Date   

Re: Greetings From a New Member

Jim Ford
 

Hi, Gordon.

Welcome to TekScopes! Say, did you know Tony Ma at General Atomics? PM me at jfordATieeeDOTorg.

Jim Ford

------ Original Message ------
From: "Gordon Smith" <gfsmith@cox.net>
To: TekScopes@groups.io
Sent: 12/5/2020 8:47:25 AM
Subject: [TekScopes] Greetings From a New Member

Hi All,
Just wanted to introduce myself. I'm Gordon Smith, a technology enthusiast down here in San Diego, CA. Was recently given a Tek 502 Dual Beam Oscope and in researching it found your group. A Tek 547 with cart and three plug ins was also adopted (yes, it's got the dreaded HV transformer issue). Other than being dragged willingly into the vintage Tek Oscope cult, I enjoy Vintage technology like ham radio stuff (want to the learn Morse code. Have way too many radios), Test equipment (I have some wonderful Non-Linear systems edge lit voltmeters) and have wayyyyy too much....errr...."Stuff" in the garage. I'm a mechanical engineer by trade doing mainly R&D over many fields and was forced by circumstance to learn a lot of electrical and some electronics. Currently employed by General Atomics. Thank you for allowing the introduction and stay safe out there. Gordon






Re: 575 Curve Tracer - $550

Glydeck
 

My first 575 was a discard from a Santa Barbra hamfest that my friend picked up for me. The guy selling for $20 couldn’t get any takers and did not want haul it back home. Here it is in use:

http://glydeck.blogspot.com/2011/03/motorola-mystery.html

The second 575 I picked up for $50 because it had the optional 400 volt supply which made it great for testing tubes for audio gear at work.

http://glydeck.blogspot.com/2012/01/testing-dual-triodes-with-tek-575.html

George

On Dec 8, 2020, at 10:44 AM, Dave Seiter <d.seiter@att.net> wrote:

I missed one of these at an estate sale last weekend. $20 with cart and in great condition! I didn't need it, as I have two already, but at $20, I would have snapped it up!
-Dave
On Tuesday, December 8, 2020, 09:57:11 AM PST, jfdickens via groups.io <jfdickens=icloud.com@groups.io> wrote:

Another Craigslist curve tracer in Wisconsin (I have no affiliation with the seller)

This vintage curve tracer has been in storage for many years. We are trying to find a good home for it. After cleaning it out inside and out, the unit powered up nicely. We haven't run many tests on it other than the basic display and power supply, but it seems perfectly functional. It is listed as fair right now, but that could change if we get more opportunity to test it. We really don't want to ship this heavy beast, so hopefully we can find a buyer in Wisconsin!
If you are unfamiliar with the 575, it is an awesome example of vacuum-tube based equipment. A picture of the vacuum tube deck is provided. It is capable of testing transistors or similar devices with up to 200 Volts and, at lower voltages, up to 20 Amps. See the attached pictures. Let us know if there is a specific test you would like to see verified.

https://madison.craigslist.org/bfs/d/verona-tektronix-type-575-curve-tracer/7233377161.html









Re: Tek blue (and gray) paint

greenboxmaven
 

In the USA, you can check with Fastenall stores. Many of them do accept frieght for movement from one of their stores to another. They sell many aerosol products, including paint, so carrying a few cans of paint should not be an issue. I have not had any problem ordering aerosols and liquid products in the last few months, or lithium batteries, as long as they were labeled and shipped by ground.

Bruce Gentry, KA2IVY.

On 12/8/20 12:28, Dave Casey wrote:
On a pallet in the back of an 18-wheeler either belonging to the
distribution company itself or a contracted freight carrier.

Dave Casey

On Tue, Dec 8, 2020 at 11:26 AM Colin Herbert via groups.io <colingherbert=
blueyonder.co.uk@groups.io> wrote:

One wonders how any of this stuff gets to retail outlets, presumably by
the manufacturing company itself?
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
Jean-Paul
Sent: 08 December 2020 16:36
To: TekScopes@groups.io
Subject: Re: [TekScopes] Tek blue (and gray) paint

Hi there Nothing to do with the Virus, the regs are worse ever year as
prices rise on shipping anything.

All common carriers Post/Fed/UP have tightened restrictions in recent
years, eg Li batts, Haz mat, chemicals, and Aerosol.

Blame the liability lawyers.


Suggest to take the numbers on the can, check with a Pan-tone book, and
get a custom (NON aerosol) mix at a good paint store.

Of course, it must be an oil based lacquer, so many jurisdictions (EG all
of Claif) will prohibit due to VOC.

Will they ever just let us be to do our work?

Jon














Re: Tek blue (and gray) paint

Dan Abell
 

It’s not liability lawyers in this case, it’s a safety issue for, in particular, air carriers. Yes I know this because I was responsible for hazardous materials on my aircraft in USAF.
Dan w3dka


Re: Gauging interest in a run of reproduction knob tips

 

I could use 10 of them if you can keep the cost around $2 to $3 each.
Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of thespin@gmail.com
Sent: Wednesday, December 02, 2020 1:12 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Gauging interest in a run of reproduction knob tips

I'm only considering one single part at the moment. Injection molds are extremely expensive, and I'm a mere postdoc. I only have one lecroy scope and it's relatively modern, and this project is mostly motivated by my love for my 556 and 547. I have a few options for how to make the parts -- have a mold made, or make it myself and make the parts on a friend's press. The former is expensive, and the second is labor intensive. I want to make sure I break even on the money invested or am appropriately compensated for the labor.







--
Dennis Tillman W7pF
TekScopes Moderator


Re: Yet another use for a curve tracer

 

Hi Ed,
Curve tracers are very versatile instruments and the only real limitation they have is the person at the controls.
Nearly everyone I know who owns a curve tracer thinks they are only good for checking transistors.

What you did was think outside the box, and as you said in the subject, you found another use for a curve tracer.
I hadn't thought of using it to test lamp dimmers myself so I learned something new.
But I have used it to test capacitors, inductors, transformers, pots, SCRs, TRIACs, DIACs, MOVs, OpAmps, Voltage Regulators ICs, Spectrum Tubes, light bulbs, etc.
Anything with two or three leads is fair game for a curve tracer.

Anyone who owns a curve tracer is extremely fortunate. You can learn a great deal about how electronic parts of all kinds respond when you connect them to a curve tracer.

Thanks for sharing your clever idea.

Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Ed Breya via groups.io
Sent: Friday, December 04, 2020 7:52 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Yet another use for a curve tracer

The old-fashioned way would work too, but this was simplest for me to turn it on and set up. The whole thing took only a few minutes to check them all. It would take me much longer just to find a bulb socket - I know I should have one somewhere around here.

Ed







--
Dennis Tillman W7pF
TekScopes Moderator


Re: 575 Curve Tracer - $550

Dave Seiter
 

I missed one of these at an estate sale last weekend. $20 with cart and in great condition!  I didn't need it, as I have two already, but at $20, I would have snapped it up!
-Dave

On Tuesday, December 8, 2020, 09:57:11 AM PST, jfdickens via groups.io <jfdickens=icloud.com@groups.io> wrote:

Another Craigslist curve tracer in Wisconsin (I have no affiliation with the seller)

This vintage curve tracer has been in storage for many years. We are trying to find a good home for it. After cleaning it out inside and out, the unit powered up nicely. We haven't run many tests on it other than the basic display and power supply, but it seems perfectly functional. It is listed as fair right now, but that could change if we get more opportunity to test it. We really don't want to ship this heavy beast, so hopefully we can find a buyer in Wisconsin!
If you are unfamiliar with the 575, it is an awesome example of vacuum-tube based equipment. A picture of the vacuum tube deck is provided. It is capable of testing transistors or similar devices with up to 200 Volts and, at lower voltages, up to 20 Amps. See the attached pictures. Let us know if there is a specific test you would like to see verified.

https://madison.craigslist.org/bfs/d/verona-tektronix-type-575-curve-tracer/7233377161.html


Re: Greetings From a New Member

Jean-Paul
 

Gordon, been a test equipment aficionado since 1970, using TEK scopes since 1967 at Lawrence Berkeley labs. I think they were 545s.



Is General Atomic the firm that developed nuclear reactors in 1950s and was guided by some top Nuclear Physicists at the time? Beware...TEK scopes can be addictive!



Enjoy,

Jon

PS: Be fine to see some photos of the NLS VMs!


Re: 575 Curve Tracer - $550

David Holland
 

Funny, the last one I had to get rid of (I had two) I couldn't get 20$
because I didn't want to ship... That is a mind boggling price...

Definitely not shippable BTW, the rear CRT bracket in the 575 is nylon, and
has a fair chance to be split by now...
That one looks like it has power supply issues (caps likely) as well.

David

On Tue, Dec 8, 2020 at 12:57 PM jfdickens via groups.io <jfdickens=
icloud.com@groups.io> wrote:

Another Craigslist curve tracer in Wisconsin (I have no affiliation with
the seller)

This vintage curve tracer has been in storage for many years. We are
trying to find a good home for it. After cleaning it out inside and out,
the unit powered up nicely. We haven't run many tests on it other than the
basic display and power supply, but it seems perfectly functional. It is
listed as fair right now, but that could change if we get more opportunity
to test it. We really don't want to ship this heavy beast, so hopefully we
can find a buyer in Wisconsin!
If you are unfamiliar with the 575, it is an awesome example of
vacuum-tube based equipment. A picture of the vacuum tube deck is provided.
It is capable of testing transistors or similar devices with up to 200
Volts and, at lower voltages, up to 20 Amps. See the attached pictures. Let
us know if there is a specific test you would like to see verified.


https://madison.craigslist.org/bfs/d/verona-tektronix-type-575-curve-tracer/7233377161.html






Re: FS: Tek P6102 probe [Actually P6012]

Oz-in-DFW
 

Håkan observed:

Your pic says P6012 so I guess that's what it is .....
D'oh! I must be lysdexic. It is! TekWiki says: The Tektronix P6012 is a passive 10× probe with 33 MHz bandwidth. It comes with 3.5", 6" or 9" cable and a BNC connector.

--
Oz (in DFW) N1OZ


Re: SUCCESS! The "sick" 475A is now the "fixed" 475A!

Tom Lee
 

Jeff,

I would not spend too much time looking at the 491’s docs — it’s a very primitive instrument architecturally, and today serves mainly as an example of how not to design an SA. The 492 is a completely different instrument. If you’re going to study a Tek SA, that’s probably the best starting point (along with the related Tek Concepts books).

Raymond pointed you to the HP Memory site, which has an amazing wealth of information, including many reminiscences of the design teams who created many of their groundbreaking instruments. Often they’ll utter a throwaway sentence that explains many mysteries (“Oh — THAT’s why they did it that way!”). You can spend many hours there. Way better than anything on Netflix; it’s Nerdflix, except no flix.

One of my favorite stories is about their first SA, the 8551A. It was revolutionary because they were able to tame a beast called the backward-wave oscillator (BWO), which is a vacuum tube oscillator that can be tuned over octaves. The BWO was, and is, infamous for having a maddening ability to burst into song at unwanted frequencies, but HP’s engineers figured out how to tamp down that tendency. I won’t burden this thread with a long explanation about why a broadly-tunable oscillator is a good thing for an SA, but just accept for now that More is Better here, and that HP’s solution enabled a kick-ass SA.

Polarad, which was then the dominant SA supplier, attempted to defend their franchise by underbidding HP for a huge DoD contract, and set about copying the 8551A. Polarad’s engineers could not solve the BWO problem, though, so they ended up fulfilling the contract by buying 8551As from HP at full price and rebadging them. HP made a fortune off of that.

Cheers,
Tom



Sent from my iThing, so please forgive typos and brevity.

On Dec 8, 2020, at 8:42 AM, Jeff Dutky <jeff.dutky@gmail.com> wrote:

Tom,

Well, my neural net seems to be quite open to calibration, but my eyes are another story

I have actually been running tests (quantitatively unsuccessful, but qualitatively enlightening) on the visual bandwidth of my scopes (feeding in a Z-axis signal and seeing how many discernible dots I can fit across the screen), and this has really driven home what the actual precision of the scope display is (it's not more than about 9 bits in either direction). I recall my father saying something similar about the 4014 terminals that he used: the resolution of the drawing commands was 4k x 4k, but the actual screen resolution was much lower (I don't recall the exact numbers, but i now expect that they couldn't resolve more than 512 dots across the small [12 inch?] screens, and probably not more than 1k across the large [20 inch?] CAD displays we saw once at a Goddard open house). By my calculation the 400 and 2200 series scopes aren't actually displaying more than 640x400 pixels, and only 320x200 resolvable, distinct lines. This severely limits the precision of any measurements you make by eye on screen despite the apparent smoothness of the waveforms.

I'm still a little mystified by exactly what concrete tasks I might need a volts or watts per frequency measurement for, but I'm happy to wait for enlightenment while I play with a new toy. I'm a very hands-on learner, even when I'm rigorously going through theory need to have concrete examples to test myself against and to illustrate academically presented topics.

I see that there were two SAs in the 400 series, one much more "analog" (and of much older manufacture) than the other, and at least two more in the 2700 series (they look like siblings to the 2200 and 2400 series scopes). They seem pretty rare on eBay, and are asking much higher prices than the comparable era scopes. At some point I will need to read through the manuals for the 491, just to see how the spectrum analysis was done in the days before microprocessors.

Everything I have learned since taking up this hobby has fed a keen awareness that, even when they are in perfect working order, your instruments are lying to you (if only by omission).

-- Jeff Dutky





Re: Greetings From a New Member

Michael W. Lynch
 

Gordon,

Welcome to the club or the crazy house (depending on whether you are speaking to me or my wife). You will find a lot of like minded people here.

--
Michael Lynch
Dardanelle, AR


Re: 576 Curve Tracer

Eric
 

It would be interesting to know the serial number. Based solely on the
condition of the knobs I would be it has the epoxy hv transformer

On Tue, Dec 8, 2020, 12:57 PM jfdickens via groups.io <jfdickens=
icloud.com@groups.io> wrote:


This is near Madison Wisconsin. I have no connection to the seller or
curve tracer.

Tektronix Type 576 Curve Tracer - $800 (Verona)

This vintage curve tracer has been in storage for many years. We are
trying to find a good home for it. After cleaning it out inside and out,
the unit powered up nicely. We haven't run many tests on it other than the
basic display and power supply, but it seems perfectly functional. It is
listed as fair right now, but that could change if we get more opportunity
to test it. We really don't want to ship this heavy beast, so hopefully we
can find a buyer in Wisconsin!
If you are unfamiliar with the 576, it is capable of testing transistors
or similar devices with up to 1500 Volts and, at lower voltages, up to 10
Amps continuous. See the attached pictures. Let us know if there is a
specific test you would like to see verified.


https://madison.craigslist.org/bfs/d/verona-tektronix-type-576-curve-tracer/7233373156.html






Re: Greetings From a New Member

Tom Lee
 

Welcome to the group, Gordon! I grew up in SD, still have family there.

As to stuff, well, this is the place to learn how to fix it so that you can get more. :)

—Cheers
Tom

Sent from my iThing, so please forgive typos and brevity.

On Dec 8, 2020, at 9:57 AM, Gordon Smith <gfsmith@cox.net> wrote:

Hi All,
Just wanted to introduce myself. I'm Gordon Smith, a technology enthusiast down here in San Diego, CA. Was recently given a Tek 502 Dual Beam Oscope and in researching it found your group. A Tek 547 with cart and three plug ins was also adopted (yes, it's got the dreaded HV transformer issue). Other than being dragged willingly into the vintage Tek Oscope cult, I enjoy Vintage technology like ham radio stuff (want to the learn Morse code. Have way too many radios), Test equipment (I have some wonderful Non-Linear systems edge lit voltmeters) and have wayyyyy too much....errr...."Stuff" in the garage. I'm a mechanical engineer by trade doing mainly R&D over many fields and was forced by circumstance to learn a lot of electrical and some electronics. Currently employed by General Atomics. Thank you for allowing the introduction and stay safe out there. Gordon






Re: Can capacitors

Eric Boyle
 

I bought one of these for both of my 75A-4's, i
they seem to be working well. I didn't buy the kit because I can source the other capacitors from Mouser far cheaper. And one of my 75A-4's is usually on 24/7 for weeks at a time. I don't know who made them, they aren't the same as the one's from tubes and more.

http://nationwide-radio--amp-amp-amp--eq-sales-llc.mybigcommerce.com/collins-75a-4-new-chassis-mounted-replacement-capacitor-can/


Re: Can capacitors

Richard Coberly
 

I have been repairing tubed guitar/bass amps since the 1970's and mostly I use modern replacement caps. But now that some of these amps have become collector items, some believe that they must have OEM replacement parts. Thankfully, these folks seldom play/use these amps so the reliability is not much of a problem. And they don't seem to mind spending their money. Trickle down economics. If the client actually uses the amp, especially to play gigs for money, they get modern parts.
All my test equipment gets modern caps. I delineate between repair, refurbishment, and restoration with my clients.
Rick


Greetings From a New Member

Gordon Smith
 

Hi All,
Just wanted to introduce myself. I'm Gordon Smith, a technology enthusiast down here in San Diego, CA. Was recently given a Tek 502 Dual Beam Oscope and in researching it found your group. A Tek 547 with cart and three plug ins was also adopted (yes, it's got the dreaded HV transformer issue). Other than being dragged willingly into the vintage Tek Oscope cult, I enjoy Vintage technology like ham radio stuff (want to the learn Morse code. Have way too many radios), Test equipment (I have some wonderful Non-Linear systems edge lit voltmeters) and have wayyyyy too much....errr...."Stuff" in the garage. I'm a mechanical engineer by trade doing mainly R&D over many fields and was forced by circumstance to learn a lot of electrical and some electronics. Currently employed by General Atomics. Thank you for allowing the introduction and stay safe out there. Gordon


575 Curve Tracer - $550

John Dickens
 

Another Craigslist curve tracer in Wisconsin (I have no affiliation with the seller)

This vintage curve tracer has been in storage for many years. We are trying to find a good home for it. After cleaning it out inside and out, the unit powered up nicely. We haven't run many tests on it other than the basic display and power supply, but it seems perfectly functional. It is listed as fair right now, but that could change if we get more opportunity to test it. We really don't want to ship this heavy beast, so hopefully we can find a buyer in Wisconsin!
If you are unfamiliar with the 575, it is an awesome example of vacuum-tube based equipment. A picture of the vacuum tube deck is provided. It is capable of testing transistors or similar devices with up to 200 Volts and, at lower voltages, up to 20 Amps. See the attached pictures. Let us know if there is a specific test you would like to see verified.

https://madison.craigslist.org/bfs/d/verona-tektronix-type-575-curve-tracer/7233377161.html


576 Curve Tracer

John Dickens
 

This is near Madison Wisconsin. I have no connection to the seller or curve tracer.

Tektronix Type 576 Curve Tracer - $800 (Verona)

This vintage curve tracer has been in storage for many years. We are trying to find a good home for it. After cleaning it out inside and out, the unit powered up nicely. We haven't run many tests on it other than the basic display and power supply, but it seems perfectly functional. It is listed as fair right now, but that could change if we get more opportunity to test it. We really don't want to ship this heavy beast, so hopefully we can find a buyer in Wisconsin!
If you are unfamiliar with the 576, it is capable of testing transistors or similar devices with up to 1500 Volts and, at lower voltages, up to 10 Amps continuous. See the attached pictures. Let us know if there is a specific test you would like to see verified.

https://madison.craigslist.org/bfs/d/verona-tektronix-type-576-curve-tracer/7233373156.html


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

wagnerlip
 

I worked 19 years for IBM as a mainframe engineer until 1993, and added
teleprocessing in the curriculum.
3270 terminals were everywhere, they were tough, strong and dependable.

I even design and produced one portable device to test the controller and
terminals remotely (3271/3274/3275/3276/3278/3705/3725/2703 etc), without
the need of a mainframe, that became an IBM patent.
The 3270 protocol is something fascinating, you can find online the 3270
programming language, it means, the attributes to send to the terminal
memory in order to show text, position the cursor, create input fields,
start field, protected fields, highlight, etc. It was a great jump for IBM
and it was used for decades.
The best way to dive into this, is using a serial terminal, like the
3275/3276, just plug your computer with a cross cable (no modems necessary)
and talk to the unit at 2400/4800 bps.
The only problem for you, will be the new idiom, conversation language to
the unit, it doesn't use ASCII char set, they uses EBCDIC, and the
communication is not RS232-C async (start/stop) like your PC does.

The communication protocol is synchronous and the protocol is Bisync "BSC"
(Binary Synchronous Communication) or SNA SDLC (Synchronous Data Link
Control). BSC is much simpler (even so is complicated), SNA SDLC is
somehow similar to Ethernet, it is bit orientated instead of bytes, and
uses packages, frames, counters, etc. SNA SDLC is much more efficient for a
multitude of devices and addresses in a large environment and not very
productive for small network (communication flow bit count vs useful data
really transferred).
If you really want to play with it, look for a 3275 (very old) or 3276 (new
style terminal), both incorporate the communication controller inside, and
you can talk using a simple RS232C (full interface, 25 pins, the DBE 8 pins
connector doesn't carry all the interface wires necessary, including Tx/RX
clock, it is synchronous).

By the other side, it is very difficult to talk to 3278/3277 terminals via
the coax cable, the communication and speed is very very tricky, even so,
some external competitors made some hardware boards to insert into the
ISA/PCI slots of the PC and emulate such terminals, connected to
3271/3272/3274/3174 controllers. I don't remember seem something driven
directly a terminal via the coax cable, even that, it might exist.

BSC uses flow control as SOH, STX, ETX, EOT and CRC32 at the end to certify
at the reception end the frame is not corrupted.
Each frame sent requires an answer from the receiver ACKnowloging or
NotACKnowloging the block received, etc. The protocol is a bit complex and
has several other situations and actions.
By far, the SNA SDLC/HDLC is much more complex.

Wagner Lipnharski


On Tue, Nov 24, 2020 at 2:03 PM cheater cheater <cheater00social@gmail.com>
wrote:

Thanks everyone. Not really bothered about the dependency on a control
unit for two reasons. First of all, finding /anything/ of this era will be
difficult, whether it's the rarer RS232 kind, or less rare control unit
based type. Second of all, emulating the bus will likely be part of an
interesting challenge and a good way of figuring out the inner workings of
the display and input device, which is what I want to do, so rather than a
problem it's a positive thing for me. A $10 computer nowadays will be able
to do the job. My current biggest problem is locating those older terminals
in the first place. My assumption is they're mostly in defunct computer
graveyards, warehouses, university store rooms, or bank or utilities store
rooms, dusting and decaying away.





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