It appears that C427 and C418 are 2.5V electrolytic capacitors. Their low
voltage rating suggests that they are associated with a switch-mode
regulator that supplies power to the CPU. Notice that the inductors, L30
and L31, are very close to the place you identified as the source of
sound. I sugge
Hello both,
Thanks for your replies.
Fortunately I found a way to crank up the noise and bring it a bit under
my control. By accident I found out that putting some strain on the
Nginx http server increases the tone significantly. It doesn't seem to
matter whether the data comes from an externally
