There are things you can do. First thing I would try is using an external service degaussing coil to try and get the impurity to go away, then if it doesn't I would go through the purity adjustments and see if I could adjust it out. (Edge purity is highly dependent on deflection yoke position so doing a full by the book purity may fix it). If that doesn't fix purity maybe try a refrigerator magnet on the bell near the bad spot as a last ditch.

EDIT: to keep from going off topic others mentioned some sets are a pain to converge... I've found 2 things influence that bad convergence board parts (R,C and diodes), and convergence yoke placement and warping. Sometimes the yoke needs to be back or forward ~1/4" from where it's at to either have more range or overshot less, I've also seen some plastic yokes where one set of petals is angularly closer than it should be due to plastic degradation... That's not easy to deal with.
What probably gave me my worst headaches until I realized was a 19" metal cabinet Zenith a respondent to this thread sold me a while ago...I spent a bunch of time troubleshooting the board because of top hat diodes that looked like they'd been soldered in by Ray Charles, then finally realized that the convergence yoke was installed BACKWARDS and the red yoke petal was over the green gun and vice versa....It got really good when I fixed that.

The biggest question that I always had was exactly WHERE to place the parts on the neck of a 21fjp22(a), convergence clover, ETC, cause of the internal markings, you can't see where it goes like you can on later rectangular delta types, on which you can very easily see where to put it.

But I can never find a definitive answer for the rondies saying it goes, HERE!

SO, I have it placed exactly as it was on my GE CTC-15 clone set when I first got it, down to the mm. in placement.

So very true! With my 21AX, I did a lot of fiddling, looking for the position with maximum effect and then comparing with the un-dimensioned illustrations in the service literature, readjusting, round and round. The results I get for both purity and convergence on this rebuilt tube suggest to me that the replacement gun may be slightly rotated from nominal position.

Down to the mm is getting pretty serious!

Well, i took a ruler, and measured how far every part was on the clone was from the socket cap, and place that same distance on my RCA.

http://suzaku.live-evil.org/GE-ctc-15-clone.jpg

http://suzaku.live-evil.org/rca-ctc-16xl.jpg

that is assuming they were correct on the clone in the first place! :tears::D

My default is over the giant focus element that the 3guns go into at the end of the gun...some tubes leave it exposed, others you can peak under the dag , some have a red band and others you have to guess.

Perhaps +/- 0.25 inch would be adequate (for placement of neck convergence parts) :scratch2:

https://frank.pocnet.net/sheets/168/2/21CYP22.pdf

jr

As +/-0.25" is the range of adjustment, convergence can be within a few mm. on the edges and smack on in the center.

Great, thanks! So there is some hope.

Too bad, the service for this model have the complete setup only for the in-line CRT (at least indicates the preferred sequence for the convergence board adjustments), so I need to apply/use the "generic" delta gun alignment then... What is the most preferred documentation for learning that (if extra degaussing not solve the problem)?

About EDIT: inspired by the simple "Convergence?" thread title, I ended posting about it just here... ;-) but if moderators prefer to change this postings to a independent thread, I'm also happy :-)

So, I guess I will try and touch it up this Sat, gonna have to get to it soon anyway as one of the fans I have on the back is starting to make noise and has to be lubed, most likely due to the cold.

So I'll assume the parts on the neck are correct for now.
As mentioned, the biggest pain I have with it is the nonlinearity of the R/G horz lines on the right side, always been a pain on this set. :(

As suggested, gonna start with vertical height and linearity, and perhaps vertical and horizontal centering if needed, before going to convergence, however my test generator has no output to do height and linearity, I do have the Digital Video Essentials DVD, and hidden deep in a horrid to navigate menu system is the right tools and screens to do so, it's just a nightmare to find it!

If you mean purity process that's fairly simple. Degauss first. Turn down all screens except red (I sometimes cheat and use a pure red video field if I don't want to do grayscale), loosen the deflection yoke and slide back until it touches the convergence yoke...The picture should now look tie-dye with a red spot near center, adjust the neck purity rings until the red dot is centered then slide the deflection yoke forward until both full screen and best Purity is obtained (there's usually 1/2"-1" of wiggle room in the full screen range to allow adjustment for best edge purity) and lock it down there. Preform grayscale and check static convergence (the 2 can interact.... badly enough that if you swap CRTs you may have to do 2-3 consecutive Purity and static convergence adjustments before both are right)... Sometimes I've had to cheat purity by adjusting rings a bit with the yoke forward because the above by the book process didn't work as good as desired after a couple of tries.

Interesting, sounds simple.
Just at this moment I'm reading the post, I'm at work, but I checked this TV photos, since just now I remebered some... issue: I saw that the yoke is integrated to the convergence assembly. Even the static rings seems to be lying at same structure... oh-oh... maybe if I try at least to move the assembly sideways and back and forth, maintaning the rotation angle, to check?

Don't move the dual yoke assembly. The deflection yoke should be inside the assembly and held in place with wingnuts that slide in grooves on the assembly. You should be able to loosen the yoke wingnuts and pull back on them to move the deflection yoke independently of the convergence yoke and dual yoke assembly. RCA and Zenith adopted similar assemblies when they went to solid state.

And done. aside from putting the back on the set.

http://suzaku.live-evil.org/o1ne.jpg
http://suzaku.live-evil.org/t2wo.jpg

took a while to find the right pattern, buy i did find it!:D

http://suzaku.live-evil.org/done-1.jpg
http://suzaku.live-evil.org/done-2.jpg

and after an hour of messing with it...

Can never get it perfect, but who can with these things?

Looks pretty good to me! You did a good job on the edges.

Even the wrinkles in Jonathan Harris' face look good.