There's got to be some sort of art form to this. Would anyone be so kind as to describe the tricks and tips of using a degaussing coil? :)

Start 5-6 feet away from the screen. Hold the coil perpendicular to the tube face, and apply power. Rotate the coil so it is parallel to the tube face, and slowly move it in a circular pattern while approaching the screen. Get all the way up to the screen, and make sure to cover the entire screen area. Having the set turned on is optional, but makes for a nice psychedelic effect. After covering the whole screen area, keep, moving the coil in circles, while slowly backing away from the screen, to the original starting distance. Rotate the coil perpendicular again before cutting off the power.

Not difficult.

First rule: be away from the set when turning the current on or off.
Second rule (applies only to metal-cone CRTs): make sure the edge magnets are fully retracted into their shields.

It will be easier to tell what you're doing (and more fun) if the set is on.

Start 5 or 6 feet away, turn on the coil (just plug it in if there is no switch).

Approach the set, and with the coil flat (parallel with) the face or side you are working on, swirl the coil in circles over the face, top and sides. See beautiful swirling colors in the picture.

Gradually move away from the face while making swirling motions, and finally turn the coil at a right angle to the set. You should see the swirling colors gradually decrease until there is no effect.

While away from the set, turn off / unplug the coil.

This shouldn't take more than 10 or 20 seconds. The coil will be getting warm and eventually could overheat.

Now you are ready to adjust purity and fine convergence.

Added note: especially in sets that do not have automatic degaussing, you should have the set facing the direction it will face in use. Hypothetically, if you degauss, then set purity, and later turn the set, only a degaussing may be needed and not a fresh purity adjustment. Note I said "hypothetically."

Got it pretty dang close, on every color except red. I just can't get the blue adjusted out of the red in the upper right corner when a red screen is displayed. The red convergence is also off, but only vertically off, horizontally it's right on.

Sometimes adding a small magnet around the bell of the crt (like a refrigerator magnet) will fix this. Have you noticed that many shower curtains have little disc magnets made into the bottoms? When we throw an old one away I save those. You can stack them up, move them around, until you get correct purity in that spot, then glue them in place.

Got it pretty dang close, on every color except red. I just can't get the blue adjusted out of the red in the upper right corner when a red screen is displayed. The red convergence is also off, but only vertically off, horizontally it's right on.

I have a 21axp22 with the same issue. Nothing I do corrects the situation including moving deflection yoke in and out. It is possible that one of the purity magnets has become weak. The other possibility is that the shadow mask is slightly distorted in that area caused by heat in the evacuation oven. My purity issue also is most evident on the red screen.

Have you turned the edge magnet more than one turn?

I believe it goes like this (but I haven't messed with mine for some time, so I hope I remember correctly) (Bob please verify):

You start with them retracted into their shield cups. then as you turn the screw, their effect changes polarity from helpful to harmful with each 180 degrees turn, getting stronger with each turn as you screw them out of the shield cups. Have you turned the one near your trouble spot more than one turn to get a stronger or weaker effect?

Are you referring to the magnets on the yoke?

Are you referring to the magnets on the yoke?

No, the ones around the edge of the tube face.

Y'know, I replaced the picture tube and have had everything in this set taken apart at one time or another, and I don't remember any.

This is the CTC-36, 19HNP22 tube. Here's a shot of where I am now.....

Hey those are really nice sets when they work right I use to have a few of those wish I had one again maybe one will follow me home from the Early Television convention next year...Timothy

Y'know, I replaced the picture tube and have had everything in this set taken apart at one time or another, and I don't remember any.

This is the CTC-36, 19HNP22 tube. Here's a shot of where I am now.....

OOPs - since Bob mentioned a 21AXP, I thought that's what you were asking about. No later sets had edge magnets, although some much later sets (especially with huge CRTs like 35 inch and above) used small trimmer magnets stuck in various places. On that rectangular tube, it could be a slight shadow mask deformation as stated, and playing with extra small magnets might help.