Re: "Barrel" connectors

On 6/16/2025 3:47 AM, Chris Jones wrote:

On 16/06/2025 11:28 am, Don Y wrote:

On 6/15/2025 1:50 PM, Don Y wrote:

Is there a better way?

>
Cancel that.  A colleague has something in the mail to me, already!

 Let us know if it is any good. It is a problem that I have too.

What I do is label (pTouch labeller) every wall-wart/brick with the
identity of the device that it is intended to power.  Often, this
may not be an intuitive label (e.g., "three device USB3 dock")
but, rather, some other more specific identifier (e.g., "KA-1772-P4").
While this can be frustrating to resolve ("What the hell is a KA-1772-P4?"),
it is guaranteed to be explicit and unique.  (imagine having two different
"three device USB3 docks"!)
[pTouch labeller sees more use than any other bit of kit, here!  Each
networked device is so labelled with its network name, "root" account
name, password, magic keys recognized at boot; external disk
enclosures are labeled witht he number and size of the media within;
NASs with network names as well as media sizes;  wall-warts/bricks;
etc.  Plus, any items stored in unexpected/opaque containers
("dowel centers", "3mm M3-0.5 nickel 100°", "8P8C dust covers", etc.)]
In the past, I've used the "adapter connectors" from a universal power
pack as go/nogo gauges to identify the appropriate mating connector
(works for selecting the female plug but not the male receptacle).
But, this approach requires care in keeping track of the little
"adapter connectors" AND having a cheat-sheet to identify them
specifically (ID & OD).  It's not the sort of thing these people are
likely able to make effective use of -- for more than a day!  <frown>
(they'll be misplaced, damaged, etc.)

I somewhat distrust that type of connector in general, unless both parts come from the same manufacturer - some of them have a slit inner pin that is slightly springy/compliant and would be appropriate to fit in a solid tube in the other part, whereas others have a solid pin and some of the sockets have a bifurcated springy inner contact. Where there is a solid pin fitting in a solid tube, it seems they only work because there is a sideways force on the whole thing from the asymmetrical outer contact. Seems dodgy.

Yes.  But, in our case, we're trying to rescue devices that still have useful
life -- if we could only find the appropriate "power pack".  Or, fabricate
one (I recently cobbled together a power pack for an electric piano that
would, otherwise, have been in the tip).
So, we're stuck with the choice made by the manufacturer and just need
to locate/fabricate something equivalent.

I've also come across the belief amongst the general public that it's ok to plug in any of these barrel connectors as long as they fit, presumably because that's mostly true of USB and so on. So they fry their modem that wants 12VDC by plugging in a 15VAC adapter or whatever.

LaCie uses a 4 pin power connector (12, 5, GND, GND).  It is so unique that
one is immediately tempted to use any power pack that bears such a connector.
However, other folks use the exact same power connector but pinned differently!
And, pinouts aren't incompatible enough to just short out the power pack;
instead, they fry the device being powered!
[I've adopted the policy of banning any device that uses such a power
connector!]
[[I've also seen devices use a PS2 "keyboard" connector for power 12/5/GND.
Really?  Talk about a flimsy choice compounded by the possibilities of
frying a PC/keyboard!!]]