Re: GEC Junior Fineline project.
Hi GM,
One ring tends to shift the whole picture diagonally. The other ring tends to shift it diagonally in the opposite direction. Moving both rings together also has an effect so it is usually very easy to get the picture where you want it.
If it's cutting off the corner, that is often because the scan coils are too far back. The beam is running into the cone of the CRT before getting to the screen. Try slackening off the scan coil clamp and (after making sure the coils are free to move) make sure they are as far forward as they will go.
The small magnets used to correct raster distortion are usually small cylinders 3/4" long. These are very weak. The magnetised tip of a screwdriver is more than powerful enough to experiment with.
It would be worth posting some pictures of the raster with a test card and also the scan coil assembly.
All the best
Nick
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