Date   

Re: 7S12 TDR Cable

 

That 7S11 will require a sampling head such as an S-5 25pSec head
I guess that's an S-4 sampling head ;-(

Raymond


Yahoo was rejecting emails Monday night

 

I noticed Yahoo did not accept any of the emails I sent Monday night.

It appeared that whatever caused this problem occurred from 6:30PM until
about 11:30PM Monday night since there are no entries for that period of
time.

Dennis Tillman W7PF


Re: 7S12 TDR Cable

 

When I tried to send this last night at 8:07PM PST Yahoo rejected it. In
fact it seemed to have been rejecting emails for a few hours.
Dennis

-----Original Message-----
From: Dennis Tillman [mailto:@Dennis_Tillman_W7pF]
Sent: Monday, April 04, 2016 8:07 PM
To: 'TekScopes@...' <TekScopes@...>
Subject: RE: [TekScopes] 7S12 TDR Cable

Hi Nathan,

One more thing. The 7S12 has a "shoe" on it which allows you to connect a
7S11 to it to add another vertical amplifier to your scope. Ordinarily most
TDR measurements will only involve sending a pulse down a line and measuring
the reflections that come back. But with two vertical channels you can
monitor two ports. This comes in handy for measuring the response of power
splitters or two port devices.

That 7S11 will require a sampling head such as an S-5 25pSec head.

Both the S-6 and the S-5 were designed by the very talented George Frye at
Tektronix back in the late 1960s. George now owns a company that
manufacturers Audiological Test Equipment in Tigard, OR.

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@... [mailto:TekScopes@...]
Sent: Monday, April 04, 2016 7:36 AM
To: tekscopes@...
Subject: [TekScopes] 7S12 TDR Cable

One of my new scope acquisitions(currently in transit) is coming with a
7S12/S-6/S-52 TDR setup. Of course no cables. Right now I'm looking at the
S-6 manual and looking at the interconnection diagram. It looks like I
should be using the 750ps cable(015-1017-01) and the "Test Line" cable
015-0123-00. Obviously these cables all got lost, and I can't locate any at
the moment. I've saved my searches and will keep an eye out. I'm trying to
understand the requirements of a replacement.
As I understand this, the interconnect cable being of a certain electrical
length was to delay the pulse reaching the S-6 until after the trigger? So
that would be satisfied by anything that delayed at LEAST 750ps? I have some
6 inch RG-402 jumpers that using book figures for 402, should be around
780-820ps. Hoping that will work, as I don't have anything to measure the
exact electrical length of a cable... Until I get the TDR working. Go
figure.
The "Test Line" is specced at 1ns, and I assume that this was to make the
interconnection from "trusted test gear" to "circuit under test" a
fixed/known distance from the sampler as well as avoiding too short a cable
total/too short pulse+reflection? I'm thinking that once I get this working
I can use a "roughly 1ns" cable to attach another cable to the end, and trim
to 1ns?
Any idea what the tolerances would be on these cables from the factory?
Nathan KK4REY
------------------------------------
Posted by: Nathan Johnson <jdownj@...>
------------------------------------


Re: 7S12 TDR Cable

 

When I tried to send this last night at 7:51PM PST Yahoo rejected it. In
fact it seemed to have been rejecting emails for a few hours.
Dennis

-----Original Message-----
From: Dennis Tillman [mailto:@Dennis_Tillman_W7pF]
Sent: Monday, April 04, 2016 7:51 PM
To: 'TekScopes@...' <TekScopes@...>
Subject: FW: [TekScopes] 7S12 TDR Cable

Hi Nathan,
TDR is a fascinating world unto its own. There are many things you can do
with it but it is so unlike everything you probably know about electronics
that you will want to get some help. One great source is the Tektronix Time
Domain Reflectrometry Measurements book. It was written in 1970 but
everything in it is still current today.

It is interesting to note that the fastest TDR systems available today are
still only about 50% faster than the 7S12 /S-52 / S-6 system equivalent
risetime of ~30pSec. So, in other words it was an outstanding system in its
day, and it is an excellent system to have today.

Dennis Tillman W7PF

-----Original Message-----
Sent: Monday, April 04, 2016 7:36 AM
Subject: [TekScopes] 7S12 TDR Cable

One of my new scope acquisitions(currently in transit) is coming with a
7S12/S-6/S-52 TDR setup. Of course no cables. Right now I'm looking at the
S-6 manual and looking at the interconnection diagram. It looks like I
should be using the 750ps cable(015-1017-01) and the "Test Line" cable
015-0123-00. Obviously these cables all got lost, and I can't locate any at
the moment. I've saved my searches and will keep an eye out. I'm trying to
understand the requirements of a replacement.
As I understand this, the interconnect cable being of a certain electrical
length was to delay the pulse reaching the S-6 until after the trigger? So
that would be satisfied by anything that delayed at LEAST 750ps? I have some
6 inch RG-402 jumpers that using book figures for 402, should be around
780-820ps. Hoping that will work, as I don't have anything to measure the
exact electrical length of a cable... Until I get the TDR working. Go
figure.
The "Test Line" is specced at 1ns, and I assume that this was to make the
interconnection from "trusted test gear" to "circuit under test" a
fixed/known distance from the sampler as well as avoiding too short a cable
total/too short pulse+reflection? I'm thinking that once I get this working
I can use a "roughly 1ns" cable to attach another cable to the end, and trim
to 1ns?
Any idea what the tolerances would be on these cables from the factory?
Nathan KK4REY
------------------------------------
Posted by: Nathan Johnson <jdownj@...>
------------------------------------


Re: SG504 Frq. Display & Digital amplitude flattening.

 

@1: Is HiSpeed CMOS fast enough these days to allow 1 GHz frequency measurement and if so, at what power dissipation?

@ 3: I think sampling and timestamping the samples during calibration will need careful thought to make it work. Sampling takes the full gate time of the frequency measurement.

Raymond


Re: SG504 Frq. Display & Digital amplitude flattening.

mosaicmerc
 

Good comments...:

1. A digital frequency meter operating at up to 1+ GHz running for long hours on a lithium battery is no easy thing to accomplish, to say the least. Tricks may be possible because of the limited band.

An enhanced PIC 16F micro (32Mhz) only needs 10mAh while active, thus a small, flat pack, 1 Ah Li ion will last quite a while. A bit hi speed CMOS division logic might be needed in the front end.

2. Creating D/A (level control) and A/D (level measuring) circuits with resolution and accuracy matching the (desired) performance of the head and consuming very little energy (again, Li battery), may be a challenge.

I can do 2 decimal voltage ADC sampling to +/- 0.02V precision ref'd to a 6.5digit DMM. DAC is prob. insufficient => 28khz PWM with a LPF to get 1024 steps over the voltage range to achieve precision at the low Vpp scale of the SG504.

3. Digital calibration/normalisation is a nice thing. Your uP would have to recognise sweeping (too fast) during calibration, take care of all intermediate (non-calibrated) frequencies during normal use, creating a fluent interpolation. The simplest uP probably wouldn't do. I wonder whether sweeping during sampling frequencies would work at all.

It's a balance of power consumption vs processing. A DSP micro would have hardware DSP speeds but take more power. Since a cal. needs to be done infrequently, I don't see why a slow sweep/pause/sweep over, say a minute, can't be done once every few months as required. To use a simple micro might require a 74HC divider front end to do the frequency count.

4. Noise from the digital side would have to be very well controlled. That takes up physical space.

Yes, it would require a board sandwich with an intervening shield with a pass through cap and a type R ferrite bead. But we're not talking LNA level stuff, so it's not a big difficulty.

5. I'm not convinced that putting the display in the head would be a good thing. The limited viewing angle comes to mind

I am seeing the HMI would be on the rear of the remote head, so if it is installed on the DUT the screen will face the user.


Re: 465 oscilloscope problem

Tewell, Kevin <tewell.ka@...>
 

-----Original Message-----
From: TekScopes@... [mailto:TekScopes@...]
Sent: Saturday, April 02, 2016 8:26 PM
To: TekScopes@...; TekScopes@...
Subject: Re: [TekScopes] 465 oscilloscope problem

OK here is what I have starting over :) I got a 465 scope and the power would come on and that was it. So I took the cover off and found that the fuse was bad, I put a new one in and turned it on and immediately blew the fuse on the outside. So I checked the test points and +55 was ý.9 ohms and I was told to check the C1534 from the antique radio forum person so I did and I thought it was bad and took it off. And that is all I have done to the scope. And from what I hear so far was a mistake :( So where should I go from here besides ordering a new part for C1534. Thanks for the help. So how do you check the capacitors to see if they are bad? Since I messed one up already.

Sent from my BlackBerry 10 smartphone.
From: David @DWH [TekScopes]
Sent: Saturday, April 2, 2016 7:00 PM
To: TekScopes@...
Reply To: TekScopes@...
Subject: Re: [TekScopes] 465 oscilloscope problem




Thanks for reminding me John. I was only refering to C1419 in the high voltage inverter circuit.

There is a good free scan of the late 465 service manual out there.

On Sat, 02 Apr 2016 17:58:03 -0500, you wrote:

That about covers it.

A solid tantalum capacitor would be pretty expensive so assuming it
will fit, I would use a low impedance high frequency 105C aluminum
electrolytic intended for switching power supply applications. To get
an equally low ESR as a solid or wet tantalum capacitor, increase the
capacitance 2 to 4 times.

One of the capacitors on this list would be ideal but as a practical
matter, almost any 220uF aluminum electrolytic capacitor should work:

http://goo.gl/Oc2MBt

A new solid tantalum capacitor would be much more expensive. I almost
always buy NOS (new old stock) solid tantalums from my local
electronics surplus store:

http://goo.gl/A1ynvX

For once an aluminum polymer capacitor would work but they can be
almost as expensive as a solid tantalum capacitor and would not last as
long as the less expensive electrolytic. The capacitance would only
need to be 22 microfarads (or lower but I would need to make
measurements to determine how low). This would be the best choice if
the physically larger aluminum electrolytic will not fit but that seems
unlikely:

http://goo.gl/BPudsE

On Sat, 2 Apr 2016 21:32:40 +0000, you wrote:

So what do I replace it with?
On 02 Apr 2016 14:50:27 -0700, you wrote:

Usually common aluminum or solid tantalum electrolytic caps, depending on the application and ratings needed. As I said, I don't know the application here, but I'm sure others here with 465s will respond soon with advice. I can say that it's unlikely that the original cap even had to be wet Ta - they are special, but were more commonly used back then, usually to save space because of their high C-V product. They are essential though, in certain low-leakage, higher voltage, higher temperature applications, which are unlikely to be encountered in a scope.

Ed
On Sat, 02 Apr 2016 18:23:38 -0400, you wrote:

Aluminum electrolytic. Look for 105 °C rating.

http://www.ebay.com/itm/5x-Panasonic-FC-47uF-50v-low-ESR-radial-Capaci
tors-caps-105C-New-low-impedance-/251942149865?hash=item3aa8ec1ee9:g:~
1gAAOSwVFlT~K3t

One of many.



[Non-text portions of this message have been removed]



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Yahoo Groups Links


Re: TM5006 Capacitors

J Mcvein
 

Not at all overkill.  I guess I won't be finding the5-pin Sprague footprint. 

JimMc



From: "David DiGiacomo telists@... [TekScopes]" <TekScopes@...>
To:
Cc: TekScopes <TekScopes@...>
Sent: Tuesday, April 5, 2016 7:53 AM
Subject: Re: [TekScopes] TM5006 Capacitors

  On Mon, Apr 4, 2016 at 7:18 PM, <jmcvein@...> wrote:
Anyone have a source for a replacement, or substitute for the 1100 uF 200V
line side filter caps in a TM5006 power unit? Recommendations?
Tek p/n 290-0878-00 - 1.5"D (38mm) x 4.0"L (105mm)
How about CDE 380LX122M400A082? Overkill?

http://www.findchips.com/search/380LX122M400A082
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[Non-text portions of this message have been removed]


Re: TM5006 Capacitors

David DiGiacomo
 

On Mon, Apr 4, 2016 at 7:18 PM, <jmcvein@...> wrote:
Anyone have a source for a replacement, or substitute for the 1100 uF 200V
line side filter caps in a TM5006 power unit? Recommendations?
Tek p/n 290-0878-00 - 1.5"D (38mm) x 4.0"L (105mm)
How about CDE 380LX122M400A082? Overkill?

http://www.findchips.com/search/380LX122M400A082


For sale in UK: 549 with 1A4 plugin

cmjones01
 

Hi Tek fans,

Due to lack of space, I reluctantly have to part with my 549 and its 1A4
plugin. I restored it to clean working order a couple of years ago and it's
still in excellent shape.

You can read the full restoration story starting here:

http://martin-jones.com/2013/06/08/t...oscope-part-1/

And there are lots of nice photos here:
http://martin-jones.com/2016/04/05/tektronix-549-storage-oscilloscope-restored/
and even a movie here:
https://www.youtube.com/watch?v=1SRtm7eva0A

The Tektronix 549 is the only storage scope in the Tektronix 500 series of
plug-in scopes. It dates from the late 1960s, and uses an analogue storage
tube. It's bistable rather than variable-persistence, and has the
enormously cool feature that storage mode can be used separately in the
upper and lower halves of the screen.

http://w140.com/tekwiki/wiki/549

It's a big, heavy, power-hungry monster. It weighs 65lbs (30kg) or so and
draws more than 500W from the mains. I wouldn't say it's a practical
everyday scope, and it's definitely not for beginners. The brightness from
the storage tube is low (it's best used in a darkened room) and getting the
best results from it needs patience. Using it is like playing a musical
instrument. It has all the usual Tek trimmings: dual timebases, multi-level
calibrator, and connections for every imaginable accessory. Its bandwidth
is about 30MHz but sadly it doesn't have tunnel diode triggering so really
fast stuff is a bit of a chore.

This example of the 549 comes with the elusive 1A4 plugin. This plugin has
four fully-featured channels, and allows dozens of combinations of
chopping/alternating between them. You can freely choose the trigger source
from any of the four channels. I know this plugin is particularly sought
after, and this one is in good working condition on all four channels,
albeit a bit drifty until it's warmed up.

http://w140.com/tekwiki/wiki/1A4

There are not many of these scopes around in this condition. It even has
the correct rectangular CRT bezel. This particular one, being built in
Guernsey, doesn't have the 'Bumble Bee' paper capacitor problem that
plagues US-built examples. It's also had a replacement hand-made EHT
transformer which doesn't suffer from the lossy epoxy problem that the
original transformer had.

Calibrated? No, not formally, but I've adjusted everything to within spec
as best I can. I'd be surprised if anything was more than a few percent
wrong. And the icing on the cake: I've got the printed paper manuals for it
and the plugin. They themselves are works of art.

The price for this slice of technology history? I'm asking £120, including
the plugin and manuals. Come and get it from Cambridge, UK. I will be
driving across Europe in a couple of weeks time, so may even be able to
deliver to somewhere between Cambridge and Warsaw.

Chris


Re: SG504 Frq. Display & Digital amplitude flattening.

 

I think the idea is very nice in terms of usefulness, however, IMHO it may be taking things a bit too far. I see a few issues that would have to be dealt with, especially if you'd want to power the thing from a Li battery: The continuous display of the frequency would be the least of your problems. I mean the *displaying* itself only.

1. A digital frequency meter operating at up to 1+ GHz running for long hours on a lithium battery is no easy thing to accomplish, to say the least. Tricks may be possible because of the limited band.
2. Creating D/A (level control) and A/D (level measuring) circuits with resolution and accuracy matching the (desired) performance of the head and consuming very little energy (again, Li battery), may be a challenge.
3. Digital calibration/normalisation is a nice thing. Your uP would have to recognise sweeping (too fast) during calibration, take care of all intermediate (non-calibrated) frequencies during normal use, creating a fluent interpolation. The simplest uP probably wouldn't do. I wonder whether sweeping during sampling frequencies would work at all.
4. Noise from the digital side would have to be very well controlled. That takes up physical space.
5. I'm not convinced that putting the display in the head would be a good thing. The limited viewing angle comes to mind

Personally, apart from the challenge of the project, I'd rather go and look for a nice (HP/Agilent) synthesizer...

Just a few thoughts, I'd love to see my doubts taken away by those with more knowledge of modern components.

Raymond


Re: 2465B U400 Availability?

 

In an earlier post, I said that I too had a 2465B showing vertical compression of ch 1 and ch 2
only in the lower half of the screen and I suspected a U400 problem. For the record my
replacement part arrived today and has fixed the problem.
Join the club... Happy that your 'scope is fixed.

Raymond


Re: 2465B U400 Availability?

Roger Evans
 

In an earlier post, I said that I too had a 2465B showing vertical compression of ch 1 and ch 2 only in the lower half of the screen and I suspected a U400 problem. For the record my replacement part arrived today and has fixed the problem.

Hope this helps people searching in the future.

Roger


SG504 Frq. Display & Digital amplitude flattening.

mosaicmerc
 

Hi all:
My recent efforts in optimizing the SG504 head has led to this concept which addresses a lack of accurate freq. display and amplitude compensation using digital controls.


These functions can be 'built in' to an upgraded leveling head (Li Ion battery powered, rechargeable).



Concept statement subject to refinement.


In using the SG504, one of the areas I think could make the unit more useful is a reasonably accurate frequency counter display. Perhaps to 1Khz via a uC comparator triggered pulse counting.

I've come up with a concept 'head' which adds a battery operated low power microcontroller to do the job via a small 8 x 2 LCD display (58mm x 32mm) mounted in the head. LCD display triggers by detection of a FRQ sweep or flashes the static FRQ one sec in every 5 secs to conserve power.

Now this approach will allow anyone to also 'flatten' the head output relative to the ref. 6Mhz level to potentially within 0.01dB steps via a 0.31dB range of adjustment ((5 bit) DAC output). This requires an additional schottky detector coupled @ the head output.

The process works by activating the cal. mode (pushbutton) while in the 6Mhz range. The controller then locks the amplitude ref. . Then the user switches to the Low range and starts to sweep, slowly, then the high range, repeat sweep. The controller monitors the frequencies and determines amplitude offset points to 'map' the head amplitude flat. Once the frequency stops changing for a few secs the head comes out of cal mode and applies frequency mapped corrections (every 3.2 Mhz step) via it's (5 bit) DAC output. No PWM.
It 'corrects' the head amplitude by modifying the DC level amplitude signal to the SG504.


In terms of operation, I see it working like this.
The user sets the amplitude and selects the 6Mhz SG504 ref. The controller detects the 6Mhz ref and grabs the ref. amplitude. Then it can properly apply all the stored corrections to the current amplitude level.
Thus when changing amplitude the user would need to activate the 6Mhz ref, set the amplitude and switch back to the frequency of interest for precision leveling.(Perhaps using 12 or 14 bit oversampling)


The system can permit an RS232 to USB serial link to a PC to output live frequency and ref. amplitude data.
I might look at a 10Mhz ref input as a feature for syncing to a common source, which can then provide direct means to cal the SG504 6Mhz frq ref. with just the head alone.


Idk whether this seems worthwhile to the forum, but it's an idea that is interesting to me and seems economically viable and adds usefulness to the instrument without having to 'hack' the instrument itself.


Re: The 7J20 Patent is now in the archives

Miguel Work
 

Thanks!



De: TekScopes@... [mailto:TekScopes@...]
Enviado el: martes, 5 de abril de 2016 1:28
Para: TekScopes@...
Asunto: [TekScopes] The 7J20 Patent is now in the archives





For all of you that are interested in the 7J20, Egge Siert just uploaded the entire US patent for it. It makes for interesting reading if you are interested in electro-optics, or in learning more about this unusual plugin.

Dennis Tillman W7PF

File : /7J20 Patent #3886331.pdf
Uploaded by : calibrationfixture < <mailto:eggeja2@...> eggeja2@...>
Description : Addition to 7J20 & J20 Photo Album

You can access this file at the URL:
<https://groups.yahoo.com/neo/groups/TekScopes/files/7J20%20Patent%20%233886331.pdf> https://groups.yahoo.com/neo/groups/TekScopes/files/7J20%20Patent%20%233886331.pdf
calibrationfixture < <mailto:eggeja2@...> eggeja2@...>


Re: The 7J20 Patent is now in the archives

Egge Siert
 

Hi to All,

Dennis Tillman provided me the pdf of the 7J20 Patent Document. This for uploading it into the 7J20 & J20 Photo Album. This didn't work, therefore it is now in the Files Section,


Greetings,


Egge Siert


TM5006 Capacitors

J Mcvein
 

Anyone have a source for a replacement, or substitute for the 1100 uF 200V
line side filter caps in a TM5006 power unit? Recommendations?
Tek p/n 290-0878-00 - 1.5"D (38mm) x 4.0"L (105mm)
JimMc


Re: TDS 380 calibration and vertical scale problem

David Wilson
 

Ha! It is interesting that you mention the 465, I originally had my eye on that or the 475 when I decided on the 380. What sold me is the 380 was its advanced precise calculating features and FFT function. In fact I thought the FFT function was particularly interesting as I also had interest in spectrum analyzers so I felt I got the best of both worlds. My one regret with going with the 380 is update rate depending how I set the horizontal scale as it seems to be the case with many digital scopes (except maybe the really good digital scopes), that is when I realize how nice a analog scope is with its instantaneous update rate. Also depending on how I set my horizontal scale I can get aliasing and I am guessing that is another possible reason why the previous owner might have blown out both channels on one decade. Could not get readings on the screen so turned up the vertical scale but was deceived by aliasing, I was fooled by this as well, wondering why I wasn't getting the reading I was excepting until I adjusted the horizontal scale and and then there it suddenly appeared.


Re: The 7J20 Patent is now in the archives

Craig Sawyers <c.sawyers@...>
 

For all of you that are interested in the 7J20, Egge Siert just uploaded the entire US patent for
it. It
makes for interesting reading if you are interested in electro-optics, or in learning more about
this
unusual plugin.

Dennis Tillman W7PF
Indeed most interesting. Because the patent dropped off the perch in the early 90's the basic
principle is adopted by several manufacturers, chief of which is Ocean Optics who make them like
shelling peas. They use the same Czerny-Turner approach (Ocean's is actually a crossed Czerny Turner
for compactness), and up to date arrays from Hamamtsu. About $3k - $6k , powered from USB and
complete with spectral analysis software.

But in 1973, and typical for Tek, it was decades ahead of the curve.

Craig


The 7J20 Patent is now in the archives

 

For all of you that are interested in the 7J20, Egge Siert just uploaded the entire US patent for it. It makes for interesting reading if you are interested in electro-optics, or in learning more about this unusual plugin.

Dennis Tillman W7PF

File : /7J20 Patent #3886331.pdf
Uploaded by : calibrationfixture <eggeja2@...>
Description : Addition to 7J20 & J20 Photo Album


You can access this file at the URL:
https://groups.yahoo.com/neo/groups/TekScopes/files/7J20%20Patent%20%233886331.pdf
calibrationfixture <eggeja2@...>