Astigmatism and uneven focus

[peter scott]

Astigmatism is probably the result of gas in the CRT. I think you will find it gets better after more extended use. That was my experience anyway.

As for edge focus I have that problem too and have tried various things to no avail although the "push about coil" centring tends to worsen the edge focus but if you have the rubber screen mask rather than the earlier more rigid one then you can move the CRT withing the mask for centring. I did wonder if the edge focus might be caused by the surrounding steelwork being magnetised but no amount of degaussing changes it and I couldn't sense any magnetism with a compass anyway.

You can see my edge defocus particularly in the corners.



Peter