I tried pulling the plug on trace rotation, and on
y-axis rotation, and the only effect was the trace
rotated one line width clockwise.
I guess that eliminates them, and any fringing effects
from the current in their shielded wires as they pass
down the CRT's funnel section under the mumetal shield.
What I am seeing is pretty much exactly what I would
expect to see if the box lens got moved off axis a little
bit. A hard hit on the bottom (top?) of the scope might
do that, I suppose.
-Chuck Harris
Chuck Harris wrote:
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I did take the CRT out, and did not see anything
rattling about inside the shield, but it is possible
that a magnet could be stuck up in there somewhere.
The trace rotation could be eliminated by pulling
its plug. I have been meaning to try that, but
keep forgetting.
If you hold a magnet anywhere near the screen, the
trace moves drastically. Which you might expect
as the speed of the electrons from the MCP to the
screen isn't all that fast.
-Chuck Harris
Ed Breya via Groups.Io wrote:
I see that possibly adding correction magnets to fix the problem has been mentioned here somewhat. Here's another idea, that may seem far-fetched, but not impossible: What if the 2467 CRTs originally did have small tweaking magnets attached, to assist in geometry. What if the adhesive or tape or whatever used became ineffective after many years, and let go, so the magnets would come loose and stick somewhere, like inside the mu shield? t wouldn't be obvious, because it wouldn't be rattling around loose inside the scope.
Has anyone seen any sign of magnetic assistance on these CRTs, or anything in the manuals, etc? Just wondering.
One other far-fetched one: Is there any possibility of the trace rotation coil popping out of place, putting it off-axis?
Ed
