Got an Admiral "roundie" today!!!!

An old Zenith engineer once told me that Admiral needed the
color fidelity pot to compensate for the color temperature drift
caused by the 6LE8 demodulator tube.This tube is a high
level demodulator with built in matrixing.They were trying
to copy Zenith's scheme of high level demodulation to save money by using less tubes but
could not use the sheet beam demodulator tubes that Zenith
used.I guess Zenith had a patent on that circuit.Motorola
also used the 6LE8 but they decided to call the pot the
tint control.I think the proper way to adjust the color fidelity
is to turn the color intensity all the way down for a b&w picture.
Then adjust color fidelity for the best grey scale.You may also
want to install a fresh 6LE8 because this tube is pushed kinda
hard in these sets.
Swanson

[jstout66]

got the set up and running last night. It has a pretty good picture, altho the picture tube has a weak gun. I don't have my rejuvinator anymore, so I will have to make do. All functions seem to work pretty good on this set and I am impressed! I will post a screen shot tonight.

[Kamakiri]

You can borrow mine as long as you promise to send it back when you're done

[jstout66]

really?!? kewl I would send it back. I'm only used to B&K and the RCA one I sold to Doug. Is it easy to use? Also..... As I mentioned in an earlier post, the bakelite base on the tube has cracks in it. Does that make the tube unstable if I try to take the socket off? I would hate to have it implode in my face.

[captainmoody]

No, Just be sure to hold the plug by the bakelite when pulling the socket off. You dont want any trouble with broken wires!

[andy]

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[Jeffhs]

Magnavox, in the mid-1960s, used a circuit it called "Chromatone" in its high-end sets of the period (e. g. their three-way color theatre sets) to inject one soft color into the background of a black-and-white picture, not enough to ruin it, just enough to add a touch of warmth to it. The color injected could be varied from, IIRC, blue to close to brown by means of a control on the front panel. Another manufacturer, whose name escapes me as I write this, put a switch on its sets it referred to as a "sepia switch" to achieve the same results. Admiral's "color fidelity" control, again IIRC, worked on the same principle as the Magnavox system. Zenith, however, did not, to the best of my knowledge, have any kind of monochrome enhancement systems in any of its sets, from the earliest roundies through its 1980s production (before GS bought them out in the early '90s).

These b&w picture enhancement controls were sometimes confusing to adjust, so a lot of set owners would just put them at midrange and forget them. Since most of today's network programming is in color, it is probably just as well to leave any color fidelity or other b&w picture controls at that position as well if you are watching modern programming on a very old set (such as jstout66's Admiral) with any kind of monochrome enhancement.