Date   

Re: worst condition Tektronix scope?

Oz-in-DFW
 

Looks like it's been stored in a tropical jungle for a few years!
I'm thinking just below a pigeon loft or leaky garden shed.

Priced to be sucker bait, especially given the description. He's let all the smoke out and cut the cord!

--
Oz (in DFW) N1OZ


Re: Tek Glass Tracing

Oz-in-DFW
 

The main feature of the photograph you provide looks more like some sort of residue to me than a crack (if I'm looking at the correct feature in the photo.). It's also not clear why a crack would develop there as it does not appear to be a flexure or stress line. The photo you provide has neither the magnification to see cracking, nor an indication of where you think the cracking has occurred.

While you may already understand that all you state is a hypothesis that needs to be proven and have made measurements to verify it, your post does not indicate you do or have. Cracking can be tricky in printed traces.
You should be able to prove your hypothesis by probing the trace. You'll want to use a rounded probe tip, or a small piece of metals as a pad so as not to damage the trace. Fix one end and drag the probe along the trace. resistance should increase steadily for a healthy trace and increase abruptly at a crack.

Most of the time when I see cracking in these kinds of older flex circuits it's at the connector pins. More often than not it's invisible without considerable magnification and careful lighting.

I've repaired these kinds of traces with conductive epoxy. If the crack is at a mechanical stress location you'll want to use a small jumper that terminates outside the stress zone and is formed to survive the stress source (like a bend or repeated motion.) I have some 17 strand silver plated 30 AWG teflon wire that I use for this kind of thing.

--
Oz (in DFW) N1OZ


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

 

Just wanted to ask again if anyone has any 70s IBM stuff. System/3, 5xxx,
etc. Old terminals. You can tell them apart because the keyboards look more
like a typewriter than a computer, and the gear is usually encased in thick
metal plating, and often comes in the form of a full desk.

On Fri, Nov 27, 2020 at 4:14 PM n4buq <n4buq@knology.net> wrote:

Hi Steve,

Looks like your email address and the version that uses "at" and "dot"
aren't the same. Is that a typo?

Thanks,
Barry - N4BUQ

On 11/27/2020 9:06 AM, stevenhorii wrote:
Bill,

Since this is so far off-topic, please feel free to contact me off-list:

sonodocsch@gmail.com

If this gets blocked, it is sonodoc at gmail dot com.

My interest in guidance and nav stuff is not professional but I’d guess
you
would call it “hobby”. I have quite a bit of Litton stuff - a lot turned
up
in the Los Angeles surplus stores since they were in Woodland Hills.

I’d be interested to discuss my interests in the G&N hardware. I’m a
radiologist by trade, but I have more books on G&N than I have books on
radiology. I am also a member of the Institute of Navigation as well as
the
IEEE (well, in addition to the American College of Radiology and a few
other radiology societies).

Steve Horii

On Fri, Nov 27, 2020 at 09:38 Bill Higdon via groups.io <willard561=
aol.com@groups.io> wrote:

Is the F-111 Nav computer part of the INS system? Also the Navy boxes
might be part of an INS system. I worked at Litton in SLC back in the
70's
& worked on the Analog INS as well as the digital. The analog systems
had
electro-mechanical inetegrators for all 3 axis. I left when I was told I
was going to be put on the Astro INS, in retrospect I should have
stayed,
oh well.






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

n4buq
 

Hi Steve,

Looks like your email address and the version that uses "at" and "dot"
aren't the same. Is that a typo?

Thanks,
Barry - N4BUQ

On 11/27/2020 9:06 AM, stevenhorii wrote:
Bill,

Since this is so far off-topic, please feel free to contact me off-list:

sonodocsch@gmail.com

If this gets blocked, it is sonodoc at gmail dot com.

My interest in guidance and nav stuff is not professional but I’d guess you
would call it “hobby”. I have quite a bit of Litton stuff - a lot turned up
in the Los Angeles surplus stores since they were in Woodland Hills.

I’d be interested to discuss my interests in the G&N hardware. I’m a
radiologist by trade, but I have more books on G&N than I have books on
radiology. I am also a member of the Institute of Navigation as well as the
IEEE (well, in addition to the American College of Radiology and a few
other radiology societies).

Steve Horii

On Fri, Nov 27, 2020 at 09:38 Bill Higdon via groups.io <willard561=
aol.com@groups.io> wrote:

Is the F-111 Nav computer part of the INS system? Also the Navy boxes
might be part of an INS system. I worked at Litton in SLC back in the 70's
& worked on the Analog INS as well as the digital. The analog systems had
electro-mechanical inetegrators for all 3 axis. I left when I was told I
was going to be put on the Astro INS, in retrospect I should have stayed,
oh well.


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

stevenhorii
 

Bill,

Since this is so far off-topic, please feel free to contact me off-list:

sonodocsch@gmail.com

If this gets blocked, it is sonodoc at gmail dot com.

My interest in guidance and nav stuff is not professional but I’d guess you
would call it “hobby”. I have quite a bit of Litton stuff - a lot turned up
in the Los Angeles surplus stores since they were in Woodland Hills.

I’d be interested to discuss my interests in the G&N hardware. I’m a
radiologist by trade, but I have more books on G&N than I have books on
radiology. I am also a member of the Institute of Navigation as well as the
IEEE (well, in addition to the American College of Radiology and a few
other radiology societies).

Steve Horii

On Fri, Nov 27, 2020 at 09:38 Bill Higdon via groups.io <willard561=
aol.com@groups.io> wrote:

Is the F-111 Nav computer part of the INS system? Also the Navy boxes
might be part of an INS system. I worked at Litton in SLC back in the 70's
& worked on the Analog INS as well as the digital. The analog systems had
electro-mechanical inetegrators for all 3 axis. I left when I was told I
was going to be put on the Astro INS, in retrospect I should have stayed,
oh well.






Re: Tek Glass Tracing

Dave Wright
 

No direct experience, but looks like a conductive ink was used.

Perhaps this, or something similar would work:
https://www.tierney.com/products/circuit-scribe-conductive-pen/


_Dave KC6UPS


Re: worst condition Tektronix scope?

greenboxmaven
 

For decades I have taken equipment that was discarded in disgust or stored horribly and restoring it to operation. Initially, it was because of poverty, now I get great enjoyment from rescuing it from the dumpster and solving the puzzle of it's problems. In 1971 I had returned from duty in southeast Asia to Griffiss Air Force Base in Rome, New York to finish my term. Having worked on some neat stuff, I was interested in having some of the rigs for my own. At that time, a Tektronix 524 would cost $200.00 or more, and a Collins R-390 receiver would be $500.00 . Once I got to the base, I felt certain there would be surplus stores around, and there were, in nearby Utica. Enroute to one I had been told about, I noticed piles of gear out in the open in the heaped ruins of a burned building. Some of it was totally wrecked, but most was a bit smoked up and covered with dirt and ashes. The owner was delighted to sell us anything we wanted from the ruins for very low prices. I got an R-390 for $15.00, quite literally half buried in the ground, and a friend with me got a 535 scope that was just about as bad for the same price. After an initial stop at a self service car wash to get the worst of the dirt and ashes off, we both spent many evenings and a few weekends, and a good amount of penetrating oil and contact cleaner, dismantling and cleaning the rigs. Manuals were easily obtained, I worked in the radio shop and my friend had a connection in the instrumentation lab. We were both very surprised and impressed at how well they turned out physically, indeed good enough that some of the lifers and officers gave us a lot of crap about having "misappropriated" them. Fortunately, we were both returnees from the Vietnam theater, and knew what to expect and do. We had receipts from the surplus store and pre-restoration photos. The lifers then just shrugged in disappoinment and left us alone. We both enjoyed the fruits of our work, I kept the R-390 for years, and my friend used the scope for digital experimenting and very early computer crafting. What frightens me today is so few young people having the interest or ability to do such work, and the priceless learning and skill they could gain from doing so.

Bruce Gentry, KA2IVY

On 11/27/20 5:59 AM, Richard Steedman wrote:
Have you read the full description of this guy's scope?
"i plugged it in but it started smoking (white smoke) so i turned it off"
"i will take the side panel off tomorrow and take some pictures"
Those pictures should be a sight to behold!





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

Bill Higdon
 

Is the F-111 Nav computer part of the INS system? Also the Navy boxes might be part of an INS system. I worked at Litton in SLC back in the 70's & worked on the Analog INS as well as the digital. The analog systems had electro-mechanical inetegrators for all 3 axis. I left when I was told I was going to be put on the Astro INS, in retrospect I should have stayed, oh well.


Re: Choosing the right replacement cap

toby@...
 

On 2020-11-27 1:37 a.m., Thomas Dodge wrote:
I am not sure if I am doing this the correct way. I have three Tektronix
scopes. I have a Tektronix 533 scope that there is no trace. I have a
Tektronix 7704A, and the intensity is very very bright, and the
Time/Division switch has no effect. I also have a Tektronix 684A that I
bought from a surplus place, and had been on the shelf for a long time.
When I first brought it home and plugged it in, it didn't do anything, so I
turned it off and on again. After a while, it decided to work, and went
through the self test, and it was fine. I turned it off again, and then on
again, and it was still ok. I just turned it on again some months later,
and now it has no display on the screen at all. Usually when it was powered
on, the front panel lights will come on and start to initialize, but it is
not doing that now. Can anyone help with this? This is really a great scope
This might be a redundant suggestion but have the basic power supply
checks been done? Do you have a service manual?

--Toby


and the best one I have. Any help with this is appreciated. I did read
somewhere that it might need a chip replacement, but not sure. Thanks very
much.
Thanks,
Tom Dodge

On Tue, Nov 24, 2020 at 5:58 PM Dave Peterson via groups.io <davidpinsf=
yahoo.com@groups.io> wrote:

What parameters besides capacitance, voltage, and temperature are
appropriate for replacement capacitor selection?

I guess configuration and size, of course. What fits.

This is the typical C1419 for a 465 scope. Just did an online search and
am overwhelmed by the number of varieties.

Are there most reliable, quality, trusted brands? Are there some to be
sure to stay away from? How to choose!?

Thanks,
Dave









Re: worst condition Tektronix scope?

Richard Steedman
 

Have you read the full description of this guy's scope? "i plugged it in but it started smoking (white smoke) so i turned it off" "i will take the side panel off tomorrow and take some pictures" Those pictures should be a sight to behold!


Re: worst condition Tektronix scope?

Dave Seiter
 

I did hear a story a few years ago about a 500 series scope that was partially melted in one of the big north bay fires (2014 or 2016?), but no pictures.  (Also, it may not even have been a Tek; it was described as something like "one of those big old tube oscilloscopes with the round screen")
-Dave

On Thursday, November 26, 2020, 11:33:21 PM PST, Jeff Dutky <jeff.dutky@gmail.com> wrote:

I'd like to try to drag this thread back on topic, however: I can't believe that my dirty 475 is the worst scope that anybody has seen. Somebody has to have better stories, at least, whether or not they have the pictures to prove it.

-- Jeff Dutky


Re: worst condition Tektronix scope?

 

I'd like to try to drag this thread back on topic, however: I can't believe that my dirty 475 is the worst scope that anybody has seen. Somebody has to have better stories, at least, whether or not they have the pictures to prove it.

-- Jeff Dutky


Re: Tek Glass Tracing

satbeginner
 


Re: Choosing the right replacement cap

Thomas Dodge
 

I am not sure if I am doing this the correct way. I have three Tektronix
scopes. I have a Tektronix 533 scope that there is no trace. I have a
Tektronix 7704A, and the intensity is very very bright, and the
Time/Division switch has no effect. I also have a Tektronix 684A that I
bought from a surplus place, and had been on the shelf for a long time.
When I first brought it home and plugged it in, it didn't do anything, so I
turned it off and on again. After a while, it decided to work, and went
through the self test, and it was fine. I turned it off again, and then on
again, and it was still ok. I just turned it on again some months later,
and now it has no display on the screen at all. Usually when it was powered
on, the front panel lights will come on and start to initialize, but it is
not doing that now. Can anyone help with this? This is really a great scope
and the best one I have. Any help with this is appreciated. I did read
somewhere that it might need a chip replacement, but not sure. Thanks very
much.
Thanks,
Tom Dodge

On Tue, Nov 24, 2020 at 5:58 PM Dave Peterson via groups.io <davidpinsf=
yahoo.com@groups.io> wrote:

What parameters besides capacitance, voltage, and temperature are
appropriate for replacement capacitor selection?

I guess configuration and size, of course. What fits.

This is the typical C1419 for a 465 scope. Just did an online search and
am overwhelmed by the number of varieties.

Are there most reliable, quality, trusted brands? Are there some to be
sure to stay away from? How to choose!?

Thanks,
Dave






Re: Choosing the right replacement cap

 

Dave,

That this is the amount of ripple current the cap can take to make the lifetime spec? YES
A spec with twice the ripple for a given lifetime can take more power supply noise? YES
A UCY2C470MPD1TD with 375mA ripple and 10000 hr lifetime can take more power supply noise than a ULD1H470MED with 190mA ripple and 10000 hr lifetime? YES

The UCY is cruising in the 465 HV oscillator supply while the ULD might suffer degradation despite being well within voltage and temperature specs? MAYBE, and MAYBE not.

It depends on the actual ripple current. If say, there's only 100mA of ripple current, then both the UCY and ULD are cruising. If there's 250mA of ripple current, then that removes the ULD from the equation.

You can measure ripple current on a(nother) scope. You can FEEL how well the cap is handling ripple current by its temperature. All other factors being equal, a hot cap is battling to handle the ripple current, and a cool cap is handling the ripple current just fine. And if the cap is running hot, then the 10,000hr lifetime is meaningless.

ESR is the "internal resistance" of the cap. The lower the ESR, the more efficiently the cap is passing the current onwards. It's all about circuit efficiency, translated into MTBF, and signal cleanliness down the line. SMPS's require absolutely the lowest ESR caps possible that the bean-counters will authorize (and will stop working if a cap's ESR rises above a certain threshold), but a Linear PSU is far more tolerant of higher ESR caps.

Menahem


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

Matt Patoray
 

Steve,
The museum also has a non Facebook web page, https://www.mact.io/
Once Covid is a bit more under control, the museum will be resuming in person tours.
Matt
Chief Technician LSSM

On Nov 26, 2020, at 9:00 PM, stevenhorii <sonodocsch@gmail.com> wrote:

Has anyone mentioned these folks?

Large Scale Systems Museum
https://www.facebook.com/lssmuseum/

They are located near Pittsburgh. I visited them a couple of years ago and
they have an amazing amount of stuff, most of which is running. Once we get
past the COVID-19 pandemic, they will likely come out (with at least a
pickup truck) and pick up a few things I have to donate. I've got an EAI
TR-20 analog computer, a couple of ROLM RuggedNOVA computers (with the
front panels), a very early Sun workstation box (long before the Pizza Box
versions - this one uses a Motorola 68000-series CPU), and a couple of
mechanical computers (an early Air Force F-111 navigational computer and
some US Navy thing - both have a large number of gears and synchros in
them; the Navy one I think also has one or two mechanical integrators). The
Large Scale Systems Museum has a lot of IBM hardware and they have it
operational. Also early DEC large computers. They may have some IBM
terminals in excess of their needs or be able to provide some
documentation. I think they had the carts full of IBM schematics that used
to live in the machine rooms with the computers for use by the service
folks. Worth a visit if you are ever near Pittsburgh. If you grew up with
this stuff as I did, it can induce some major nostalgia.

May be worth sending them an e-mail message.

Steve Horii

On Tue, Nov 24, 2020 at 10:42 AM cheater cheater <cheater00social@gmail.com>
wrote:

Hi all,
sorry for the offtopic message, not sure where to go with this one, so I
thought the smart heads around here might be connected somewhere. I'm
looking to get a 70s IBM terminal, either for a System/3, /6, /32, /38 (or
contemporary), 3600 FCS, a Display Station (or terminal) for the IBM 32xx,
37xx, 49xx, 52xx, 65xx, or 74xx, or an IBM 5100/5110/5120 portable
computer. I'm interested to see how they were built and would like to see
how it is to use them. If you know any good places to go other than the
website which should not be named, especially any forums that could have
enthusiasts of the same hardware, or if you know someone willing to part
with one such machine, let me know please.

Thanks!









Re: worst condition Tektronix scope?

 

Raymond Domp Frank wrote:

The 466 is eminently suited to doing exactly what you're suggesting, much more so than even a 464.
With a 466 it's quite possible e.g. to store and then observe an edge with a rise time of 3.5 ns (the
fastest for the 100 MHz BW), either in Variable Persistence (repeating at say 1 Hz) or Fast Storage
(single shot) mode. Compare that with trying to view it on a 'scope like the 465, or for that matter,
a 475. Unless the signal has a repetition rate of at least 10 to 100 kHz, it'll be completely invisible!
That's fascinating. I might need to add the 466 to my wish list as well.

The computers that my father worked with in the late 70s had memory cycle times of 330 ns - 990 ns, so I expect that he could sustain a repetitive signal on target hardware at better than 200 kHz, so the 475 would have been able to show the signals of interest pretty easily.

Before I fell down this rabbit hole of fixing old scopes (started because the 475 malfunctioned) I was trying to use the 475 to decipher the control interface for a laptop plasma display panel. I was having some luck, but my fluency with the scope was terrible, and it was obvious that I was limited by my ignorance of how to use the delayed time base. When I've got the 475A working again I will be going back to the plasma display, and I hope that I have now learned enough about how to use the delayed time base to make better progress.

I know that this would be child's play if I just had a modern DSO, but that's not what I trying to do with this hobby, at least not right now. The 475 (and the 2200 series scopes) are exactly the right vintage to have been used with the hardware that I'm trying to investigate, and part of the fun is doing things the way that they would have been done at the time.

Of course it sounds like a 466 would make things a lot easier, while still being the proper vintage (the 468 is just slightly too new for my biases).

I have enough insight into my condition to understand that this is how one winds up with a basement full of scopes.


Re: Why you now Paypal

EJP
 

I get the Captcha nearly every time, and sometimes the spot-the-traffic-light game as well. They also keep enabling fast login on my iPad or computer when I don't want it, and there is no apparent way to stop that, although you can turn it off again when notified. And I can always eventually find the Send to Friend option.

I wouldn't be without it, but:

- the fees are too high considering they are holding the float and paying no interest to me.
- the UI keeps changing, and there are some things that are only accessible from the home screen, like items pending shipping for example (or else I've never found them).
- the statements are rudimentary, and when they changed from the old to the new statement format they didn't balance at the changeover point. From memory this was due to different timezones for one as against the other.
- I had a major argument with them a few years ago when their invoice form was charging GST on the undiscounted amount, meaning I was paying GST on my own discount. The call centre guy just argued black and blue until I said I wouldn't discuss it further with anyone who wasn't a qualified accountant. Eventually they put in what I wanted as an option, when the other option is never correct.
- from the programming perpsective the API is enormous and unwieldy, unless you use IPN, which is tiny and unwieldy ;-); and both are poorly documented.

EJP


Re: worst condition Tektronix scope?

 

That's not the worst... ask Mike how he got his first tek...

On Thu, Nov 26, 2020 at 7:26 PM Sparky99 <jnolan@iprova.com> wrote:

Just saw this on ebay in the UK :
https://www.ebay.co.uk/itm/Tektronix-Type-545-Oscilloscope-Vintage-Antique-Collectors/353290325095?hash=item5241be8c67:g:-GYAAOSwBPZfvDOx

Looks like it's been stored in a tropical jungle for a few years!

Anyone got any worse examples?






Re: Delay Time Position Vernier

Shailendra Krishan
 

Hi Jeff,

I clearly recall using a brand new 475 at my work place some forty years ago, on which delay timer pot was not set to zero, it was set at 0.20. I don't exactly know why, but perhaps it represented the minimum inherent delay, that would always be there when using delayed sweep, due to circuit design.

My personal 465b also has this pot set at 0.20, but I am not sure whether it was set by the manufacturer, as this scope was a used, and possibly repaired one when I acquired it. Recently, I had to do some fixing on my personal 465b, and when I reassembled, I took care to set it to 0.20, whatever it means. I don't use the delayed sweep during my home use.

Hope this helps.

Shailendra

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