Name of this plug/connection?

[adzyp]

Ever so slowly you are "leaking out" some of the information that you should have supplied in the first instance!

From that which you have written (so far) it is not clear that the "Power Supply" IS faulty", since you are reading Voltage

Reading the labels on the pictures (eventually) supplied, we now know (?) that you have "Hafele" Kickboard Strip LEDs - supplied from a 12 V AC (500 mA) TRANSFORMER via that which Hafele calls a "Master Junction Box" - rated at up-to 16 V AC, 500 mA.

(One might wonder if this "Master Junction Box" actually contains a "Bridge Rectifier" - given that it has a "rating"
AND
Polarized output connectors ! )

The "Strip LEDs" (how many?) may be connected via 2-Pin DIN connectors to the TEN sockets on this "Master Junction Box"

19 V (?) - on "No-Load" (?) - Where measured (?)
AC or DC (?)

You can plug one or more "Strip LEDs" into the "Master Junction Box" and measure the voltage supplied at one of the unused 2-Pin DIN sockets.

If you read 19V AC, the chances are that the supply is OK but there is "No-Load", indicating that the "Strip LED(s)" is/are Open Circuit. (Faulty)
If so, OBTAIN a (say) 150 Ohm/1 Watt resistor, insert its leads into a vacant 2-Pin DIN socket and check the voltage reading - on its leads.
(150 Ohms would represent about a 20% Load on the Transformer.)

You should then read around 12 V AC, if the supply is OK
- or 12V DC, if there IS a rectifier in the " Junction Box".

Thanks for the detailed response, apologies, but some of the information wasn't clear to me at the start, we've just moved house so i just keep coming back to this when I can.

Wall wort was showing 19v when switched on at the wall and multimeter set to AC.

I am not at home at the moment but will get the junction box plugged in and powered up later and check voltage at an empty terminal.

 

[FrodoOne]

You need to check under Load.

 

[adzyp]

You need to check under Load.

Ok so power supply plugged in and powered on. One LED connected to junction box, reading at an empty connection is 0.8v.

 

[pcaouolte]

reading at an empty connection is 0.8v.

That is 0.8v AC. What does it read on DC?

 

[adzyp]

That is 0.8v AC. What does it read on DC?

DC showing 1.6

 

[FrodoOne]

From your "tests", it does appear that the 12 V AC (500 mA) screw socket power supply is faulty and needs to be replaced.
(The 19 V AC which you read at its outputs is a "spurious reading" - because you were using a "high impedance" (Digital) meter, under "no-load" conditions.)

Since
it has failed
and
500 mA is quite a low rating,
I suggest that you replace it with a higher rated 12 V AC "Power Supply"/Transformer
at least 1000 mA - or even higher, since they do not cost much.

12v ac/ac power supply for sale | eBay

Find great deals on eBay for 12v ac/ac power supply. Shop with confidence.

www.ebay.co.uk

Amazon.co.uk : 12 v power supply

https://cpc.farnell.com/c/electrical-lighting/batteries-power-supplies/power-supplies/ac-ac-power-supplies/12v-ac-power-supplies

contain examples.

Most of these devices come withe 2.1 mm Plugs - although some may have 2.5 mm Plugs (or other connectors).

Because of this, you will need to cut off the existing connector and replace it with an appropriate "mating" socket.
Polarity does not matter, since this is for AC.

It would be interesting to know if the "Master Junction Box" does contain a Bridge Rectifier.
From your readings, I suspect that it does.

 

[adzyp]

From your "tests", it does appear that the 12 V AC (500 mA) screw socket power supply is faulty and needs to be replaced.
(The 19 V AC which you read at its outputs is a "spurious reading" - because you were using a "high impedance" (Digital) meter, under "no-load" conditions.)

Since
it has failed
and
500 mA is quite a low rating,
I suggest that you replace it with a higher rated 12 V AC "Power Supply"/Transformer
at least 1000 mA - or even higher, since they do not cost much.

12v ac/ac power supply for sale | eBay

Find great deals on eBay for 12v ac/ac power supply. Shop with confidence.

www.ebay.co.uk

Amazon.co.uk : 12 v power supply

https://cpc.farnell.com/c/electrical-lighting/batteries-power-supplies/power-supplies/ac-ac-power-supplies/12v-ac-power-supplies

contain examples.

Most of these devices come withe 2.1 mm Plugs - although some may have 2.5 mm Plugs (or other connectors).

Because of this, you will need to cut off the existing connector and replace it with an appropriate "mating" socket.
Polarity does not matter, since this is for AC.

It would be interesting to know if the "Master Junction Box" does contain a Bridge Rectifier.
From your readings, I suspect that it does.

Thanks for this, I will take a look later however when I looked before I struggled to find an AC/AC supply and could only find AC/DC.

Assume it cant be supplied with a DC supply? My previous attempts with other DC supplies would suggest not but maybe I was using the wrong thing.

 

[adzyp]

So managed to find an identical junction box today, swapped it over and all is working ok.

Might still look at getting another power supply so the same doesnt happen again

 

[Rodders53]

My money is on something inside that Hafele master junction box / led driver part 830.12 - 0001 that has failed, rather than the AC wall wart... which has, itself, still not been tested 'on load'.

EDIT cross posted. So wall wart is OK.