How to remove DC jack and solder wire directly onto pcb.

Thread Starter

roberthein

Joined Apr 24, 2020
19
Hi guys,

So my son and i made a little digital clock, but would like to remove the DC power jack pcb mount and instead solder wire directly to the back of the board because of the design we have in mind, the plug is in the way.
220C0B55-6102-4C4E-B8BE-28ACD87228F5.jpeg09CF72E0-685A-490C-B11F-85D975041D4D.jpeg

I did try myself, but it did not work. I connected the positive to the middle and the black to the right (outer)

Im no pro so its learning by doing, but im afraid to fry the board.

Thank you
 
Last edited:

Irving

Joined Jan 30, 2016
797
On the basis of that picture i'd say you were correct. Did you measure the voltage across those pins when running on the plug to verify voltages? and then measure again afterwards on the other supply?
 

Thread Starter

roberthein

Joined Apr 24, 2020
19
On the basis of that picture i'd say you were correct. Did you measure the voltage across those pins when running on the plug to verify voltages? and then measure again afterwards on the other supply?
Thanks for you reply, let me make a video, because i not sure if i use this multimeter correct..
 

Thread Starter

roberthein

Joined Apr 24, 2020
19
On the basis of that picture i'd say you were correct. Did you measure the voltage across those pins when running on the plug to verify voltages? and then measure again afterwards on the other supply?
It working after i used the inner pad for negative. Thanks for helping me, i thought i was on the right track but scared to burn it thank you

image.jpg
 

jpanhalt

Joined Jan 18, 2008
9,718
This is my understanding. Green = solder spots

1591869046555.png

You assumed the outer two contacts were connected, as they may have been on the socket. But they are not connected on the board. So solder your wires positive to center and negative to the other spot furthest from the edge.

Edit: I see you came to the same solution while I was drawing and typing.
 

Irving

Joined Jan 30, 2016
797
Yep, measurement always beats guesswork!

Though looking at the PCB traces it does look like both sides are joined together (which is common practice), there's nothing obvious on the top side of the board to suggest otherwise. Anyway, sorted!
 

Thread Starter

roberthein

Joined Apr 24, 2020
19
This is my understanding. Green = solder spots

View attachment 209417

You assumed the outer two contacts were connected, as they may have been on the socket. But they are not connected on the board. So solder your wires positive to center and negative to the other spot furthest from the edge.

Edit: I see you came to the same solution while I was drawing and typing.
Yes, once i head i was on the right track, i figured it out after measure. for the illustration, do you know why they have a 3rd that has no contact?
 

MrChips

Joined Oct 2, 2009
21,329
Power and audio jacks often come with three contacts. The third contact is often a NC (normally closed switch).

As an audio jack, inserting earphones or headphones into the jack breaks the connection to the internal loudspeaker.
As a power jack, inserting an external power adapter breaks the connection to internal batteries.

Hope this helps.
 

Thread Starter

roberthein

Joined Apr 24, 2020
19
Power and audio jacks often come with three contacts. The third contact is often a NC (normally closed switch).

As an audio jack, inserting earphones or headphones into the jack breaks the connection to the internal loudspeaker.
As a power jack, inserting an external power adapter breaks the connection to internal batteries.

Hope this helps.
Thanks for explaining, i ask because i have this other plug , for a small usb speaker, and it also has 3 legs, and could not figure out how to connect it but i guess its the same case, one will not be used then

7802B0B3-747E-417C-A978-F8F2F0F67FF2.jpeg58FB1AFA-9EDC-4B60-997E-3551D609AD73.jpeg
 
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