Dennis & John..thanks for this interesting point about Tek "soul"..I have a SC502 & SC504 recently brought & I calibrated to a 0,3% in vert & Horizontal, with fine and crisp trace, and I wonder exactly what you unveiled..thanks guys.
Gabriel.
toggle quoted message
Show quoted text
--- In TekScopes@..., "Dennis Tillman" <dennis@...> wrote:
It also made it possible to keep the length of the CRT reasonable. Without
the mesh dome the CRT would have to be much longer.
This mesh dome makes possible many improvements in the 7000 series over the
earlier 500 series. But the price you pay is a fatter trace and the halo.
Once you understand the benefits and drawbacks of the mesh dome you can see
why Tek ultimately chose it.
However, there are many who long for the remarkably crisp trace of the 545
and 547 scopes and others designed prior to the mesh dome
Dennis.
-----Original Message-----
From: TekScopes@... [mailto:TekScopes@...] On Behalf
Of johncharlesgord
Sent: Saturday, October 06, 2012 12:04 AM
To: TekScopes@...
Subject: [TekScopes] Re: What causes thick trace and "halo" behind the
trace?
Jamie,
The 5440 is a much faster scope which uses a mesh dome beam diverging system
to give better deflection sensitivity, allowing a lower voltage but high
bandwidth vertical amplifier. The mesh dome causes the halo effect and some
general increase in spot size. It is a common phenomenon in the faster
scopes like the 465, 475, and almost all of the 7000 series.
--John Gord
--- In TekScopes@..., "imaradiostar" <jamietyson@> wrote:
I have a few older abused tek scopes with a clear fine trace.
Specifically, a 5110, a 5111, and an SC502. The trace is bright and only
about a mm wide. There is no "glow" around the trace on any of them- just
dark unlit screen.
I have a "new old stock" 5440 that I just bought on Ebay and an old 561A
that I revived and both have a slightly thicker trace with a "halo" or glow
behind the trace. It doesn't appear to relate to the chop or alt functions
as it's the same regardless of those settings. Focus seems to do little for
the problem.
It's a bit frustrating that my most beat up scope, a 5111 that arrived
with a broken chassis and major issues has become the nicest working scope!
Should I be looking for power supply ripple or should I suspect that some
of the high voltage supplies are off? Or is it perhaps something else?
Jamie
------------------------------------
Yahoo! Groups Links
