Date   

Re: 5000 series power supply potentiometers

Dave Peterson
 

I know!

I stumbled across them looking for some kind of electronics shop. What was I looking for? A cap, some coax? Something Radio Shack kind of thing. Oh, right, 1.1M resistors in small quantities. Google maps found them for me: https://www.smelectronics.com/

One of my favorite places, but only been there twice so far. But it's like going back in time. A good old fashioned shop. Go there! Spend lots of money! Keep them in business! Or enjoy it while it lasts.

Makes for a fun lunch hour.


Evidence of open deflection plate connection

John Atwood
 

What is described here was found while fixing an HP 180A scope mainframe, but is applicable to Tek scopes as well.

I wanted to test an old HP 180A mainframe (rackmount type). I didn't have a working vertical + sweep plugin, but I had a mostly-working 8558B spectrum analyzer plugin. When powered-up, I got the familiar white noise trace at the normal horizontal width, but the height of the noise seemed low and the vertical position control had little effect. The trace was a little blurry, as well. In an effort to clarify the trace, I started manipulating the focus and astigmatism controls and found something really unusual: adjustment of the astigmatism control (but not the focus control) moved the whole trace significantly up and down - almost the full height of the screen - something which should not happen.

Pondering this, I realized that this is evidence of an open vertical deflection plate connection. The purpose of the astigmatism control is to equalize the electrostatic fields between the horizontal and vertical deflection plates. If they are all normally connected, the fields are balanced and changing the astigmatism voltage doesn't deflect the trace. However, if one plate is unconnected and floating, the other plate has nothing to work against, so the deflection is essentially between the connected plate and the astigmatism electrode, a very unbalanced situation.

I checked the connection to the vertical deflection plates at the side of the CRT, and they seemed good. The problem was found in the sliding edge connector that connects the plugin to the vertical plates. One of the spring contacts was slack. After bending up this with needle-nose pliers, everything worked as normal. This sliding connector is unique to the 180 series of HP scopes, but there are opportunities for open deflection plate connections in Tek scopes, especially at the wimpy connectors to the side of the CRT.

So, if you see the astigmatism control noticeably move the trace, check the deflection plate connections!

- John Atwood


Re: 5000 series power supply potentiometers

Dave Seiter
 

Wow, I've never heard of San Mateo Electronics before, and it's less than 20 miles away!  How did that happen?!
-Dave

On Thursday, July 29, 2021, 10:57:10 AM PDT, Dave Peterson via groups.io <davidpinsf=yahoo.com@groups.io> wrote:

Looks like my tired brain typed in a cross of two part numbers - crossed rows in the E Parts List. Not as bad as crossing streams, but yeah, there ya go. SUE - stupid user error.

I have some 10k pots that go down to 30 ohms that are of somewhat similar construction. I'm going to try soldering/hacking one in while I wait for the eBay seller to contemplate my low-ball offer for two of the 311-1120-00's. I can/could/will head down to San Mateo Electronics to see what they have. I need to get some teflon wire to repair some overheated ones between the Z-axis board and the CRT. I think I saw an interesting Y-tube video of someone examining the beads-on-a-string pattern wire makes when heated to failure in a vacuum. Looks like that, only more like braided string. Weird, but fun.

Back on topic - my query really was, how are these pots colloquially referred to? Composition pots? Something else? What can I search for online that's similar, if not the same, in the modern supply chain? I'll pay this eBay guy for instant gratification purposes, but I prefer to find like-kind replacements over hacking something in. It's like trying to match Tek-blue paint. I don't have to, but would like to keep to original as much as possible. These seem so ubiquitous in the 5000/TM500 realm that I'm surprised I'm not finding them on Sphere, etc.


Re: 5000 series power supply potentiometers

Dave Peterson
 

Looks like my tired brain typed in a cross of two part numbers - crossed rows in the E Parts List. Not as bad as crossing streams, but yeah, there ya go. SUE - stupid user error.

I have some 10k pots that go down to 30 ohms that are of somewhat similar construction. I'm going to try soldering/hacking one in while I wait for the eBay seller to contemplate my low-ball offer for two of the 311-1120-00's. I can/could/will head down to San Mateo Electronics to see what they have. I need to get some teflon wire to repair some overheated ones between the Z-axis board and the CRT. I think I saw an interesting Y-tube video of someone examining the beads-on-a-string pattern wire makes when heated to failure in a vacuum. Looks like that, only more like braided string. Weird, but fun.

Back on topic - my query really was, how are these pots colloquially referred to? Composition pots? Something else? What can I search for online that's similar, if not the same, in the modern supply chain? I'll pay this eBay guy for instant gratification purposes, but I prefer to find like-kind replacements over hacking something in. It's like trying to match Tek-blue paint. I don't have to, but would like to keep to original as much as possible. These seem so ubiquitous in the 5000/TM500 realm that I'm surprised I'm not finding them on Sphere, etc.


Re: Tek 2440 Repair - Battery/RAM.

wkibler
 

Sorry about that the DS1230 is a direct replacement for the DS1235 according to https://www.maximintegrated.com/en/design/technical-documents/app-notes/2/202.html#q13
So you should be able to use DS1230AB-100 https://www.mouser.com/ProductDetail/Maxim-Integrated/DS1230AB-100%2b?qs=LHmEVA8xxfZqkqBXpeOlMg%3D%3D

When I get home I am going to crack open my 2440’s and see what I installed, LOL. It was some time ago.

Be sure you are grounded because that CPU dies when you look at it cross eyed. Be ready to replace it also.


Re: Tek 2440 Repair - Battery/RAM.

Bob Albert
 

I replaced the NAVRAM modules in my 2440 and the scope stopped working.  I reviewed my work and it looked okay.  I used Chinese chips that perhaps were counterfeit.  I put one of the old chips back (the other was damaged) with no success.  So I have a doorstop.  It's on my list of projects to take another look at it but I am not optimistic.  Power supply voltages are good.
Bob

On Thursday, July 29, 2021, 04:59:52 AM PDT, wkibler via groups.io <will.kibler=me.com@groups.io> wrote:

Apologies I meant faster than 200ns. Not 100. The original battery backed chips in my unit were 150. 200 works fine.


Re: What to do with these files?

Dave Daniel
 

And TekWiki.

DaveD

On 7/29/2021 11:33 AM, Ken Eckert wrote:
Why not both sites, it give a measure of backup...


On Thursday, July 29, 2021, Paul Amaranth <paul@auroragrp.com> wrote:

Back before I shut down my company, I hosted a set of web pages
covering things I had learned about the Tekmate add-on processor.
The 2402 added some capabilities to the 2400 series of DSOs
including FFT, storing waveforms, etc. Given the record size,
it was a bit limited, but still nice to have.

The web pages included the elusive software files and information
to actually make the thing [somewhat] useful. I haven't looked
recently, but you could find the Tekmate pretty cheap, but
nobody had the program files.

Anyway, long story short, I closed up shop and shut down the
web server. I just got a query on these files and it occured
to me that I should put them somewhere useful. The only
thing questionable about it is, of course, the files are
Copyright by Tektronix. AFAIK, I was the only source for
free distribution of this software.

Haha, I just looked and current ebay asking prices on the
2402A are around $200. I just bought a 1GHz Lecroy 4 channel
scope for $300. I remember paying around $50 for my tekmates.
People are nuts :-)

Anyway, archive.org has snapshots of the web pages, but they did
not archive the .zip files containing the software.

I'll be happy to load the files into either the files section
or to K04BB, whatever people would want. I'm not really
interested in running a web server at this point.

So, what should I do with them?

Paul
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@AuroraGrp.Com | Unix/Linux - We don't do windows






--
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus


Re: What to do with these files?

Ken Eckert
 

Why not both sites, it give a measure of backup...

On Thursday, July 29, 2021, Paul Amaranth <paul@auroragrp.com> wrote:

Back before I shut down my company, I hosted a set of web pages
covering things I had learned about the Tekmate add-on processor.
The 2402 added some capabilities to the 2400 series of DSOs
including FFT, storing waveforms, etc. Given the record size,
it was a bit limited, but still nice to have.

The web pages included the elusive software files and information
to actually make the thing [somewhat] useful. I haven't looked
recently, but you could find the Tekmate pretty cheap, but
nobody had the program files.

Anyway, long story short, I closed up shop and shut down the
web server. I just got a query on these files and it occured
to me that I should put them somewhere useful. The only
thing questionable about it is, of course, the files are
Copyright by Tektronix. AFAIK, I was the only source for
free distribution of this software.

Haha, I just looked and current ebay asking prices on the
2402A are around $200. I just bought a 1GHz Lecroy 4 channel
scope for $300. I remember paying around $50 for my tekmates.
People are nuts :-)

Anyway, archive.org has snapshots of the web pages, but they did
not archive the .zip files containing the software.

I'll be happy to load the files into either the files section
or to K04BB, whatever people would want. I'm not really
interested in running a web server at this point.

So, what should I do with them?

Paul
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@AuroraGrp.Com | Unix/Linux - We don't do windows






What to do with these files?

Paul Amaranth
 

Back before I shut down my company, I hosted a set of web pages
covering things I had learned about the Tekmate add-on processor.
The 2402 added some capabilities to the 2400 series of DSOs
including FFT, storing waveforms, etc. Given the record size,
it was a bit limited, but still nice to have.

The web pages included the elusive software files and information
to actually make the thing [somewhat] useful. I haven't looked
recently, but you could find the Tekmate pretty cheap, but
nobody had the program files.

Anyway, long story short, I closed up shop and shut down the
web server. I just got a query on these files and it occured
to me that I should put them somewhere useful. The only
thing questionable about it is, of course, the files are
Copyright by Tektronix. AFAIK, I was the only source for
free distribution of this software.

Haha, I just looked and current ebay asking prices on the
2402A are around $200. I just bought a 1GHz Lecroy 4 channel
scope for $300. I remember paying around $50 for my tekmates.
People are nuts :-)

Anyway, archive.org has snapshots of the web pages, but they did
not archive the .zip files containing the software.

I'll be happy to load the files into either the files section
or to K04BB, whatever people would want. I'm not really
interested in running a web server at this point.

So, what should I do with them?

Paul
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@AuroraGrp.Com | Unix/Linux - We don't do windows


Re: Tek Scopes found in old picture book

 

I was wondering what such a TV would look like, and what do you know,
YouTube has a good answer. https://www.youtube.com/watch?v=I4c2XTnl3Ao

On Thu, Jul 29, 2021 at 10:30 AM cmjones01 <chris@stumpie.com> wrote:

The naked CRT in the foreground looks very much like a VCR97 to me.
That was the CRT developed for WWII airborne radar and navigation
applications and it was available at low cost in large quantities as
surplus after the war. Thousands of enthusiasts built TVs using the
VCR97 tube, often based around the Indicator No 62:
https://timeandnavigation.si.edu/multimedia-asset/type-62a-gee-mark-ii-indicator-unit
There were constructional projects published in the popular magazines
of the day - "Practical Television" being one of the biggest. They
were quite happy to watch TV in long-persistence green!

The B12D base is distinctive, as is the shape of the tube itself. It's
certainly representative of the sort of components which would have
been readily available to the constructors of the original Manchester
Baby, along with bucketloads of EF50s.

Chris

On Wed, Jul 28, 2021 at 11:01 PM Jeff Dutky <jeff.dutky@gmail.com> wrote:

I had dismissed the notion that this was picture of a vacuum tube computer when I first saw the image, partly because of the description of the contents of the book ("How the Microchip is Changing Our World" sure doesn't seem like the place for a picture of a vacuum tube based device), and partly because I misinterpreted what I saw on the computer screens in the background. Now it seems obvious that the computers were running software to either emulate or monitor a Williams tube. In any case I must (publicly) admit to being spectacularly wrong about the picture in a private conversation: I had expected that this was an image of a radio astronomy lab, or maybe a radio or microwave transmission facility.

Also, I had assumed that the CRT we see in the foreground was for a Tek 500-series scope, but now it seems like it is probably the replacement for the Williams tube display, which makes more sense of why it would be just sitting there, naked like that.

-- Jeff Dutky








Re: More hard to find Tek parts, and a great EPROM programmer

Paul Amaranth
 

First let me say that anything I've received from Walter has been fantastic.

However, I'm not so happy with the Canadian postal service. A couple months
ago I got some "free" Tek manuals from a member and shipping those came to
$40. Media mail in the US would have been around 10 or so.

Whenever Walter posts his sale notices I wish that either he was closer
to Toronto or I was in driving distance of BC. Then I look around and
realize I have more than enough stuff to keep me busy :-)

Paul

On Thu, Jul 29, 2021 at 05:48:39AM -0700, Michael W. Lynch via groups.io wrote:
I recently received a pair of HP power supplies from Walter. The shipping, even on these heavy items, was reasonable and less that most E-Bay sellers charge from the USA. There were not any customs charges or import duties on this shipment. In fact, I do not recall any such charge on any of my Sphere Research orders?

Perhaps I have been lucky or the charges were included in the price of the item? I can say that the quality of the items offered for sale and the service is exceptional from Sphere.

Based on my past experiences, your results may vary. .

--
Michael Lynch
Dardanelle, AR







!DSPAM:6102a3b111472061540572!
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@AuroraGrp.Com | Unix/Linux - We don't do windows


Re: Recreating an old board for the 7854

Paul Amaranth
 

Quite a while ago i wrote a script that would generate edge connector footprints for gEda
mostly because anytime I have to do something more than 3 times I automate it. You
could generate an entire library in a couple minutes.

Paul

On Wed, Jul 28, 2021 at 07:29:10PM -0700, Jeff Dutky wrote:
I would like to second Harvey's recommendation of the manual step and repeat process. I've used this process successfully to make card edge connectors in EasyEDA (the free PCB layout package used by JLCPCB) and it was easy and quick. I do one or two spacing verifications along the way, which helps prevent having to go through the whole connector and fix a bunch of slightly off-center pads.

I'm certainly comfortable writing scripts, I just haven't bothered to figure out if EasyEDA has any scriptability, and I've been able to make relatively large, regular, repeating structures without much trouble.

-- Jeff Dutky
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@AuroraGrp.Com | Unix/Linux - We don't do windows


Re: More hard to find Tek parts, and a great EPROM programmer

Michael W. Lynch
 

I recently received a pair of HP power supplies from Walter. The shipping, even on these heavy items, was reasonable and less that most E-Bay sellers charge from the USA. There were not any customs charges or import duties on this shipment. In fact, I do not recall any such charge on any of my Sphere Research orders?

Perhaps I have been lucky or the charges were included in the price of the item? I can say that the quality of the items offered for sale and the service is exceptional from Sphere.

Based on my past experiences, your results may vary. .

--
Michael Lynch
Dardanelle, AR


Re: More hard to find Tek parts, and a great EPROM programmer

Lawrance A. Schneider
 

When the COVID restrictions ease, I hope you open a 2nd shop in America. Shipping and customs make it so I don't even bother to look at you site any longer. This is a suggestion and not a complaint and I hope you view it in a positive way.

larry


Re: Tek 2440 Repair - Battery/RAM.

wkibler
 

Apologies I meant faster than 200ns. Not 100. The original battery backed chips in my unit were 150. 200 works fine.


Re: Tek 2440 Repair - Battery/RAM.

wkibler
 

Heres the memory replacement I used: https://www.digikey.com/en/products/filter/memory/774?s=N4IgTCBcDaICIGUCMYwAYCCAhEBdAvkA
Specifically DS1220AB-200+ but I linked to the search because stock changes. I think if it's faster than 100ns you should be fine.

Heres the processor I got to work, https://www.ebay.com/p/170019433?iid=163333777328
Again, here's the part number in case the link expires, Motorola MC68B09P

There was rumor of a hitachi equivalent but it wasn't pin compatible and would not work without modification. I tried.

If you re-cap the supply be sure to match the temperature rating of the caps 105 degrees if I remember correctly.

The calibration process was pretty straight forward and well documented in the manual. However the firmware of the scope may differ than the manual in a few steps. The manual specifies that the scope will ask for a certain voltage and the scope will actually ask for something else. Keep an eye out for that and just do what the scope asks for. A good precision meter in parallel as specified by the manual is a good idea.

If you have problems post be sure to include pictures of what you see on screen. I'll do my best to help out.


Re: Tek 2440 Repair - Battery/RAM.

wkibler
 

I’ve done that repair several times. The Dallas chips were available from Digi-Key but I hear some had replaced them with modern SRAM. I opted to use the original DS1220’s from digikey in my scopes. I also recapped the supply’s while I was in there. It’s not a difficult task. The only issues I ran into was the main processor was dead in more than one unit so I had to find a supplier for that which was not easy. At one point I had a ZIF socket installed in a 2440 auditioning CPU’s. That was fun…

It’s early and I’m on my phone. Later I’d be happy to dig out my notes and find some links for you if you’d like.


Re: Tek Scopes found in old picture book

Dave Brown
 

Agreed- I also thought of the VCR97 when I saw that base - in fact I'm going to follow this up and if I can, confirm or otherwise as regards the CRTs used in the first and following several generations of Williams Tube storage.
DaveB, NZ

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of cmjones01
Sent: Thursday, July 29, 2021 20:30
To: TekScopes@groups.io
Subject: Re: [TekScopes] Tek Scopes found in old picture book

The naked CRT in the foreground looks very much like a VCR97 to me.
That was the CRT developed for WWII airborne radar and navigation applications and it was available at low cost in large quantities as surplus after the war. Thousands of enthusiasts built TVs using the
VCR97 tube, often based around the Indicator No 62:
https://timeandnavigation.si.edu/multimedia-asset/type-62a-gee-mark-ii-indicator-unit
There were constructional projects published in the popular magazines of the day - "Practical Television" being one of the biggest. They were quite happy to watch TV in long-persistence green!

The B12D base is distinctive, as is the shape of the tube itself. It's certainly representative of the sort of components which would have been readily available to the constructors of the original Manchester Baby, along with bucketloads of EF50s.

Chris

On Wed, Jul 28, 2021 at 11:01 PM Jeff Dutky <jeff.dutky@gmail.com> wrote:

I had dismissed the notion that this was picture of a vacuum tube computer when I first saw the image, partly because of the description of the contents of the book ("How the Microchip is Changing Our World" sure doesn't seem like the place for a picture of a vacuum tube based device), and partly because I misinterpreted what I saw on the computer screens in the background. Now it seems obvious that the computers were running software to either emulate or monitor a Williams tube. In any case I must (publicly) admit to being spectacularly wrong about the picture in a private conversation: I had expected that this was an image of a radio astronomy lab, or maybe a radio or microwave transmission facility.

Also, I had assumed that the CRT we see in the foreground was for a Tek 500-series scope, but now it seems like it is probably the replacement for the Williams tube display, which makes more sense of why it would be just sitting there, naked like that.

-- Jeff Dutky





Re: Tek Scopes found in old picture book

cmjones01
 

The naked CRT in the foreground looks very much like a VCR97 to me.
That was the CRT developed for WWII airborne radar and navigation
applications and it was available at low cost in large quantities as
surplus after the war. Thousands of enthusiasts built TVs using the
VCR97 tube, often based around the Indicator No 62:
https://timeandnavigation.si.edu/multimedia-asset/type-62a-gee-mark-ii-indicator-unit
There were constructional projects published in the popular magazines
of the day - "Practical Television" being one of the biggest. They
were quite happy to watch TV in long-persistence green!

The B12D base is distinctive, as is the shape of the tube itself. It's
certainly representative of the sort of components which would have
been readily available to the constructors of the original Manchester
Baby, along with bucketloads of EF50s.

Chris

On Wed, Jul 28, 2021 at 11:01 PM Jeff Dutky <jeff.dutky@gmail.com> wrote:

I had dismissed the notion that this was picture of a vacuum tube computer when I first saw the image, partly because of the description of the contents of the book ("How the Microchip is Changing Our World" sure doesn't seem like the place for a picture of a vacuum tube based device), and partly because I misinterpreted what I saw on the computer screens in the background. Now it seems obvious that the computers were running software to either emulate or monitor a Williams tube. In any case I must (publicly) admit to being spectacularly wrong about the picture in a private conversation: I had expected that this was an image of a radio astronomy lab, or maybe a radio or microwave transmission facility.

Also, I had assumed that the CRT we see in the foreground was for a Tek 500-series scope, but now it seems like it is probably the replacement for the Williams tube display, which makes more sense of why it would be just sitting there, naked like that.

-- Jeff Dutky





Tek 2440 Repair - Battery/RAM.

Brian Gaff
 

Hi All - I've reviewed the posts here regarding the repair of a Tek 2440 due
to dead batteries in the Dallas Semi NVSRAMs. Notwithstanding the great
information in those posts, as well as in Hugo Holden's August 2013 paper,
I'm looking for someone with experience doing that repair who can handle
that for my 2440, and calibrate it. Please reply if you can suggest
someone. Thanks.

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