i get the ..I guess famous Serial connections Error on my Ender 3 with Marlin 2.0.7:
Unexpected error while reading serial port, please consult octoprint.log for details: SerialException: 'device reports readiness to read but returned no data (device disconnected or multiple access on port?)' @ comm.py:_readline:3860
Please see OctoPrint randomly loses connection to the printer with a "SerialException" - FAQ - OctoPrint Community Forum for possible reasons of this.
Changing monitoring state from "Printing" to "Offline after error"
Connection closed, closing down monitor "
I already checked the PI for undervoltage but there is no such Icon or Issiue in the logs (I had these problems in the past but it never led to an serial connection problem) Further when I print via octorpint in a virtual maschine it does it without any problem, therefore I can rule out an broken cable or something with the printer itself.
Of Course my cable is "modified" and the +5V pin is covered mit electrical tape.
I am not sure what else to check. I already reinstalled Octoprint on an fresh SD Card and I am without a clue.
I think still this could be a power Problem , because the PI is powered by a buck converter in the micro USB port.
Can I add an capacitor to rule out any fluctuations with the power supply?