RCA CTC-4 Clones
In 1955 many manufacturers were reluctant to develop their own color TV sets, because of the high costs involved and the very sluggish sales of color sets. RCA, on the other hand, wanted to see as many color sets on the market as possible, to speed the proliferation of the color system they had invested so much in. As a result, RCA produced a number of "clones" of their CTC-4 series color sets for other manufacturers.
Until recently, it was known that RCA produced sets for Magnavox, DuMont, Hallicrafters, and Stromberg Carlson:
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The discovery of a Sylvania set, the model 21C609, added a fifth clone:
All of these sets use a cabinet that is very similar to the RCA CTC-4 "Director":
The 3 surviving "clone" models (Hallicrafters, Stromberg Carlson, and Sylvania) are so similar to the RCA that they must have been made by RCA. For instance, here are the tube location charts for the Stromberg, Sylvania, and RCA:
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We are in the process of getting a list of serial numbers from collectors. So far, there doesn't appear to be a pattern in these numbers. We will publish a table when we've received the numbers.
The surviving Hallicrafter set has 1955 vintage Hallicrafter labeled tubes, while the Stromberg Carlson has RCA tubes. The Sylvania has had all of its tubes replaced, so it is not known which brand tubes it originally had.
This excerpt from a December, 1955 issue of Radio News, describes RCA's production of "clone" sets for Magnavox, and implies that the same was done for other manufacturers:
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Are there other CTC-4 "clone" models yet to be discovered? Are there clones that use cabinets different from the Director style?
RCA continued the policy of making color sets for other manufacturers for many years. Here is a posting on Pete Deksnis' Tidbits IV page on his CT-100 site:
| ...mention of CTC12 on your site
instantly brought into my mind the first horizontal chassis from
RCA's Bloomington plant. I visited that plant in late 1962 and saw the transition from CTC11 to CTC12 at that time! About a dozen assembly lines were running and some 11s were coming off of a few. I had no knowledge of the 12s being made before that visit and it was the start of full scale production for competing brands. Admiral's were getting labels put on chassis and being stacked for cabinets that were coming in during the next week. |
(Thanks to Pete Deksnis, Steve Dichter, John Folsom, and Ed Reitan for information and pictures used here)
Cloning wasn't limited to RCA. Here are two sets that appear to have identical chassis:
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Sentinal IU-816 |
Airline GSE-6000A |
These pictures are from Sams Photofact folders. The Airline folder was published in July of 1956, while the Sentinal folder was published in January of 1957. Sentinal probably made both sets. Click for a schematic diagram.
(Information and pictures courtesy of Steve Dichter)