Date   

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.


Re: 5000 series power supply potentiometers

 

Aren't the CRTs in the 5000-series ceramic neck with a plate glass face? The CRT may well have been replaced after something unfortunate happened to the original one.

I'm really jealous about the blue phosphor screen, that or the green/orange phosphor is something that's on my collection list. I'm still kicking myself that I missed out on a 485 with a P11 phosphor CRT. That would have checked two boxes at once, and it would have been a joy forever.

-- Jeff Dutky


Re: 5000 series power supply potentiometers

Dave Peterson
 

What the heck! I looked there!

Well you have the touch Jeff. eBay likes you better?

I'm curious why the scope has the serial number and option windows on the back plate, and the option window isn't marked. Perhaps someone put the P11 tube in later? Might explain the bit of glass found in the scope. Though it looks more like a shard of plate glass. For whatever that's worth. The blue is lovely.


Thanks again.

Dave

On Wednesday, July 28, 2021, 11:26:14 PM PDT, Jeff Dutky <jeff.dutky@gmail.com> wrote:

Dave,

I see the exact part (Tek P# 311-1120-00, CTS P# 201-YA5531) on eBay for eight bucks (plus $3.68 shipping) which seems a bit steep, but you get two pieces for that price (still a bit steep, maybe). Here is the item (https://www.ebay.com/itm/193605708230) and they do have the "Make an Offer" button enabled, so maybe?

The part seems to have a 4 pin footprint. Obviously two of those pins must be common (probably the wiper), so you should be able to fit one of those blue Bourns cermet trim pots in the same place by bending one pin to meet one of the common pads for the old pot. Those can be had ten for $8.24 on eBay (free shipping, from China! https://www.ebay.com/itm/313619649115), or you could just buy them from a reputable source.

Also, while perusing the 5103 service manual I found the list of options: it looks like you have Option 78: P11 Phosphor, which is "best suited for waveform photography."

-- Jeff Dutky


Re: 5000 series power supply potentiometers

 

Dave,

I see the exact part (Tek P# 311-1120-00, CTS P# 201-YA5531) on eBay for eight bucks (plus $3.68 shipping) which seems a bit steep, but you get two pieces for that price (still a bit steep, maybe). Here is the item (https://www.ebay.com/itm/193605708230) and they do have the "Make an Offer" button enabled, so maybe?

The part seems to have a 4 pin footprint. Obviously two of those pins must be common (probably the wiper), so you should be able to fit one of those blue Bourns cermet trim pots in the same place by bending one pin to meet one of the common pads for the old pot. Those can be had ten for $8.24 on eBay (free shipping, from China! https://www.ebay.com/itm/313619649115), or you could just buy them from a reputable source.

Also, while perusing the 5103 service manual I found the list of options: it looks like you have Option 78: P11 Phosphor, which is "best suited for waveform photography."

-- Jeff Dutky


Re: 5000 series power supply potentiometers

Ed Breya
 

You can use almost any pot that has the same R, and fits in the spot. Nothing special.

Ed


5000 series power supply potentiometers

Dave Peterson
 

I have a 5103N in which the 30v adjust, R858, a 100 ohm 1/4w potentiometer, PN 311-1120-00 has failed. It's innards have rotted and fallen out. The resistance goes infinite as soon as it is turned from its limit. Results in the 30v output jumping from ~26v to 40v with no variability.

I've done some preliminary searching without finding any good info. Sphere does seem to have any. I get the feeling these are a fairly common part - I see them in my 5111A and 5440 scopes as well as some plug-ins. Of course the values will be different in those applications.

Are these pots generally available? Who is (are) the manufacturer(s)? How are these pots referred to in the Tek Scopes community?

Thanks,
Dave


Re: Recreating an old board for the 7854

Harvey White
 

That's one reason why you set the grid to the connector finger spacing.

Harvey

On 7/28/2021 10:29 PM, 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





Re: Recreating an old board for the 7854

 

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


Re: Recreating an old board for the 7854

Andy Warner
 

Eagle doesn't have python scripts, but I can highly recommend using their
scripts to generate things like connectors.
You get to place everything declaratively, exactly where you need it, with
exactly the right name.

It is trivial to generate these scripts via python/<whatever> if they are
beyond cut and paste in an editor.

On Wed, Jul 28, 2021 at 8:06 PM Harvey White <madyn@dragonworks.info> wrote:

It's actually less work than you might think. Creating the connector
finger is easy enough. I don't remember that I had to do too much other
than create a single rectangle. However, aligning each to the gridwork
that is the pin spacing, that eliminates errors there. That's
essentially the trick here.

Then you make one, then copy that and make 2, then 4, then 8, and so on

Delete the ones you don't need. It turns out to be less effort than you
might think.

All of which is true if you don't want to use a script (I think that
Eagle doesn't have python scrips). Many can't program, or don't want
to, so the alternate does work.

Ultimately, you do what makes sense to you. Either method works....

Harvey

On 7/28/2021 8:07 PM, Ke-Fong Lin wrote:
What the python script does is to do a step and repeat that you're doing
manually.
Hi Harvey,

I agree that you can do it manually.
However, it's very tedious and error prone, whereas a computer would
basically shine at that kind of repetitive task.
Plus a script can be retargeted, just plug-in the new pitch value and
voila.

Best regards,









--
Andy


Re: Recreating an old board for the 7854

Harvey White
 

It's actually less work than you might think.  Creating the connector finger is easy enough.  I don't remember that I had to do too much other than create a single rectangle.  However, aligning each to the gridwork that is the pin spacing, that eliminates errors there.  That's essentially the trick here.

Then you make one, then copy that and make 2, then 4, then 8, and so on

Delete the ones you don't need.  It turns out to be less effort than you might think.

All of which is true if you don't want to use a script (I think that Eagle doesn't have python scrips).  Many can't program, or don't want to, so the alternate does work.

Ultimately, you do what makes sense to you.  Either method works....

Harvey

On 7/28/2021 8:07 PM, Ke-Fong Lin wrote:
What the python script does is to do a step and repeat that you're doing
manually.
Hi Harvey,

I agree that you can do it manually.
However, it's very tedious and error prone, whereas a computer would basically shine at that kind of repetitive task.
Plus a script can be retargeted, just plug-in the new pitch value and voila.

Best regards,





Re: Recreating an old board for the 7854

Ke-Fong Lin
 

What the python script does is to do a step and repeat that you're doing
manually.
Hi Harvey,

I agree that you can do it manually.
However, it's very tedious and error prone, whereas a computer would basically shine at that kind of repetitive task.
Plus a script can be retargeted, just plug-in the new pitch value and voila.

Best regards,


Re: Recreating an old board for the 7854

Ke-Fong Lin
 

Awesome that would be great. I am kind of out of my depth on this one. The
connectors on the board are

Large connector in the front of the scope - AMP 3-530662-0-8301
Small connector towards the back of the scope - AMP 2-530662-5-8110
Hi,

I've done some search for "AMP 3-530662-0" and there was already some interest about 7854.
https://groups.io/g/TekScopes/topic/7649085

There are 2 modern current production models for the 80 and 44 pins .125" pitch connector:

EDAC 346-080-555-201
EDAC 346-044-555-201

Full dimensional specs are available here:

https://files.edac.net/edac/content/series/og/English/English%20346%20Ordering%20Guide.pdf

I can definitely change the values in my script to generate the two required footprints.
Give me a day or two.

Best regards,


Re: 7000 test/cal module(s) and backplane breakout board.

Ke-Fong Lin
 

Also, here is the dimensional drawing of the outline for my breakout board:
https://drive.google.com/file/d/1axeTjjcMswiNkfJGYOcPmpCzqPjXmuZ-/view?usp=sharing
it seems to fit well with the plug-in frames that I have.
Hi Andy,

Thanks for your quick answer, I think you're absolutely correct at 3.9 inches.

I've double checked the datasheet edge connector (made by EDAC) I'm using for my extender project.
https://files.edac.net/edac/content/series/og/English/English%20345%20Ordering%20Guide.pdf
And the "D" size for 38 pins (76 pins double sided) is 3.9 inches.
I didn't pay that much attention to that and used 3.8 inches for my project, whereas the exact information was right in front of me.

I also work in metric, I live in Europe (France) after all. But for electronics, I always try to make it imperial compatible, hence my board is 96.52mm (it should have been 99.06mm).
If you have some time to spare, there's a funny video by an english guy about metric vs imperial:

https://www.youtube.com/watch?v=hid7EJkwDNk


Best regards,


Re: 5642 rectifier tubes in a Tek 535: Replace or swap for silicone?

Tom Lee
 

That should take care of your needs for at least a couple of weeks.

Have fun building your 2MV rectifier stack!

Cheers
Tom

Sent from my iThing, so please forgive brevity and typos

On Jul 28, 2021, at 10:00, Michael A. Terrell <terrell.michael.a@gmail.com> wrote:

I bought a reel of 5000 - Vishay HER105-T High Efficiency 400V 1A DO41
Diodes, a couple years ago for under $23.

On Wed, Jul 28, 2021 at 12:34 PM Tom Lee <tomlee@ee.stanford.edu> wrote:

A series string of UF4007s with a 10kV breakdown voltage would have of
the order of 1pF capacitance. The problem with 1N4007s is with their
slow reverse recovery (hence the UF4007 recommendation). But reverse
recovery is distinct from junction capacitance.



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