Topics

11801C and the T1331 error: lost factory TB calibration data.

freemail8877
 

Hi, first post to this forum. I have very much enjoyed browsing, and thought I could contribute with this information. Thanks guys for keeping this forum so interesting. The T1331 (loss of battery backed up information in the Time Base/Controller board NVRAMs) seems to be an error to avoid, by backing up/replacing the NVRAMs on that board. See e.g. the topic "Saving A5 Timing Board NVRAM calibration constants CSA803 (A/C) and 11801(B/C)" for how to. To answer some question raised there, here is some information from the Tektronix documentation.

In the 11801C User Manual (070-9971-01), on p. 3-112 (p.262/440 of the pdf), I found this:

"Initializing and Erasing Nonvolatile RAM:
...
The following information is not lost:
...
- Factory calibration constants, which are established at the factory and cannot be changed by the user or by the 11801C

- Enhanced Accuracy calibration constants, which are periodically calculated and updated
..."

And in the 11801C Service Manual (070-9972-02) on p. 6-108 (p.244/286) it is stated:

"Time Base Calibration Errors:
...
Calibration data to enhance the time interpolator linearity is stored in NVRAM on the Time Base/Controller board. If this NVRAM fails, a T1331 error occurs during power-up diagnostics. The values are written at the factory with the GPIB command CALCORRECTION.

CALCORRECTION<ui>:N

where <ui> = 0..32 and N = -128..+127

CAUTION: The calibration enhancement values are set at time of manufacture. There is no query form of this command. Do NOT reset these values. If a T1331 failure occurs during extended power-up diagnostics or you suspect a time interpolator error, contact Tekronix factory service.

A T1331 failure causes all N values in the 33 ui locations to be reset to zero. The oscilloscope will still run, but with decreased accuracy in the time interpolator linearity. Resetting NVRAM with the Teksecure feature does not affect the Time Base/Controller board NVRAM."

So now the big question seems to be:
Does anybody in the group know, or know who might know, how the factory calibration procedure is, how the 33 N-values are determined?

Does anybody know how much the accuracy is affected?

Monica A.

PS:
I have for many years been a Tektronix scopes addict, It started with the fascination in late 60's and early 70's, when I saw and used a 535 with Type CA plugin at my father's workplace. Being interested in electronics, this was heaven. I now have a 7904a with sampling and non-sampling plugins, a 7704a which rudely enough let the smoke out of the power supply, a newly acquired 7603, and a 468. The design and layout of the fronts are just so great. An 11801C is on the way in, so I have used search a lot lately. It is said to pass POST, and a picture shows the graticule on the screen, so hopefully it's OK.

Reginald Beardsley
 

very interesting information. Thanks.

The 11801 series has what has to be the worst FW anyone has ever written for a scope as you will shortly experience first hand. But they really are *fantastic* despite that. Just watch out for the bugs. If I execute the wrong sequence of operations I get a 1-2 order of magnitude error in the times on my 11801.

IIRC they will interpolate to 200 femtoseconds. Even at coax velocity of 2e8 m/s, that's so small a distance as to be rather "challenging". As in measuring 40 microns "challenging".

Without a detailed theory of operation, schematics, etc, it is nearly impossible to divine what Tek was doing. I'd love to know. The circuitry is so fast, that even 30 years later, Keysight can just barely beat the rise time of the 11801 calibrator.

I've got 2x SD-22, 4x SD-26 and a nice crisp 11801, with another 11801 and SD-26 for parts in CA and an SD-24 in transit. Honest, all I need now is just *one* SD-32 ;-)

Prepare to be amazed. With an SD-24 or SD-26 & the calibrator, you can test RF connectors to 20 GHz as fast as you can connect and disconnect them.

Have Fun!
Reg

Jim Ford
 

Hi, Reg.I am so envious of the 11000 series toys, er I mean tools, you have!  For now, I will have to be content with my 7000 series sampling gear including two S-4 heads.  Not that easy to even get a stable trace on the screen.  But, at a few hundred dollars, the price is right these days. I agree with you that this is a golden age for test equipment acquisition.   May it continue for posterity!Enjoy!Jim Ford Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------From: "Reginald Beardsley via Groups.Io" <pulaskite=yahoo.com@groups.io> Date: 8/17/19 5:40 PM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] 11801C and the T1331 error: lost factory TB calibration data. very interesting information.  Thanks.The 11801 series has what has to be the worst FW anyone has ever written for a scope as you will shortly experience first hand.  But they really are *fantastic* despite that.  Just watch out for the bugs.  If I execute the wrong sequence of operations I get a 1-2 order of magnitude error in the times on my 11801.IIRC they will interpolate to 200 femtoseconds.  Even at coax velocity of 2e8 m/s, that's so small a distance as to be rather "challenging".  As in measuring 40 microns "challenging".Without a detailed theory of operation, schematics, etc, it is nearly impossible to divine what Tek was doing.  I'd love to know.   The circuitry is so fast, that even 30 years later, Keysight can just barely beat the rise time of the 11801 calibrator.I've got 2x SD-22,  4x SD-26 and a nice crisp 11801, with another 11801 and SD-26 for parts in CA and an SD-24 in transit.  Honest, all I need now is just *one* SD-32 ;-)Prepare to be amazed.   With an SD-24 or SD-26 & the calibrator, you can test RF connectors to 20 GHz as fast as you can connect and disconnect them.Have Fun!Reg

Albert Otten
 

[This topic continued from https://groups.io/g/TekScopes/message/158778 ]
I know the discussion was about the later CSA803(A/B/C) and 11801(B/C). I have an 803 and an 803A. The U500/U511 batteries in my 803 were dead, so factory calibration constants would have been lost and I could freely experiment with the CCALCORRECTION command. To my surprise this command was unknown to the 803. This is also confirmed by the commands lists in U810/U910 EPROM images. The CSA803 Service Reference is now available at Tekwiki (thanks Håkan!). There is no reference at all in that manual to factory set calibration constants. The corresponding texts in the C version was obviously added later on.
So I am convinced that in the CSA803 nothing is lost when an A5 time base board Dallas chip dies.

[[BTW in the pdf manuals provided by Tek you won't find words in the added text with an ordinary search. Likely Tek used a custom character coding in the added text. If you copy-paste for instance T1331 from the added text into the search field then you will find the other instances of T1331 in the added text.]

Albert

On Thu, Aug 15, 2019 at 04:21 PM, freemail8877 wrote:


Hi, first post to this forum. I have very much enjoyed browsing, and thought I
could contribute with this information. Thanks guys for keeping this forum so
interesting. The T1331 (loss of battery backed up information in the Time
Base/Controller board NVRAMs) seems to be an error to avoid, by backing
up/replacing the NVRAMs on that board. See e.g. the topic "Saving A5 Timing
Board NVRAM calibration constants CSA803 (A/C) and 11801(B/C)" for how to. To
answer some question raised there, here is some information from the Tektronix
documentation.

In the 11801C User Manual (070-9971-01), on p. 3-112 (p.262/440 of the pdf),
I found this:

"Initializing and Erasing Nonvolatile RAM:
...
The following information is not lost:
...
- Factory calibration constants, which are established at the factory and
cannot be changed by the user or by the 11801C

- Enhanced Accuracy calibration constants, which are periodically calculated
and updated
..."

And in the 11801C Service Manual (070-9972-02) on p. 6-108 (p.244/286) it is
stated:

"Time Base Calibration Errors:
...
Calibration data to enhance the time interpolator linearity is stored in NVRAM
on the Time Base/Controller board. If this NVRAM fails, a T1331 error occurs
during power-up diagnostics. The values are written at the factory with the
GPIB command CALCORRECTION.

CALCORRECTION<ui>:N

where <ui> = 0..32 and N = -128..+127

CAUTION: The calibration enhancement values are set at time of manufacture.
There is no query form of this command. Do NOT reset these values. If a T1331
failure occurs during extended power-up diagnostics or you suspect a time
interpolator error, contact Tekronix factory service.

A T1331 failure causes all N values in the 33 ui locations to be reset to
zero. The oscilloscope will still run, but with decreased accuracy in the time
interpolator linearity. Resetting NVRAM with the Teksecure feature does not
affect the Time Base/Controller board NVRAM."

So now the big question seems to be:
Does anybody in the group know, or know who might know, how the factory
calibration procedure is, how the 33 N-values are determined?

Does anybody know how much the accuracy is affected?

Monica A.

PS:
I have for many years been a Tektronix scopes addict, It started with the
fascination in late 60's and early 70's, when I saw and used a 535 with Type
CA plugin at my father's workplace. Being interested in electronics, this was
heaven. I now have a 7904a with sampling and non-sampling plugins, a 7704a
which rudely enough let the smoke out of the power supply, a newly acquired
7603, and a 468. The design and layout of the fronts are just so great. An
11801C is on the way in, so I have used search a lot lately. It is said to
pass POST, and a picture shows the graticule on the screen, so hopefully it's
OK.

 

Everyone:
The following subject threads with their email responses are "very" or "some what" relevant to this discussion of fixing lost cal data in the 11K series. These are the TekScopes archive email numbers and the dates they were posted:

VERY RELEVANT
Programming a new NVRAM (Dallas DS1220Y) with a EPROM programmer
By Dennis Tillman W7PF · #119113 · 10/01/15
By Dennis Tillman W7PF · #119111 · 10/01/15

Repairing an expired NVRAM batteryin11A32,11A33,11A34, 11A72 plugins
By Vince Vielhaber · #118126 · 08/19/15
By Dennis Tillman W7PF · #118121 · 08/19/15
By Dennis Tillman W7PF · #118115 · 08/19/15
By Dennis Tillman W7PF · #118063 · 08/16/15

Addendum: Repairing an expired NVRAM battery in 11A32, 11A33, 11A34, 11A72 plugins
By Dennis Tillman W7PF · #118098 · 08/17/15
11801 Sampling Head
By Dennis Tillman W7PF · #119056 · 09/29/15 ·
By Dennis Tillman W7PF · #119043 · 09/28/15 ·

SOME-WHAT RELEVANT
Tektronix 11000 series vs. modern scopes. Sampling rate and aliasing questions.
By ditter2 · #96382 · 07/26/13

11A33 - what are possible problems, gotchas, and revisions?
By cheater cheater · #96393 · 07/27/13
By fjh001 · #96406 · 07/27/13

I hope this helps. Often, although it may not be the exact answer to your specific problem, it will guide you to a solution. If that is the case please share it with the forum so we can add it to our "bag of tricks".

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Albert Otten
Sent: Friday, August 23, 2019 9:22 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 11801C and the T1331 error: lost factory TB calibration data.

[This topic continued from https://groups.io/g/TekScopes/message/158778 ] I know the discussion was about the later CSA803(A/B/C) and 11801(B/C). I have an 803 and an 803A. The U500/U511 batteries in my 803 were dead, so factory calibration constants would have been lost and I could freely experiment with the CCALCORRECTION command. To my surprise this command was unknown to the 803. This is also confirmed by the commands lists in U810/U910 EPROM images. The CSA803 Service Reference is now available at Tekwiki (thanks Håkan!). There is no reference at all in that manual to factory set calibration constants. The corresponding texts in the C version was obviously added later on.
So I am convinced that in the CSA803 nothing is lost when an A5 time base board Dallas chip dies.

[[BTW in the pdf manuals provided by Tek you won't find words in the added text with an ordinary search. Likely Tek used a custom character coding in the added text. If you copy-paste for instance T1331 from the added text into the search field then you will find the other instances of T1331 in the added text.]

Albert
On Thu, Aug 15, 2019 at 04:21 PM, freemail8877 wrote:


Hi, first post to this forum. I have very much enjoyed browsing, and
thought I could contribute with this information. Thanks guys for
keeping this forum so interesting. The T1331 (loss of battery backed
up information in the Time Base/Controller board NVRAMs) seems to be
an error to avoid, by backing up/replacing the NVRAMs on that board.
See e.g. the topic "Saving A5 Timing Board NVRAM calibration constants
CSA803 (A/C) and 11801(B/C)" for how to. To answer some question
raised there, here is some information from the Tektronix documentation.

In the 11801C User Manual (070-9971-01), on p. 3-112 (p.262/440 of
the pdf), I found this:

"Initializing and Erasing Nonvolatile RAM:
...
The following information is not lost:
...
- Factory calibration constants, which are established at the factory
and cannot be changed by the user or by the 11801C

- Enhanced Accuracy calibration constants, which are periodically
calculated and updated ..."

And in the 11801C Service Manual (070-9972-02) on p. 6-108 (p.244/286)
it is
stated:

"Time Base Calibration Errors:
...
Calibration data to enhance the time interpolator linearity is stored
in NVRAM on the Time Base/Controller board. If this NVRAM fails, a
T1331 error occurs during power-up diagnostics. The values are written
at the factory with the GPIB command CALCORRECTION.

CALCORRECTION<ui>:N

where <ui> = 0..32 and N = -128..+127

CAUTION: The calibration enhancement values are set at time of manufacture.
There is no query form of this command. Do NOT reset these values. If
a T1331 failure occurs during extended power-up diagnostics or you
suspect a time interpolator error, contact Tekronix factory service.

A T1331 failure causes all N values in the 33 ui locations to be reset
to zero. The oscilloscope will still run, but with decreased accuracy
in the time interpolator linearity. Resetting NVRAM with the Teksecure
feature does not affect the Time Base/Controller board NVRAM."

So now the big question seems to be:
Does anybody in the group know, or know who might know, how the
factory calibration procedure is, how the 33 N-values are determined?

Does anybody know how much the accuracy is affected?

Monica A.

PS:
I have for many years been a Tektronix scopes addict, It started with
the fascination in late 60's and early 70's, when I saw and used a 535
with Type CA plugin at my father's workplace. Being interested in
electronics, this was heaven. I now have a 7904a with sampling and
non-sampling plugins, a 7704a which rudely enough let the smoke out of
the power supply, a newly acquired 7603, and a 468. The design and
layout of the fronts are just so great. An 11801C is on the way in, so
I have used search a lot lately. It is said to pass POST, and a
picture shows the graticule on the screen, so hopefully it's OK.




--
Dennis Tillman W7PF
TekScopes Moderator

 

For some unexpected reason the formatting of my previous post was lost so here it is again in what I hope will be a more readable version:

Everyone:
The following subject threads with their email responses are "very" or "some what" relevant to this discussion of fixing lost cal data in the 11K series.
These are the TekScopes archive email numbers and the dates they were posted:

VERY RELEVANT
Programming a new NVRAM (Dallas DS1220Y) with a EPROM programmer
By Dennis Tillman W7PF · #119113 · 10/01/15
By Dennis Tillman W7PF · #119111 · 10/01/15

Repairing an expired NVRAM battery in 11A32, 11A33, 11A34, 11A72 plugins
By Vince Vielhaber · #118126 · 08/19/15
By Dennis Tillman W7PF · #118121 · 08/19/15
By Dennis Tillman W7PF · #118115 · 08/19/15
By Dennis Tillman W7PF · #118063 · 08/16/15

Addendum: Repairing an expired NVRAM battery in 11A32, 11A33, 11A34, 11A72 plugins
By Dennis Tillman W7PF · #118098 · 08/17/15

SOME-WHAT RELEVANT
11801 Sampling Head
By Dennis Tillman W7PF · #119056 · 09/29/15 ·
By Dennis Tillman W7PF · #119043 · 09/28/15 ·

Tektronix 11000 series vs. modern scopes. Sampling rate and aliasing questions.
By ditter2 · #96382 · 07/26/13

11A33 - what are possible problems, gotchas, and revisions?
By cheater cheater · #96393 · 07/27/13
By fjh001 · #96406 · 07/27/13

I hope this helps. Often, although it may not be the exact answer to your specific problem, it will guide you to a solution. If that is the case please share it with the forum so we can add it to our "bag of tricks".

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Albert Otten
Sent: Friday, August 23, 2019 9:22 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 11801C and the T1331 error: lost factory TB calibration data.

[This topic continued from https://groups.io/g/TekScopes/message/158778 ] I know the discussion was about the later CSA803(A/B/C) and 11801(B/C). I have an 803 and an 803A. The U500/U511 batteries in my 803 were dead, so factory calibration constants would have been lost and I could freely experiment with the CCALCORRECTION command. To my surprise this command was unknown to the 803. This is also confirmed by the commands lists in U810/U910 EPROM images. The CSA803 Service Reference is now available at Tekwiki (thanks Håkan!). There is no reference at all in that manual to factory set calibration constants. The corresponding texts in the C version was obviously added later on.
So I am convinced that in the CSA803 nothing is lost when an A5 time base board Dallas chip dies.

[[BTW in the pdf manuals provided by Tek you won't find words in the added text with an ordinary search. Likely Tek used a custom character coding in the added text. If you copy-paste for instance T1331 from the added text into the search field then you will find the other instances of T1331 in the added text.]

Albert
On Thu, Aug 15, 2019 at 04:21 PM, freemail8877 wrote:


Hi, first post to this forum. I have very much enjoyed browsing, and
thought I could contribute with this information. Thanks guys for
keeping this forum so interesting. The T1331 (loss of battery backed
up information in the Time Base/Controller board NVRAMs) seems to be
an error to avoid, by backing up/replacing the NVRAMs on that board.
See e.g. the topic "Saving A5 Timing Board NVRAM calibration constants
CSA803 (A/C) and 11801(B/C)" for how to. To answer some question
raised there, here is some information from the Tektronix documentation.

In the 11801C User Manual (070-9971-01), on p. 3-112 (p.262/440 of
the pdf), I found this:

"Initializing and Erasing Nonvolatile RAM:
...
The following information is not lost:
...
- Factory calibration constants, which are established at the factory
and cannot be changed by the user or by the 11801C

- Enhanced Accuracy calibration constants, which are periodically
calculated and updated ..."

And in the 11801C Service Manual (070-9972-02) on p. 6-108 (p.244/286)
it is
stated:

"Time Base Calibration Errors:
...
Calibration data to enhance the time interpolator linearity is stored
in NVRAM on the Time Base/Controller board. If this NVRAM fails, a
T1331 error occurs during power-up diagnostics. The values are written
at the factory with the GPIB command CALCORRECTION.

CALCORRECTION<ui>:N

where <ui> = 0..32 and N = -128..+127

CAUTION: The calibration enhancement values are set at time of manufacture.
There is no query form of this command. Do NOT reset these values. If
a T1331 failure occurs during extended power-up diagnostics or you
suspect a time interpolator error, contact Tekronix factory service.

A T1331 failure causes all N values in the 33 ui locations to be reset
to zero. The oscilloscope will still run, but with decreased accuracy
in the time interpolator linearity. Resetting NVRAM with the Teksecure
feature does not affect the Time Base/Controller board NVRAM."

So now the big question seems to be:
Does anybody in the group know, or know who might know, how the
factory calibration procedure is, how the 33 N-values are determined?

Does anybody know how much the accuracy is affected?

Monica A.

PS:
I have for many years been a Tektronix scopes addict, It started with
the fascination in late 60's and early 70's, when I saw and used a 535
with Type CA plugin at my father's workplace. Being interested in
electronics, this was heaven. I now have a 7904a with sampling and
non-sampling plugins, a 7704a which rudely enough let the smoke out of
the power supply, a newly acquired 7603, and a 468. The design and
layout of the fronts are just so great. An 11801C is on the way in, so
I have used search a lot lately. It is said to pass POST, and a
picture shows the graticule on the screen, so hopefully it's OK.




--
Dennis Tillman W7PF
TekScopes Moderator





--
Dennis Tillman W7PF
TekScopes Moderator

Reginald Beardsley
 

I'm beginning to think I need to make a femtosecond adjustable trombone line. Though the horizontal display jitter is more important as it says failing part in the video display.

BTW If you'll forgive a gloat, I got an SD-24 yesterday via ebay for $250 + shipping. Return address on the label said "Tektronix, Inc" :-) It is *so* sweet. Now if I can just get an SD-32 for $500.

John Griessen
 

On 8/23/19 3:37 PM, Reginald Beardsley via Groups.Io wrote:
I got an SD-24 yesterday via ebay for $250 + shipping. Return address on the label said "Tektronix, Inc":-) It is*so* sweet.
So it must have been Tek ebay-selling old stock that had been lurking. New old stock!

Bob Koller
 

Good deal on the SD-24!
CHIPXS on ebay, is the Tektronix "Country Store", as it used to be called, RAMS now.
They have a physical location, and are open to the public on the 1st and 3rd Thursdays of the month.
I visit almost every time they are open. The items listed on eBay are not available in the store, but there are tons of other stuff!

Reginald Beardsley
 

I plan to browse chipxs regularly. This is hardly an NOS SD-24. Last cal was 2011 due next in 2013. Measured rise times are ~14 ps with uncertainties of 4 ps. I am extremely pleased with it.

I did some calculations this morning. With an adjustable shorted stub on a 0.0001" reading micrometer head, the reflection would shift ~25 femtoseconds for each 0.0001" movement.

At 5 ps/div and 5120 samples we've got samples at ~10 femtosecond intervals. So measuring timebase nonlinearity is rather challenging.

I don't think any piece of gear I have has been as just plain amazing. The idea that it is 30 year old technology blows me away. I just wish I had better service data for it. I'm quite alarmed that after being idle for a few months I now have display jitter even after warming up for several hours.

I'd love to know who designed it and whether they are still alive.

Bob Koller
 

Reg,

The display jitter;
Is this timing/trigger related, or a problem with the display, ie. CRT circuitry proper?

Leo Bodnar
 

On Sat, Aug 24, 2019 at 05:06 PM, Reginald Beardsley wrote:
I'd love to know who designed it and whether they are still alive.
I think most heads were designed by Agoston Agoston. Other than that:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This product was made possible by the dedicated efforts of a group of inspired, tireless, and often times ingenious individuals of the design team.

The following is a list of a few of the cast of many that contributed to the development of this oscilloscope.

Design Team:
Mark Anderson
Brian Colony
John DeLacy
Rob DeVoe
Jim Edwards
Larry Hattery
Tim Holte
Roy Kaufman
Jim Lamb
Les Larson
Chan Lee
Jim Long
Ben McCarroll
Clark Morgan
Jim Peterson
Jim Schlegel
Bob Simpson
Ken Smith
David White
Wayne Wilburn

Contributing Engineers:
Ray Blohm
Thomas Dye
Scott Halsted
Ron Henricksen
Steve Herring
Bev Kramlich
Mehrab Sedeh
Jim Stanley
Gil Stephens

Engineering Support:
Bob Chandler
Hilde Cochran
John Eskeldson
Pam Fodrea
Lorna Goedel
Dick Griffin
John Hazard
Diane Kemper
Beverly McClenathan
Jerry Sternes
Wally Sutton
Pat Wiley

Manuals:
Brian Diehm
Amy Farrell
Susan Grace
Julie Leonetti
Krystn McCaleb
Chuck Melikian
Roland Parenteau
David Powe
Mark Stade
Carolyn Strong

Manufacturing:
Tim Bennington-Davis
Donna Brown
Jerry Brucken
Kevin Cosgrove
Lew Cummings
Jeanne Eick
Jerry Feickert
Berdine Garner
Clark Jarvis
Paulette Jesse
Murlan Kaufman
Phil Lloyd
Woody Ngincharoen
Tina Noll
Howard Nutt
Carol Parks
Al Phillips
Steve Ratner
Doug Rowe
Bill Schell
Colleen Swanson
Mark Swenson
Ron Tegner
Rod Van Loon
Walt Ventgen

Marketing/Service:
Denny Chamberlin
Roger Ensrud
Tom Freeman
Theresa Graf
Ivan Jackson
Dennis Kucera
Paul Kristof
Ray Blohm
John Boatwright
Betty Bonham
Bob Bousquet
Jim Carter
Dennis Chamberlin
Jo Chi
John Cooper
Jerry Coulter
Connie DeClerck
Laszlo Dobos
Tom Dye
Brad Figg
Dean Gehnert
Ted Gerlinger
Larry Hershiser
Ken Holland
Will Hott
Shirley Humphreys
David Irwin
Stan Kaveckis
Ray Kazlauskas
Hedy Leidelmeyer
Roy Lewallen
Ken Longgrear
Tina Newkirk
Reba Norris
Oris Nussbaum
Mike O'Shanecy
Janet Peters
Barbara Ports
V. Prasannan
Mary Rehse
John Rettig
Glen Rollins
Ava Stupek
Dan Taylor
Erik Teose
Mark Tilden
Jan Todd
Harold Vandecoevering
Mona Webber
Vaughn Weidel
Bob Windham

Reginald Beardsley
 

Wow!!! Leo, where did you find that information? Does anyone reading this know if any of them might have some schematics in a box some where? I'd really like to prevent these from all dying off for lack of repair data. And if you've worked around a packrat, you know who they are. So if someone recognizes the name of a packrat they worked with who might still be around, please drop me a private email.

I have been having a blast with my SD-24. Being able to see the SMA-F to SMA-M connection separately from the N-F to N-M connection on an adapter which is ~32 mm long is incredible. I could sort of manage it using the calibrator output and a tee, but the mismatch produced by parallel 50 ohm loads at the tee obscured things. Lots of reflections in the SMA tee to sort out.

It's especially fun for me coming from reflection seismology because I'm so used to interpreting time domain data in the frequency domain by inspection. I'm still getting used to having complex reflection coefficients instead of the pure real coefficients of elasticity, but the wave equation is still the same and transmission lines are *much* simpler than 3D.

All I need now is an SD-32 at a sensible price.

The jitter I'm referring to is video system jitter. It makes me very nervous not having any data for it. Can it be repaired without data? Sure, but that's a long slog even with very simple gear. And these are anything but simple.

BTW To return to the thread topic, has anyone investigated substituting a GPSDO for the timebase clock? It would seem to me that one of Leo's units would completely obviate the T1331 issue. But the errors might be gate and divider delays in which case it would be device specific. However, in that case I'd question whether they would be the same after 30 years.

Have Fun!
Reg

 

Hi Leo,

The S-4 and S-6 were designed by George Fry. They were a radical departure from the previous, much slower sampling heads. I once asked George why they were faster and he said it was because he saw the problem in terms of a wave front moving through the sampling gates. George is alive and well. He sells custom hearing aids in the Portland area.

A few years ago I visited Agoston Agoston in Beaverton. I'm not sure when he left Tek but I don't believe he designed the newer heads for the 11K series. Right after he left Tek he formed HyperLabs and produced a series of sampling plugins that are the same form factor as the S series plugins. That's why I don't think he ever designed anything for the 11K series. His S series heads had better specs than the Tek heads.
Here are the plugins HyperLabs made:
HL-11 100 pS 50Ω BNC SAMPLING HEAD
HL-12 100 pS 10 KΩ BNC SAMPLING HEAD
HL-13 20 pS 50Ω, K (SMA), SAMPLING HEAD
HL-14 <35 pS 50Ω, K (SMA), TDR HEAD
HL-15 25 pS PHOTONICS HEAD
HL-16 25 pS, 50Ω, K (SMA), PULSE GENERATOR HEAD
Hyperlabs is still in business. You can read about what they are up to at
http://www.hyperlabsinc.com/about-us.aspx

I have datasheets somewhere for each of these sampling heads but I never saw a price list so I have no idea how much they sold for. In 20 years searching for them on eBay I have never come across any of them.

When I was at his house we did not discuss the sampling heads. His company is now making TDR based systems that test and characterize the performance of extremely fast cables. His wife worked at Tek at the time of my visit.

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Leo Bodnar
Sent: Saturday, August 24, 2019 3:47 PM

On Sat, Aug 24, 2019 at 05:06 PM, Reginald Beardsley wrote:
I'd love to know who designed it and whether they are still alive.
I think most heads were designed by Agoston Agoston. Other than that:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This product was made possible by the dedicated efforts of a group of inspired, tireless, and often times ingenious individuals of the design team.

The following is a list of a few of the cast of many that contributed to the development of this oscilloscope.

Design Team:
Mark Anderson
Brian Colony
John DeLacy
Rob DeVoe
Jim Edwards
Larry Hattery
Tim Holte
Roy Kaufman
Jim Lamb
Les Larson
Chan Lee
Jim Long
Ben McCarroll
Clark Morgan
Jim Peterson
Jim Schlegel
Bob Simpson
Ken Smith
David White
Wayne Wilburn

Contributing Engineers:
Ray Blohm
Thomas Dye
Scott Halsted
Ron Henricksen
Steve Herring
Bev Kramlich
Mehrab Sedeh
Jim Stanley
Gil Stephens

Engineering Support:
Bob Chandler
Hilde Cochran
John Eskeldson
Pam Fodrea
Lorna Goedel
Dick Griffin
John Hazard
Diane Kemper
Beverly McClenathan
Jerry Sternes
Wally Sutton
Pat Wiley

Manuals:
Brian Diehm
Amy Farrell
Susan Grace
Julie Leonetti
Krystn McCaleb
Chuck Melikian
Roland Parenteau
David Powe
Mark Stade
Carolyn Strong

Manufacturing:
Tim Bennington-Davis
Donna Brown
Jerry Brucken
Kevin Cosgrove
Lew Cummings
Jeanne Eick
Jerry Feickert
Berdine Garner
Clark Jarvis
Paulette Jesse
Murlan Kaufman
Phil Lloyd
Woody Ngincharoen
Tina Noll
Howard Nutt
Carol Parks
Al Phillips
Steve Ratner
Doug Rowe
Bill Schell
Colleen Swanson
Mark Swenson
Ron Tegner
Rod Van Loon
Walt Ventgen

Marketing/Service:
Denny Chamberlin
Roger Ensrud
Tom Freeman
Theresa Graf
Ivan Jackson
Dennis Kucera
Paul Kristof
Ray Blohm
John Boatwright
Betty Bonham
Bob Bousquet
Jim Carter
Dennis Chamberlin
Jo Chi
John Cooper
Jerry Coulter
Connie DeClerck
Laszlo Dobos
Tom Dye
Brad Figg
Dean Gehnert
Ted Gerlinger
Larry Hershiser
Ken Holland
Will Hott
Shirley Humphreys
David Irwin
Stan Kaveckis
Ray Kazlauskas
Hedy Leidelmeyer
Roy Lewallen
Ken Longgrear
Tina Newkirk
Reba Norris
Oris Nussbaum
Mike O'Shanecy
Janet Peters
Barbara Ports
V. Prasannan
Mary Rehse
John Rettig
Glen Rollins
Ava Stupek
Dan Taylor
Erik Teose
Mark Tilden
Jan Todd
Harold Vandecoevering
Mona Webber
Vaughn Weidel
Bob Windham




--
Dennis Tillman W7PF
TekScopes Moderator

Leo Bodnar
 

On Sun, Aug 25, 2019 at 12:54 AM, Dennis Tillman W7PF wrote:

A few years ago I visited Agoston Agoston in Beaverton. I'm not sure when he
left Tek but I don't believe he designed the newer heads for the 11K series.
I have probably concluded it rather than established it. In 1987 Aki was with Tek, in 1992 he was already with Hyperlabs. 11800 came out in late 1980's?
Agoston Agoston is listed as an inventor in dual TDR head design https://patentimages.storage.googleapis.com/6e/80/e3/84f58712244c9d/US4755742.pdf which is, essentially what SD-24 is http://w140.com/tekwiki/images/f/f0/SD24_4.jpg
Leo

Egge Siert
 

Hi To All,

Around April this year I uploaded the most relevant SD-Patent Papers in a special Folder on TekScopes. named:

Patent Papers SD_heads e.a.

Enjoy.

Greetings,

Egge Siert

Leo Bodnar
 

On Sun, Aug 25, 2019 at 12:48 AM, Reginald Beardsley wrote:
All I need now is an SD-32 at a sensible price.
What are you going to use it for?
I have two SD-30 that I use interchangeably that I have bought broken and fixed: one had blown termination resistors, another - faulty trigger pick-off hardline.
I don't trust *any* SD heads, even sold as guaranteed working. My approach with them: if it works - it's a bonus.
SD series had really bad manufacturing quality track record. From delaminating PCB gold plating to cracked solder to tin whiskers to missing bond wires to dying EEPROMs.
I reckon S-series will still be alive and kicking while SD-series will perish in time.
Cheers
Leo

Reginald Beardsley
 

These are just toys for an old man. I bought my 11801 because of the CSA803A plots that you send out with your pulsers. I thought it was just *so* cool. I got lucky and picked up an 11801 with a bad NVRAM error for $145 delivered and a pair of SD-22s for $150 delivered. With some help from a UK member of the list I got the NVRAM replaced. To my delight it all works fine Except for the video display jitter I mentioned earlier.

I bought 4x SD-26 heads for $200 each, one of which would not calibrate correctly. The seller replaced it. Thursday I got my SD-24 which eliminates the issues of impedance mismatch using a tee to pick off reflections.

I bought the 4x SD-26s to measure timing skew for various DSP filter topologies implemented on a Zynq for use in a DSO. After spending some time with an MSOX3104T and RTM3104 I am quite underwhelmed by what you get for $20K. So rather than complain, I'm going to fix the issue by writing proper FW.

I have a 2nd 11801 sitting in CA at my sister's with an SD-22 or 26 head. I'm told one channel is wonky. but won't know for sure until I get it. I know it has an NVRAM error. I primarily got it as a parts mule.

About all I can think of right now to do with an SD-32 is check my Leo Bodnar pulsers ;-)

If I do get an SD-32 I'll try to build a faster rise time pulser than yours. I've read a bunch on non-linear pulse generators.

I have had more sheer fun fooling around doing completely insignificant experiments with this beast than any other piece of electronics I have ever owned. Partly this is because a transmission line is the EM analog to the 1D plane layered medium problem in reflection seismology. So it's *very* familiar. Being able to see on the screen things I have calculated in countless numerical simulations is just a blast.

Have Fun!
Reg

Leo Bodnar
 

Reg,
If you are out for exotic toys, try finding 1180x or CSA803x with fast calibrator.
You can tell it apart visually by the calibrator jack being gold 3.5mm type instead of Nickel plated SMA.
It's basically a TDR part of SD-24 in a separate enclosure used instead of regular calibrator.
They are rare but not unique. Here's random example https://www.artisantg.com/itemimages/Tektronix_CSA_803_View1.jpg

I have never found who and why did this and why this is not documented anywhere.
Leo

Reginald Beardsley
 

Mine has it and it's documented in the 11801 user and service manuals. The user reference manual on p 42 says:

"The signal from the calibrator output is a 250 mV square wave with a rise time of approximately 20 ps and a period of approximately 10 us."

I did a lot of work with it and my SD-26s until I found the SD-24. It was what go me hooked.