Re: Advice about buying a 7904


Hi Sean,
The revised March 1988 7104 Operators Manual says the display of the 7D01 Hardware Logic Analyzer and the 7D02 Software Logic Analyzer can cause permanent reduction in CRT microchannel plate gain; consequently, a permanent reduction in writing rate. For more information refer to "Reduction of Display Gain with Display Output Change" in the 7104 Service Manual.

Dennis Tillman W7pF

-----Original Message-----
From: [] On Behalf Of
Sent: Friday, May 29, 2020 10:09 PM
Subject: Re: [TekScopes] Advice about buying a 7904


To add to Harvey's excellent response, yes indeed most (all?) 7k plugins will work in any 7k mainframe. HOWEVER, there are at least a couple plugins (I cannot recall which ones right now, perhaps someone else knows off the top of their head) that explicitly must never be used in a 7104 because the way they drive the crt can cause damage to it. You absolutely could simply use the plugins you have for your 7104 in a 7904(A).


On Fri, May 29, 2020 at 05:53 PM, Reginald Beardsley wrote:

Please forgive me my ignorance, but for most of my life these things
were pure unobtainium for budgetary reasons. And as I was not an EE
and not allowed to touch the ones at work, there was no incentive to
torture myself by looking at catalogs of things I could not afford. Getting a 465 was a huge event for me.
And I don't mean all the work it took to repair it. I am acutely aware
of how fiddly adjusting the vertical amplifiers is. But when you get it right, wow!
Though in all honesty, I like my Dumont 1062 better as it does not have a fan.
It's only 60 MHz, but otherwise matches the 465 in features.

Can I use my 7104 plugins in a 7904 mainframe, albeit with reduced BW
and sweep speeds? That would greatly ease my concerns about using the
7104 on a regular basis. And make getting a 7904 mainframe pretty much a no-brainer.
Just a question of getting a good deal.

Is there a matrix which shows which plugins will work in which
mainframes? I'm really only interested in the vertical and horizontal
plugins. For the other stuff I have HP gear. I'm not aware of anything
Tek made that can compete with an 8566B or 8510C.


Dennis Tillman W7pF
TekScopes Moderator

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