Date   

Re: Tek 24xx calibration -- How to store constants before finishing the entire procedure

Chuck Harris <cfharris@...>
 

The calibration routines automatically save the steps
when you finish a large step, like CAL01, or CAL02...

If you don't finish all of the steps in such a large
step, like CAL01, the calibration will get stored, but
it will also be stored with a flag that tells the
calibration isn't valid.

-Chuck Harris

Rogerio O wrote:

Thank you for the replies.
I have used a TG501, PG506 and a SG503 to execute the cal procedure.
But as have been pointed out by Jean-Paul, I find the text describing some of the step quite confusing.
I will execute all the steps, of course, but not all in one day.
So that is why I would like to save the constsnts after finishing CAL01, then stop for the day (this is s big one).
Than CAL02 and maybe CAL03, and stop again.






Re: 475A Z-Axis Amp and Q1338 Confusion

 

Roy, Michael, and Raymond,

I have checked on eBay, and most of the curve tracers I found there were DEFINITELY more expensive than an iPhone. All of them were over my impulse-buy threshold (though some not by very much).

I also saw the octopus devices, which were in my impulse-buy range, but they don't seem to produce the kind of output that I expect from what I've seen the Tek devices do in YouTube videos.

There is one (a "D1 577") that is only $400 (Buy It Now, free shipping!) but seems to be lacking a front module to mount the DUT. Still, if this were on my wish list, I'm not sure I would be any kind of impediment. It shows a trace on the screen, and appears to have all its knobs and buttons intact. It's really quite beautiful.

https://www.ebay.com/itm/TEKTRONIX-D1-577-CURVE-TRACER-OSCILLOSCOPE/133554810318?hash=item1f187cadce:g:2PcAAOSw6oFfkjZd

Then there are these kits: https://www.ebay.com/itm/Transistor-Curve-Tracer-adapter-Oscilloscopes-Plus-Power-supply-UnAssembled-Kit/291531434190?hash=item43e0a0a8ce:g:XLYAAOSw~gRVwN4i

But the best deal looks to be this (but it's "local pick-up only"): https://www.ebay.com/itm/Pallet-of-Tektronix-Equipment-Oscilloscopes-Modules-Mainframes-Curve-Tracer/313080719471?hash=item48e510a86f:g:~ggAAOSw7kReut4L

-- Jeff Dutky


Re: (OT) Where to go for 70s IBM hardware? I'm looking for a terminal.

 

On 29. Nov 2020, at 03:58, Roy Thistle <roy.thistle@mail.utoronto.ca> wrote:

It's reading 204
That's a Cannon D Submini connector...
Hi Roy,

what is reading 204, the two dials combined? I would have said its 200,4

I checked out the other 4 or 5 modules I got, they are all different. Tried to add some photos to the Album, but did not work.

Its amazing to see all these parts moving with such a precision. How can the different servos and motors affect each other?
All I see is a kind of integration device, perhaps to compute remaining fuel out of fuel flow or similar. But it seems much more complicated than that.

cheers
Martin


Re: Vintage Tektronix ceramic terminals

Bob Albert
 

George I am very interested.  I'm in the San Fernando Valley and maybe one of us knows someone traveling up this way to bring them.  Or maybe USPS?
73, Bob K6DDX

On Sunday, November 29, 2020, 12:15:32 PM PST, George Kerber <gk5220@gmail.com> wrote:

All-
I am doing a bit of fall cleaning and have several hundred (10 lbs.) vintage Tek ceramic terminal strips and plastic inserts. I only need a few of them. The rest of the terminals need to go to a good home.

I offered the terminals to the Vintage Tek Museum, but they have several life times supply too. All terminal are new unused, but may have some cosmetic defects. All of the silvered slots are still perfect. I can send pictures.

I am not interested cataloging the terminals or mailing a few at time. They are free and available for local pickup. I am in the San Diego, CA area.

- George


Re: Tek 24xx calibration -- How to store constants before finishing the entire procedure

Rogerio O
 

Thank you for the replies.
I have used a TG501, PG506 and a SG503 to execute the cal procedure.
But as have been pointed out by Jean-Paul, I find the text describing some of the step quite confusing.
I will execute all the steps, of course, but not all in one day.
So that is why I would like to save the constsnts after finishing CAL01, then stop for the day (this is s big one).
Than CAL02 and maybe CAL03, and stop again.


Vintage Tektronix ceramic terminals

George Kerber
 

All-
I am doing a bit of fall cleaning and have several hundred (10 lbs.) vintage Tek ceramic terminal strips and plastic inserts. I only need a few of them. The rest of the terminals need to go to a good home.

I offered the terminals to the Vintage Tek Museum, but they have several life times supply too. All terminal are new unused, but may have some cosmetic defects. All of the silvered slots are still perfect. I can send pictures.

I am not interested cataloging the terminals or mailing a few at time. They are free and available for local pickup. I am in the San Diego, CA area.

- George


Re: Tek 24xx calibration -- How to store constants before finishing the entire procedure

Jean-Paul
 

Chuck 100% perfect, but your one hour cal time is because you have every correct test fixture and generator, and have done 1000s of them!

A newcomer will be sure to have issues and need some hours IF he has the TEK CAL units.

If he is doing a CAL without the TEK recommended lab, expect long time.

Transient is indeed the most challenging!

Jon


Re: OT: Analog Computer Comdyna GP-6

Ed Breya
 

I also caught the analog computer bug a few years ago, and studied the Comdyna stuff and lots of others from the old days. I started a project to build a sophisticated analog computer with a wide variety of functions, from scratch, with more "modern" components. I have it partly built, but it's a long way to go, so it may never be finished. Instead of lots of banana jacks, the plan is to use a number of those plastic plug in IC etc prototyping plates, with the function circuits wired to the bottom, inside, and programming with wire jumpers on top. It's very compact, and provides hundreds of connection nodes.

Speaking of X-Y displays, there happens to be a somewhat related thread, regarding possible uses for an old 528 TV waveform monitor. I suggested making it an X-Y monitor, here:

https://groups.io/g/TekScopes/message/173941

You should view the whole thread for context.

Ed


Re: 475A Z-Axis Amp and Q1338 Confusion

 

On Sun, Nov 29, 2020 at 03:28 AM, Jeff Dutky wrote:


I did as you said, and using that method the Q1338 shows a diode voltage of
0.773 from base to collector and the same (or nearly so) from base to emitter
Hi Jeff,
These are quite fast, low current transistors and their construction/geometry could explain the largish voltages. Still, I'd expect the BE-voltage to be slightly larger than the BC-voltage. OTOH, I don't know the geometry...

A "serious" curve tracer is a treasure: I use my Tek 576 for looking at small and large transistors, (tunnel) diodes, MOSFets etc. It's also quite useful for checking capacitor leakage and breakdown voltage.
It also keeps my house solidly fixed to the ground underneath.

Raymond


Re: Another A5 board repair attemp - help needed

Jokken Feldhaar
 

Hello Rogerio,

this group is most certainly the right place for your problem!

Cheers Jochen DH6FAZ

Am 29.11.2020 um 16:28 schrieb Rogerio O:

Hi Folks,
Bad news on the front.
I tried to start the automated calibration procedures (CAL01, CAL02, etc) and realized that the Horizontal position control is not working.
Since I have replaced U2101 and U2521, I guess that U2420 is faulty.
I have to stop working on the scope now, but I would like to ask if this is the right place to check.
thank you
Roger




Re: Tektronix 492A input attenuator repair ????

Bent Andersen
 

I have now disabel the attenuator and inside I have clean it whit Alcohol + Glasfiber brush so now it is working....but it looks as one of the pad is not getting contact whit the gold-spring ???
but I have uploade som close-up picture and write down the Resisten I found whit my DMM.


Re: Another A5 board repair attemp - help needed

Rogerio O
 

Hi Folks,
Bad news on the front.
I tried to start the automated calibration procedures (CAL01, CAL02, etc) and realized that the Horizontal position control is not working.
Since I have replaced U2101 and U2521, I guess that U2420 is faulty.
I have to stop working on the scope now, but I would like to ask if this is the right place to check.
thank you
Roger


OT: Analog Computer Comdyna GP-6

Wolfgang Schraml
 

Hello,

I recently took an interest in analog computers. I ended up buying two Comdyna GP-6 units, serial numbers 269 and 019.
For #269, the available documentation (I spent hours googling and downloading PDFs) is pretty close to the physical unit. The one I have seems to be a little bit of a Frankenstein device since it has various boards from what looks originated out of very different production times. It also shows signs of heavy use, repairs, and potentially modifications at some point in its life. But again, the two versions of manuals I have applied to it very closely when read in combination. I am at a point where I think most problems with it (broken/cold solder joints, bad Op-Amp in the time base, missing banana jacks, broken knobs) have been or will soon be resolved, and all that's left is a thorough calibration (still trying to decipher the manuals in that regard).

Now to the second unit, serial #019. It is a very different design from the other one; none of the boards are the same or look even close. The built-in voltmeter is a nixie type (working), and even the capabilities are much less than serial #269. For example, the whole block of push buttons that select "IC", HD", "OP", and "RO" is not there yet. So as the serial number would indicate, it is a very early unit.
None of the documentation I found is even close. I contacted a YouTuber who has a video about one of these, and he also was not successful in obtaining any early Comdyna documentation.

So my question is - does anyone have any documentation for these very early units? Or any other Comdyna related info that would give me a starting point for a restoration? If you have anything in paper, I would gladly offer to scan it in and make it available for others to use.

Thank you,
Wolfgang Schraml, KI7PFX


PS: There is a little bit of a connection to the Tek forum … I ended up buying a Tektronix 455 to get clean outputs in XY-mode compared to my Rigol 1054Z). And a second one is on the way as a spare/backup unit.


Re: (OT) Where to go for 70s IBM hardware? I'm looking for a terminal.

Brian
 

Check Elliots Elecrtonics in Tucson AZ. 
Elliott Electronic Supply - Electronic Component Parts Supplier
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Elliott Electronic Supply - Electronic Component Parts Supplier

Elliott Electronic Supply components distributor offers 1M+ products from 200+ manufacturers. A Huge selection in stock and ready to ship same day with no minimum orders.
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They do have a "used" electronics area that isn't on the website. But if you call and tell them what your looking for they should be able to help you.
On Sat, Nov 28, 2020 at 9:58 PM, Roy Thistle<roy.thistle@mail.utoronto.ca> wrote: On Sat, Nov 28, 2020 at 01:26 AM, Martin wrote:


electro-mechanical computer, I inherited some modules I wonder if anybody can
shed some light on them.
It's reading 204
That's a Cannon D Submini connector
Looks to me that you have 3 synchros (selsyns) and a resolver... along with a motor
And 2 Bridge circuits
You've got some cams that active some microswitches, and gear trains.
The outputs appear to be on the linear pots.
It seems like a state machine to me... it executes a mechanical program... and also sends data. (position?... and feedback)
Potentially it seems like you've got 3 dependent degrees of control, with feedback.


Re: 475A Z-Axis Amp and Q1338 Confusion

Michael W. Lynch
 

On Sat, Nov 28, 2020 at 11:38 PM, Jeff Dutky wrote:


I'm a little surprised that I haven't seen an external curve tracer that could
be attached to a scope operating in X-Y mode. I know that you can do some
kinds of component checks using a scope in X-Y mode, but I haven't gotten
around to learning exactly how to do that.
Jeff.

Knowing what I know now, a Curve Tracer would be one of my first acquisitions, if for no other reason than a learning tool as well as to test and match components. I use mine to find replacements for those TEK part numbers that can no longer be had. There are several curve tracer or "octopus circuit" kits that can be had or constructed that use the scope in the X-Y mode. These work to some extent, but fall far short of the capabilities of say a TEK 576 or 577 Curve Tracer. I am certain that there are many here that can diagnose or interpret data sheets and schematics far better than myself; but for me there is no substitute for seeing a part function, real time, in a graphical or visual mode. The value and utility of a dedicated curve tracer, properly and skillfully used cannot be understated.

--
Michael Lynch
Dardanelle, AR


Re: Tek 24xx calibration -- How to store constants before finishing the entire procedure

Chuck Harris <cfharris@...>
 

Calibration constants are stored as you work through the various
stages of the major calibration steps. The checksums are done in
blocks at the end of the major calibration steps (eg. CAL01, CAL02,
CAL 03...).

Not finishing a major calibration step will always cause a failed
calibration indication. So, always do all of CAL01, then all of
CAL 02... You can stop after you complete such a major calibration
step.

Tektronix had no desire for you to only do a single stage in a
major calibration step. That would be shoddy work. They wanted
you to do the full calibration.

If you have suitable calibration equipment, it should only take you
a little over an hour to do a complete calibration. The biggest
time suck in the whole process is transient calibration...

-Chuck Harris

Rogerio O wrote:

Dear all,
I have read somewhere on this forum what is necessary to do in order to store the calibration constants without finishing all the calibration steps.

However I have spent more that an hour searching for this information and I did not find it, so I decided to ask this specific question again so me and other members would be able to find the answer quickly.

I have calibrated one 2465B a long time ago and I remember that it took the entire day since I had to go though some step many time until I get it right.
Sine I no longer have such long time available without disturbances, my plan is to execute one step and store the constants so I can stop the work without loosing the previous work.

Thank you

Roger






Re: EZ Test for 4041

Monty McGraw
 

Gary,

I have shipped all three of your DC100 tapes back to you - all working now, with a couple of new plastiband drive belts.

The 4.25" plastibands don't last long if you are actively writing files to tape - they stretch slightly and then you get tape errors.

Just booting the System Verification tape to change the console to COMM0: - the belt lasts longer.

I also created and posted on my github site a 4041 BASIC program that creates an entire SYSVER tape - but it needs 512KB of 4041 memory to hold the all the tape files in DATA statements. It should be easy to divide the program into several smaller ones for those that don't have 512KB of memory. I load the program into memory from my PC through 4041 COMM0: at 9600 baud.

Your first post in this thread indicated you had a EZ-TEST software tape that is not reliable anymore. I would love to try to recover those files - and put them on a NOS tape for you.

Monty


Tek 24xx calibration -- How to store constants before finishing the entire procedure

Rogerio O
 

Dear all,
I have read somewhere on this forum what is necessary to do in order to store the calibration constants without finishing all the calibration steps.

However I have spent more that an hour searching for this information and I did not find it, so I decided to ask this specific question again so me and other members would be able to find the answer quickly.

I have calibrated one 2465B a long time ago and I remember that it took the entire day since I had to go though some step many time until I get it right.
Sine I no longer have such long time available without disturbances, my plan is to execute one step and store the constants so I can stop the work without loosing the previous work.

Thank you

Roger


Re: worst condition Tektronix scope?

 

Paul Amaranth wrote:

Well, if you want to enjoy the madness, I have a pair of 468s to get rid of. One was
working pretty much but is showing signs of bad filter caps and the other is a parts scope.
I would actually be interested in the 468s, especially if there's work required (that's at least half the fun).

I'm willing to pay shipping. Is there other compensation you would like?

-- Jeff Dutky


Re: There is no good time to be SICK

tek_547
 

Good to hear it´s going better Dennis so keep safe and watch out for THE virus.
René

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