SMART X-Port 10 buzzing audio fix

[poot36]

If you have a X-Port 10 switcher and you are getting buzzing audio when even just the power supply is plugged into the unit with no other cables plugged in then I have the fix for you.  You will need to change the capacitor in location C8.  It is a 100uf 25V cap.  This is for the negative 9V rail for the serial ports.  I have circled it in red in the attached photo.  If your are interested C31 is a 100uf 25V cap as well for the positive 6.4V rail for the serial port and C37 is 330uf 16V cap for the 5V rail if I remember correctly.  C42 is a 220uf 25V cap for the 12V main input rail.