Westinghouse K840CK15 Restoration

[trinescope]

I'm hoping I can get mine to work as well as this. It gives me something to look forward to. Congratulations on having it working that well!

[old_tv_nut]

What these "were capable of" is the right description. Plus, the current result will be much more reliable than in 1954, firstly due to the greatly improved stability of modern sources, and secondly due to the painstaking recent restoration/adjustment of the receiver.

It really has been a joy to follow this process.

[trinescope]

That 1958 Eisenhower video tape looks really good even today, and probably did so at the time it was broadcast. Also, the tint controls on these old sets we play around with here seem to stay put once set, which leads me to believe the "never twice the same color" problem was more on the transmitter side than in the receiver. I can only try to think of what these sets looked like back when they were new with the broadcasts of the time.

[Electronic M]

Originally Posted by trinescope

That 1958 Eisenhower video tape looks really good even today, and probably did so at the time it was broadcast. Also, the tint controls on these old sets we play around with here seem to stay put once set, which leads me to believe the "never twice the same color" problem was more on the transmitter side than in the receiver. I can only try to think of what these sets looked like back when they were new with the broadcasts of the time.

I've read that tint (among other things) varied from station to station and if the viewer was not aware that they would need to adjust color controls of the set between stations, one channel could look great and the next not so much.

[etype2]

Originally Posted by Steve D.

Marshall, Mike's work on this restoration continues to dazzle me every time you post a screen image. How impressive to see what these sets were originally capable of when introduced in 1954. So many malign early color and hopefully they will finally realize what the technology of the day could provide in reproducing color television broadcasts. Congratulations to you both.

-Steve Dichter

Coming from you Steve, that is quite a complement. Thank you.

[etype2]

Originally Posted by trinescope

I'm hoping I can get mine to work as well as this. It gives me something to look forward to. Congratulations on having it working that well!

I know you will. Anyone that can wind a transformer from scratch is amazing in my book.

[etype2]

Originally Posted by old_tv_nut

What these "were capable of" is the right description. Plus, the current result will be much more reliable than in 1954, firstly due to the greatly improved stability of modern sources, and secondly due to the painstaking recent restoration/adjustment of the receiver.

It really has been a joy to follow this process.

Thank you.

[old_tv_nut]

Originally Posted by trinescope

That 1958 Eisenhower video tape looks really good even today,...

I suspect a large part of that is due to it being recovered with a later state-of-the-art quad machine, which would have had much more capable servos and correction circuits than the 1958 machine that recorded it. Remember, the match between recording heads of the first quad machines was so rough that the same head assembly that recorded the tape had to be used for playback. This was improved over time for monochrome, but early color tape was often plagued by visible bands of different color, noise level, moire', etc.
By the mid 60s, the machines were so good at playing each other's tapes, even in color, that they could be used for the ten-second delay at the World's Fair RCA exhibit just by running 150 inches of tape from the recording deck to the playback deck.

[etype2]

Originally Posted by trinescope

That 1958 Eisenhower video tape looks really good even today, and probably did so at the time it was broadcast. Also, the tint controls on these old sets we play around with here seem to stay put once set, which leads me to believe the "never twice the same color" problem was more on the transmitter side than in the receiver. I can only try to think of what these sets looked like back when they were new with the broadcasts of the time.

I watched the Eisenhower tape. I have noticed the tint control on my 21CT55 is stable. Once I got to the point of liking the the way things looked, I have not readjusted. The tuner on the 21CT55 seems to drift a bit after about two hours, and that is all I adjust. Thank you for the compliment.

[old_tv_nut]

Originally Posted by Electronic M

I've read that tint (among other things) varied from station to station and if the viewer was not aware that they would need to adjust color controls of the set between stations, one channel could look great and the next not so much.

Yes, absolutely true. And just about the time the networks got their acts together on this problem, analog cable came in, with the chance for individual burst and chroma errors on each of dozens of channels, plus the multiplicative degradations of cascaded analog amplifiers before the signal got to your house.

When color TV market penetration was still ramping up, people who knew I worked on it would ask me "Do you think they'll ever perfect color TV?" I'd reply "I hope not- that's my job!"

[etype2]

Originally Posted by Electronic M

I've read that tint (among other things) varied from station to station and if the viewer was not aware that they would need to adjust color controls of the set between stations, one channel could look great and the next not so much.

There is some truth to that. Being there in the day, folks did not know what good color looked like. They tended to over saturate the color control. In department stores, customers would adjust the controls on the floor models and you would see green faces on one set, over saturated color on another, ETC., hence NTSC.

[etype2]

Originally Posted by old_tv_nut

Yes, absolutely true. And just about the time the networks got their acts together on this problem, analog cable came in, with the chance for individual burst and chroma errors on each of dozens of channels, plus the multiplicative degradations of cascaded analog amplifiers before the signal got to your house.

When color TV market penetration was still ramping up, people who knew I worked on it would ask me "Do you think they'll ever perfect color TV?" I'd reply "I hope not- that's my job!"

I can tell you I never saw well adjusted color on the early 50’s sets. In my opinion, the color chain just was not as capable as what we have today.

[old_tv_nut]

Early on, was common to have differences between networks, individual network shows, network vs. local, program vs. commercials, and so on.

[old_tv_nut]

Originally Posted by etype2

There is some truth to that. Being there in the day, folks did not know what good color looked like. They tended to over saturate the color control. In department stores, customers would adjust the controls on the floor models and you would see green faces on one set, over saturated color on another, ETC., hence NTSC.

There was also the unfortunate inefficiency of the red phosphor, which prompted the set makers to settle on a cyan white balance to avoid overdriving the red gun too much (9300+27 MPCD, which, if you look at it on a chromaticity chart, just means "turn down the red").

This meant that visual adaptation to the white point depended on room lighting, viewing distance, etc. It's no wonder that people couldn't decide on the correct saturation for good skin tones - it probably changed from hour to hour for the same viewer.

The white point adjustment specs for the CT-100 and Westinghouse were for daylight white, avoiding the visual adaptation problems of somewhat later sets, but putting a huge strain on the red gun.

[Tom9589]

What was the final disposition on the tint control? Did you leave it as a flexible cable running through the back cover?