Director 21 resto begins....

[Phil Nelson]

I know a great refinisher here, but you probably don't want to ship the cabinet to Seattle.

Looks like you're making real progress. I'm glad you mentioned the horizontal squiggle. I have seen that before (don't recall exactly when). If I see it another time, I'll know what to look for.

Phil Nelson

[miniman82]

No, I'm definitely not up for shipping it across the country. I'll just have to keep bothering the refinishers around here till they help me I guess, I just can't believe more people aren't getting into woodworking. With the economy in the tank, you would think people would flock to a trade that's always telling me they have no spare time to help...

Maybe they just want nothing to do with an old TV cabinet.

[miniman82]

Thanks for the nice Sams CTC-4 Photofacts, Brian! Now I can align the matrix correctly.

[miniman82]

OK, overdue update!

Long story short I was able to get acceptable matrix alignment after a long time messing with it, but the 21FJP22 CRT I borrowed from Mark has some purity issues that the CTC-4 magnets cannot correct. What it needs is more correction closer to the center of the screen, and the -4 edge purity ones run out of steam after a couple inches or so. I think I could get it near perfect if I had a spare CTC-9 purity ring assembly, but I don't have one. I'll either save it for another set, or give it back to Mark so he can put it into one of his. It has perfect emission.


Which leads me to the next big thing- Tom Schulz over on ARF was very generous indeed by GIVING me a 21AXP22A for free! Neither of us was sure if it even worked, but I just put it in and it has a raster!!!


Much more to come in a short while, the tube obviously needs to be set up. But from what I can tell right now all the guns respond to the screen controls, and I can see a plain image on the face. Here's hoping for the best!

[miniman82]

It's confirmed, the tube is good!


Now off to do a full setup...

[Electronic M]

Here is my theory about the cabbinet refinishers. When they hear the words "vintage TV" they think of plastic that is made to look like wood or in the case of more experienced refinishers those annoying "photo phinishes", and decide to try and avoid working on something that ,in their minds, is either not wood or very anoying very crappy wood in disguise.

I maybe wrong, but that is what I think.
You could prove this by haveing someone you know call about having some nice piece of furniture restored...

Tom C.

[miniman82]

I don't think that it, though. Like I said, all the ones I called around here were too busy with other projects to help me. The type of work most around here do is custom cabinetry, where they go to a home and build things right into the house. Very involved work, and very costly.

Example, here's a picture from a guy's site that I called:






I guess that's why I can kind of understand when I come along with a relatively cheap job- it's simply not worth them putting down their $10,000 job to do a $300 TV case. What I need to do is get in touch with someone who works out of their garage, someone who has the time to take this task on. I still may end up doing it myself, I just don't know what to do about the worn spot fingers have made near the tuning dial.

[miniman82]

Back to the electronic resto...


One of the tube sockets (V109, 3rd IF/1st sync amp) has been giving me fits since the beginning, so I finally gave in and repinned it. The wore out contacts had been causing goofy sync since day one. It's actually not as hard as I thought it would be, just tedious. Below you can see how bad they really were compared to a new pin, and what the socket now looks like.

[miniman82]

Looking better now, but man, convergence is a real PITA on this set! You can't change the settings to get exactly the result you want, it's always a little bit off in one part of the screen or another. If the center is smack on, the sides are horrible and vice versa. I know I shouldn't expect perfection on a set this old, but I've been able to get all my other ones very close.

Anyone have tips on how to converge the CTC-4? All I have to go on right now is what's in the RCA service manual, and a Sams folder. Those are great and all, but actual experience trumps the textbook every time if you ask me.

[old_tv_nut]

Originally Posted by miniman82

If the center is smack on, the sides are horrible and vice versa.

I may be telling you stuff you already tried, but here goes:

If it's like the CTC-5, you have to forget making it right in either the center or the edges, but first get the 3 colors to make parallel lines on the crosshatch using the dynamics. Then you can do a static adjustment, then retouch the dynamic, then final retouch on the static. Later sets had clamping diodes so the center would stand still when the dynamics were adjusted.

Can you see the pole pieces in the neck? If not, experiment with the forward/back position of the convergence yoke to get maximum effect. Towards the end, a very slight turn of the convergence yoke CW or CCW may also affect the coupling between the 3 guns and give you the final tweak.

[ohohyodafarted]

I agree with what Wayne had to say. To this I will add that there are two versions of the wiring for the convergence circuit. One of them works a bit better than the other, I don't remember which one is the better one. I would presume it is the version used on the ctc4A. I will have to find out when I get my ctc4 up and running in about 4 to 6 weeks after the cabinet is finished. Chassis is 90% done but I will not waste my time converging the picture on my 21AX crt test jig.

BAck in the early 70's is the last time I had the chance to converge a 4 that I owned when I was in my 20's. But I do recall that I was never happy with the convergence. No matter how hard I worked at it, it was always off somewhere. I learned to just accept it. I can tell you that it will never be as good as the convergence that I got on my ctc5 Wingate.

But Wayne is correct. Use a cross hatch with the static convergence out about 1/8" in the center. Then do your best to create lines that are as close to parallel and equidistant as you can get them using the dynamic controls. Then pull the 3 images together using the static magnets on the convergence yoke. Pull red and green together first, then drop the blue vertically and finally use the blue lateral to move it left and right. It will always be a comprimise and will never be perfect. I try to get a good average across the entire screen. I do not strive for perfection in the center, because that will only cause the edges to be GROSSLY out of convergence. A little bit off in the center usually allows for much more acceptable convergence in the outer areas. I never use dots, I always use cross hatches because you can see the direction of the displacement better as you are in the process of making the adjustments.

AS I recall the phasing coils will have a sweet spot where it will cause maximum deflection of the amplitude controls. Once you find the sweet spot, you won't have to adjust the phasing coils very far in either direction from the sweet spot. I also recall on my old 4 some of the controlls had little to no effect.

That is about all I can offer. Less than perfect convergence is just something a person learns to live with. And I don't know why convergence on a 4 should be problematic. After all, the convergence on my 21ct55 is dead nuts on, after it's warmed up. You would think that it would be as good or better on a 4, being that it's a generation later.

Good luck..

[old_tv_nut]

My guess is that the CTC-5 circuit is better at producing symmetrical waveforms, and the CTC-4 has less-perfect parabolas therefore making differences either left to right or between edge and halfway to center.

How does the horizontal linearity look? It occurs to me that poor linearity could affect convergence of left vs. right also.

[miniman82]

Thanks Wayne and Bob!

The linearity is fine horizontally, but vertical could use work. I'm not too concerned about it though, because every single roundie I've owned had a slightly stretched vertical near the top and I've just come to accept it. It's like the scanning lines get farther apart near the top, but the voltages in the vert circuit always check out fine.

Anyhow, I'll give what you guys say a try when I get off work today. Here's what it looks like after this morning's effort.

[Bill R]

It's hard to tell, but the top horizontal line looks to be slanted up towards the right. Even allowing for the misconvergence. You may want to look at a circle pattern and see if there are still some linearity issues, or if the yoke may be turned slightly.

[miniman82]

The yoke is just tilted a little bit, that's all.