JRK Board/Soldering issue

Hi there.

I have just this week purchased 2 JRK 12v12 boards from your good selves and have run into a snag.

I soldered the three pins I require for my pot feedback on the first board, along with the block terminals, without an issue. When I began on the “FB” pin/terminal on the second board, solder appeared in the “Aux” terminal. It didn’t flow from the outside, but seem to just appear inside the terminal. I have checked the difference in resistance between the fist boards’ “FB” and “Aux” pin and it is very much higher than the board that has solder now showing inside the “Aux” terminal, indicating to me it is in fact connected to the “FB” terminal.

If I understand the way this board works correctly, I should use either the “FB” terminal as feedback from my pot, or the “Aux” terminal (depending on how you want it set up). If they are somewhat connected this will be an issue, for me.

I am a hobbyist solderer, so not an aficionado, however I feel I don’t do a bad job. I have attached phone pics showing the issue, and a pic of the good board, showing my soldering results. (apologies but the pics looked much clearer on my phone)

What do you recommend I do, or do you think it could be a faulty board? Is it possible for solder to track internally from one terminal to the adjacent terminal?

Any help or suggestions would be appreciated.

Hi Richard,

it is unlikely that solder has transferred from one pin to the other, However it is possible to overheat the board an melt surrounding solder connections through conducted heat. This can easily happen if your soldering iron is too hot. Its also possible that you touched the aux pin while soldering the FB connection, and residual solder ran into the opening.

I did a little checking, the AUX output is a digital signal, so it shouldn’t have much voltage. From the Users Guide, “The AUX line is an output that is generally high whenever the jrk has power. The line will only go low for two
reasons…”. Also from the User Guide “Two closed-loop feedback options: 0–5 V analog voltage”.

To check if everything is alright, set the feedback input to analog input and see if you have any input. Because Feedback can read between 0 and 5v, if the aux and feedback have been connected then it will show 5v whenever powered. If they aren’t connected then your feedback will show no input or 0V.

Let me know how it works out!


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Thanks Stephen,

If the board wasn’t as expensive I would of just continued on. I’ll keep on going and see what happens.

I’ll let you know if I let the smoke out or not :laughing:


If its cooked its cooked Id say. My point is that there is not enough voltage coming out of Aux to damage your board. It would just give you a bad reading on your Feedback pin.

Hi Stephen.

I managed to find some time over the week and put the second board together, and added it to our project. It worked like a charm. Very happy with the result. I think there is a project posting area on the site somewhere. I’ll put up a video, if I am able to.

I’ll obviously have to work on my soldering technique, though.

Thanks again


You can share your project on our dedicated projects platform:

or you can share it under the projects category of our forum:

Looking forward to seeing the final product! :slight_smile: