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  #1  
Old 01-13-2008, 05:50 PM
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RCA 21CT55 B8802897 is Alive!

I've got this 21in roundie in 1965 from a newspaper want ad, for $50 I think. It didn't work but I got it running with a few tube changes. Picture looked good on the 21AXP22 metal but was was very dim. I exchanged it at the CRT re builder for the brightest rebuilt he had, a 21FBP22 glass for $45. He told me the "FB" meant Full-Bright", what did I know? When I started the conversion from metal to glass, I decided to cut-up the cabinet and mount the chassis vertical so I could get to the under side much easier. This was no big deal since it was never going into the house and would reside in my garage TV repair workshop.This B88002897 proved to be the highest serial and last discovered 21CT55 with CTC2B chassis on a list of only 15 known to still exist!Anyway, I got it working this week after 38 years of storage. I'm using external video since the tuner/video IF isn't passing chroma yet. The 21FBP22 sure is bright, no problem with room lights. The reds are closer to CT-100 then most TV I've seen. I've got a 3in Pilot and a Norelco projector TV that I intend to get working next.
I am truely grateful for the interest that John Folson, Pete Dexnis and Ed Reitian took in this reactivation project. I only wish I didn't destroy the cabinet, but that's life. I'm not a restoration person. In 1957, I installed a 346ci Olds V8 engine in my 1954 Healey roadster. Then in 1964 and 2000 I reworked the car's frontend to resemble a Cobra roadster and installed a 418ci Olds V8. I now I have over 400hp in a 2500# car that is a drastic improvement over the original. These modifications made it virtually impossible to restore the Healey to its original configuration even if I wanted to, much to the disappointment of the Healey restorers. This RCA 21CT55 reactivation is history repeating itself 50 years latter. I hope the restoration members of this forum are more tolerant of my efforts to restore and possibly improve the performance of this classic color TV then the restoration members of the Healey car clubs. I hope this explains where I'm coming from, thanks.....Tom
Attached Images
File Type: jpg AC150-5003.JPG (43.4 KB, 246 views)
File Type: jpg AC149-4995.JPG (67.9 KB, 162 views)
File Type: jpg AC149-4974.JPG (78.4 KB, 218 views)
File Type: jpg AC149-4985_IMG.JPG (49.0 KB, 176 views)
File Type: jpg AC149-4990.JPG (88.1 KB, 209 views)

Last edited by Tomcomm; 01-14-2008 at 03:24 PM. Reason: required additional background info
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Old 01-13-2008, 06:28 PM
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Great job getting 'er going again. Do you plan to restore it to original?
Mark
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Old 01-13-2008, 10:56 PM
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Awesome picture, and great story! Glad you came on and shared!
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Old 01-14-2008, 09:41 PM
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I congratulate you on your great success! Back around 1975, I saw an ad in a magazine by RCA that featured a 21CT55 that had supposedly been bought new by a family, and had been under contract with RCA Service Co. since. The ad showed a screen shot of a macaw, and told of the "updating" of the TV with a new CRT (presumably a 21FB), the idea being that they can keep your RCA TV going forever, IF you have a service contract. Don't know which mag it was in, but it made an impression.
I have yet to see a 21CT55 in operation, but we do have that CT-100 in the museum in Windsor, CT. Fired it up last Sat night for our holiday party using a "Cinderella" DVD. The CTC-2 and 2B are incredible chassis!
Kevin
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Old 01-15-2008, 11:40 AM
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Wait a minute... What's with that horizontal cabinet with upright chassis ???????

I am assuming that it was some sort of custom built-in, or something? Is there any RCA model number on the cabinet (other than 21CT55), or is that a custom cabinet, or a Clubman series?

When I first glanced at your avatar photo of the set, I thought it was a CTC-4. Then I saw that it's a 2B.

Charles
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Old 01-15-2008, 03:03 PM
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Quote:
Originally Posted by stromberg6 View Post
Back around 1975, I saw an ad in a magazine by RCA that featured a 21CT55 that had supposedly been bought new by a family, and had been under contract with RCA Service Co. since. The ad showed a screen shot of a macaw, and told of the "updating" of the TV with a new CRT (presumably a 21FB), the idea being that they can keep your RCA TV going forever, IF you have a service contract. Don't know which mag it was in, but it made an impression.
Kevin
I recall that ad. I was in Jr. High and thought that was the neatest thing I had ever seen. I could not remember exactly what model it was but I remember the colorful macaw. If I recall properly, there was an older lady (the owner) standing next to the TV. I think it was either in Time or U. S. News or something like that. It was in a class where they had us read from magazines or periodicals for part of the class, must have been english or literature or something like that. I thought that I would like to have a set like that sometime and many years later, I do!

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Old 01-16-2008, 05:29 PM
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It's a 21CT55 with a CTC2B chassis for sure. I cut up the cabinet so I could mount the chassis vertical. I used the removable top as the base and cut the front panel's lower control portion off and mounted it to the front panel side. I explained all this in my thread's introduction, please read it. Attached is my original 1960's concept drawing and some recent detail pics.....Tom
Attached Images
File Type: jpg ctc2b vert concept 1.jpg (96.9 KB, 171 views)
File Type: jpg 151-5184_IMG.jpg (84.3 KB, 207 views)
File Type: jpg 146-4627_IMG.JPG (117.2 KB, 233 views)
File Type: jpg 151-5185_IMG.jpg (72.5 KB, 228 views)
File Type: jpg 150-5082_IMG.jpg (60.0 KB, 187 views)
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Old 01-16-2008, 08:24 PM
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Thanx for posting the detailed photos...since this set is more rare than a CT-100 I am glad to see it operational in any configuration..Great picture on the set btw
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Old 01-20-2008, 06:47 PM
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Old 01-21-2008, 09:05 AM
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At least you kept it! Forty years ago, who knew how rare these would be.
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Old 03-28-2008, 12:33 PM
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21CT55 Progress with Background

Thanks for your response to my 21CT55 postings. Seems the screen display keeps getting more impressive as I learn thru trial and error how to get it setup properly. It operates as a video monitor with the imbedded IC video op-amp I installed that presently allows two matched switched inputs to the CTC2B's 1st video amp grid. This 3vpp level matches the original RCA designed diode video detector output. Those engineers did everything right on these first CTVs in 1953. I went to work for RCA in west Los Angeles in 1953 straight out of high school as a lab tech. Made engineer in 1956. I did defense stuff, no interest in color TV until my Dad won a new '56 CTC4 in a raffle. I stayed up the first night till 3am trying to "improve the convergence". Not a good start in color TV but I was hooked on the technology.

When I bought my 21CT55 for $50 in '64, I brought it into the house after I got it working and ran it along side my Dad's old CTC4 he left me. Both had 21FBP22s so it was a good comparison of narrow bw color R-Y B-Y vs. full bw color I Q. The extension of full color into fine detail on the CTC2B was startling! Color persisted in fireworks until extinction which I never saw before. The CTC4 fireworks turned into white long before extinction. The CTC2B carried full color way into the shadows, the CTC4 went gray to black. I kept the CTC4 in the house for the kids but brought the CTC2B back to the garage workshop for further study. Ease of working on the chassis and CRT "forced" me to destroy the cabinet and configure the remains into the vertical chassis configuration I am blessed with today. That’s alright with me. I respect the original CTV restores but that’s not my thing.

Since ota NTSC is headed for oblivion in Feb '09, I see little incentive to go thru the futile exercise of getting the chassis's tuner, video and sound IF sections operational. I intend to open the heater string to all involved tubes and just let them hibernate. Probably lose about 100w off the present > .5kw it draws from the "mains". I've got plenty of quality NTSC composite video sources to keep the "old guy" demonstrational indefinitely. In addition to the C-Band Big Dish analog and 4DTV digital I've got a Koss DVD player (don't laugh) and a Magnavox Laser Disk player with about 20 disks including most of the Star Wars transfers. And of course, I expect to get my ASTC tuner coupons any day now (sic) for ota digital reception. I'm sure I'll be disappointed with the PQ of network SDTV, but then its free.

Big problem now is the poor quality of off-screen digital camera images. I get really awesome displays on the 21FBP22A with vibrant, accurate colors. Having the CTC2B's super wide dynamic range due to full bandwidth I Q demodulators feeding low level I-Q-Y matrixing to the CRT grids only. So I grab my Canon S40 digital and try to capture what I see. Results are disappointing to say the least. I tried everything possible with this full feature camera to no avail so far. If I manage a good shot, its got moiré that I can't get out. Surely there must be a technique described that will allow me to convey the picture quality of this 53yr old beast in digital camera form for emails and on the web? Anyone out there have good results or is my disappointing experience typical? I need to show the CTC2B's picture to some knowledge person on site in real time to get their opinion and critique.

I live in the country, 25mi north of Santa Barbara CA. This is wine and horse country, not techi antique Hi Fi, color TV and classic car country, so I don't communicate with anyone who shares my interests. If any of you ever get out my way, let me know, I'd surely like to show you what I got here. Right now is the best time, all the hills are lush green and the oak trees are fresh with new leaves .....Tom
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Old 03-28-2008, 12:49 PM
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I have long been impressed by the engineers who developed these sets; I think they would be impressed by the experiments still taking place with them. I wouldn't want everyone to do this with their 21CT55, but I'm glad you can.
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Old 03-28-2008, 01:03 PM
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I think you must be some sort of a mad genius..And that's meant as a compliment...But I think most of us in the Olde TV hobby are about a half-bubble or so off center anyway, at least...(grin)
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Old 03-30-2008, 12:47 AM
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Quote:
Originally Posted by Tomcomm View Post
The extension of full color into fine detail on the CTC2B was startling! Color persisted in fireworks until extinction which I never saw before. The CTC4 fireworks turned into white long before extinction. The CTC2B carried full color way into the shadows, the CTC4 went gray to black.

I'm sure I'll be disappointed with the PQ of network SDTV, but then its free.

Big problem now is the poor quality of off-screen digital camera images. ....So I grab my Canon S40 digital and try to capture what I see. ....If I manage a good shot, its got moiré that I can't get out. .....Tom
A few comments:
Color saturation on fireworks details - yep, that's what wideband chroma will do for you - you get the same effect only better when you run a digitally mastered DVD through component inputs into a modern set.

Full color into the shadows - actually, in a dark room, any set *should* do that - but the CTC-4 and some other sets after yours apparently had very non-linear chroma amps, since the color control operated by changing the bias of the amplifier tube. We noticed this at ETF when trying to adjust the color level on "The Wizard of Oz."


Screen shots - On the moire' problem, it of course comes from the phosphor dots on the TV screen vs. some other regular structure - maybe the pixel structure of the camera, but maybe in the computer program that is scaling the image for viewing on the computer monitor. Try zooming your viewing program to 1:1 view and see if you have a clean image without moire'. If so, then try looking for some other viewing software. Sometimes the viewing software does a cleaner job of reducing resolution for file storage than for display. Try reducing the resolution and viewing the reduced file. If nothing works, you may need a different camera with more Megapixels. Note also, if you are really clearly resolving the phosphor dots, your image will either look somewhat dark, or the dots will be overexposed since they are only a part of the image area. The latter can ruin the contrast and saturation of the image. [Note: There used to be a similar problem taking film pictures of black and white sets that had clearly resolved scanning lines.] So, examine what you are getting at 1:1, and try reducing the exposure somewhat when you take your pix if necessary. Slightly dark will look better than compressed gray scale and chroma.
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Old 03-30-2008, 12:53 AM
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One other thing - the picture quality with a converter box (especially for prime time stuff broadcast in HD) should be excellent - the converter boxes usually have fairly wideband chroma, feeding the wideband digital R-Y and B-Y into a chroma modulator.
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