What's missing from this picture (RCA CTC-11)?

[Phil Nelson]

I was just about to try my hand at adjusting purity and convergence on my newly working RCA CTC-11 -- even the audio works now -- when someone told me that I'm missing the purity rings and blue lateral magnet.

True?

If so, any idea where I could get spares? I was told that assemblies from some other 21" roundies might work.

Thanks!

Phil "color newbie" Nelson

[jpdylon]

Yup, they're gone.

I've got a spare set. Just PM me with your address and I'll send them off to you. Might take me a few days to get the time to do it - but they're yours, gratis, if you want them.

[drz01]

Again ths site is the best!

[Phil Nelson]

Originally Posted by jpdylon

I've got a spare set. Just PM me with your address and I'll send them off to you.

An offer to good to refuse. PM on the way! I'll be happy to pay shipping.

Thanks.

Phil

[reeferman]

Wow that set is clean! Looks like it just came off the line.

[Phil Nelson]

It's clean because I cleaned it The CRT is supposed to be almost new, however.

Here are the parts, courtesy of jpdylon (thanks!). I sent him a manual for another TV, so I think we came out square on the deal.

Phil

[Phil Nelson]

I'm continuing this thread because my original post has a photo of the CRT neck minus the blue lateral magnet and purity rings. Maybe that view will help answer this question:

How important is the front-to-back position of the convergence assembly on the CRT neck? Is it supposed to be located around anything in particular, or just "behind the yoke?"

I can't get red and green vertical lines to converge horizontally in the edge areas. At this stage, I have replaced the vertical centering pot (which helped w/ linearity). I also replaced the selenium rectifier and one of the adjustment pots on the convergence board.

The center of the screen looks great, but red/green are way off in edges, and more than one of the pots is run all the way to the end of its travel when I try to converge those colors.

Maybe there's something going on besides parts on the board that had obviously failed. It's also pretty hard to do static convergence using the stick magnets on the converg. assembly. One is pushed in almost all the way, another is pulled out all the way . . .

Ideas? I don't want to blindly shotgun everything on the board and end up with the same problem.

Thanks!

Phil

[andy]

---

[Steve K]

" It's also pretty hard to do static convergence using the stick magnets on the converg. assembly. One is pushed in almost all the way, another is pulled out all the way . . ."


Phil:

One thing that might help here is to pull out the magnet and turn it a half turn and reinsert it. Do this to the ones that are all the way in and all the way out. That should bring the adjustment back into normal range.

Steve

[kx250rider]

Originally Posted by Steve K

One thing that might help here is to pull out the magnet and turn it a half turn and reinsert it. Do this to the ones that are all the way in and all the way out. That should bring the adjustment back into normal range.

Steve

Excellent suggestion... I've done that many times. Also, depending on the construction of the tube, sometimes I've had to locate the purity rings and blue lateral magnet slightly forward or aft of the flags. That's not kosher, but it may be the only option if the tube is a rebuilt, or has a defect.

Steve, are you messing with the Color wheel today by any chance??? I missed the invitation last time due to 4th of July plans.

Charles

[Phil Nelson]

Originally Posted by andy

The convergence yoke should line up with the convergence pole pieces inside the CRT neck. They are just in front of the final grids in the electron gun, and you should be able to see them if you look into the neck. In practice, it's not super critical, but try to get it close.

What would the pole pieces look like? As you can see in the first photo, there's a plastic sleeve over the CRT neck in the area where the convergence assembly is located.

I believe I've tried flipping the stick magnets every which way, including endwise, but it couldn't hurt to try again. Can they become demagnetized? I suppose I could try to remagnetize them by petting with another magnet, but that seems a little off the wall. They still have some (approximately equal) magnetism left, as I determined with my trusty old hiking compass.

Phil Nelson

[Pete Deksnis]

Originally Posted by Phil Nelson

I believe I've tried flipping the stick magnets every which way, including endwise, but it couldn't hurt to try again. Can they become demagnetized? I suppose I could try to remagnetize them by petting with another magnet, but that seems a little off the wall. They still have some (approximately equal) magnetism left, as I determined with my trusty old hiking compass.

Phil Nelson

Not certain it will help here, but with a CT-100 it's best to remove the three static convergence magnets before trying to adjust anything. Then, on a flat surface, orient them so they all attract, and then replace them with a common pole -- doesn't matter which, N or S -- inserted first. RCA alignment procedures call for reversing a magnet if deemed necessary, and so some ancient flip of the magnet can make things difficult when setting up a restoration.

Pete