UKAEA Geiger-Müller Counting System - Cable Repair

[Dobby]

Hello friends,

 

I've got an ancient piece of kit here which our science department has said works intermittently. If you hold the cable the right way it works fine etc.

 

 

I couldn't find much online about it so assumed the cable was a coax. I bought a few male BNC connectors to rewire it, however upon opening it I found it had a stranded core rather than a solid one. I can't for the life of my get even half the wires into the gold pin for the BNC connector.

 

This is the internals of the current faulty wire:

 

This is what I've bought to replace the connection:

 

 

Any advice on what connector to buy or any tricks to rewire a stranded core would be greatly appreciated.

 

Thanks

 

[3s-gtech]

Can you thin the core? Cut away small amounts of the strands with fine side cutters until it fits. It may pay to solder it in then, so a good pool in the receptacle of the pin. Fine blowtorch.

[Andrew_C]

The voice of experience says - if you haven't got the right tooling for BNC connectors, buy a pre-made lead and cut one end off, fit it into the GM tube.

 

ETA - BLOWTORCH???!!

Edited February 10 by Andrew_C

[Dobby]

36 minutes ago, 3s-gtech said:

Can you thin the core? Cut away small amounts of the strands with fine side cutters until it fits. It may pay to solder it in then, so a good pool in the receptacle of the pin. Fine blowtorch.

 

I managed to get some of it in once, I tried to solder it but I have very unsteady hands and ended up making a bit of a mess of it.

 

2 minutes ago, Andrew_C said:

The voice of experience says - if you haven't got the right tooling for BNC connectors, buy a pre-made lead and cut one end off, fit it into the GM tube.

 

I'm not sure if I can even open up the tube but I feel like this is what I'm going to end up doing.

 

I'll have another go at soldering it, if I make a mess I'll speak to the department and see if they're bothered about me trying to open it up (and possible breaking it further).

 

Thank you for the advice

[Andrew_C]

Or a join 1/2 way along the lead.  Carefully heatshrunk.

 

I'll get one of ours out and have a look.

 

ETA - Yeah, glued.  And the sticker that says "Very Fragile" - believe it.  There will be a thin mica window on the end of the actual tube.  Go for splicing the cable.

Edited February 10 by Andrew_C

[Chris_Cook]

There are 2 different sizes of BNC - 50 Ohm and 75 ohm. The pin size is slightly bigger on one of them. The outer is the same.

 

50 ohm is more for test equipment and networking

 

75 ohm is for video and cctv.

 

I've never had much luck making up BNC ends.

[Sirbendy]

Given I was until recently a science tech responsible for these things, tin the strands of the inner core, or pliers and twist them tightly together first.

 

We have a BNC unit, and an older type with a screw connector.

Edited February 10 by Sirbendy