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Sampling head extender missing coax connectors


 

When I bought my 3S2 sampling plug-in, it came with a 012-0124-00 Sampling Head Extender (3 ft). Thought that was a nice bonus. Unfortunately some genius seems to have removed the push-on coax connectors from each end (the trigger pickoff). No idea why. But that means I can't use the extender for normal operation! (Although the 3S2 doesn't have internal triggering, that's an easy work-around by connecting a short cable from the 3S2 trig out to the 3T77A ext trig in. Still need to run the trigger from the sampling head to the 3S2, though).

I took the scope-end and the cable hood apart, and the coax is there - someone cut it off, and inside the scope-end it was taped into a half loop with scotch tape. No way was that Tek factory original.

So, any idea what kind of push-on connectors those are, and where I can get one male and one female? If they're crimp style the remaining coax won't be long enough, so I'll have to run another piece of coax alongside the cable, too.
thanks.


 

After searching through the TekWiki connector page, I think it might be an SMB?


snapdiode
 

Whoever did that did a pretty despicable thing... This connector kind of looks like a SMB but isn't. The manual seems to suggest it is built of parts intended for other things.

The inner female conductor is a DM53740-5001 which still exists today https://www.mouser.ca/ProductDetail/ITT-Cannon/DM53740-5001/?qs=qCxwlXJ4fnyo0PCCdeMbuA==

...which says it's meant for RG187 or RG188 coax, which leads to these connectors

http://www.coax-connectors.com/products/cables/ab/rg187.aspx http://www.coax-connectors.com/products/cables/ad/rg188.aspx

They could be dsub coaxial contacts, as used in 13W3 connectors. I'd have to measure it.

...beats me.


 

Thanks! Please post if you find out more details or measurements :)
The extender is still partially useful to start debugging the S-1 once I get the Schottky diodes from Digikey, assuming that doesn't fix it right away.
Meanwhile I can just leave the sampling heads in the scope and run a GR-874 cable to whatever I'm playing with. I've got a bunch of those cables in various lengths/delays and a variety of 874 adapters too.


snapdiode
 

Forgot to link

https://www.norcomp.net/series/682m-series-solder-cup

sort of looks right. Don't know.


 

Those look good, but I wonder how the contacts were originally mounted in the extender cable. There is no mark where a nut or clip would have been, and no separate bracket. Perhaps it's a push-in lock (as it works in the D-sub connector body)?


snapdiode
 

I think that will be the bigger problem, naturally the connectors need to be mounted at the right distance to work... Check out my exciting photo album.


 

I'll look for your album, thanks.

The NorComp contacts are proving elusive (DigiKey lists them as "obsolete" and no price. Of course).

However, it appears that other manufacturers also make similar coaxial contacts, for example:
https://www.mouser.com/datasheet/2/18/amphenol_d-sub_inserts-1157297.pdf

I might as well chase this mirage while I'm waiting on Schottky (and tunnel) diodes ;)


-
 

"They could be dsub coaxial contacts, as used in 13W3 connectors. I'd have
to measure it.

...beats me."

If they are then those same contacts were used in some of the old Sun
and SGI monitors and you might be able to get one of the video cables and
rob the connectors out of it. HP also used the same contacts in various
extender and unit interconnect cables.

On Sun, Feb 14, 2021 at 7:27 PM snapdiode via groups.io <snapdiode=
yahoo.com@groups.io> wrote:

Whoever did that did a pretty despicable thing... This connector kind of
looks like a SMB but isn't. The manual seems to suggest it is built of
parts intended for other things.

The inner female conductor is a DM53740-5001 which still exists today

https://www.mouser.ca/ProductDetail/ITT-Cannon/DM53740-5001/?qs=qCxwlXJ4fnyo0PCCdeMbuA==

...which says it's meant for RG187 or RG188 coax, which leads to these
connectors

http://www.coax-connectors.com/products/cables/ab/rg187.aspx
http://www.coax-connectors.com/products/cables/ad/rg188.aspx

They could be dsub coaxial contacts, as used in 13W3 connectors. I'd have
to measure it.

...beats me.






snapdiode
 

Meh, I creatively destroyed my connectors to get the contacts inside. Why not, I don't even know how or why I have a 7W2 in my box of shiny things. If they fit, I can ship them to you for the price of postage.


 

If you have a male and a female (since I need one for each end of the extender) ;) I'd happily pay postage.

D-sub coax contacts can be had, for example:
https://www.digikey.com/en/products/filter/d-sub-d-shaped-connectors-contacts/332?s=N4IgjCBcoLQdIDGUBmBDANgZwKYBoQB7KAbXDAFYQBdAgBwBcoQQBfVggJlJACUBxOAHYALAAJEhNAA8arIA

For almost $16 for just one pair. Plus postage!
I'm going to check my cable bin, maybe there are some coax contacts as mentioned...


snapdiode
 

PM me


Albert Otten
 

Be aware that the missing trigger connector affects the Transient response of the S-1. The transient response amplifier (Q13/Q17) will do almost nothing.
The 7S12 cannot be triggered internally by the sampling head. However, the 7S12 trigger connector is still present and terminated to GND via 51R.

Albert

On Mon, Feb 15, 2021 at 01:37 AM, Charles wrote:


The extender is still partially useful to start debugging the S-1 once I get
the Schottky diodes from Digikey, assuming that doesn't fix it right away.


 

Thanks for the heads-up. Snapdiode is sending me a couple of coax contacts that hopefully will fit - they sure look the same.
I'll check transient response with the head directly in the plug-in and on the extender to see how different they are.
Of course I have to install new diodes first... ;)


snapdiode
 

Snapdiode would like to tell you that an important thing has been overlooked: the need for a ferrule and crimping tool to properly terminate the cable to the connector. I do not have these ferrules... You're on your own basically as to how to attach the ground braid of the cable to the connector. I suppose a brass tube of some sort, if you still have hobby shops in your area, would work, and delicate squishing with pliers will do the job.


 

No problem, I'll figure something out! I have various crimp tools, and a friend who used to install alarm systems and cable TV and still has the tools.

I'm more concerned about mounting the connectors. I don't have anything to inspect for the original mounting scheme (except my more expensive S-2 head and since it works, I do not want to mess with it). But it almost has to be a snap-in since there are no marks where a nut or spring clip would have been.

Guess that's what JB Weld is for :D


 

The sampling heads have the trigger out connector mounted directly to the PC board anyway, so looking inside wouldn't have helped. Hopefully the hole is the same size as in a D-sub connector and it just snaps in.


snapdiode
 

Did the connectors ever show up?


 

Not yet :(
As I mentioned in the 3T77A thread, mail from Canada to the US is even slower than usual these days. Still waiting on the hybrid for my S-4 head that Walter sent, too.


snapdiode
 

Weird, I just mailed a part to Massachusetts and it got there in two days.