Electrostatic Deflection "Bunching" - Solved

[Tom Albrecht]

Here's what I mean when I refer to "bunching" of the vertical deflection. I put the .005 uF caps back in the set to demonstrate.

1. A moderate case of bunching. Note also the trapezoidal (or "keystone") image. This is all the vertical size I can get with the .005 uF caps.



2. A more severe case:



3. If you push the contrast up too far, it will go completely nuts:



Now, with the .01 uF caps in there, there is plenty of vertical deflection (the vertical size control has been backed off a great deal, and it still produces a full raster). The trapezoidal picture is gone. Most importantly, the "bunching" is gone, even in a picture like this, where the bright spot would normally have bunching:



I'll be trying this on my other identical set (a Sentinel) very soon. It has the same problem. I've seen this effect to various levels on other electrostatic sets as well, so it will be interesting to see if it fixes the problem in all cases.