Worrying noise while running

I got things assembled and turned on, and immediately noticed a high pitched whine, reminiscent of a bad cap in a power supply. It doesn’t seem to be the fan, as the fan isn’t running, and I checked that it does turn freely. Any idea if this is indicative of an issue? I can live with it, I just don’t want something to blow up after being used for a few days. Short recording of it is at Dropbox - cpi_noise.mp3 - Simplify your life

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I’ve noticed this only happens when running on USB power. Running off the cells doesn’t seem to trigger the noise.

Don’t quote me on this because I can’t seem to find the thread where I read this but I believe it was explained that while charging current takes a different path and whoever explained it mentioned why you’ll hear such noises. I can’t recall the exact explanation, which I realize makes my response super vague, but it is normal (mine does it as well).


It’s the speakers, noise from charging is coming from there.

I had the same issue before, the noise went away after I tried a different USB power adapter. (same spec, both are 5V 3A, but different brand)

Thanks all, good to know it’s nothing to be concerned of!