Author Topic: Beware - Certain types of HIRSCHMANN plugs get stuck, won't come out of 34461A  (Read 3616 times)

0 Members and 1 Guest are viewing this topic.

Offline daqqTopic starter

  • Super Contributor
  • ***
  • Posts: 2321
  • Country: sk
    • My site
Hi guys,

So, I bought some banana plugs, namely the type BUELA 20 K, made by HIRSCHMANN, made cables from them, plugged them in my Keysight 34461A, done my measurements... and one of the bastards won't come out.

I'd guess that the head is stuck, since the construction is such, that 6 plated bits are springy and when inserted make contact with the outer tube of the socket. The tip of the plug is a metal bit that holds them in place. This means that the diameter of the body of the plug can be smaller than the tip, when the springy bits are pressed into the body.

I'm guessing that the sockets in the Keysight device are a tube, but not all the way through - as such the head got caught on the end of the tube and the bastard won't come out. Bonus points if the head gets deformed by more frustrated attempts at pulling it out, making it more stuck.

So, yeah. This will be fun.

Attached are the photos of the culprit.
Believe it or not, pointy haired people do exist!
+++Divide By Cucumber Error. Please Reinstall Universe And Reboot +++
 
The following users thanked this post: Andreas, bck, CalMachine

Offline daqqTopic starter

  • Super Contributor
  • ***
  • Posts: 2321
  • Country: sk
    • My site
Update: After using much more force than I'm comfortable with when used in combination with a pretty damn expensive meter I pulled the plug out... without the tip, which is probably still stuck in the socket. Also, a quick inspection of the socket reveals some internal damage - a small bump in the metal. I can't make a photo of it at the moment.
Believe it or not, pointy haired people do exist!
+++Divide By Cucumber Error. Please Reinstall Universe And Reboot +++
 

Offline cat87

  • Regular Contributor
  • *
  • Posts: 230
  • Country: nl
Where I work, we have many types of banana plugs, among which the same Hirschmann as you have. And I've noticed the same issue with these. It's that damn dome in the end of the banana jack, that gets stuck and is a real pain to pull out. I've even had the thing get stuck in another banana jack.
Now, I stay away from any plug that has the same  type of tip on it. I  prefer the jacks from Schutzinger. They seem to be much more robust and tend to have a nice contact pattern with the mating jack


Offline Mr. Scram

  • Super Contributor
  • ***
  • Posts: 9821
  • Country: 00
  • Display aficionado
Where I work, we have many types of banana plugs, among which the same Hirschmann as you have. And I've noticed the same issue with these. It's that damn dome in the end of the banana jack, that gets stuck and is a real pain to pull out. I've even had the thing get stuck in another banana jack.
Now, I stay away from any plug that has the same  type of tip on it. I  prefer the jacks from Schutzinger. They seem to be much more robust and tend to have a nice contact pattern with the mating jack
Is the type pictured the right or the wrong type?
 
The following users thanked this post: rs20

Offline capt bullshot

  • Super Contributor
  • ***
  • Posts: 3033
  • Country: de
    • Mostly useless stuff, but nice to have: wunderkis.de
I don't use this kind of plug anymore for many years.
Safety devices hinder evolution
 

Offline Vtile

  • Super Contributor
  • ***
  • Posts: 1146
  • Country: fi
  • Ingineer
Where I work, we have many types of banana plugs, among which the same Hirschmann as you have. And I've noticed the same issue with these. It's that damn dome in the end of the banana jack, that gets stuck and is a real pain to pull out. I've even had the thing get stuck in another banana jack.
Now, I stay away from any plug that has the same  type of tip on it. I  prefer the jacks from Schutzinger. They seem to be much more robust and tend to have a nice contact pattern with the mating jack
beware of the cheap connectors of these type (type 5. in picture), almost everyone of them have substandard connection when wires/leads are moved. It also seems that some of the "Chinese" factories are littering (based on my two online orders) the markets with too tight banana sockets.

In my mind variations of this mechanical contact structure of the type 1 and 2 are really good ones and actually the connector 2 in picture is a standard test leads for Unigor 6e meter. The best ones are the three finger connectors numbered 4. and close to that are the type 3 (Pomona seems to like it)., but it usually is "too short".


« Last Edit: November 03, 2017, 09:37:28 pm by Vtile »
 

Offline HighVoltage

  • Super Contributor
  • ***
  • Posts: 5561
  • Country: de
I had this problem once, many years ago and damaged a 34401A.
Since that time I have never again plugged a Hirschmann banana plug in to an expensive instrument.

I am using only gold plated MultiContact (MC) banana plugs since then.
The first time you insert one of these, you feel the quality!


There are 3 kinds of people in this world, those who can count and those who can not.
 

Offline Vtile

  • Super Contributor
  • ***
  • Posts: 1146
  • Country: fi
  • Ingineer
^^ That almost sounds like one of those audiophoolery reviews.  ;D

Edit. This "The first time you insert one of these, you feel the quality!" part.  :D
« Last Edit: November 03, 2017, 10:31:15 pm by Vtile »
 

Offline HighVoltage

  • Super Contributor
  • ***
  • Posts: 5561
  • Country: de
^^ That almost sounds like one of those audiophoolery reviews.  ;D

Edit. This "The first time you insert one of these, you feel the quality!" part.  :D
Funny: It does sound like it.

Also, watch out for some of those banana plugs that have a plastic (dome) tip at the front.
Some of these plastic tips are so tight, that they start expanding from the temperature of the instrument
and then they are so tight inside the receptor, that you can not take them out anymore.

There are 3 kinds of people in this world, those who can count and those who can not.
 

Offline cat87

  • Regular Contributor
  • *
  • Posts: 230
  • Country: nl
Quote
Is the type pictured the right or the wrong type?

The picture is the kind on banana plug I DO use. Notice the Hirschmann has the bit on the tip riveted, while the  Schutzinger one in my previous photo has a different way of holding the tip (brazed perhaps? or just turned?)
 On the Hirschmann, the rivet tends to loosen and the tips is no longer is line with the rest of the lead, that's why it gets stuck.
I've also used No.1 and No.2 plugs from Vtile's photo and are also quite good, except the contact pattern may not be well suited for some high-ish current applications (> 3A). At least that's whay my mind thinks.

Offline Kleinstein

  • Super Contributor
  • ***
  • Posts: 15206
  • Country: de
I had a similar problem with one of the Hirschmann  or similar plugs too - though not in an expensive instrument, but a self made box and rather cheap terminal (just a tube open at the end). So in this case I could see the inside and remove it reasonable easy.

In my case to cap at the front of the plug was bend a little, maybe stepped on it, dropped something heavy on it or maybe just bend to the side when removing from a terminal.

Otherwise this type of plug is rather good. It is more like the simple split plugs like No 4 type that can have poor contact.
 

Offline Neomys Sapiens

  • Super Contributor
  • ***
  • Posts: 3268
  • Country: de
I experienced the same problem on a Beckman DM25xL. I traced the condition to a less than perfect fit of the thin hemispherical cap in combination with PCB-mounted jacks, which have a distance from the PCB (except for the solder pins), which allows the rim of the cap to get caught.
 

Offline daqqTopic starter

  • Super Contributor
  • ***
  • Posts: 2321
  • Country: sk
    • My site
OK, after some testing, the plugs are usable (safe), if you remove the metal cap. That said, I'm never touching this particular type again.
Believe it or not, pointy haired people do exist!
+++Divide By Cucumber Error. Please Reinstall Universe And Reboot +++
 

Offline Jeroen3

  • Super Contributor
  • ***
  • Posts: 4210
  • Country: nl
  • Embedded Engineer
    • jeroen3.nl
Hirschmann SKS makes a lot of banana plugs.
This type with the spring wires put into rings it a high insertion force type, probably for high current, and you can't stack them touch safe. I don't know why people even get these.

The one with the bent sheet metal as shown by cat87 is much better.

There is also the one with a single curved strip, it will be loose quickly.
 

Offline GigaJoe

  • Frequent Contributor
  • **
  • Posts: 524
  • Country: ca
It seems right - BUELA 30 K (20K ? ) -30 Ams rated,   MZS 4 - probable better  in this application

 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf