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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

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

Has anyone mentioned these folks?

Large Scale Systems Museum


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@...>
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!

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

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

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.

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=
[email protected]> 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

搁别苍é别, 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.

That might be true, for something that is rarely used. If used at least
weekly, it will be fine. If it is a shelf queen, all bets are off.

On Thu, Nov 26, 2020 at 5:00 PM Glenn Little <glennmaillist@...>
wrote:

Baking the resistor will only fix it for the short term.
It will absorb moisture again as you have not fixed the problem, only
the symptom.
There is a crack or 0r other point of moisture incursion in the resistor
case.

The resistor needs to be replaced.

Glenn

On 11/26/2020 6:59 AM, Michael A. Terrell wrote:

Carbon Composition resistors absorb moisture. Bake them for a while

before

tossing them out. Also, high value resistors require voltage across them

to

work at their marked value This used to be plainly marked on reels of CC
resistors. I posted a scan once. I caught hell for 'making up that
bullshit'. They also don't realize the first resistor series was 50%
tolerance. yet they were working on pre-war radios. Once again I was told
that I was 'making up that shit'.

On Thu, Nov 26, 2020 at 12:18 AM Jeff Dutky <jeff.dutky@...>

wrote:

Tom,

Yes, I had anticipated that these NOS components might not have retained
their specified values. I've been going through my father's effects

while

working on his scopes and finding all sorts of now-50-year-old

components,

some of which were expensive when purchased new, and thinking that some
fair fraction of them are probably now terribly out of spec, if not
completely destroyed (there are a number of big metal can capacitors

that I

know were stored for at least 20 years in a hot attic, and I don't have
much hope that they are still in good condition). I purchased a dozen
resistors in the hope that I could find two that were within spec.

Back in college I worked in receiving QC for a NASA contractor that

built

flight-rated systems. We would first receive a lot of 10 or 20

components

of some description, which we would label and ship over to Goddard. They
would eventually ship us back 2 or 3 components with paint marks and
certification sheets, and we were required to use only those marked
components in the parts we built for them. The other components we had
shipped to them had been tested to destruction, and only the surviving

10%

had been returned to us as flight qualified components. Careful

selection

of parts is something I have thought about ever since.

But what you're saying is that while my intuition was correct, the

actual

math makes a fool of me. I should really just use the metal film

resistors

when they arrive because they are lower noise and the inductance is a
non-issue.

I can always gaze lovingly at the old Allen Bradleys. I'm quite sad that
nobody seems to make resistors that have those nice sharp edges anymore
(or, at least, I haven't found them for sale).

-- Jeff Dutky

--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@... AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"

Hey Roger,

I tried cleaning the edge connector, but that didn't seem to help. So took
the head apart and gave the two pots as well as the board-to-board
connectors some D5 and I gave the pots each a wiggle. The "wobble" is now
gone and I have a rock-steady trace.
However, I clearly need to calibrate the head - not that it didn't already
need calibration. I guess I'll need to hunt for an extender (
) - people on
ePray sure are proud of their extenders...

In any case, thanks,
Siggi

On Mon, Nov 16, 2020 at 7:14 AM Roger Evans via groups.io <very_fuzzy_logic=
[email protected]> wrote:

Siggi,

There are two preset pots in the S6 head for gate balance (R30) and 'gain'
(R45), either could be noisy, but a more obvious suspect is the edge
connector from the S6 to the 7S12 since the DC / low frequency feedback
path has to travel through the edge connector.

Hi Jeff,
Shafts straightened with large pliers; they were only a little bent. Am considering grey PVC pipe as a knob replacement: the metal centres are still present so i just need to find a suitable diameter to fit over them.
For the 545B i have collected an assortment of eBay high voltage arc generators and LOPT's with which to experiment and replace the existing potted TX. The former have isolated secondaries, making them ideal. A theoretically possible option is some kind of large MW or LW coil that might fit over the ferrite core as a replacement secondary. I already tried driving the 6AU5 grid separately but this still takes more power than it should -and it is not difficult to have the 6AU5 anode glowing red. One could use an EL34 etc instead, assuming the unregulated 325V line has the spare capacity. Disaffected TEK EHT transformers need to operate at a lower frequency: from around 50 down to 45KHz or less. I wonder how they might manage with a 15KHz sawtooth via an EL34?
Regards

On Thu, Nov 26, 2020 at 10:46 PM, Raymond Domp Frank wrote:

At the time, the 466 was one of the fastest-storing GP portable analog storage
'scopes on the market, certainly in the 100 MHz BW range.

Sorry, incorrect. The HP 1744A was faster: 100 MHz BW, 1800 cm/us vs Tek 466 @ 1350 cm/us!
The HP was storage-only, with a very wide range of variable persistence; from almost zero to many seconds.

Raymond

On Thu, Nov 26, 2020 at 11:06 PM, Jeff Dutky wrote:

I was trying to keep the summary list short and sweet, so I omitted the A and
B versions (but included the M to illustrate the range of variation in the
models), as well as the lower bandwidth models.

Hi Jeff,
I guess you saw my comments on your summary; different summaries from different points of view, all very incomplete and personal to some degree...

Raymond

satbeginner wrote:

Add a 475A @ 250MHz to the list ;-)

I was trying to keep the summary list short and sweet, so I omitted the A and B versions (but included the M to illustrate the range of variation in the models), as well as the lower bandwidth models.

If you meant "add it to my wish list" then you're too late: I am currently restoring a 475A (as mentioned in a follow up)

-- Jeff Dutky

Baking the resistor will only fix it for the short term.
It will absorb moisture again as you have not fixed the problem, only the symptom.
There is a crack or 0r other point of moisture incursion in the resistor case.

The resistor needs to be replaced.

Glenn

--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@... AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"

Congrats on getting your 2710 working!

In regard to manuals, there are several revisions of the 2710 manual, but try downloading one for the 2712, 2711, 2714, or 2715.

You will find that the analyzer models are very similar in the base design, with certain software or hardware differences depending on the intended market. The quality of the Tektronix manuals varies quite a bit; later ones usually have very good documentation and clarity for schematics and parts layouts, besides narratives explaining the circuit design, function, and operation.

Martin-
I just acquired a 2710...I know it has a battery....Does it store anything important that is lost if battery dies...like those NVRAM in some scope?
搁别苍é别

On Thu, Nov 26, 2020 at 10:49 PM, Dave Peterson wrote:

And know that there's an ocean out there waiting for me to wade into should I
care to.

Now I know what that landscape of about 50 'scopes, mainly Tek portables and 7000-series, around me really is.

Raymond

Ah, big heavy sigh. The human condition is just too limited: between turkey prep and having some lunch, the number of thoughts and threads gone through my head on this conversation is just too vast to begin to convey. I've apparently already hijacked this thread too far into the weeds as it is.
I'll just share: the taxonomy of Tektronix test equipment is so large that I just reflexively focus on what's in front of me. And know that there's an ocean out there waiting for me to wade into should I care to. I was startled to see the picture of the 475 - that it was like a 465 with a different digit in the logo. There's a whole other conversation I'd enjoy getting into regarding product development and history surrounding these scopes. I never knew the two were so closely related. So thanks to this thread there's a whole other bay into which I might sail this boat that I've just boarded. Sailing is an apt analogy. Patience Dave.
Happy Thanksgiving everyone. What a pleasant set of days it's been of late - joining in with you guys. Thank you everyone.Dave

Since you're giving a summary, I'd like to add some comments (my response embedded):

On Thu, Nov 26, 2020 at 09:52 PM, Jeff Dutky wrote:

Here is a quick summary of some of the models in the 400 series:

1. The older 45x family, consisting of the 453, 453A, 454 and 454A. Very solid and heavy construction.
2. The newer family, with very different construction, consisting of the 464, 465, 465B, 466, 468, 475 and 475A. These share the same frame (with size adaptions) and construction and almost the same main board.
3. The 455 and 465M are from the same generation, with very similar front layout. Their internal construction is different from the 464 - 475A group.
4. The 485, with its 350 MHz BW @ 50 Ohm / 250 MHz BW @ 1 MOhm, although from the same period as the series 2. has a very different internal and front panel layout. I consider it one of the best and most beautiful 'scopes from the period, although not the easiest to service. It is absolutely packed with dipped tantalum caps...

The 454 is a 150 MHz dual time base analog scope (fastest GP scope to NOT use
proprietary hybrid ICs)

AFAIK, the 454 was the first portable 'scope to employ Tek's revolutionary bridged t-coil circuit. It also used distributed vertical plates. Its slower brother was the 453 (50 MHz).

The 455 is a 50 MHz dual time base scope with a non-rectangular front profile
The 465 is a 100 MHz dual time base scope

The 465B is an upgraded 465, with fewer components, easier to assemble and adjust, and containing several Tek proprietary IC's.

The 465M is basically the same scope as the 465, but in the cabinet of a 455
(commercial version of the AN/USM 425)

The 455 is built like a 455, not just a 465 in a 455 *cabinet*, e.g. it has the plug-in vertical input and time base module construction of the 455.

The 466 is a 100 MHz dual time base scope with analog storage feature,
otherwise similar, if not identical to the 465.

At the time, the 466 was one of the fastest-storing GP portable analog storage 'scopes on the market, certainly in the 100 MHz BW range. It had a reduced scan mode, with a different CRT with smaller graticule divisions in the center of the screen and control electronics modified to achieve the faster storage.

The 464 is like the 466 but has much slower storage. It lacks the reduced scan mode.
The 466 is a 465 with analog storage, it's more than just similar: The storage board is mounted in front of a 465 main board.

The 468 is a 100 MHz analog scope with a 10 MHz digitizing feature, DMM, and
an ALT rather than MIX horizontal display mode

The 468 is built on the 465B base.

The 475 is a 200 MHz dual time base scope, basically a faster, but otherwise

functionally

identical version of the 465.

The 475A is a "tuned" version of the 475. It lacks the 2 mV/div max. vert. sensitivity of the 475.

The 485 is a 350 MHz dual time base scope with ALT horizontal display mode and
a different front panel arrangement.

The 485 has a completely different internal construction than the 465/475

There are some model numbers below the 454,

like the 453 (50 MHz) but they are all lower bandwidth and the 422 (15 MHz)

and I don't bother to think about them.

Raymond