USB interference

Dear community, I have a question that I’d like to answer but it’s not anything vital. More something that tickles my curiosity ( ͡° ͜ʖ ͡°). I have power bar with 6 USB ports that was given to me because half of it can’t be turned off anymore with a button that’s on it. I took it immediatly because has a fuse in it, a giant power cable that would easly support 2kW going through it and looks alright. But there’s something about the USB ports that’s not right. For reasons unknown to me all of them emit an obscene amount of EMI. I discovered that because when I plugged my phone the capacitive fingerpint reader couldn’t lock the phone while holding on it for one second like it used to. And when I connected and older phone it just made the whole touchscreen unresponsive. So I was thinking how could I fix this issue on my own? Is it even possible? What are the risks of charging devices with such strong EMI emissions? Thanks!

It may not be EMI. It may be that the USB ports are over volted or pulsing/polling too fast/slow. I would recommend to toss it unless you are good at soldering and electronics.

Basically, find a schematic and fix the issue of why the strip cannot be turned off. Otherwise, you will fry something.


If it’s EMI it should effect the phone without being plugged in.

I agree with @Mastic_Warrior sounds more like electrical interference, or a software malfunction.

USB is a really rugged interface.

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I don’t know if this is related…
Driving with the fm radio on. Plug in my phone into an aftermarket cigar lighter charger via usb and the radio goes static.

@Mastic_Warrior Thanks for the reply! I’m just okay at soldering. So than I’ll just never use those USB ports, what a shame.

Both the cigarette lighter and the FM radio are connected to the 12V. The charger might be so out of spec that’s returning radio frequencies through the 12V cable making the radio go static.

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Sotware malfunction?