A "meshless" CRT would have to be much longer to achieve the same deflection (screen display size) at the bandwidths of the upper 7000 series. The fuzziness and other abberations due to the electron optics are annoying, but that's the tradeoff that was made. There's also more electronic noise as BW goes up, which would be unavoidable even without a mesh. I think the 7600 mainframes, being of much lower bandwidth, are meshless, allowing for much sharper traces and slightly bigger screens.
Ed
toggle quoted message
Show quoted text
--- In TekScopes@..., d.seiter@... wrote:
Re trace width- Most, if not all, of the 7K series scopes have an expansion mesh in the CRT which effectively blurs the trace to some degree. There has been some debate about whether a mesh-less design would be any sharper at the usually higher frequencies of the 7k scopes, but it's a moot point. Typically, looking at the same signal with a 547 and a 7704A, the 547 will be much sharper. From a previous post- Tek even spec'd the spot size of the 547 at .004".
Which reminds me; I still need to fire up my main 547 again to see if it's trace has returned. I wish days had 30 hours....
-Dave
----- Original Message -----
From: "Fabio Eboli" <fabioeb@...>
To: TekScopes@...
Sent: Thursday, June 28, 2012 12:21:22 AM
Subject: Re: [TekScopes] 7704A, should I go for it?
Thank you david and all for your opinions.
Yesterday I had problems with personal email and
send the messages using online yahoo form, but the
second message seem that has gone lost, I cannot find
it into the messages list.
Anyway I was saying that the noise is important
to me for an everyday scope, I was curious if
there was a source where I can control if a mainframe
has a fan or not.
Also as for trace thickness, I prefer remain confined
into the 7k series, the plugins flexibility is wondeful.
I imagine that it's easier for a lower bandwidth to
show a better defined trace, Is there any noticeable
difference in the 7k series ?
At the end I'll go for it, hoping that it will be an
easy enough repair.
Rob can you confirm if the 7704A shows any dot without
plugins installed?
Fabio.
David < davidwhess@... > ha scritto:
I have been using the Nichicon PW series as general replacements since
they are inexpensive, long life, low impedance, and available up to
450 volts. Unfortunately I have found no equivalent axial leaded
----------------------------------------------------------
This message was sent using IMP, the Internet Messaging Program.
