Hi Chuck,
Have you had the tube out of the scope and inspected for bits of broken glass inside the tube?
Regards
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On 3/13/2019 8:03 AM, Chuck Harris wrote:
I am certain that they are NOT all like this.... At least
not to the same degree mine is.
For instance, mine cannot, ever, under any circumstances
develop a straight trace at the center of the screen. It
always bows upwards.
The center should be the one place that is golden for any
CRT, as it is the sweet spot for the vertical deflection
plates, geometry, and the box lens.
The center should not be affected by the geometry control;
only the outer 1/4 of the screen. And, on further more
careful observation, the center wiggle on my CRT is not
affected by the geometry control... only the outer edges.
Most folks run into some trouble with the geometry setting
because they can't see, division-by-division what the
geometry setting is doing to the screen's distortion.
Displaying a grid, with 1 division/square, shows this up
very easily... allowing you to simply turn the geometry
from one side to the other, observing the effect, and
deciding what is least annoying to you.
Similarly, the Edge Focus, only affects the outer 1/8
of the screen.
I think it is probable that my scope has been the subject
of a series of Dr. Frankenstein experiments by its previous
owner. The scope was probably subject to a major hit, and
all of the broken bits of the case or front panel were
replaced.
There is probably a good reason why it was relegated to
the scrap bin.
-Chuck Harris
John Ferguson via Groups.Io wrote:
Chuck,
I'm a little surprised that someone hasn't surfaced to tell us that they were all
like that. Surely one of the thousands of participants on this wonderful site must
know, or have been there when these scopes were designed.
perplexing.
