PSU coil whine
#1
The PSU of my RockPro64 sometimes has a high pitched noise, coil whine. Do others have this issue too and can it be fixed?
#2
(11-08-2018, 04:37 PM)Unkn0wn Wrote: The PSU of my RockPro64 sometimes has a high pitched noise, coil whine. Do others have this issue too and can it be fixed?

Seems like you have a good ear that able to hear high frequency range :-)

Most of the time, the switching power supply operate in high frequency and sometime produce high pitch noise. In general, this cannot be fixed by end user and also not suggest due to high voltage. If not comfortable with the pitch, you can file a support ticket at http://support.pine64.org and check out whether able to exchange one for you. However, I am no sure whether you will hear the high pitch noise again on the replacement unit.
#3
I have two 5A EU PSUs and they both whine. One is not that bad but I cannot have it on the table. The other is instant headache Big Grin Whining is bad only only RP64 is idling. Under load it goes away.

I recorded the whine from louder PSU using Sound Analyzer on Samsung S7. Microphone was placed directly against the PSU so depending on playback device and setting recordings may sound even louder then it actually is. I've attached recordings (ogg inside zip as ogg attachment is not allowed) and screenshots of Sound Analyzer if anyone's interested of how it sounds like.

In the first recording there's running top in SSH terminal. You can actually hear top updating its statistics. The second recording demonstrates how having load makes whine go away. In that case I'm running this:
Code:
$ while true; do stress-ng -t 1 --cpu 6; sleep 1; done


Today I got Salcar 6A PSU from Amazon and it's silent. Its barrel plug is little too long but it works fine.


Attached Files Thumbnail(s)
       

.zip   5A-psu-01-running-top.zip (Size: 159.91 KB / Downloads: 205)
.zip   5A-psu-02-stress-and-sleep.zip (Size: 160.11 KB / Downloads: 201)


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