Restoring a RCA 21CT55

[etype2]

Update: we have been working on our RCA 21CTC55 receiver. Bottom line we intend to do a third test soon.

Below is what we wrote for our blog.

“We are very excited, proud and pleased with the results Mike and I achieved restoring this RCA 21CT55, a 62 year old television. Credit also to Dave, Kevin, Walter and Bob. I’m not ashamed to say “I like showing it off”.

A comparison test of a 1954/55 RCA 21CT55 and a 1958 RCA CTC-7 Worthington.

A new test to compare the image and color reproduction of the two sets. We wanted to show the differences in the first production 21 inch color set with wide-band, six IF stages and superior demodulation. The 21AXP22 also has the wide color gamut phosphors. The CTC-7 came four years later and considered to be the first truly reliable RCA color television. This CTC-7 has a rebuilt 21CYP22A. It must be said that both CRT’s tested “Good” at cut off, but the 21CYP22A tested very strong and the 21AXP22 tested weaker. The red gun in the 21AXP22 is the weakest.

We found a good quality, low loss signal splitter in my “pile of stuff” and hooked up both sets, so we can photograph both simultaneously. Experience with the camera I’m using (not the best) shows that ambient light in the room will influence the true color reproduction subject to the cameras limitations, because the camera is reading ALL the light in the room. Because collectors like to see the cabinet as well as the images, we can limit the ambient light interference by dimming the light source just enough to show the cabinet highlights with the majority of the lit screen composed in the viewfinder.

In photographing both CRT screens at the same time in the same frame, we must move further back and the ambient light will definitely influence the results. We must eliminate the light and photograph in near total darkness.

Both sets were adjusted and set up to RCA procedure recommendations. The two sets were first adjusted by eye individually for the best combination of color saturation, hue, brightness and contrast. No test instruments. (the eye can be the best test instrument). This is subjective, what I like, you may not like. My eyes have been “trained” to prefer ISF calibrated color starting in the 1990’s. I don’t claim to be an expert. ISF color calibration is scientific and quantitative and not subjective.

We used the Gentlemen Prefer Blondes DVD. It is known for great quality, three strip Technicolor.

We powered up both sets and let them settle in for 30 minutes and tuned off the lights. This time we had to take an “average” exposure. Unlike a good DSLR, my camera only has one focus and aperture point to set. We set the camera focus and exposure point in a darker area equal distance between the two lit screens. This created under exposed dark screen images, so we compensated by increasing the exposure with the camera to match what my eyes were seeing.

Both sets have fans added to the flyback cage to help cooling. The fans can be switched off. Both sets are protected by a Furman Discrete Symmetrical Power Model IT Reference 7.

After this test was completed, it occurred to me that we should have calibrated both sets using the SMPTE color bars from the Joe Kane Video Essentials DVD and blue filter. Maybe next time when we get a good DSLR.

Update notes and analysis: During the test which took over an hour, the 21CT55 screen images enlarged and increased in brightness. The CTC-7 stayed constant. The CTC-7 came up about 10 seconds later. In these shots and live, to my eyes, the 21CT55 consistently resolves more detail then the CTC-7. The geometry is adjusted better in the 21CT55. Look at slides 1 and 9. Blue shifted to violet. The CTC-7 could not register the bright spotlight scenes properly during the dance sequences. (Slide 26) The facial tones shifted to green and the dress shifted to violet. This could be adjusted, but we wanted to leave all setting the same from start to finish. The CTC-7 images are slightly brighter but is expected in the newer 21CYP22A. You can also see the differences in the red phosphors and the 21CT55 shows better details in the shadows and in bright areas. The results of this test show that we need to adjust the 21CT55 “warmer”, less blue and the CTC-7 should be “cooler” more blue.

Onward we go. Maybe my wife will buy me a nice DSLR for Christmas? Hint …..��❤️ The Tournament of Roses parade is coming soon. We intend to do a third test prior to the parade live telecast via rooftop antenna converted to analog, after calibration with the SMPTE color bars and blue filter.

Back on that historic day, January 1, 1954 when RCA and NBC broadcast the first coast to coast color program of the parade, folks in my hometown of Milwaukee could not view that color broadcast unless they were invited to one of the four private demonstrations or the one public demonstration at a television dealership. The color televisions used for those demonstrations were prototype Model 5 receivers.

The following year parade telecast on January 1, 1955, could be viewed on Admiral, Westinghouse, RCA, and other color sets, including a 1954/55 RCA 21CT55. Next years telcast (January 1, 2018) will be our first opportunity to recreate that historic event, but this time we will see the technology differences made possible with modern color cameras and studio chain equipment. Let’s do this.”

Once again, we can’t give you a direct link to the slide show. The slideshow and future slideshow can be viewed at the bottom page of this link:

https://visions4netjournal.com/vinta...tv-page-two-2/

[Dave A]

Another movie for consideration. Shot on Anscocolor film stock, the prints were by Technicolor. "Kiss Me Kate". 1953. Astounding color divided between darker scenes and full light stage scenes.

[etype2]

Originally Posted by Dave A

Another movie for consideration. Shot on Anscocolor film stock, the prints were by Technicolor. "Kiss Me Kate". 1953. Astounding color divided between darker scenes and full light stage scenes.

I will check it out and probably buy a copy. Thanks.

[stromberg67]

Originally Posted by Dave A

Another movie for consideration. Shot on Anscocolor film stock, the prints were by Technicolor. "Kiss Me Kate". 1953. Astounding color divided between darker scenes and full light stage scenes.

I agree that "Kiss Me Kate" is visually stunning in its own way. the first time i saw it I probably viewed a poor print, and didn't think much of it, technically. Having recently viewed it on TCM, I am pleasantly surprised about how good it can look. I'll ask Santa for a Blue ray copy for Christmas LOL;.l BTW, I haven't been keeping up with the thread. Does your 21-CT-55 have a rare earth 21FB?

[etype2]

Originally Posted by stromberg67

I agree that "Kiss Me Kate" is visually stunning in its own way. the first time i saw it I probably viewed a poor print, and didn't think much of it, technically. Having recently viewed it on TCM, I am pleasantly surprised about how good it can look. I'll ask Santa for a Blue ray copy for Christmas LOL;.l BTW, I haven't been keeping up with the thread. Does your 21-CT-55 have a rare earth 21FB?

It has a 21AXP22, somewhat tired but still tests good on all three guns.

Here is a link to a video we made last night. The 21CT55 and the CTC-7 Worthington running side by side.

https://vimeo.com/244628587

Here is a link to an image carousel with test images after calibration of both sets with the Joe Kane Video Essentials DVD. It will be boreing to some. Hope the members here are not bored by my never ending quest to get the sets as best as they can be.

https://visions4netjournal.com/vinta...-carousel-4074

The images will open to full resolution by taping on the tab in lower right of the carousel.

[miniman82]

Originally Posted by etype2

It will be boreing to some. Hope the members here are not bored by my never ending quest to get the sets as best as they can be.

Is it at 25kv yet? If not, you’re not getting the best...

[etype2]

Larry,

Those screenshots were in the beginning when we had weak green. We traced the weak green to a transformer in the chroma circuit. 1/16 turn CCW of the slug did the trick.

The gray scale is on the blue side. Today, been tweaking to get it right.

[etype2]

This update shows both the RCA 21CT55 and CTC 7 playing the 2018 Rose Parade on NBC.

The first (color) Rose Parade was telecast by NBC on January 1, 1954, but very few people saw it because you could not purchase a color television, even though Admiral put their color set on sale December 30 and possibly as early as December 17, 1953.

The lucky few television distributors were invited to private color showings of the parade on prototype colors sets and the public were invited to see the parade on prototype sets with various demonstrations staged in dealerships across the nation.

The wealthy and well connected were the first to view the Rose Parade telecast on January 1, 1955 in their homes on a few RCA 21CT55’s that trickled into RCA showrooms in time for Christmas purchase in 1954.

The 64th anniversary of that first telecast is replicated on the same set folks first used to watch the parade telecast, an RCA 21CT55 and the early 15 inch color sets. The signal received via a roof top analog antenna as close as we can get to original reception.

The first four screenshots were taken with an iPhone X and the last three with our new Sony Alpha 6300 DSLR. I haven’t mastered the new camera as yet which my wife gifted me for Christmas. The shots are basically point and shoot as we had limited understanding of all the controls. We hopefully can improve as we go through the learning curve of the camera. Many settings .... aperature priority, shutter priority, white balance settings, ISO, etc.

This link will open an image carousel which has full resolution shots.

https://visions4netjournal.com/vinta...-carousel-4235



We have two videos of the parade to post here soon.

[mbates14]

its weird, its like the set on the right has squishy vertical compared to the left.

[etype2]

Originally Posted by mbates14

its weird, its like the set on the right has squishy vertical compared to the left.

Yes, we saw that. The vertical (CTC7) is adjusted better then it was originally. Could be better. We have to upload two videos, 5 minutes each and will post soon.

[etype2]

Update to post two 6 minute videos of the 2018 Rose Bowl Parade. Screen grabs from the videos. See links below.



https://vimeo.com/250363347



https://vimeo.com/250371760

[old_tv_nut]

Thanks. Very nice. What CRT is in the CTC-7?

[etype2]

A 21CYP22A. Tested very strong on all three guns.

[etype2]

It has been 3 months since last posting on this thread. Decided to revisit “The Red Shoes” movie with an update.

After completion of the film, still not satisfied with the color images, we went back into the chassis searching for the reason why the greens were weak. The problem was a transformer in the color circuit. 1/16 CCW turn of the slug fixed the poor green response. We then did a complete new setup which improved overall color response. Using Joe Kane’s Video Esentials DVD and blue filter, we adjusted the gray scale and color calibrated this set. The movie and screenshots therin, were taken with cell phone cameras. Below, a few screenshots after the adjustment and calibration taken with our new camera.

Camera: Sony A6300 DSLR

Aperture: 3.5

Focal length: 16mm

Shutter speed: 1/30 and 1/40

Auto white balance

Resolution: 6000X4000

Sample screenshot reduced in size for this thread.



It looks blurry, but you can see 33 additional shots in full resolution, 6000X4000 at this link: https://visions4netjournal.com/2018/...-carousel-4656

Tap on any image to open a carousel and tap the resolution icon to see full resolution. The screenshots captured scenes from a 69 year old film, “The Red Shoes” on a 63 year old color television.

[etype2]

Here is the next series of screenshots from the Wizard Of Oz using the new camera. These were shot yesterday, April 14, 2018. We plan to also show Gentelmen Prefer Blondes and a request to show scenes from Kiss Me Kate coming soon.

This thread was created to show the progress of our restoration of the RCA 21CT55 and how good the old 21AXP22 can reproduce color images. I hope you have enjoyed the photos and I did not bore you.

As always click on this link https://visions4netjournal.com/2018/...-carousel-4803 to open an image carousel and once opened, click on the full resolution icon to open 4000X6000 resolution images. The below images are only samples.