High Pitch Noise Coming From Pinebook Pro

[eKeith]

I received my new production batch PBP yesterday and was playing with it today, and unfortunately, most of the "coil whine" problems identified on this thread seem to still exist in the new August 2020 production batch. 

1) Screen buzzes  unpleasantly and noticeably at intermediate brightness levels, CAPS LOCK changes the "tone" of the buzzing, goes away at min and max brightness;
2) Unit has a less-unpleasant, but still noticeable buzzing when charging by USB-C;
3) When the speakers are un-muted, they hiss and crackle constantly, even while audio is playing.  Goes away when the speakers are muted in the OS, but can't really listen to anything.  

The screen buzzing goes away at maximum or minimum brightness, so the PWM issue noticed early on is still present in my unit.  Can make it go away at max brightness, so there is a workaround available.  But, still shouldn't be there and will likely wreck battery life.  

The charging buzzing is irritating, but, I can live with it.  

The speaker static definitely not a software problem, it sounds like electronic interference or feedback, as if they weren't shielded properly or installed correctly.    Makes watching movies, listening to audio of any sort not really possible, it's hard to even make out words over the hissing and crackling.

Unfortunate to have to deal with these issues - the hardware is beautiful and doesn't have the serious physical defects (e.g., touchpads falling out) problems of the previous batch.  But, as was pointed out in the community updates a while back, these kinds of coil whine noise issues are hard to catch when your testing is done in a noisy factory setting, and likely point to a need for QA process improvements.  Difficult during a pandemic, I know.  Would be curious to hear if any of the other August units have these kinds of issues. and whether any component hardware fixes are possible.

Very good report; thank you.

I'm looking forward to innovative user ideas and solutions...

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