Date   

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


Re: worst condition Tektronix scope?

 

Hi Jeff,

See my embedded responses.

On Fri, Nov 27, 2020 at 03:02 AM, Jeff Dutky wrote:


It's a shame that Tek did not make a range of plugins for the 465M. It looks
like it's a lot nicer to work on than the 465/475. I wonder why they didn't
pursue that avenue of development. There is no mention of other plugin modules
for the 455 either, but that TekWiki page appears to be almost a stub.
I've sometimes wondered what the technical differences between the central modules of 455 and the 465M were but didn't bother to investigate. I only have a 455, no 465M.
I'm not sure what plugins would be possible and make sense for the 455/465M mainframe(s) but then I'm spoiled by the 7000 family. Besides, I'm sure one would have difficulty configuring the 'scope with the modules needed in preparation for on-site use, the main (intended) environment for a portable 'scope.

I'm curious about how the analog storage scopes like the 466 were used. Were
you able to get a snapshot of a single wave form? Or did this just capture a
persistent image of the repeating signal that we can see on a non-storage
scope?
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 why I love my analog storage 'scopes, at least until I pull out a reasonably modern DSO...

I remember my father using the 475 to debug minicomputer hardware. His
method involved setting the machine in a tight loop that exercised the suspect
part or function, then observing the repeated signal with the scope. Now you
would just use a DSO to capture a few microseconds of signal to memory and
wander through it at your leisure, but such a thing would have been
prohibitively expensive in 1978.
One way was using an Analog Storage 'scope as above, using the delayed time base to move the observable (B-trace) window by adjusting the delay time, until either signal- or delay time-jitter spoiled the fun. A next-level procedure in many cases then would be using the delayed time base not in the common "Runs After Delay" mode but in the "Triggerable After Delay" mode.
In those days, the operator controlled the tools, not vice versa...

Raymond


Re: worst condition Tektronix scope?

 

Raymon,

Yes, I saw your comments, and I agree with every one of them. I was making compromises for brevity (and personal bias).

Since I had linked to the TekWiki page I figured that any insufficiency in my descriptions could either be remedied by following the link, or that any truly gross mischaracterizations would be put aright by other comments (such as your own). I have no personal experience with anything but the 475/475A (and the 2213/2215A) so I was wary of writing too much about any of the scopes beyond what I got off the TekWiki pages.

It's a shame that Tek did not make a range of plugins for the 465M. It looks like it's a lot nicer to work on than the 465/475. I wonder why they didn't pursue that avenue of development. There is no mention of other plugin modules for the 455 either, but that TekWiki page appears to be almost a stub.

I'm curious about how the analog storage scopes like the 466 were used. Were you able to get a snapshot of a single wave form? Or did this just capture a persistent image of the repeating signal that we can see on a non-storage scope? I remember my father using the 475 to debug minicomputer hardware. His method involved setting the machine in a tight loop that exercised the suspect part or function, then observing the repeated signal with the scope. Now you would just use a DSO to capture a few microseconds of signal to memory and wander through it at your leisure, but such a thing would have been prohibitively expensive in 1978.

-- Jeff Dutky


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

stevenhorii
 

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: Tek Glass Tracing

Craig Cramb
 

Added the photo album picture number but that doesn’t link To picture.
Picture album name is Tek Glass Tracing


Tek Glass Tracing

Craig Cramb
 

Photo Album
949D5068-213D-42B6-BA83-64C59169606B.jpeg

Dealing with a touch pad that has what think is glass tracing that has developed a crack thru multiple tracks. Anyone had any experience In repair of this type of situation?
This is on a Tek Ths700 séries scope


Re: worst condition Tektronix scope?

-
 

I've seen ones in worse condition but I don't have pictures. Stuff
coming back to the US from some of the NASA tracking and communications
stations on the Caribbean islands looks much worse. That one looks like it
sat in an unairconditioned outdoor storage shed for 20 years. It's rather
typical of some of the equipment that I find at garage sales here in
central Florida.

On Thu, Nov 26, 2020 at 1:26 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: Why you now Paypal

stevenhorii
 

For improved PayPal security, I added the “two-factor authentication” for
PayPal since my primary payment method is a deduction from my bank checking
account. I do this for all my online banking transactions, my work and
personal e-mail (both if I am logging in from devices the mail servers do
not know are usually associated with my user name and password), and
two-factor identification running over a VPN is required for remote work
access (healthcare).

Steve H




On Thu, Nov 26, 2020 at 12:09 Frank DuVal via groups.io <corvairduval=
netscape.net@groups.io> wrote:

Weird. I NEVER have a Captcha / Not A Robot screen or button when using
PayPal....

I do not save my password. Have to enter it every time, my choice. Works
for me.

I do not understand the "how far along in the buying process you are"
comment. All the screens on PayPal seem logical to me. And there are not
many when sending money, either on their website only or through a
vendor link to send funds.

So far it works well for me! Both as buyer and sending money to friends.
Even for Tek supplies, to keep it on subject.😉

Frank DuVal

On 11/26/2020 1:01 AM, Jeff Dutky wrote:
I don't have particular issues, other than complaints about this
particular process (not being offered the options that would have made
this process easy), and about the quality of their buyer interface
(every time I have tried to log into their web interface I have had to
do the "I'm not a robot" dance, and every time the site has responded
with "something went wrong on our end" throwing me back to the "I'm
not a robot" screen, so that I get to do the dance again, and maybe a
third time. That's shoddy UX on PayPal's part, and I haven't got any
patience for that sort of thing. Also there's no indication of how far
along in the buying process you are, so you just have to keep clicking
Continue until suddenly the process is over. That's also shoddy UX).
My only other complaints about PayPal are mere hearsay, but I've heard
too many stories of sellers having their funds frozen over the years
to think that maybe there isn't at least a little bit of fire behind
that smoke.
That said, I understand why people want to use PayPal: they fill a niche
that, even today, has very few players. If you want to accept payment over
the web you just don't have many choices, and the established choices
(credit card merchant accounts) are not well suited to small players. When
PayPal got started they were basically the only game in town for people who
couldn't afford to set up a merchant account, and that benefit can not be
overestimated. Still, I'm a grumpy sort, and this is one of the things I'm
grumpy about.

-- Jeff Dutky





Re: 2710 Spectrum Analyser 'Cannot count VCO, IF' error

Martin Whybrow
 

Renée, there is a lithium battery on the display & storage board which will probably need replacing; yes, the analyser will lose settings when the battery dies, however a nice feature of these analysers is that they can self calibrate and reset these values; there are some interactive settings, such as display positions that may need setting, but they are well documented in the manual. Let me know if you are having trouble finding a replacement battery, I had to buy several to satisfy the minimum order quantity from Conrad, so I have extras I'd be willing to sell.

9861 - 9880 of 183519