Tektronix S-6 Questions

[Electro Fan]

Anyone happen to know what the proper configuration is for the back of a Tektronix S-6?

In the photo there is a 1cm long pin at location "1"; other Tek sampling heads simply have a Philips head screw in that location.  What is the function of this pin?  Does it clear or make contact with the insides of a 7S11 or 7S12?  (Is it for one or the other or both?).  Also, in location "2" there doesn't seem to be the usual copper or brass pin receptacle that is found in other S sampling heads - is that normal?

Thanks

[Electro Fan]

Not sure exactly what is happening here but it looks like even with a S-1 in the 7S12 using a S-52 Pulse Gen that the Tek 7000 is showing a pretty fast rise time.  Any suggestions on how to set things up / measure stuff is welcome.

[PA2HK]

Your picture shows a normal S-6 configuration. Sampling heads that offer internal triggering have a coaxial connector at that back that carries a high frequency triggering signal to the sampling plugins. Actual sampling is done at max 50kHz and those low frequency signals are carried via the card edge connector, high frequency signals being sampled never leave the sampling head. The S-6 sampling head has a spring loaded pin (marked 1 in your picture) and 3 screws at the back. Coaxial connector (hole marked 2 in your picture) is not required as the S-6 does not support internal triggering; triggering is normally done in a TDR setup via a pulse generating head like the S-52. That spring loaded pin is unique to the S-6 head and offers an additional ground/shielding connection to the plugin.

[Electro Fan]

Your picture shows a normal S-6 configuration. Sampling heads that offer internal triggering have a coaxial connector at that back that carries a high frequency triggering signal to the sampling plugins. Actual sampling is done at max 50kHz and those low frequency signals are carried via the card edge connector, high frequency signals being sampled never leave the sampling head. The S-6 sampling head has a spring loaded pin (marked 1 in your picture) and 3 screws at the back. Coaxial connector (hole marked 2 in your picture) is not required as the S-6 does not support internal triggering; triggering is normally done in a TDR setup via a pulse generating head like the S-52. That spring loaded pin is unique to the S-6 head and offers an additional ground/shielding connection to the plugin.

Thanks - The S-6 pin is indeed spring loaded! 

Back on the S-1/7S12/S-52 combination - the outer ring on the 7S12 has 3 settings 10x/1x/.1x.  With the S-1 the length of the pulse doesn't seem to change on the screen as the inner knob is changed - what seems to change is the intensified region of the waveform, along with the associated time div read out; does that seem correct?  And the knob with the fold out handle seems to also control the intensified region, yes?  (It behaves like the "Master Lock" tumbler knob on a 7B92A - but without the nice distance readout dial).

Thanks again!   

[Electro Fan]

Ok, need some help to determine if the multiple plugins are working properly - Please/Thanks.

Too many variables with too many unfamiliar products with too little knowledge and experience - so the plan is to isolate some variables.

Here is an image of a S-52 in a 7S12 outputting to the input of a 7A29.  Any chance this waveform looks like something that would be expected?  Something looks off to me but I don't know what I'm looking for   

I'm pretty confident the 7A29 and the 7B92A (which is out of sight but in use) and the Tek 7904 are all working properly, so I think we're down to seeing if we should have confidence in the S-52 and the 7S12.  If those are working A-OK than I'll try to tackle the S-6 next. 

Questions, comment, suggestion all welcome!

[Electro Fan]

Here is a known good pulse generator sending a pulse into the S-6 with the loop thru taking the signal from the S-6 to the input of the 7A29.  Signal looks ok - so maybe the S-6 isn't doing any harm to it - but I don't know if the S-6 is actually sampling anything or simply passing the signal thru?  If I could confirm the S-6 is functioning properly then I'd be down to confirming the 7S12 and the S-52.  Kinda feel like the saying that goes "we're lost but we're making good time." 

[Alex Eisenhut]

That pin on the S-6 moves the decimal point on the 6R1 digital readout because it's more sensitive. This is used in the 3S5 unit.
And the S-3A head with its more modest 1GHz bandwidth has the same pin, since I guess the probe attenuates.
The coax is a trigger pickoff, a copy of the front panel signal, but only for certain heads, the slower ones.

[Alex Eisenhut]

Here is a known good pulse generator sending a pulse into the S-6 with the loop thru taking the signal from the S-6 to the input of the 7A29.  Signal looks ok - so maybe the S-6 isn't doing any harm to it - but I don't know if the S-6 is actually sampling anything or simply passing the signal thru?  If I could confirm the S-6 is functioning properly then I'd be down to confirming the 7S12 and the S-52.  Kinda feel like the saying that goes "we're lost but we're making good time." 

The S-6 is pass-through, there is no trigger pickoff, so its best used for TDR with the S-52, at least that seems to be the most useful setup in the 567 and 6R1 read out.
Basically the S-52 triggers the scope and fires into the S-6, and you put your JUT (junk under test) on the other SMA and look for what comes back.

I wouldn't hang that much stuff off the S-6 connectors myself, there's a hybrid module in there and those SMAs make friction contact to the ceramic thingyjiggy inside.

Seems fragile. Maybe I'm too cautious, but it doesn't look fixable in there.

[Electro Fan]

Alex, thanks.  Just checking to see if you think this waveform looks normal?  EF

[Alex Eisenhut]

No, looks bad. Tunnel diode pulsers really make a step. You should see 0V, then a few nanoseconds of "feed through": a gentle rise, then the step, then it holds the level for a few microseconds then it slowly decays for the next cycle.

If that cable that goes off the picture really just connects the head to the vertical, that's a bad waveform. Bad amplitude too.

Here's the S-52 manual

http://w140.com/Tek_S-52_Manual.pdf

And might as well get the S-6 manual, it's tricky to find since I guess the OCR got the S wrong...

http://exodus.poly.edu/~kurt/manuals/manuals/Tektronix/TEK%2056%20Instruction.pdf

[Electro Fan]

Thanks Alex - I'm coming to the conclusion that the S-6 is not working properly.  I have one last idea though - I discovered the Bridge Balance adjustment.  The photo below happens to show it for a S-1 in an older scope but I believe the Bridge Balance adjustment is on most or all of the S heads including the S-6.  It looks like in this older scope it might have been adjustable with the scope covers off but it also seems like maybe this is something that was intended to be adjusted iteratively while the S head was outside the scope.  I'm going to try some settings through the range on the S-6 to see if it makes any difference.  Plz let me know if you have any experience with the Bridge Balance. 

I have all the manuals (S-1, S-6, S-52, 7S12, 7S11, 7T11) - they are pretty helpful but sometimes a bit hard to decipher; too bad they aren't pdf searchable but for decades latter beggars can't be choosers.

Also, just for the record I'm posting an image from the S-52 outputting to the S-1 in the 7S12 - look about right, right?  The image I posted looks pretty similar to the (A) image from the 7S12 manual - but maybe inverted?  I think the manual probably is showing a S-52 pulse sampled with a S-6 vs. my image which is the S-52 pulse sampled with a S-1.  I'm inclined to think the image shows that the S-52, S-1, and 7S12 are working (but so far the S-6 is not).  What do you think?  Thanks again.  EF

[Alex Eisenhut]

Yeah, that might be better; you have a ~200mV step in there, I don't know why there is a smaller step after. I'd have to set up my 567 to try it, can't do that right now.

I'd recommend picking the brains over at TekScopes at Yahoo.

[Martin.M]

Oh, there is an insider for Sampling Heads 

If possible I will have also some questions.
Here is a 564 in the collection, arrived with 3T2, 3S2, S1, S2, S3 complete set and S4

greetings
Martin

[EV]

Here are 2 pictures from my R7633 scope with 7S12 plugin and following modules S-6 and S-52 installed. Loop is terminated with 50 Ohm terminator and time distance is 0 in picture 7.

[Alex Eisenhut]

Here are 2 pictures from my R7633 scope with 7S12 plugin and following modules S-6 and S-52 installed. Loop is terminated with 50 Ohm terminator and time distance is 0 in picture 7.

Super good. The bottom trace is pretty much perfect IMO for a tunnel diode step. At least it looks like what all my other pulsers look like too. The feedthrough just before the step is normal for TD pulsers.

You should head over to Tekscopes for the real scoop on these things, I'm just a dabbler.

[Electro Fan]

Here are 2 pictures from my R7633 scope with 7S12 plugin and following modules S-6 and S-52 installed. Loop is terminated with 50 Ohm terminator and time distance is 0 in picture 7.

Mighty fine rise time.

Just noticed that the R7633 displays the "7S12" plugin as being plugged-in (and it also shows "Tek R7633"); is this a feature unique to the 7633 or is it something any 7S12 should do in any 7000 mainframe?

Also, you wouldn't happen to have a S-1 you could put in place of the S-6 to see what type of trace it would show with the S-52 in the 7S12 and R7633?  Thx

[dom0]

Just noticed that the R7633 displays the "7S12" plugin as being plugged-in (and it also shows "Tek R7633"); is this a feature unique to the 7633 or is it something any 7S12 should do in any 7000 mainframe?

Also, you wouldn't happen to have a S-1 you could put in place of the S-6 to see what type of trace it would show with the S-52 in the 7S12 and R7633?  Thx

Looks like 7M13 to me

[Electro Fan]

Oh -
http://w140.com/tekwiki/wiki/7M13
didn't know of this previously, Thx

[EV]

...
Just noticed that the R7633 displays the "7S12" plugin as being plugged-in (and it also shows "Tek R7633"); is this a feature unique to the 7633 or is it something any 7S12 should do in any 7000 mainframe?

Also, you wouldn't happen to have a S-1 you could put in place of the S-6 to see what type of trace it would show with the S-52 in the 7S12 and R7633?  Thx

Yes the left texts are made By 7M13 plugin. R7633 is rack model of 7633. Sorry I don't have S-1 any more. I had it some years ago but it was not working and I have teared it down.

[dom0]

Yeah, neat little documentation tool. Kind of sad that only few DSOs(*) have similar functionality. It would be quite handy to be able to annotate screens, just connect a keyboard to the USB port that all scopes now have and write away, or use an OSD and the knobs. But, no, let's not have that. Would be too easy, I guess.

(*) Windows scopes can do this of course

[Electro Fan]

Yep, a USB port for keyboarding on any scope would be good - for annotating and even just saving/writing file names. Could be wired or wireless.  Or maybe Bluetooth.

[EV]

I changed the cable between S-6 and S-52 to a semi rigid 15 cm cable. Here are 2 pictures about the rise time. It is now about 30 ps.

[EV]

Here is wave form of S-52 from Rigol DS2202.

[EV]

Here is picture about the rise time when S-4 and S-52 are installed to 7S12. S-4 and S-52 are connected with semi rigid 15 cm cable. Rise time is now a little under 30 ps ( about 28 ps).

[dom0]

Looks like both are very well inside their specs. If they had both identical rise times 28 ps system rise time would work out to ~20 ps component rise time, neglecting the cable.