Date   

Re: 7A26 edge distortion

Roger Evans
 

Raymond,

A simple test - lift one end of each of CR860, CR880 and see if the signal behaves as it should.

Roger


Re: 7A26 edge distortion

Roger Evans
 

Raymond,

The picture suggests that the signal might be switching from the full bandwidth to the 20MHz version at around the 40% level. Have you looked at the biassing of Q860, Q880 and also for leakage in Q860, Q880, CR860 CR880? It seems to me that the problem must be related to the semiconductors since a purely linear circuit should affect positive and negative edges equally.

Regards,

Roger


Re: 7A26 edge distortion

John Gord
 

Raymond,
The 7A26 has a number of small ceramic trim caps of a design that has proved to be prone to going open circuit. You may have failures at the same point of both channels, unlikely as that seems. I would suspect C1432 and C2432 in particular, since they seem likely to affect the highest frequency signals. Try turning them: if they have gone open circuit turning them will have little to no effect. If those are not the problem, try others!
--John Gord

On Tue, Oct 20, 2020 at 07:20 PM, Raymond Domp Frank wrote:


Dear experts,
One of my 7A26's distorts a 1 ns falling edge (PG506, followed by 50 Ohm
attenuator) as shown in this photo:

https://groups.io/g/TekScopes/album?id=255438

Both channels show the same. I've looked for what I considered obvious
problems like the Display Switching area (7A26 SM dwg 4) but haven't found the
cause yet. Other 7A26's show the edge fine.
Any ideas?

Thanks,
Raymond


Tek 2430A collapse screen image

jwdtek@...
 

Does anyone know what can cause the screen image to collapse and only show a large dot in the middle of the screen on a TEK 2430?


Tek 2430A collapsed screen image

jwdtek@...
 

Does anyone know what can cause the screen image to collapse and only show a large dot in the middle of the screen on a TEK 2430? I'm new to this group. I post a photo in "Tek 2430A collapse Screen image"

Thanks!


Re: 7A26 edge distortion

John Gord
 

Is the rising edge OK?
--John Gord

On Tue, Oct 20, 2020 at 07:20 PM, Raymond Domp Frank wrote:


Dear experts,
One of my 7A26's distorts a 1 ns falling edge (PG506, followed by 50 Ohm
attenuator) as shown in this photo:

https://groups.io/g/TekScopes/album?id=255438

Both channels show the same. I've looked for what I considered obvious
problems like the Display Switching area (7A26 SM dwg 4) but haven't found the
cause yet. Other 7A26's show the edge fine.
Any ideas?

Thanks,
Raymond


Re: Tek 4654M; No Trace, No +5V, No +95V; Help

adesilva_1999@...
 

Agreed. As long as we can get to the 10 kV as required, it does not matter how many stages it needs to have. I wonder what made them use the same part number for two entirely different things - one with the tripler and the rest of the HV circuitry and one that has just the tripler!


Re: Tek 4654M; No Trace, No +5V, No +95V; Help

Michael W. Lynch
 

Both 455 and 465M use the same U550 by TEK Part number (152-0635-00) and the same transformer T550 by part number. TEK calls the device a 1.5X multiplier in the semiconductor book, I believe that the 3X notation in the schematics is in error. One way or another they both cannot be correct. In the end, I built a 3 Diode/3 Capacitor Multiplier and I get the appropriate 10kVDC PDA Voltage. To me. this is a 3 stage device and what TEK calls a "1.5X multiplier" in the catalog.

The 465/475 Series uses a stand alone Multiplier, without the extra circuitry built in. X-Rays of that device show 6 diodes and 6 caps. TEK calls this Device out as a "3X multiplier" in the semiconductor book. PDA on 465/475 is something like 16kV, so it obviously uses a more complex multiplier. To me, this is a 6 stage device and what TEK Calls a "3X Multiplier" in the catalog.

The TEK specifications are, at least, consistent between the two aforementioned devices.

The confusion is in the specs where the AC voltage at theT550 is typically measured in RMS or Peak voltage but the Multiplier is Rated using and supplied with Peak/Peak AC voltage. The 455/465M Transformer T550 delivers about 2.4kV RMS or 3.39kV PEAK or 6.78kV p/p; therefore a 1.5 multiplier, supplied with 6.78kV p/p would deliver 10.2kV DC. So if you TRIPLE the Peak Voltage or One and a Half Times the P-P voltage, you get the same results.

I am using the Cockroft-Walton configuration for both my multiplier circuits. They produce the desired PDA voltages in both units.

Interestingly, the tutorial link shows a Cockcroft-Walton configuration in one example. The 455 uses one full and one half section and the 465/475 configuration uses 3 full sections. Perhaps this is where TEK got the 1 1/2X and 3X specs??

I know mine all work, so that is all that I care about. Not sure why TEK describes these as they do, but they should know what they are talking about. They certainly do not make it easy to figure out.

There is a ton of discussion about this very topic in the TEKScopes archives if anyone cares to search and read. The discussion involves people in the group who are a whole lot smarter than I am.

Thanks!
--
Michael Lynch
Dardanelle, AR


Re: Tek 7934

Jim Cotton
 

I have two 7904 frames and two 7904a frames looking for new homes located in Kalamazoo, MI.  One of the 7904a has no trace, the others worked when last used.  Appropriate time bases and vertical modules are available too also a flexible extender for service.  Are you anywhere close?
I hate to ship them since the CRTs get trashed in shipping frequently.  Local pickup.
Jim, n8qoh
On Tue, Oct 20, 2020 at 10:49 PM, Chris J via groups.io<cjuried=yahoo.com@groups.io> wrote: I hear you Up to 1.1 THz with the Millimeter wave converter. Amazing!

https://www.rohde-schwarz.com/us/products/test-and-measurement/network-analyzers/high-end-network-analyzers_229190.html


Sincerely,    
 
Chris
https://juriedengineering.com/

FCC Licensed RF Coordinator
Audio Engineering Society (AES) Member  


This e-mail, and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail, you are hereby notified that any distribution or copying of this email, and any attachments thereto, is strictly prohibited. If you have received this email in error, please immediately notify me at (954) 478-4355 and permanently delete the original and any copy of any e-mail and any printout thereof.

On Tuesday, October 20, 2020, 10:40:04 PM EDT, Tom Lee <tomlee@ee.stanford.edu> wrote:





Keysight actually has VNA (ok, PNA; to me it's always going to be VNA)
options that go to 1.5THz, which is pretty amazing. I do not have that
setup, as much as I wish I did. I haven't checked recently to see what
R&S or Anritsu have these days, but I know that as of a few years ago,
both had offerings beyond 100GHz. I've got an E8361A, which tops out at
67GHz. It's an older model (obsolete, by Keysight's official
declaration), but it's served my students well. I may have to upgrade
soon, though, as one of my students has her heart set on working at
220GHz for some radar idea she has.

--Cheers,
Tom



--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 10/20/2020 19:13, Chris J via groups.io wrote:
Tom,

What are you using for your 70 GHz work at Stanford? Rohde and Schwarz is the only game in town or are there other players?


Sincerely,
 
Chris
https://juriedengineering.com/

FCC Licensed RF Coordinator
Audio Engineering Society (AES) Member


This e-mail, and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail, you are hereby notified that any distribution or copying of this email, and any attachments thereto, is strictly prohibited. If you have received this email in error, please immediately notify me at (954) 478-4355 and permanently delete the original and any copy of any e-mail and any printout thereof.






On Tuesday, October 20, 2020, 10:03:59 PM EDT, Tom Lee <tomlee@ee.stanford.edu> wrote:





Ah yes, so many options. Collect the entire set of plug-ins! Spouses
love them, too. I am very fond of the 7000 series. I'd always lusted
after the 7104 in particular (1GHz of pure analog goodness), after
seeing one in college and learning about the MCP crt -- a miraculous
device. The lab manager didn't allow riff-raff like us undergrads to
touch it. I think the catalog price for that scope with its plug-ins
exceeded $30k, so I don't blame him.

My first 7000 was a 7904. One of the plug-ins had a problem with the
on-screen display showing alien hieroglyphs. "Must be a bad character
ROM". Looked at the documentation and saw that there was no ROM, at
least not a digital ROM. Tweaking a couple of /pots /fixed it. I
wondered what evil genius could have conceived of such a thing. It
turned out to be none other than Barrie Gilbert (who sadly passed away
early this year). I feel lucky to have gotten to know him. I wish I'd
recorded his impromptu lecture about that character generator when I
told him my story about encountering it. He explained how it had led to
his miraculous sine shaper, which then turned into a pure-analog
trigonometric function chip (computes every trig function -- hyperbolic
ones, included -- /and /their inverses). Brilliant.

--Tom


Re: Nice 556 still available for free but pickup only

Grayson Evans
 

Hi Chris,
You are welcome to come pick it up. Ft. Lauderdale to here is about an hour and 15 maybe 30 I think.
If you are interested, send me an email and I will send you an address.

Grayson


Re: Tek 7934

Chris J
 

I hear you Up to 1.1 THz with the Millimeter wave converter. Amazing!

https://www.rohde-schwarz.com/us/products/test-and-measurement/network-analyzers/high-end-network-analyzers_229190.html


Sincerely,    
 
Chris
https://juriedengineering.com/

FCC Licensed RF Coordinator
Audio Engineering Society (AES) Member  


This e-mail, and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail, you are hereby notified that any distribution or copying of this email, and any attachments thereto, is strictly prohibited. If you have received this email in error, please immediately notify me at (954) 478-4355 and permanently delete the original and any copy of any e-mail and any printout thereof.

On Tuesday, October 20, 2020, 10:40:04 PM EDT, Tom Lee <tomlee@ee.stanford.edu> wrote:





Keysight actually has VNA (ok, PNA; to me it's always going to be VNA)
options that go to 1.5THz, which is pretty amazing. I do not have that
setup, as much as I wish I did. I haven't checked recently to see what
R&S or Anritsu have these days, but I know that as of a few years ago,
both had offerings beyond 100GHz. I've got an E8361A, which tops out at
67GHz. It's an older model (obsolete, by Keysight's official
declaration), but it's served my students well. I may have to upgrade
soon, though, as one of my students has her heart set on working at
220GHz for some radar idea she has.

--Cheers,
Tom



--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 10/20/2020 19:13, Chris J via groups.io wrote:
Tom,

What are you using for your 70 GHz work at Stanford? Rohde and Schwarz is the only game in town or are there other players?


Sincerely,
 
Chris
https://juriedengineering.com/

FCC Licensed RF Coordinator
Audio Engineering Society (AES) Member


This e-mail, and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail, you are hereby notified that any distribution or copying of this email, and any attachments thereto, is strictly prohibited. If you have received this email in error, please immediately notify me at (954) 478-4355 and permanently delete the original and any copy of any e-mail and any printout thereof.






On Tuesday, October 20, 2020, 10:03:59 PM EDT, Tom Lee <tomlee@ee.stanford.edu> wrote:





Ah yes, so many options. Collect the entire set of plug-ins! Spouses
love them, too. I am very fond of the 7000 series. I'd always lusted
after the 7104 in particular (1GHz of pure analog goodness), after
seeing one in college and learning about the MCP crt -- a miraculous
device. The lab manager didn't allow riff-raff like us undergrads to
touch it. I think the catalog price for that scope with its plug-ins
exceeded $30k, so I don't blame him.

My first 7000 was a 7904. One of the plug-ins had a problem with the
on-screen display showing alien hieroglyphs. "Must be a bad character
ROM". Looked at the documentation and saw that there was no ROM, at
least not a digital ROM. Tweaking a couple of /pots /fixed it. I
wondered what evil genius could have conceived of such a thing. It
turned out to be none other than Barrie Gilbert (who sadly passed away
early this year). I feel lucky to have gotten to know him. I wish I'd
recorded his impromptu lecture about that character generator when I
told him my story about encountering it. He explained how it had led to
his miraculous sine shaper, which then turned into a pure-analog
trigonometric function chip (computes every trig function -- hyperbolic
ones, included -- /and /their inverses). Brilliant.

--Tom


Re: Nice 556 still available for free but pickup only

Grayson Evans
 

I was only there Saturday, near the front inside.


Re: Tek 7934

Tom Lee
 

Keysight actually has VNA (ok, PNA; to me it's always going to be VNA) options that go to 1.5THz, which is pretty amazing. I do not have that setup, as much as I wish I did. I haven't checked recently to see what R&S or Anritsu have these days, but I know that as of a few years ago, both had offerings beyond 100GHz. I've got an E8361A, which tops out at 67GHz. It's an older model (obsolete, by Keysight's official declaration), but it's served my students well. I may have to upgrade soon, though, as one of my students has her heart set on working at 220GHz for some radar idea she has.

--Cheers,
Tom



--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 10/20/2020 19:13, Chris J via groups.io wrote:
Tom,

What are you using for your 70 GHz work at Stanford? Rohde and Schwarz is the only game in town or are there other players?


Sincerely,
Chris
https://juriedengineering.com/

FCC Licensed RF Coordinator
Audio Engineering Society (AES) Member


This e-mail, and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail, you are hereby notified that any distribution or copying of this email, and any attachments thereto, is strictly prohibited. If you have received this email in error, please immediately notify me at (954) 478-4355 and permanently delete the original and any copy of any e-mail and any printout thereof.






On Tuesday, October 20, 2020, 10:03:59 PM EDT, Tom Lee <tomlee@ee.stanford.edu> wrote:





Ah yes, so many options. Collect the entire set of plug-ins! Spouses
love them, too. I am very fond of the 7000 series. I'd always lusted
after the 7104 in particular (1GHz of pure analog goodness), after
seeing one in college and learning about the MCP crt -- a miraculous
device. The lab manager didn't allow riff-raff like us undergrads to
touch it. I think the catalog price for that scope with its plug-ins
exceeded $30k, so I don't blame him.

My first 7000 was a 7904. One of the plug-ins had a problem with the
on-screen display showing alien hieroglyphs. "Must be a bad character
ROM". Looked at the documentation and saw that there was no ROM, at
least not a digital ROM. Tweaking a couple of /pots /fixed it. I
wondered what evil genius could have conceived of such a thing. It
turned out to be none other than Barrie Gilbert (who sadly passed away
early this year). I feel lucky to have gotten to know him. I wish I'd
recorded his impromptu lecture about that character generator when I
told him my story about encountering it. He explained how it had led to
his miraculous sine shaper, which then turned into a pure-analog
trigonometric function chip (computes every trig function -- hyperbolic
ones, included -- /and /their inverses). Brilliant.

--Tom


Re: 7A26 edge distortion

 

On Wed, Oct 21, 2020 at 04:20 AM, Raymond Domp Frank wrote:


I've looked for what I considered obvious problems like the Display Switching
area
The fact that the circuit is current driven makes following the signal a bit inconvenient...

Raymond


7A26 edge distortion

 

Dear experts,
One of my 7A26's distorts a 1 ns falling edge (PG506, followed by 50 Ohm attenuator) as shown in this photo:

https://groups.io/g/TekScopes/album?id=255438

Both channels show the same. I've looked for what I considered obvious problems like the Display Switching area (7A26 SM dwg 4) but haven't found the cause yet. Other 7A26's show the edge fine.
Any ideas?

Thanks,
Raymond


Re: Tek 7934

Chris J
 

type fix... Have always loved my Tek!


Sincerely,    
 
Chris
https://juriedengineering.com/

FCC Licensed RF Coordinator
Audio Engineering Society (AES) Member  


This e-mail, and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail, you are hereby notified that any distribution or copying of this email, and any attachments thereto, is strictly prohibited. If you have received this email in error, please immediately notify me at (954) 478-4355 and permanently delete the original and any copy of any e-mail and any printout thereof.

On Tuesday, October 20, 2020, 10:09:13 PM EDT, Raymond Domp Frank <hewpatek@gmail.com> wrote:





On Wed, Oct 21, 2020 at 04:03 AM, Tom Lee wrote:


I'd always lusted after the 7104 in particular (1GHz of pure analog goodness),
after seeing one in college and learning about the MCP crt -- a miraculous
device. The lab manager didn't allow riff-raff like us undergrads to touch it.
I think the catalog price for that scope with its plug-ins exceeded $30k, so I
don't blame him.
My 7104 has been kept in the dark, hidden from view at a research lab, only to be lent out when needed, and it shows.
It's in like new condition and guess where I keep it?

Raymond


Re: Tek 7934

Chris J
 

Raymond,

My first scope was a 2215, which I still have today. I have since then added and 2465B which I refurbished and use on a daily basis. I also recently acquired a 2221A and 2445 which I have rebuilt the PSU's on. Have also love my Tek!


Sincerely,    
 
Chris
https://juriedengineering.com/

FCC Licensed RF Coordinator
Audio Engineering Society (AES) Member  


This e-mail, and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail, you are hereby notified that any distribution or copying of this email, and any attachments thereto, is strictly prohibited. If you have received this email in error, please immediately notify me at (954) 478-4355 and permanently delete the original and any copy of any e-mail and any printout thereof.

On Tuesday, October 20, 2020, 10:09:13 PM EDT, Raymond Domp Frank <hewpatek@gmail.com> wrote:





On Wed, Oct 21, 2020 at 04:03 AM, Tom Lee wrote:


I'd always lusted after the 7104 in particular (1GHz of pure analog goodness),
after seeing one in college and learning about the MCP crt -- a miraculous
device. The lab manager didn't allow riff-raff like us undergrads to touch it.
I think the catalog price for that scope with its plug-ins exceeded $30k, so I
don't blame him.
My 7104 has been kept in the dark, hidden from view at a research lab, only to be lent out when needed, and it shows.
It's in like new condition and guess where I keep it?

Raymond


Re: Tek 7934

Chris J
 

Tom,

What are you using for your 70 GHz work at Stanford? Rohde and Schwarz is the only game in town or are there other players? 


Sincerely,    
 
Chris
https://juriedengineering.com/

FCC Licensed RF Coordinator
Audio Engineering Society (AES) Member  


This e-mail, and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail, you are hereby notified that any distribution or copying of this email, and any attachments thereto, is strictly prohibited. If you have received this email in error, please immediately notify me at (954) 478-4355 and permanently delete the original and any copy of any e-mail and any printout thereof.

On Tuesday, October 20, 2020, 10:03:59 PM EDT, Tom Lee <tomlee@ee.stanford.edu> wrote:





Ah yes, so many options. Collect the entire set of plug-ins! Spouses
love them, too. I am very fond of the 7000 series. I'd always lusted
after the 7104 in particular (1GHz of pure analog goodness), after
seeing one in college and learning about the MCP crt -- a miraculous
device. The lab manager didn't allow riff-raff like us undergrads to
touch it. I think the catalog price for that scope with its plug-ins
exceeded $30k, so I don't blame him.

My first 7000 was a 7904. One of the plug-ins had a problem with the
on-screen display showing alien hieroglyphs. "Must be a bad character
ROM". Looked at the documentation and saw that there was no ROM, at
least not a digital ROM. Tweaking a couple of /pots /fixed it. I
wondered what evil genius could have conceived of such a thing. It
turned out to be none other than Barrie Gilbert (who sadly passed away
early this year). I feel lucky to have gotten to know him. I wish I'd
recorded his impromptu lecture about that character generator when I
told him my story about encountering it. He explained how it had led to
his miraculous sine shaper, which then turned into a pure-analog
trigonometric function chip (computes every trig function -- hyperbolic
ones, included -- /and /their inverses). Brilliant.

--Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 10/20/2020 18:45, Chris J via groups.io wrote:
I was doing some comparison research here, http://w140.com/tekwiki/wiki/7000-series_scopes and am really qute intrigued. There are so many fantastic options. I would love to use the Mainframe with the TDR plugins along with some high bandwidth oscilloscope and spectrum analyser plugins. Where to get the stuff in Fort Lauderdale, FL is the question.


Sincerely,
 
Chris
https://juriedengineering.com/

FCC Licensed RF Coordinator
Audio Engineering Society (AES) Member


This e-mail, and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail, you are hereby notified that any distribution or copying of this email, and any attachments thereto, is strictly prohibited. If you have received this email in error, please immediately notify me at (954) 478-4355 and permanently delete the original and any copy of any e-mail and any printout thereof.






On Tuesday, October 20, 2020, 09:35:30 PM EDT, Sergey Kubushyn <ksi@koi8.net> wrote:





On Tue, 20 Oct 2020, Tom Lee wrote:

There is a HUGE difference -- 7934 is a 500MHz _STORAGE_ scope, the best
they ever made. It is rare as hens' teeth and it worth its price.

However it might be not worth hunting for 7934. 400MHz 7834 is exactly same,
just a bit slower. Everything else is same including the crown jewel,
variable persistence. Those are much easier to get in good working condition
(still require extensive refurbishing because of old age but that is true
for everything of that vintage) and significantly cheaper.

I was unsuccessfully hunting for 7934 myself for a couple of years but then
gave up and now I have two nice working 7834 scopes. Also have two 7104 ones
that are also finest ones ever made with their microchannel CRT and 1GHz
real time bandwidth (that extends significantly beyond that if one is not
lazy to spend time on fine-tuning) but those are not replacement for a
storage scope like 7834.

There is also dual-beam 7844 that is also nice to have -- I also have two of
those :)

If you are not absolutely determined to use a 7934 with those plug-ins, there
are many other options. A 7704 would work just fine with those PIs, for
example, and can often be found for free (or nearly so).

--Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 10/20/2020 12:17, Chris J via groups.io wrote:
    Hello Group,

    I am interested in getting my hand on a 7934. I have a 7S12 TDR/SAMPLER
    with the S-6 Sampling Head and the S-52 Pulse Generator Head, in beautiful
    condition. I would really love to put her in use and also build up a 7934
    with some nice plug-ins. Any thoughts on where I may find a reasonable
    priced unit? This would be an great addition to my home lab. Thank you.


    Sincerely,
      Chris
    https://juriedengineering.com/

    FCC Licensed RF Coordinator
    Audio Engineering Society (AES) Member
---
******************************************************************
*  KSI@home    KOI8 Net  < >  The impossible we do immediately.  *
*  Las Vegas  NV, USA  < >  Miracles require 24-hour notice.  *
******************************************************************









Re: Tek 7934

 

On Wed, Oct 21, 2020 at 04:03 AM, Tom Lee wrote:


I'd always lusted after the 7104 in particular (1GHz of pure analog goodness),
after seeing one in college and learning about the MCP crt -- a miraculous
device. The lab manager didn't allow riff-raff like us undergrads to touch it.
I think the catalog price for that scope with its plug-ins exceeded $30k, so I
don't blame him.
My 7104 has been kept in the dark, hidden from view at a research lab, only to be lent out when needed, and it shows.
It's in like new condition and guess where I keep it?

Raymond


Re: Tek 7934

Tom Lee
 

Ah yes, so many options. Collect the entire set of plug-ins! Spouses love them, too. I am very fond of the 7000 series. I'd always lusted after the 7104 in particular (1GHz of pure analog goodness), after seeing one in college and learning about the MCP crt -- a miraculous device. The lab manager didn't allow riff-raff like us undergrads to touch it. I think the catalog price for that scope with its plug-ins exceeded $30k, so I don't blame him.

My first 7000 was a 7904. One of the plug-ins had a problem with the on-screen display showing alien hieroglyphs. "Must be a bad character ROM". Looked at the documentation and saw that there was no ROM, at least not a digital ROM. Tweaking a couple of /pots /fixed it. I wondered what evil genius could have conceived of such a thing. It turned out to be none other than Barrie Gilbert (who sadly passed away early this year). I feel lucky to have gotten to know him. I wish I'd recorded his impromptu lecture about that character generator when I told him my story about encountering it. He explained how it had led to his miraculous sine shaper, which then turned into a pure-analog trigonometric function chip (computes every trig function -- hyperbolic ones, included -- /and /their inverses). Brilliant.

--Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 10/20/2020 18:45, Chris J via groups.io wrote:
I was doing some comparison research here, http://w140.com/tekwiki/wiki/7000-series_scopes and am really qute intrigued. There are so many fantastic options. I would love to use the Mainframe with the TDR plugins along with some high bandwidth oscilloscope and spectrum analyser plugins. Where to get the stuff in Fort Lauderdale, FL is the question.


Sincerely,
Chris
https://juriedengineering.com/

FCC Licensed RF Coordinator
Audio Engineering Society (AES) Member


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On Tuesday, October 20, 2020, 09:35:30 PM EDT, Sergey Kubushyn <ksi@koi8.net> wrote:





On Tue, 20 Oct 2020, Tom Lee wrote:

There is a HUGE difference -- 7934 is a 500MHz _STORAGE_ scope, the best
they ever made. It is rare as hens' teeth and it worth its price.

However it might be not worth hunting for 7934. 400MHz 7834 is exactly same,
just a bit slower. Everything else is same including the crown jewel,
variable persistence. Those are much easier to get in good working condition
(still require extensive refurbishing because of old age but that is true
for everything of that vintage) and significantly cheaper.

I was unsuccessfully hunting for 7934 myself for a couple of years but then
gave up and now I have two nice working 7834 scopes. Also have two 7104 ones
that are also finest ones ever made with their microchannel CRT and 1GHz
real time bandwidth (that extends significantly beyond that if one is not
lazy to spend time on fine-tuning) but those are not replacement for a
storage scope like 7834.

There is also dual-beam 7844 that is also nice to have -- I also have two of
those :)

If you are not absolutely determined to use a 7934 with those plug-ins, there
are many other options. A 7704 would work just fine with those PIs, for
example, and can often be found for free (or nearly so).

--Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 10/20/2020 12:17, Chris J via groups.io wrote:
  Hello Group,

  I am interested in getting my hand on a 7934. I have a 7S12 TDR/SAMPLER
  with the S-6 Sampling Head and the S-52 Pulse Generator Head, in beautiful
  condition. I would really love to put her in use and also build up a 7934
  with some nice plug-ins. Any thoughts on where I may find a reasonable
  priced unit? This would be an great addition to my home lab. Thank you.


  Sincerely,
    Chris
  https://juriedengineering.com/

  FCC Licensed RF Coordinator
  Audio Engineering Society (AES) Member
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