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Connect directly to board


May 26, 2023
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How can I solder dc supply cables directly to this board?
The male and female dc jack connectors are both broken.
Many thanks!


1) Get a soldering iron
2) Get some solder
3) Plug in the soldering iron and wait for it to get hot
4) Melt the solder with the hot soldering iron whilst holding the wire to the appropriate spot on the PCB.
dc jack connectors are both broken.
Something that looks like a power jack is near the DC1 label. Is there a chance it contains dislocated metal pieces? Before soldering wires to the nearby terminals, you must make sure there's no short circuit occurring.

This is surmise on my part. Since there are three solder terminals nearby, it suggests that the jack has an internal switch to choose between battery power or external power. You should research how such jacks operate. You must avoid soldering wires to the wrong terminals. You must figure out which is the correct positive terminal and negative terminal.
The answer really depends on where it gets its power from at the moment. We have no idea what this device is but it seems to have a USB socket and some kind of small jack socket, I'm guessing these poke through the holes on the left of the picture. "DC1" could be a power input but its pin configuration suggests it could be a 2.5mm or 3.5mm signal connection.

If it is USB powered, you connect to the outer pins of the row of four behind the USB socket but we need more information to be sure. What is the device and what markings are on the outside of the plastic case near the two holes?

Thank you. It's a Ocube alarm clock. It has the broken jack just behind where it says DC1. The black tip is peeking out.
There are 3 holes but I'm not sure what could be positive and negative and which one is for detecting switch to battery.
Extra information certainly helps, I have now found the device and can see DC1 must be the power input and the USB socket is a charger outlet. Apologies for asking questions but often it is the other way around and devices are charged through the USB socket making it a power input.

You need to connect the wires directly to the pads behind DC1 but from the photographs it isn't clear which pins to use. Can you send a close-up picture of just the area surrounding DC1 so we can see the copper tracks on the board and also pictures of the plug that goes into DC1 and the label on the wall adapter please.

Hi, it's great with questions. The questions will help me fix this (if I haven't broken it in the process of fixing it).
The pads are covered by a DC socket. I might have to remove that to access the pads. Not sure how to do it gently?
The plug is broken. I tried soldering wires to the plug but it was too destroyed hence I decided to attempt to connect power to a board inside the device. Previously I bought various plugs and another adapter to try to connect to the socket but no size of the plugs were fitting the socket
I have some issues uploading photos. I'll try after posting this text.



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Thank you. Is there any way to figure out which pins to use? Which is negative and positive? I don't have any tester to check it.
Without the original plug intact it's impossible to see which was the center pin and which was the body.

With some electronics knowledge it is easy to tell by following the copper traces on the board but if you are unfamiliar with circuit boards it might be difficult. I suggest you buy a testmeter, it can be any model and they cost just a few Euros. It doesn't have to be a digital one, a needle on a dial works just as well. You set the meter to measure resistance (Ohms) and place one of the probes on the metal shell around the USB connector. Place the other probe on each of the three solder joints under the DC socket in turn. The one that make the meter read zero (or the needle goes all the way across if it's an analog meter) is the negative connection.

You will do no damage by connecting the positive wire to either of the other joints so you can try both, do it with batteries removed in case you feed power to them instead of the clock. One will work as expected, the other probably won't work at all although I can't be certain without seeing it.

Now you have to find out which of the wires from the wall adapter is positive and which is negative. To do this, change the setting on the testmeter to measure voltage and select the lowest range that is higher than 5V (10V for example but meters vary). Make sure the black probe wire is in the negative meter socket then connect one of the probes to each wire. If the meter reads about 5V you have the probes the right way around so you have found the polarity. If the meter reads -5V or the needle goes backwards the probes are the wrong way around and you have the negative probe to the positive supply and vice versa.

Once you know the polarity of the adapter wires and which is the negative solder pad on the DC socket, all you have to do is wire negative to negative and positive to positive.


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