Thursday, June 25, 2015

Wiring a multi-pin plug

I'm making up an inter-baseboard lead for a new project and this involves wiring up a couple of multi-way plugs.
Back in the old days, these would have been honking great things that you could have used a blowtorch in. Nowadays we have stuff more suited to being stuffed in the back of a computer than a Lancaster bomber, so the work is more delicate.
After much practise, here's my (hopefully) helpful suggestion.
  • Tin each wire and then cut the exposed length to the same as the pin to be soldered to.
  • Tin the pin.
  • Bring the two together and with a tiny bit of extra solder on the iron tip, heat the joint. Take the iron away and let it cool, a matter of a couple of seconds.
  •  Tug the wire. If it stays on, the join is probably good.
  •  For extra security, you could slip a length of heat-shrink tube on each connection but I'm too lazy for that. A length of insulating tape between the rows of pins is pretty quick though and worthwhile insurance.
It's important to hold the plug/socket securely. A small but heavy hand clamp does the job here but a big blob of Blu-Tack will do if nothing else is available.

1 comment:

Huw Griffiths said...

Your basic method of wiring these things definitely works - as I found, when I needed to wire a number of the things in a previous job.

Usually though, I used a bench vice to hold D connectors - solder bucket side up. With care, I found I could tighten the vice enough to hold the connectors firmly - but not firmly enough to squash the connector shell.

Personally, I'd never connect any multipole solder connectors like these without insulating the individual connections - shrinkwrap works well (and also provides some support to the wires) - but it can be hard to keep the tubing out of the way until the solder joint has cooled.

As my job also involved fitting strain gauges, I often needed to protect the gauges after wiring them, using something similar to clear nail varnish - this was also effective at insulating them.

Some sort of lacquer would also work quite well for insulating soldered joints on multipole connectors - but, if anyone uses nail varnish for this purpose, I'd strongly suggest using a coloured one - preferably something garish - as it's easy to see that it's there.

Something else I did did in my last job was clearly identify which wire's which - mainly by colour coding the individual wires - but sometimes also by putting numbered sleeves onto the wires.

Preparing a nice, clear (and up to date), wiring diagram - with everything clearly numbered etc. - comes in very useful when you need to do repairs a few years along the line. You can be fairly sure that this will happen sooner or later.