Try inserting your USB devices, not a wet finger lol !!
Jokes aside, specifically which MINIX device do you own? (X8, U1, U9-H, etc.?) Is your PSU configured with a UK 3 pin plug for example or a 2 pin US/Euro? Is the PSU & cable in good condition? (Check closely for any damage or bare cabling etc.)
Invariably, issues like this are possibly due to a short/grounding issue somewhere. Has the problem just started or has it always done this?
USB carries a very low voltage but it'd probably be a good idea to isolate the device at the wall until more knowledgeable help is available if it's just started doing it.
@Villa is pretty handy with this kind of thing off the top of my head .
I only know very basic stuff about electricity.
The best and the important in my view is having a good (in home), well made connections made by a good electrician.
Also we should not have too many equipments plugged into the same outlet and the same phase.
We should separate to be safer.
With that made we can buy surge protectors in order to protect our devices.
And one thing i am afraid and respect is electricity ☺.
Very true. Although, I meant with regards to a possible cause rather than the actual effect PMSL . (You shouldn't have posted your pics of your DIY soldered DC pin on a U9-H. The assumption is now that you're an expert in this area .)
I've had a couple of random devices in the past that have begun to exhibit similar behaviour out of the blue.
I use Ecigs & a mod (battery pack) started to give me a decent "buzz" if I touched a certain screw when it was charging off a 1 Amp / 5V wall charger. Turned out to be a simple short which even I could fix lol.
How much juice is potentially capable of reaching his USB ports if something has really gone wrong inside? Will it just be 500 mA / 5V from the USB or could it become a serious danger?