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Old 10-07-2017, 03:16 PM
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benman94 benman94 is offline
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Join Date: Jun 2011
Location: Detroit, MI
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Quote:
Originally Posted by jr_tech View Post
Impressive! that chassis is a beast! Is the circuitry much different from the CT100, or did Westinghouse not get innovative?

I assume the chassis is copper, like my h22t155, or is that rust?

I have seen drying patterns in some early kasil settled phosphor tubes, but not rings like that... could that be a moire pattern perhaps generated by poor contact of the silk screen during the screening of one of the phosphor colors? Seems likely that RCA would sell less than perfect tubes to competitors.

Perhaps the getter above the blue gun was the first one flashed after "pinch off", in a fairly poor vacuum.

Looks like a very fun project.

jr
Totally different ball of wax compared to a CT-100. Difference demod (R-Y and B-Y), but the mixing is done CT-100 style with seperate triodes for RBG in the adder section and a triple diode clamp.

No traditional PLL like the RCA, nor the shock excited crystal approach of the 15 inch GE. Just a color hold control up front. The hue is on the rear panel like on the GE. What were they thinking?

Totally different HV and focus section compared to the RCA. Uses three 3A3s in a doubler arrangement for the ultor and a 1X2? for the focus. According to an old post on the H840CK15 from Folsom, this set has the most stable HV of all the 15 inchers.

Twin 6BG6Gs drive the flyback, compared to the 6CB5s and 6CD6s used in other sets.

The set also makes use of the unusal 6BK5 tube, a minature tube ultimately derived from the 6Y6, 6W6 family. One for audio output (about 2ish watts) and one to drive the delay line.

The audio section in particular leads me to believe this was the brainchild of a Westinghouse engineer and not some copy cat chassis; Westinghouse was one of the only manufacturers using the 6BK5 and 6BN6 combination to lower parts count. I think Zenith may have used it too.
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