Re: 465 Scan Expansion Mesh


Stan or Patricia Griffiths <w7ni@...>
 

dhuster@pb.k12.mo.us wrote:

And Stan, I don't know that I agree 100% about the mesh being a bad
deal compared to what the 535 had. I've never seen a burned CRT in a
scope with a mesh and you can't say that about the old ones. The
mesh diffused the beam enough that the CRT was pretty burn
resistant. To me, the �1 digit bobble of a digital scope is far
worse to look at than the fuzzy trace of a 465.

Dean
Hi Dean,

It is great to hear other opinions and views on this sort of thing especially
from someone who was as close to the situation as you have been.

I suspect the difference in burned phosphors was due to the change from P2 to
P31 for a standard phosphor in most general purpose scopes. Both of those
phosphors look very much alike to the eye, being blue-green in color. I
think that phoshor change took place about 1965 or so. Scopes shipped before
that time with P2 phosphors where MUCH easier to burn . . . I don't think I
have ever seen a CRT with a mesh and P2 at the same time . . .

Yes, I put some of that mesh under a regular optical microscope here and
found the same thing you did . . . it is etched rather than woven. I was
surprised to discover that . . .

Whether the fuzzy trace was a bad tradeoff or not is another one of those
opinion issues. I just talked to one guy who told me he could see stuff
(tiny wrinkles) in the trace of a 454 that just are not there in the display
of the same signal on a 475, even though the 475 has 50 MHz more bandwidth
and a much larger screen. The position I am coming from is that I was a
Sales Engineer for Tek at the time mesh CRT's were introduced and I can tell
you that MANY customers noticed the difference and were not pleased . . .
they always expected the new model to be better, in every respect, than the
one it replaced, sort of like cars. Well, they aren't always better in
performance. Sometimes they are better in price, instead. Sort of like cars
. . .

Stan
w7ni@easystreet.com

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