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The Set: Pete Deksnis's Site about the CT-100

Restoring a Vintage Color Television Set

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A couple of years ago I wrote a bit about the Color
Wars that resulted in the shakeout of CBS’s color
system in favor of 1953 NTSC compatible color.

[Color Wars link]

From that page:

“For a short while, some manufacturers made b&w television sets "color ready" by adding a rear-mounted connector that would allow consumers to buy a converter to either (1) receive color broadcasts in b&w, or (2) add a spinning wheel device to watch color transmissions in color.”

This 1951 example says "FOR ADMIRAL MODEL CA 100 COLOR ADAPTER ONLY"

And the page continues:

“Television manufacturers balked at the added expense and production pressures brought about by such a scheme.”


This 17-in. table-model 1951 Admiral I acquired because it had a “color ready” connector held a 55-year-old surprise. A little bit of history became reality. Here's the rear of that connector.


Clearly, Admiral
balked at the added expense and production pressures brought about by such a scheme!

Did a little cleaning, then discovered the dummy connector, then lost interest in restoring the set. After all, without a real connector, you can’t restore a function it never had. So I gave it a full-power start — a damn the torpedoes kind of thing.

To my surprise, it works. A nice bright horizontal line is strong enough to show up in spite of the flash. In reconstructing its operational history based upon the date codes of replacement tubes, this set was used from 1951 through 1962. The HO is the 1962 tube and shows virtually no use. A Philco (made by Sylvania) 17BP4 was installed in 1956.



The cabinet, not shown, is in very nice condition.
Maybe I'll change a few caps and look for that vertical gremlin anyway….



This next picture shows this set in a customer configuration. My set had its internal speaker disconnected. An external speaker jack on the rear connected the internal audio amplifier to a console speaker. I have only the TV. Thanks to Steve Dichter for locating this ad.


The next step…?

Admiral Model 17K12, Chassis ref 14E76-2 has affectionately been called “early analog vaporware!” for a lack of hard-wiring to its color adapter connector. Here’re my current thoughts in regard to the future of this so-called CBS Color ready set:

1. Restore the set for NTSC b&w.
2. Convert the set to receive only CBS Color in b&w.
3. Convert the set to receive either CBS Color in b&w or, via switch selection, NTSC in b&w.
4. Convert the set to receive NTSC color.
5. Convert the set to receive CBS Color.
6. Convert the set to receive NTSC and CBS Color.


You could keep going through the entire history of sweep standards adding options, of course, but as far as I know, there is no restored example of a set that receives CBS Color in b&w. It seems to me that there is no great historic value in restoring and converting this set to receive CBS Color: three made-for-CBS-Color sets have already been restored, and I suspect this set was designed for use with a color companion, a physically separate unit that contained its own CRT, vertical, and very importantly, horizontal sweep and high-voltage circuitry.

Certainly, this late production Admiral Model 17C12 does not contain sweep circuitry that can support the CBS Color standard, which is 144/29,160 rather than 60/15,750. The set would be no more historically valuable if converted to the CBS Color standard than any other period set.

So be it.

But, if I had to chose, number 2, a conversion to receive CBS Color in b&w, would be my preference. Can it be reasonable accomplished?

Historic CBS documentation describing the adaptation of RCA 8T-241 and 9T-246 sets to CBS Color calls for “1 CBS horizontal transformer to replace original.”

Furthermore, the tube complement of a 9T-246 and my Admiral is identical in the horizontal sweep/ high-voltage circuitry, so it’s reasonable to assume a conversion is possible. Original CBS Color documentation includes horizontal output transformer specification.


Perhaps one can be fabricated.

But, maybe the existing flyback in the Admiral was expected to be used in the CBS Color in b&w mode. Here's the Admiral ad from Steve's site:


Reread item 2. "Adapts set to receive color programs in black-and-white utilizing practically the full size of the picture tube.” Could be that the fly does function reasonable well at 29,160 but not well enough for full NTSC-mode sweep width. Could be a 1951 copywriter's justification for a smaller picture. Could be my Admiral doesn't need another flyback.


The following schematic shows modifications to a '51 b&w Admiral set to receive CBS Color signals. It is from a McGraw-Hill Rabinoff/Wolbrecht TV-servicing text.

According to information on the schematic, this modification did not require a new flyback or a new yoke, which suggests that the simplest conversion did result in a slightly smaller picture and that a full-width-picture conversion would require new flyback.

Illustration courtesy of Cliff Benham.


--Pete Deksnis
5-20,21,26-2006; 9-25-2006 (254); 4-23-2007 (619).
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