, Nick. Is that a hinged panel giving access to the underside of the chassis on the side? I have seen a similar feature on a Hoffman Colorcaster 4021A from 1955. That appears to be an original design as opposed to a CTC-4 or 21-CT-55 duplicate.

Yes, there's a catch on the inside of the cabinet and you lift it up to open the door. Pretty damn convenient, if you ask me.

It's somewhat of an original design, I'll explain with a bit of a history lesson.


After the CT-100 came out, an almost instantaneous size war erupted between the manufactures of color sets. The only exception was the brief segue into higher technology in the 15" realm with the 15HP22, which printed its phosphor dots directly onto the curved faceplate vice having a flat dot plate as the 15GP22 did. This innovation was quickly put to use by CBS to create the 19VP22 19" CRT, and we were off to the races. This would have been circa mid 1954 or so.

Later that year 19" sets started showing up in the market place (it was CBS and later Motorola and Hoffman making the sets), and it became evident to RCA that something had to be done since 15" sets were now obsolete and no one was buying them. So they embarked on a development program leading to the issuance of a document called LB-962, which was their report on a developmental 21" set in September of 1954. A link to my scanned copy which was included in the Gilfillan documentation is below (warning it's more than 20mb in size):

http://miniman82.4t.com/images/Gilfillan/LB-962.pdf

From the documentation, it's apparent to me that there are stark similarities to the CTC-4 chassis. So why did the CTC-2B show up instead of the one shown in LB-962? I can only assume that RCA knew they had to come up with something fast, because they were being beaten at their own game by other manufactures. Being that the chassis shown in LB-962 was in its developmental stages at that time, I suspect what happened was this (from an earlier email to Steve McVoy):


27 July, 2015:

"My assumption right now is that the reason the 21-CT-55 came before this one was that RCA had piles of Merrill chassis laying around from the CT-100 run, so instead of retooling the entire production line to suit the prototype outlined here they opted to modify the CTC-2 to support a 21" CRT. We have to remember that the 'size war' was in full swing at that period in color TV, and there had to be considerable pressure on RCA to get something to market which could compete with the 19" sets that had come out earlier that year from CBS and others. So I'm assuming they took left over Merrill chassis, slapped in the horizontal section from this prototype (the flyback looks identical to the one in the 21-CT-55), and sent it out the door."



It's the only explanation I can think of that makes sense. Interestingly this LB-962 document still calls the CRT by its developmental designation C-73685, and since the 21-CT-55 came out a few months later and used a 21AXP22, that places the emergence of the 21AXP22 CRT somewhere between Late September and early December of 1954. The date code on the CRT in the Gilfillan is 52nd week of 1954 and it's a 21AXP22 not a developmental tube, so it's in the right ballpark.



Anyhow, back to the topic at hand.

Gilfillan must have applied to get on board with the RCA developmental 21" program at some point, because their circuit is very similar to the one outlined in LB-962. Not identical, but very close. RCA was known to work with other people in developmental programs (see the history of the NTSC color signal, the panels were made up of manufactures across the entire TV spectrum, pun completely intended), so it makes sense. They got a copy of LB-962, changed a few things so as not to get caught up in patent infringement disputes as is still the custom in industry today, and made the set you see here.

Documentation states only 6 were ever built, I'm unaware of any others turning up.