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Which way do I turn the knobs on the focus board of an ECP pj to OVER focus and UNDER focus the beam?

I'm reading through the Guy Kuo focusing guide and he mentiones over and under focusing when working on astig setup.
 

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Sir


The rotation that gives a dot in some haze is for flare adjustment, the other rotation is for stig, one usually advances Contrast quite high for that, use a dots-only pattern if possible and do not leave anything up at high contrast for more than a few moments or damage could result.
 

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Quote:
Originally Posted by Outsider787
Which way do I turn the knobs on the focus board of an ECP pj to OVER focus and UNDER focus the beam?

I'm reading through the Guy Kuo focusing guide and he mentiones over and under focusing when working on astig setup.
You can't use that method on an ES focus tube. You don't turn the ES focus to set the roundness of dots.
 

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On my Esprit 2000 you turn the focus knob clockwise which increases the focus voltage to adjust the stig rings. I believe that is known as an overfocus condition. Check my drawing. The electrons leave the cathode in a cone shape, kinda like spray paint from a can. The electrostatic field (or magnetic field) redirects the cone of electrons back toward a single point. Field too strong, overfocus. Field too weak, underfocus. Field just right, focus. I hope that's right and not 180 degrees out.
 
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