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I've been watching some episodes of the outstanding US science-fiction TV
series "The Outer Limits", which aired from 1963-1965 (two seasons). The
settings of many episodes prominently feature electronic equipment,
typically in a scientific laboratory, military command post, space mission
control center, or a spacecraft.



Despite the fact that the show's opening title sequence begins with what is
probably best-known oscilloscope trace in history
(), I haven't seen a lot of
scopes in the episodes themselves, and the few that have appeared weren't
operating. A DuMont shows up from time to time, just sitting on a counter
or console as an afterthought. You'd think they'd at least be rigged up to
display the ever-popular Lissajous figures, but the series was pretty
low-budget.



One episode showed, in the background, a cart-mounted scope which had the
general form and panel layout of a Tek 500 series, but with a sort of white
cowling around the top and sides of the front panel. In another, there was
a rack-mounted 5-inch scope with a dark gray/green panel. I don't know what
brand either scope was.



In general, the electronics were a mix of real contemporary equipment and
stuff that was probably purpose-built as props. The real equipment
sometimes included those big multi-track analog tape recorders and vertical
pen plotters that were so popular in the early years of aerospace
development. The "prop" equipment was generally panels of meters, toggle
switches, pots/rotary switches and indicator lights; the meters and lights
were usually non-operational unless they had some significance in the plot.
A lot of them were in 19-inch racks or bench-type consoles.



A striking feature of these "prop" panels was the lack of labeling on any of
the devices unless, again, a particular device had a role in the story (e.g.
the radiation meter on an out-of-control reactor). But then, I guess a
scientist who's smart enough to invent a time machine or inter-dimensional
portal should be able to remember what switch does what.



Another electronics tidbit from the series: in one episode, a scientist had
developed a way to rapidly advance an individual primate's (including
human's) evolution, based on the premise that an organism's future form is
already encoded in its DNA and can brought out by the use of a machine built
for that task. To show a visitor how effective this technique was, the
scientist pointed to one of his successes - a chimpanzee seated at a bench
in a corner of the lab, quite convincingly using a VOM to troubleshoot some
piece of vacuum-tube electronics!



Albert

You might look at some of these.
?Leon Robinson ?? K5JLR

Political Correctness is a Political Disease.

From: Dewey Wyatt <kn4wddewey@...>
To: "[email protected]" <[email protected]>
Sent: Tuesday, July 10, 2018 4:34 PM
Subject: Re: [TekScopes] Low cost Scope-Mobile alternatives?

Made mine from a half sheet of ? plywood. Added wheels and a folding shelf, around 30.00 invested and around 2 hrs time.

Sent from Mail for Windows 10

From: Al Holt
Sent: Tuesday, July 10, 2018 5:30 PM
To: [email protected]
Subject: [TekScopes] Low cost Scope-Mobile alternatives?

I'd like to get my 7603 'scope onto some sort of roll around cart, but I'd like to see if it can be done within some sort of reasonable price range. This is just for getting the thing from room to room around my house and not in any professional workplace.

Do you think one of those 3-tier wire shelving units might work, and work well? The cheapest thing I've come across is a $19 wire shelf at WalMart, but it would have to have threaded casters added to get it mobile. is what they have. I'm not sure if the legs will take 'standard' threaded casters, though.

There are lots of alternatives, it would be nice to find one that is known to work well.

Ideas? Thanks for the help!!

--Al






---
This email has been checked for viruses by AVG.

Made mine from a half sheet of ? plywood. Added wheels and a folding shelf, around 30.00 invested and around 2 hrs time.

Sent from Mail for Windows 10

From: Al Holt
Sent: Tuesday, July 10, 2018 5:30 PM
To: [email protected]
Subject: [TekScopes] Low cost Scope-Mobile alternatives?

I'd like to get my 7603 'scope onto some sort of roll around cart, but I'd like to see if it can be done within some sort of reasonable price range. This is just for getting the thing from room to room around my house and not in any professional workplace.

Do you think one of those 3-tier wire shelving units might work, and work well? The cheapest thing I've come across is a $19 wire shelf at WalMart, but it would have to have threaded casters added to get it mobile. is what they have. I'm not sure if the legs will take 'standard' threaded casters, though.

There are lots of alternatives, it would be nice to find one that is known to work well.

Ideas? Thanks for the help!!

--Al






---
This email has been checked for viruses by AVG.

I'd like to get my 7603 'scope onto some sort of roll around cart, but I'd like to see if it can be done within some sort of reasonable price range. This is just for getting the thing from room to room around my house and not in any professional workplace.

Do you think one of those 3-tier wire shelving units might work, and work well? The cheapest thing I've come across is a $19 wire shelf at WalMart, but it would have to have threaded casters added to get it mobile. is what they have. I'm not sure if the legs will take 'standard' threaded casters, though.

There are lots of alternatives, it would be nice to find one that is known to work well.

Ideas? Thanks for the help!!

--Al

I would like to correct my mistake - common mode impedance of the full/high-speed USB 2.0 cable is 30 Ohms ±30%
Differential impedance is 90 Ω ±15%

This is from Table 7-12 in USB spec 2.0

Thanks
Leo

I don't know if this is a common issue (google didn't find it for me anyway) so just in case it helps others this is what I found.

Now that the 7912AD is behaving reasonably well I thought I would take a look at the 7A29 because some of the steps in the attenuator were off and on anything other that 'straight-thru' (10mV) range the rise-time was horrid.

My assumption was that some of the yoke adjusting screws needed tweaking to get the stage switches working right but once I got the thing out and started checking end-to-end resistance I realized that the resistances on anything that used the middle element were not sensible at all and visions of toasty black resistor elements began to swim in my head!

On stripping off the bottom - non actuator side - plate** I was reassured that the resistor substrates looked a normal color and careful probing showed the series resistances on the first and third elements were correct but the center one was giving weird (and slightly unstable) values. I then removed the screws from the other plate and lifted off the aluminum side blocks thus removing the ground connections to all the elements whereupon each individual resistor element on the substrate measured correctly.

It looks as if the ground connections from the resistive elements to the aluminum side blocks are made with some sort of (elastomer?) material and there was a nice white discoloration along the contact face - presumably aluminum oxide - once that was all cleaned up with cotton bud and IPA and reassembled all was good in the world and the attenuator seems spot on! I was careful to put all the actuator pins back in the holes they came from and no tweaking of yoke screws was needed, which is just as well as they seem to have been locked in place with a blob of nail-varnish in a tasteful shade of red but the adhesive properties of two-part epoxy resin!

**TIP - it is important to remove the two SMA connector end plates BEFORE lifting the bottom plate, the center pin of the SMA is slotted and the switched line keys into it, great care is needed to correctly engage this on re-assembly too!

Adrian

With the help of a friend I came home yesterday with two R230 Parts units
they're clean but they've been in a mouse infested Barn for years. We also
brought home a 3T5 that looks complete.

The biggest surprise is I was able to find 2 of the interconnect cables the
go-between the r230 and the 568.

I was able to locate enough S3A's on eBay to get started. The only thing I
don't have is the usual accessories and the power supplies. If any of you
have them available please let me know.

I have been loaned a paddleboard the one used to connect the plugins to the
rear IO. If I have enough energy I will CAD it out and get some quotes. Get
something like 50 of them made and then the excess I will give away two
other owners of this kit.

If I don't have the energy to draw out I will hire somebody.

That's all for now

-pete

Thank you, Michael. Actually I have only pieces of it (most pieces, I think), so an schematic would be ideal for making sense of them.

Best regards,
Sebastian.



Michael A. Terrell 4:19am #149579

It appears to be two, 15MHz amplifiers to convert a single channel scope into a four channel display. In other words, it is a pair of the electronic switches that were common for early single channel scopes.

They were also kit versions and construction projects. They used a twin Triode to create an adjustable square wave to drive the chopper, and each input had an amplifier with adjustments for both gain and position. Heathkit made the S1, S2 and S3, ID22, models, and at least the S3 schematic is on line because I have a copy of its schematic.

There is a description of this item in a book about scopes:

<>

Here is the Heathkit S-3S schematic:

<>


You have an advantage in having two switches, in that you can compare them to locate problems. As always, make sure the DC rails in the power supply are clean. The filter caps are likely 50 years old, or more.


Michael A. Terrell

It appears to be two, 15MHz amplifiers to convert a single channel scope into a four channel display. In other words, it is a pair of the electronic switches that were common for early single channel scopes.

They were also kit versions and construction projects. They used a twin Triode to create an adjustable square wave to drive the chopper, and each input had an amplifier with adjustments for both gain and position. Heathkit made the S1, S2 and S3, ID22, models, and at least the S3 schematic is on line because I have a copy of its schematic.

There is a description of this item in a book about scopes:

<>

Here is the Heathkit S-3S schematic:

<>


You have an advantage in having two switches, in that you can compare them to locate problems. As always, make sure the DC rails in the power supply are clean. The filter caps are likely 50 years old, or more.


Michael A. Terrell

Hi, Could somebody provide the schematics/manual of this equipment (or similar Philips model) [1] ?
It is an (independent, including power supply) chopping unit, to turn any single trace scope into a into 2-trace one.
Mainly tube-based, some silicon diodes, a couple of selenium rectifier bridges, some power transistors. Seems to be from ~1960/65.

Any data would be greatly appreciated,
Sebastian.

[1] Philips PP 1071 electronic switch unit

Yes, that would be about right. T9 = 25ppm is one of the standard ones. Somewhere, there should be listings on line, of the various codes from T0 to around T15 or maybe higher.

Ed

Can anyone confirm that Tektronix TC=T9 is equivalent to 25ppm temp coeff. on precision resistors.

On the 2465B Tektronix specifies TNPW1206-1006BT TC=T9, which I believe are 25ppm T/C resistors (the rest I know, 1206, 10k, 0.1%, thin film)
These are used in the reference for the A/D on the A5 module.

Thanks,
Victor

Sounds like a well-known problem with Tek HV transformers of a certain era. They picked an impregnant which today becomes lossy when hot, and the transformer goes into thermal runaway. The best fix is to rewind. Chuck Harris has a machine, but I don't think he has a recipe for the 634.

It can also be done by hand, although it's tedious. For example, see topic and album "453 HV Transformer Rewind", where I developed a machine and procedure from ordinary household objects. Years later, my transformer is still working perfectly. You'll have to figure out wire sizes and turns, unless someone has the spec sheet.

HTH,
Dave Wise
________________________________________
From: [email protected] <[email protected]> on behalf of Adrian <Adrian@...>
Sent: Monday, July 09, 2018 8:41 AM
To: [email protected]
Subject: Re: [TekScopes] 634 Monitor HV board issue

Having spent some more time on this I'm now wondering if the issue could be the transformer 20V primary? Do these things tend to develop shorted turns? I ask because I seem to have a normal image for the 10-15 seconds before the primary current has ramped to the point (a) my nerve fails (~2.5A) and (b) the drive transistor is cooking, so I switch off which makes me think the voltage multiplier is working?

Thanks,
Adrian

Having spent some more time on this I'm now wondering if the issue could be the transformer 20V primary? Do these things tend to develop shorted turns? I ask because I seem to have a normal image for the 10-15 seconds before the primary current has ramped to the point (a) my nerve fails (~2.5A) and (b) the drive transistor is cooking, so I switch off which makes me think the voltage multiplier is working?

Thanks,
Adrian

Thanks for this info, H?kan. I was aware of the use on 7A22 (I own one) but not the others.
Colin.

On Thu, Jun 28, 2018 at 01:49 pm, Siggi wrote:

Alan Wolke did a video on TDR using a scrap box ~1ns pulser: <
>. For ~$2 and a few minutes
soldering, you might be able to get useful results :).

I think you beat me to it :



Yup you did, I see the URL is identical. Nice that it is still there.

I was prompted fo get it because someone on Usenet is picking on one of the better members there and he said, probably sarcastically "How are you going to determine the twist in a CAT 5e cable ? He didn't ask me but I decided to answer anyway and I remembered the video that was sent to me by a cohort.

I think the guy knows what he's doing.

On 08/07/18 16:11, cheater cheater wrote:

Sorry, having trouble picturing the circuit, mind explaining it in a bit
more detail? Add a netlist maybe?

On Sun, 8 Jul 2018, 10:12 Tom Gardner, <tggzzz@...> wrote:

On 08/07/18 04:53, Ed Breya via Groups.Io wrote:

If you are concerned about setting or controlling the frequency, you can

drive the output stage instead from another with XO or a generator. My
preferred 74AC driver for fast, strong pulsing is the 74AC541, with eight
amplifiers that can be paralleled. Also, the pinout is excellent for this
sort of thing, layout-wise - all ins on one side, and all outs on the other.
My preference is 74LVC1G*, which have ~7ohms output impedance, 32mA
drive, and
work from ~1V to 5V albeit with different risetimes.

If you add a 143ohm series resistance and put three of those in series
(and
decouple them very well), then you get a clean 50ohm output. I can't
measure the
risetime; it is certainly sub nanosecond, another measure gives ~600ps,
and I've
seen a (poorly controlled) measurement of 300ps on a 1GHz scope.

I note that I wrote "put three of those in series". I meant parallel.

? - 74lvc1g* - 143R -
?|?????????????????? |
-+- 74lvc1g* - 143R -+-
?|?????????????????? |
? - 74lvc1g* - 143R -

We are into the third week of a heatwave here; it must be cooking
my brain. Well, that's the least worrying alternative.

On 08/07/18 16:11, cheater cheater wrote:

Sorry, having trouble picturing the circuit, mind explaining it in a bit
more detail? Add a netlist maybe?

On Sun, 8 Jul 2018, 10:12 Tom Gardner, <tggzzz@...> wrote:

On 08/07/18 04:53, Ed Breya via Groups.Io wrote:

If you are concerned about setting or controlling the frequency, you can

drive the output stage instead from another with XO or a generator. My
preferred 74AC driver for fast, strong pulsing is the 74AC541, with eight
amplifiers that can be paralleled. Also, the pinout is excellent for this
sort of thing, layout-wise - all ins on one side, and all outs on the other.
My preference is 74LVC1G*, which have ~7ohms output impedance, 32mA
drive, and
work from ~1V to 5V albeit with different risetimes.

If you add a 143ohm series resistance and put three of those in series
(and
decouple them very well), then you get a clean 50ohm output. I can't
measure the
risetime; it is certainly sub nanosecond, another measure gives ~600ps,
and I've
seen a (poorly controlled) measurement of 300ps on a 1GHz scope.

Sorry, having trouble picturing the circuit, mind explaining it in a bit
more detail? Add a netlist maybe?

On 08/07/18 04:53, Ed Breya via Groups.Io wrote:

If you are concerned about setting or controlling the frequency, you can drive the output stage instead from another with XO or a generator. My preferred 74AC driver for fast, strong pulsing is the 74AC541, with eight amplifiers that can be paralleled. Also, the pinout is excellent for this sort of thing, layout-wise - all ins on one side, and all outs on the other.

My preference is 74LVC1G*, which have ~7ohms output impedance, 32mA drive,? and work from ~1V to 5V albeit with different risetimes.

If you add a 143ohm series resistance and put three of those in series (and decouple them very well), then you get a clean 50ohm output. I can't measure the risetime; it is certainly sub nanosecond, another measure gives ~600ps, and I've seen a (poorly controlled) measurement of 300ps on a 1GHz scope.