Convergence issues.

[Big Dave]

I have tried to get good convergence on my 16 and have failed miserably. I've been using a VCD I made up of color bars, crosshatch and an indian head test pattern (different from the one on Chuck Pharis's site). For the most part, I can get center decent. Top and bottom are also decent, but left and right R/G vertical lines don't come close. It's throwing a bunch of other stuff off. I can't see the misalignment that well with the crosshatch, but I sure can see on regular broadcast. I am going to replace the selenium pack with silicon diodes (might solve the problem). I placed the convergence yoke, putiry rings and blue lateral magnet back on the tube according to the clean areas on the neck (I didn't clean the tube off when I swapped out the cabinet).

What is the exact placement of the elements on a 21FJP? I have experimented with different positions and have it "almost right". When I went to adjust purity, turning the rings actually threw the convergence off. So, in addition to rotten convergence, I also have rotten purity. I know I sound like a total idiot, but I never could get a decent convergence on any color set I ever had. Any help is greatly appreciated.