SE yoke connection resoldering

[cjbaker]

Hello, I've started using my trusty old SE again after many years collecting dust, and I've noticed that the screen flickers once in awhile (the display switches to a static of horizontal lines for a few moments), and the geometry is slightly off, so I decided to take the paper guard off the analog board and look at the solder joints. After reading plenty of posts here (thanks to all!), I suspected that the solder joints on the yoke connector might be a problem, and sure enough, one of the joints is brown and looks wrong (see pictures). I think this connector is the yoke connector, right? Its wires lead to the white ring around the CRT.

To fix this, do I just need to remove the old solder and resolder it? Or does the burnt appearance indicate some further problem?

I suppose I'll wait until the solder joint is fixed to try to correct the geometry. The raster is too short on the left side, too tall on the right, and the margins are much smaller on the bottom and left than the top and right. My conclusion from reading other posts is that I should start by adjusting the yoke rings to move the raster up and over, and then try turning the 8 magnets around the CRT to correct the shape.

Thanks in advance for your guidance. I don't have much experience with a soldering iron, but I'd like to learn.

 

[cjbaker]

Well, I decided to just resolder the joint. The intermittent jumping picture seems to be fixed now. I got a solder gun and solder sucker on Amazon, heated the old solder and solder-sucked it off. As recommended in an online video, I added some new solder and sucked that off too to clean it up, which worked well. Then I added the final new solder. This was my first time soldering--it doesn't look perfect, but hopefully good enough. I also re-flowed the other joints which I've seen discussed as problematic: the remaining yoke connector joints, and the ones for the flyback.

The jitter was gone, but the geometry problem remained. I turned the two neck rings to shift the picture over, using bamboo skewers; that was easy. I tried turning the top-left magnet to stretch out the top-left corner of the raster a bit. I can bring the corner to the right spot, but there are still distortions. In general, the left side of the image is vertically shrunken, the right side is vertically stretched, and the left is slightly out of focus (the right is sharp). I've seen discussion of moving the whole yoke, sounds to me like that's what I might need to do, but I think I'll leave it for now since the distortion is really pretty minor.

 

[TjLaZer]

Looks like you did a good job. You can practice on old PC boards.

 

[cjbaker]

Thanks TjLazer, I'll have to find some old boards and get practicing.