Using Google, I was able to get some great advice on convergence from previous posts on this group. But I feel I have a problem that the convergence magnet rings cannot solve.
I am fixing a Samsung CT-5012V2 television. The deflection yoke was bad and I replaced it with an equivalent yoke the electronics store gave me. It's not the exact same part number, but it's either that or order an expensive yoke off the Internet. Somehow new deflection yokes are much cheaper in my country than any yoke on the Internet.
I used a cross hatch pattern bitmap and displayed it full screen on my computer and fed the video out from the computer to the TV. Its the cheapest pattern generator I have.
I got the convergence on the vertical lines almost perfect. The problem is with the horizontal lines on the cross hatch pattern. The convergence is good at the centre, but near the top and the bottom of the picture, the green separates from the red and blue and moves closer to the top and bottom of the screen. The red and blue cnvergence remains good for the whole picture.
It appears that there is a greater vertical deflection for the green than the red or blue. The green moves closer to the top and bottom of the picture while the red and blue remains together. The rings at the back of the tube cannot solve this. I determined through experimentation that the centre pair adjusts the red and blue relative to each other and the back pair adjusts the position of both the red and blue. They do not affect the green.
Does anyone have a clue on how to solve this?