Col-R-Tel acquisition

[PMARTEL]

Beautiful and how humbling when we see how far we've come in colour tv.

Reminds me when I fist saw my neighbour's 26 inch Zenith colour console in 1966.

The 1st colour program I saw was 'Let's Make a Deal'

[zenithfan1]

Originally Posted by PMARTEL

The 1st colour program I saw was 'Let's Make a Deal'

I love that show! I watch it a lot on my '60s Zenith sets.

[Pete Deksnis]

Hey Steve,

WCBS is still broadcasting NTSC on channel 2 here. How bout shipping that contraption to Asbury Park and I'll watch it for you, input with true OTA NTSC!

Obviously I'm jealous.

Great job. Enjoy it.

Pete

[Aussie Bloke]

Fantastic restoration job mate! Seeing more examples of these colour converter wheels working and in action always amazes me, it's so cool this technology existed back in the day!!! It's like you can practically turn every B&W TV set into a colour set with one colour wheel. Couple of questions, I understand these wheels were probably commonly used with say 10 to 15 inch B&W sets made in the late 40s and early 50s, just wondering if there's been demonstrations of these wheels on that really large screen B&W TV that was put in production around 1951 (forgot the brand name but collectors would know what I'm talking about)? Also can these wheels easily be used on a pre-war B&W US TV set? Anyways if you could, put up a YouTube demo of your wheel in action, would be so cool to see this awesome technology in action!

[yagosaga]

Hi Steve,

Originally Posted by Steve K

The converter converts NTSC to field sequential. The sync pulse is taken off the vertical and the converter knows what color is in front of the CRT from a mechanical commutator at the hub of the wheel. BTW, that arrangement causes a lot of noise in the picture.

What is the converter? Is it part of the Col-R-Tel, or do you use an Aurora converter?

Best regards,
Eckhard

[jmdocs]

Originally Posted by Steve K

Thank you all for the kind replies regarding the resoration!
There is considerable flicker in the Col-R-Tel picture and fast movement causes the color to break up. That can even happen when the viewer blinks!

Steve

Fantastic to see this--kudos for an amazing job--and interesting to hear about the color break-up when blinking. The same problem occurs with DLP projectors, which is why I can't stand them, especially if black-and-white material is being projected.

Now I'd like to see a replication of the DuMont demonstration of a 24" set with a color wheel, that supposedly knocked out the power at an FCC hearing. Or that's the way I heard it...did that actually happen?

[Steve K]

Pete: Send me your good CT-100 and we'll talk!

Eckhard: By converter I am refering to the chassis that sits on top of the TV cabinet behind the disc.

I think there was a discussion some time ago about a color wheel for the 30 inch Dumont. I don't remember if it was ever reallt attemted or not.

Aussie: I believe that a wheel could be used on a prewar set. Actually there was experimentation of mechanical color before the war. If the Col-R-Tel would work on a prewar I do not know. I have no idea how to put something on YouTube- sorry.

Steve

[tubesrule]

Originally Posted by Aussie Bloke

Also can these wheels easily be used on a pre-war B&W US TV set?

There is certainly nothing unique about a pre-war set that would preclude the use of a color wheel. Somewhere I have documentation of a pre-war RCA TRK9 with an internal color wheel.

Darryl

[Dave A]

Attached are two pix from my Col-R-Tel from about 2 years ago attached to a Philco also. Brave attempts were made to use a RCA, but it narrowed the bandwidth in the video amp section which would not pass NTSC information. Philco does much better at that.

Looking at the pix, you can see the obvious degredation of the pix with this Rube Goldberg contraption, but it does work. Forget resolution in the final viewing. You can see the shift of the color in mine because there is no delay line to line up the color processing with the luminance like a color set of the day would use. So it goes for fake color. And then there is the debate of adding delay in the set which would make it not factory original. I opted for original as viewed in 1956, errors and all. And the blue information is more to the turquoise side due to the filters used.

Changing the CRT to an aluminized version helps with the brightness to get through those filters. I did this as it was a 1956 possibility

Steve K...you note about the commutators inducing noise is spot on. I found that if I pulled the wheel and buffed up the circuit traces the bent wire brushes ride on, things cleaned up right away.

The aluminum band around the shell is one of the most important parts of the assembly. It keeps the spinning disc from interacting with atmosphere outside the shell. The Bernoulli effect kicks in here. The wheel is a soft plastic and will compress against the inside of the wheel shell if unprotected and drag it down. Think old Bernoulli drives where the disc was forced down to a head as it spins.

And there is a small secondary chassis to attach to the yoke of larger CRT (more than 12") size sets to shrink the pix to a useable size for the shell opening.

A broken brush has mine sitting on the sidelines until I send the assembly to a genius for rebuilding when I find the time. Pete Y, I have not forgotten you.

Dave A

[Aussie Bloke]

Originally Posted by Steve K

Pete: Send me your good CT-100 and we'll talk!

Eckhard: By converter I am refering to the chassis that sits on top of the TV cabinet behind the disc.

I think there was a discussion some time ago about a color wheel for the 30 inch Dumont. I don't remember if it was ever reallt attemted or not.

Aussie: I believe that a wheel could be used on a prewar set. Actually there was experimentation of mechanical color before the war. If the Col-R-Tel would work on a prewar I do not know. I have no idea how to put something on YouTube- sorry.

Steve

Ahh yes, that's right, CBS were experimenting with the colour wheel with their field sequential system as early as 1940, forgot about those experiments.

I hope there will be an experimentation on setting up a large colour wheel for the 30 inch 1951 Dumont Royal Sovereign TV set http://www.earlytelevision.org/dumont_ra119.html as it would be real cool to see colour pictures out of that great TV set.

[Steve K]

Dave:

I did bend the contact wires and cleaned the traces which did help. I should have also cleaned the ends of the contacts but didn't. I hate to think about pulling that all apart again!

According to the 1956 Technician Circuit Digest there was a delay line option for the Col-R-Tel. I chose not to add it as well.

I've heard that RCAs do not work well with this color wheel. I did find that I get better color on the Philco by taking the video signal directly off the plate of the video output rather than at the CRT.

Steve

[ha1156w]

I have to wonder if one could build a modern "clone" of this thing using off-the-shelf ICs etc. I know I know it goes against the "all tube" mantra, but say you wanted to "colorize" one of those little 5" B/W chinese sets as a quirky project?

[Steve K]

Check out this link:
http://www.earlytelevision.org/2009_...os-benham.html

This was Cliff Benham's ETF presentation this past May. He is actually using CBS color but with modern components with excellent results. I believe he has made a modern NTSC version as well.

[zenithfan1]

Nevermind, I didn't read the last post before I posted. It was about Cliff Benham's presentation. It was the best Col-R-tel EVER.

[WISCOJIM]

Originally Posted by Aussie Bloke

... just wondering if there's been demonstrations of these wheels on that really large screen B&W TV that was put in production around 1951 (forgot the brand name but collectors would know what I'm talking about)?

You mean on the 30-inch DuMont Royal Sovereign? Here's Allen showing it off now: