Vertical Centering - how does it work?

[maxhifi]

Originally Posted by miniman82

Everything about the CT-100 is complicated...

This is why I was confused - check it out, I stuck together the two relevant images from the CTC-2 manual. The vertical centre choke and the two pots connected in reverse were rather hard to figure out... well, it's easier now that the two diagrams are beside each other and not four pages apart.

What I am thinking of doing, is using some big (say 2200uF) electrolytic caps to isolate the vertical yoke from the vertical output stage, and then using a small (say 0-15V, 1A) power supply to bias it with DC, in series with a choke which has a high AC impedance to allow the vertical signal through, therefore keeping DC out of the pincushion transformer and vertical output transformer. If the vertical output winding is 14 ohms, I think 2200uF with a low enough ESR should be enough to avoid problems with phase shift. Maybe I will bypass it with a smaller capacitor to avoid any problems which could be caused at higher frequencies. This would have to be replicated for both sections of the vertical winding, to keep things symmetrical. Then I could dial in vertical centering to within a millimeter, and keep the RCA going well into the 21st century.

I know, I know, it is a lot of fuss to make over a 45 year old non- top of the line TV, but this thing is absolutely pristine, inside and out, and the CRT checks as new, with PERFECT colour tracking. I watch it every day, and I am always impressed at just how natural skin tones are, and the sound is also fantastic and free of any buzz or hum which plagues my other old TVs.