Date   

Re: The pouch and handle to a 2465 #photo-notice

Lawrance A. Schneider
 

Yes, you are correct! I was simply hoping to not get into trouble and not thinking very hard.

larry


Re: 475A Chop Blanking and a Theory Question

Dave Voorhis
 

On 19 Dec 2020, at 21:49, Jeff Dutky <jeff.dutky@gmail.com> wrote:

2. index selection in SQL queries (at one time the order of terms in the selection criteria affected what indexes could be used)
That must have been specific to a particular vendor's SQL DBMS?

There isn’t anything inherent in the SQL language that would force that.


Re: Looking for an *original printed* version of a Tek Measurement Concepts book

Jean-Paul
 

Have the full set, given by TEK REP in 1970s..1980s. Thick book bindgins are cracking....

Jon


Re: Looking for an *original printed* version of a Tek Measurement Concepts book

Dave Brown
 

The museum has a number of Concept Books. I'm not there to look but suspect we have that book. Send an email to contactus@vintagetek.org


Re: Looking for an *original printed* version of a Tek Measurement Concepts book

Sean Turner
 

Perfect! I just ordered it.

Sean


Re: The pouch and handle to a 2465 #photo-notice

 

On Sun, Dec 20, 2020 at 05:56 PM, Lawrance A. Schneider wrote:


If I've broke some cardinal rule, I am sorry.
Yes, you have, since MacOS isn't built on Linux but on BSD Unix...

Raymond


Re: 475A Chop Blanking and a Theory Question

Harvey White
 

Ah, what I do, apparently, is microprocessor/microcontroller projects with embedded graphics and sensors.  To which end, the equipment does a good job.  As long as you know the limitations of your calibration equipment, then you're in good shape.

In terms of the old laptop, investigate the signals at the display, frequency, voltage levels, etc.  If you're lucky, they'll be TTL signals.  If not, then they'll be very oddly level shifted things.  You'd much rather the TTL.  Most "semi" modern displays take a parallel data, a clock, vertical and horizontal "sync", and perhaps some control lines to determine display mirroring.  The Epson S1D13781 chip can handle a single display plane (with a few bytes left over for a small overlay) in VGA resolution, 8 bit color.  It would actually do fairly well as a microprocessor driven replacement for some TEK graphics displays, but only has one active plane (The TDS54x series uses a graphics plane for the trace and a text/graphics plane for everything else).  You'd want a custom FPGA for that, given an option.  Depends on what they did in the laptop controller.  The 6809 project sounds interesting, you'd might want to investigate memory bank switching, given the cheapness of memory now.  You might consider using the LS181's as an add-on for a floating point unit for the 6809.  I had somewhat of a similar project  a long while ago, used a 513D to debug it.

Harvey

On 12/20/2020 1:20 AM, Jeff Dutky wrote:
Harvey,

What I currently do is, apparently, fix broken scopes. I've bootstrapped myself up to a point were I have enough reliable equipment that I can triangulate on almost any measurement (with the exception of observing bandwidth rolloff, but that will change in a couple weeks when my TinaSA arrives). I'm going through the calibration process on my 475A using cobbled together equipment. I have a cheap old signal generator, and I calibrate it's output amplitude using a Tek DMM916 and a 2236. The signal generator isn't really good above about 1 MHz, so that's a significant limitation for the 475A calibration process, but I think I'm doing pretty well emulating what the PG506 and SG502 would do at lower frequencies. I'm also working on a DIY calibration source that will produce square waves at several frequencies with amplitudes ranging from 5 mV to 50 V, which would make some of the work I've been doing with with the signal generator and the 2236 a little easier.

Oddly, I feel that the multiple instruments give me greater confidence in what any one of them tells me. I've got three relatively nice DMMs that I've been using the make comparative measurements, as well as a programmable power supply, and the cheap signal generator. Combine those with some TCXOs and I feel as if I can actually make some pretty good measurements of voltage, resistance, and frequency. From there I should be able to bootstrap myself into at least a couple decimal places of accuracy. For the kind of things I'm doing, I'm not sure I care about anything more than that.

What I want to be doing in the short term is investigating and documenting the display protocol for an old laptop that has a gas plasma display, so that I can then replace the innards of the laptop with a Raspberry Pi. Also, I'm working on building a 6809 microcomputer, and a homemade minicomputer using 74181 ALU slices. I've also got a couple other old pieces of equipment of my father's and grandfather's that I'd like to spend some time fixing up.

It's all just hobby stuff that has interested me ever since college, and the pandemic has given me enough extra hours in the week to actually pursue it. I suspect that I don't need much more than a 200 MHz scope to do most of this work, though I'm sure a logic analyzer would be a nice addition. At some point I expect to buy a modern Chinese DSO (probably a Siglent 1204xe), but the old (70s and 80s era) analog scopes are what really interest me, both because of my history with them, and because it feels "closer to the metal" than a DSO. I know too much about the limits of discretely sampled signals to really trust a DSO, and maybe not enough about analog amplifiers to know where my trust in analog scopes should stop.

-- Jeff Dutky





The pouch and handle to a 2465 #photo-notice

Lawrance A. Schneider
 

I installed MacOS 11.1 on my system. I like Macs as the base system is linux. HOWEVER, I'm having a seemingness endless series of problems since the install. So, I'm having communication problems.

I don't know if I've done something wrong but, I have placed some pictures of a 2465 pouch and handle in 'Photos' . There are 6 photos - I only wanted to post 4. As soon as the people who wanted to see them have done so, ( see above ) I hope Dennis or I remove them. They are only temporary.

In any event, the picture of the 2465 IS the scope from which the handle and pouch came. The pouch has NO serial number on it; nor does the handle. The handle and pouch are for sale. The front cover ( 200-3199-00 ) has been sold (Jared); I'm awaiting some Postal boxes the buyer is sending to me.

Again, I don't know if 'this' is allowed but:

The HP 8594E in the pictures is for sale - I've not put it on ebay as of yet. It has options 004, 041, 053, 101, 130 and 140 . Works great. If interested, I have photos of it in action. Make an offer; I'd rather sell it to one of the group.io lists to which I belong than on ebay.

The Rigol DS4014 is also for sale. It has been upgraded to a DS4054 (500meg) with ALL OPTIONS. AGAIN, I have pictures of it in action.

The HP 8112A and 8116A are for sale as I want to buy a more substantial Function Generator. I fixed the 8112A.

The 2465DBM IS NOT FOR SALE!! NOR THE 2465. I've managed to fix both and they are my babies.

If I've broke some cardinal rule, I am sorry.

larry


Readout for 5s14n - please validate my idea

Szabolcs Szigeti
 

Hi,

I'm working on a hobby project to enable readout for the 5S14N. As far as I
know after a lot of reading on manuals that the 7000 and 5000 series
readout is basically the same. I know that the 7S14 is a 5S14N with some
interface board and the readout board containing the resistors for the
readout row and column current settings.

My idea is to fit the readout board into the 5s14N, it does have the
mounting points on the casing for the delay line. I have also validated
that the horizontal timebase cam switches contain the contacts for the
readout and the pin header is there and it is just not connected. This of
course makes sense, since Tek used the same boards in both units, it
probably was not worth to have separate boards with only a couple of cam
switch contacts removed.

One thing I have not been able to verify if the vertical switches contain
the necessary contacts. It takes some deep disassembly to get to them,
which eventually will have to be done, but just by looking at it I was not
able to figure out if the contacts are there. . However, for these
switches, it would make sense to use different types. The 5S14N parts list
contains two part numbers for the S110 and S120 one is the same as in the
7s14 the other is not, I'm not quite sure what to make out of this.

Looking at photos of 7S14 on the net, I was not able to decide if these
switches are in fact the same or not. They do look similar, though.

So if anyone has the knowledge if these switches are the same in the 7S14
and 5S14N, that would be a big help.
I already have the schematic in KiCAD and PCB design for the readout board
in progress, so if having this retrofit makes sense (doesn't, but it is a
fun project :-) ) then I will share the design files and will probably have
some spare boards.

Thanks,

Szabolcs


Photo Notifications #photo-notice

TekScopes@groups.io Notification <noreply@...>
 

The following photos have been uploaded to the The pouch and handle to a 2465 album of the TekScopes@groups.io group.

By: Lawrance A. Schneider


The following photos have been uploaded to the The pouch and handle to a 2465 album of the TekScopes@groups.io group.

By: Lawrance A. Schneider


Re: TEK176 fixing a shorted wet tatalum capacitor

 

Unless they are known to faulty you shouldn't need to replace those.

The ones to replace if any are the tantalum beads on power rails that are running close to their voltage rating (e.g. a 6V tantalum on a 5V rail).

David

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of Miguel Work
Sent: 20 December 2020 10:26
To: TekScopes@groups.io
Subject: Re: [TekScopes] TEK176 fixing a shorted wet tatalum capacitor

As always Raymond has the reason, THF is the original capacitor, Hermetically Sealed Axial Lead Solid Tantalum Capacitors

https://www.cde.com/resources/catalogs/THF.pdf

Where I can find a similar specs capacitor?


Re: Looking for an *original printed* version of a Tek Measurement Concepts book

Glydeck
 

On Dec 20, 2020, at 4:13 AM, Dave Daniel <kc0wjn@gmail.com> wrote:

Do an author/title search on bookfinder.com. There are some copies listed there. Prices are all over the map.

DaveD

On Dec 20, 2020, at 02:04, sdturne@q.com wrote:

Hi all,

I am looking for an original copy of the Tektronix Measurement Concepts series book entitled "Semiconductor Device Measurements" by John Mulvey to add to my library. I do know of the scan available on TekWiki but this scan suffers legibility issues, so I would prefer to find a printed version.

If you have one you are willing to sell, please contact me off list.

Thanks!

Sean








Tek TDS350 : T2 Transformer of LVPS

Jack2015
 

About one month ago I took my TDS350 off the shelves(which I left unused for almost one year)
that's when I found something was rolling and making noises inside of the case.

I opened it and found a small "U" shape magnet(or ferrite?),I took it out and pressed the power button,but received no response.
couple minutes later I found the "U" shape magnet is part of the T2 transformer of LVPS(half of the ferrite core).

I put it back where it belongs and held it with a rubber band,then I pressed the power button again,
this time it worked as it should be.later I added some glue to make sure the "U" shape magnet
won't fall out again.one week later the glue dried,I removed the rubber band.
the TDS350 works well now.

https://groups.io/g/TekScopes/photo/258321/0?p=Created,,,100,2,0,0


Re: TEK176 fixing a shorted wet tatalum capacitor

 

On Sun, Dec 20, 2020 at 10:37 AM, donald collie wrote:


I am told that one method is to spray all the tantalums with "freeze" until
they are all frosted, apply power, and look for the first one to burn off
the frost - there`s your culprit. Cheers!...Don C.
In contrast with dipped (epoxy coated) tants, which go through all levels of leakage and at times burn up like fireworks, metal-encased tants seldomly fail, if treated correctly, and they tend to fail dead short (pun intended), limiting their power consumption. I'd say you need to run a significant amount of current to warm them up enough to have this trick work.

Raymond


Re: TEK176 fixing a shorted wet tatalum capacitor

 

On Sun, Dec 20, 2020 at 07:02 AM, Roy Thistle wrote:


I see what I think is a glass seal, in one of the pics (... is that a
distinguishing feature of a wet type tant?)
Wet tants are not hermetically (glass) sealed, as I wrote earlier, so no. Solid tants are hermetically glass sealed and those is what you see in the picture. A "distinguishing feature" of wet tants as I mentioned used to be the Ta anode wire.

Raymond


Re: 500 scopes n stuff

William Rice
 

Copy. Will do.Thank you Dennis!~BSent from my Verizon, Samsung Galaxy smartphone


Re: Looking for an *original printed* version of a Tek Measurement Concepts book

Dave Daniel
 

Do an author/title search on bookfinder.com. There are some copies listed there. Prices are all over the map.

DaveD

On Dec 20, 2020, at 02:04, sdturne@q.com wrote:

Hi all,

I am looking for an original copy of the Tektronix Measurement Concepts series book entitled "Semiconductor Device Measurements" by John Mulvey to add to my library. I do know of the scan available on TekWiki but this scan suffers legibility issues, so I would prefer to find a printed version.

If you have one you are willing to sell, please contact me off list.

Thanks!

Sean





Re: TEK176 fixing a shorted wet tatalum capacitor

Miguel Work
 

As always Raymond has the reason, THF is the original capacitor, Hermetically Sealed Axial Lead Solid Tantalum Capacitors

https://www.cde.com/resources/catalogs/THF.pdf

Where I can find a similar specs capacitor?


Re: Found Option 7 board DC-508

Miguel Work
 

Hi, yes, this option is for use the counter in a tracking generator/ spectrum analyzer system, for frequency cursor measurament.


Re: TEK176 fixing a shorted wet tatalum capacitor

donald collie
 

I am told that one method is to spray all the tantalums with "freeze" until
they are all frosted, apply power, and look for the first one to burn off
the frost - there`s your culprit. Cheers!...Don C.

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On Sun, Dec 20, 2020 at 9:45 PM Miguel Work <harrimansat@hotmail.com> wrote:

https://passive-components.eu/wet-tantalum-capacitors/

There is some trick to find wich capacitor is shorted, (very shorted), in
a low impedance system like that with all capacitors in parallel?








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