Merry CTC-5 Christmas 2020

[Penthode]

Been spending a number of hours working on my CTC-5N.

I gave my 21AXP22A a rejuvinate. A few years ago I attempted to with no apparent effect. The tube did not look like it had many hours and the set had sat unused for at least 35 years before I got my hands on it. I was more aggressive as I had nothing to lose and the red gun came back and it stills appears to be running fine after six hours.

I fixed the purity with the edge magnets. The biggest problem was the black and white tracking. Found that a number of resistors have driffted upward 100% to 300% around the color difference amplfiers.

I made a chassis mod in the RCA latest chassis itteration (1957) to the color difference grid bias/ clamp input reduced the color difference amplifier temperature (tube envelope not color) because of the lower plate current with a slight raise in plate voltage.

Went through the setup with special attention to the black and white tracking. I found there was too much Green gain as I could not get rid of a gren cast in the whites. I cheated by moving the green cathode down the 2nd video amp plate load divider to the same point as the Blue cathode. The tracking is very good now and it maintains a good black and white irrespective of brightness and contrast setting.

I attached the original and revised diagrams and some screenshots of my resulting efforts.

[old_tv_nut]

Very nice. Your Deluxe chassis has much better resolution than my Super chassis, which is more like permanent VHS quality.

Thanks for mentioning resistor values - I wonder if I have some that are way off like that - could help explain the weak video drive.

[TVBeeGee]

Wow! Those screenshots are very nice. Inspirational. Makes me anxious to get done with some other projects so I can begin work on my own CTC-5N. If I ever get mine to look as good as yours, I'll be absolutely delighted. Nice job.

You might be interested to know that I worked at Warner Bros. Studios when they did that restoration of Robin Hood. The movie was originally shot to three strips of black and white film running in the camera simultaneously, one for each of the three primary colors. The problem with this is the three films are not perfectly stable dimensionally. With the original Technicolor process, these color separations could be registered to overlap precisely at the center, but small errors would remain elsewhere, especially at the edges and corners.

When doing the restoration of the movie, computers were used to reregister these color separation elements in a spatially variable fashion all the way out to the corners. Very sophisticated algorithms were used to achieve this, with some human tweaking here and there to clean up trouble spots.

The result was a dramatic improvement in clarity far beyond anything that had been seen previously for Robin Hood. Detail in lace costumes even popped out that had never been seen before. Think of how much sharper a delta gun CRT looks when properly converged and you get the idea.

[TVBeeGee]

Just wanted to add an additional comment about your screenshots. In a few places, you can see a little bit of red flare. Some of this might not be in your TV, but in the actual movie. As it ran through the camera, the film strip sensitive to red was sandwiched behind the strip sensitive to blue. As a result, the red record is slightly out of focus, having a little less resolution than the other two. This presents itself as a little bit of red flare, especially around bright objects.

You can see a diagram of this here:
http://www.widescreenmuseum.com/oldc...stripprism.jpg

[old_tv_nut]

I attended a presentation by Warner Bros. of some of the restoration work at the SMPTE conference shortly after it was done. They pointed out the vast improvement of the registration in the ornate title lettering, and also mentioned the visibility of gold embroidery in Olivia de Havilland's costume, which was not possible even in the original theater prints.

This is a great restoration for viewing on vintage TVs, but even more impressive when the Blu-Ray version is viewed in hi def.
Edit: this would be the place to look for red flare originally in the negatives.

[Penthode]

Thanks for the comments. Yes I saw the red flare especially in the Olivia deHavilland close up. It certainly wan'st convergence and there was no red beam flare in the CRT that I saw after the rejuvination.

the picture is much brighter now and with better contrast. can watch it is a lighted room now. I do find that a front light on the screen affects contrast markedly i imagine due to the safty glase and the early CRT face.

I also want to remind that earlier in this forum I discussed swapping the 3A3 HV rectifier for a Zenith solid state equivalent. With the tube, the HV supply barely hit 21kV and the shunt regulator was having a very easy life. The solid state recifier now makes the 21kV steady and the 6BK4 shunt is now doing its job.

[TVBeeGee]

Back in those days, they often used silks on the lenses during the close-ups of the women to give those shots a radiant look, so that may be a factor in some of the flaring, too.

Thanks for the reminder about the solid state HV rectifier info. I'll certainly try that if (and probably when) I discover HV sagging on my CTC-5N. I must be really careful, though. My chassis unfortunately has an alarming amount of flyback wax droppings that look very fresh, so I'll need to clean and inspect that area closely and monitor HOT current very carefully. I've already put an ohmmeter on the flyback windings and didn't see anything that looked horribly wrong, but there could always be a shorted turn or two. Crossing my fingers that it is still OK. Might have been due to arcing from dirt and Florida humidity.

[Yamamaya42]

Unfortunately, I will not be able to post any CTC-16XL NYE pix/ Rose parade pix, like i had hoped, cause I ran out of time, I'm not home and away from my sets right now ( at my mom's) I had my 2nd shoulder surgery this morning, cause the first one did not heal right, and can't be alone, cause my arm must heal now.

[old_tv_nut]

Originally Posted by Yamamaya42

Unfortunately, I will not be able to post any CTC-16XL NYE pix/ Rose parade pix, like i had hoped, cause I ran out of time, I'm not home and away from my sets right now ( at my mom's) I had my 2nd shoulder surgery this morning, cause the first one did not heal right, and can't be alone, cause my arm must heal now.

Sorry to hear your arm gave you more trouble. Take it easy and follow orders - fingers crossed and best wishes for a swift recovery now.

[TVBeeGee]

We all wish you a speedy recovery. Had simultaneous leg and wrist surgeries myself awhile ago. No fun at all while it's happening, but would have been in bad shape without it. Be sure to do the physical therapy. It makes a huge difference in how things turn out. Best wishes from all of us!

[Yamamaya42]

Originally Posted by TVBeeGee

We all wish you a speedy recovery. Had simultaneous leg and wrist surgeries myself awhile ago. No fun at all while it's happening, but would have been in bad shape without it. Be sure to do the physical therapy. It makes a huge difference in how things turn out. Best wishes from all of us!

That's why I'm in this mes now, needing a 2nd operation to fix it, because of the insurance caused many problems.

was having shoulder problems about this time last year , turned out to be Adhesive Capsulitis ( im in the high risk category for it )

but due to covid, tests and diagnosis was delayed, things got worse, was first sent to PT to try and loosen it up, this failed, things degraded into a SLAP tear, ( minor ) , then covid things got better around July, and had surgery to fix it, the Doctor wanted aggressive PT for 2-3 weeks, for things to heal right, but insurance said " screw you, you have a 20 visit per year limit" and refused to listen, no matter how much they were contacted saying that more visits are needed, or it won't heal right, saying i was free to pay the $200 per visit myself.
AND, as you can guess, it did NOT heal right, and because insurance was negligent and stupid, rather than paying for more PT last summer, they get to pay 1000 times more for surgery now...