Quote:
Originally Posted by Tom Albrecht
I agree the origin of the problem is in the HV sag, not the focus coil.
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Indeed, HV sag would be the most likely cause of the defocus of a bright picture on these sets, and should be addressed first. However, triode gun CRTs have a bad reputation for worse spot size growth with increasing beam current than tetrode designs.
Just saying that if that is the case, a little "dynamic focus" could improve the beam performance.
Of course, the focus coil would be difficult/impossible to drive at video frequencies, but it should be possible to provide focus correction fast enough to improve
average focus.
jr
09-11-2010, 07:23 PM
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