Octoprint Connection Issues - Googling Fixes - Breaking More

PROBLEM: Connection issues with Monoprice Select Mini V2 + Raspberry Pi 3 + Octoprint

After a year of printing with no issues, I started to run into problems and googling fixes have probably broken it further to the point that I can't connect Octoprint to my printer. I'm a newbie when it comes to the set up of printing with the raspberry pi/octopi and Octoprint (my apologies in advance).

A few weeks ago, I had a print stop mid-print. Octoprint stated that the connection was lost (this 'is it still alive? message). Resetting computer, printer, raspberry pi, octoprint seemed to fix the issue at first... but then it kept happening. Googling pointed to a potential power issue with the pi. I upgraded the power supply to 5.25v. Problem seemed to go away for a few prints. Then popped back up.

Fast forward to a vacation last week, I unplugged everything. I'm a Nervous Nelly. When I returned, I plugged everything back in and I started getting failure to connect due to serial port messages (Failed to autodetect serial port, please set it manually). Googling pointed to adding a serial port under Additional Serial Ports. That didn't help. I moved cables. Tried running in safe mode. Tried reinstalling the Mayan/Monoprice Connection Fix plug in. At one point, something worked. I connected and got a print started.. it stopped halfway through. I just can't see what changed in the last month made this issue pop up. I've printed over a hundred prints with this set up and it's all gone perfect.

PROBLEM SOLVING ATTEMPTS:

  • Restarting literally everything (computers, printer, wifi, etc)
  • Replacing Pi power supply
  • Running in Safe Mode
  • Unplugging logitech camera from Pi
  • Reinstalling Monoprice Connection Fix
  • Adding AMA0 additional serial port (didn't help.. since removed it)
  • Replaced micro usb cable from printer to pi

CURRENT SET UP (Please let me know if I am missing anything from this list):

Printer: Monoprice Select Mini V2

Computers: Macbook to Raspberry Pi 3 Model B Rev 1.2

Octoprint: V 1.3.12 (is this the right version?? looking this up made me think otherwise....)

Octopi: V 0.15.1

Webcam: Logitech V-U0018 Webcam (currently unplugged from pi)

Third Party Plugins (disabling made no difference):

  • Automatic Shutdown
  • DisplayLayerProgress Plugin
  • Dragon Order
  • Emergency Stop Button
  • Extra Distance Button
  • Floating Nav Bar
  • Mayan/Monoprice Connection Fix
  • NavBar Temperature Plugin
  • Octolapse
  • PrintTime Genius Plugin
  • Tab Order
  • TemperatureFailsafe
  • The Spaghetti Detective *this is the only plugin in the last month that I've added... I disabled this at first to see if it was causing issues)
  • Themeify
  • Webcam Tab

I realize that this could be any number of issues... so thank you in advance for any suggestions. I've attached logs but not sure if I picked all the correct ones. I've now turned on serial logging... so I only have that from today.. which I would say is the most broken it has been.

octoprint.log (492.6 KB) serial (1).log (1007 Bytes)

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Serial port list: []

It looks like the underlying operating system is not even seeing your printer. Do the following please:

  • SSH into your Raspberry Pi (if you are on Windows you can use Putty for this). Default user/password is pi/raspberry
  • Unplug your printer from the Pi, plug it back in and power it on
  • Run dmesg
  • Share the last ~50 lines

There should be something in there that says something along the lines of a new device having been detected and hopefully also some information on what kind of device and if said device exposes a serial port. That's what we are looking for here to determine if your printer is even still recognized by Linux.

You might also want to try a different USB cable between Pi and printer to rule that out as the culprit (things can break).

Also just let me say, thank you so much for this very thorough and encompassing opening post. It's rare that someone puts in this much effort to describe their issue so precisely! :+1:

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Thank you for the help!! So it's a good news, bad news situation. I worked to get SSH enabled on the pi but I also switched the cord BACK to the original one and it started working again... I got one print done and the next print disconnected at 15%. I'm guessing the solution is still try another cord.. maybe there was something wrong with the new one??

I've attached the new log in case it will help... octoprint (2).log (72.9 KB) and here are the last few lines of the serial log.

2020-01-29 11:46:03,949 - Send: N110 G1 X39.759 Y13.03 E3.3236386
2020-01-29 11:46:03,954 - Recv: ok N110 P0 B15
2020-01-29 11:46:03,958 - Send: N111 G1 X39.443 Y14.673 E3.38766
98
2020-01-29 11:46:04,299 - 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:2793
2020-01-29 11:46:04,307 - Please see https://faq.octoprint.org/serialerror for possible reasons of this.
2020-01-29 11:46:04,339 - Changing monitoring state from "Printing" to "Offline (Error: SerialException: 'device reports readiness to read but returned no data (device disconnected or multiple access on port?)' @ comm.py:_readline:2793)"
2020-01-29 11:46:04,358 - Connection closed, closing down monitor

Again, thank you so much for any insight!

Brand new cable installed... disconnected after a few minutes with this error:

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:2793
Please see https://faq.octoprint.org/serialerror for possible reasons of this.
Changing monitoring state from "Operational" to "Offline (Error: SerialException: 'device reports readiness to read but returned no data (device disconnected or multiple access on port?)' @ comm.py:_readline:2793)"
Connection closed, closing down monitor

:frowning:

So after all my changes... I've come to the conclusion that any movement of the micro usb port causes the serial port connection. Any vibration while printing is probably the reason the print stops. I'm wondering if switching the cable to one with a ferrite core would fix this issue or if this is a bigger issue with the printer?

Thanks again..

It could easily be that the micro-usb connector on the board has gone “wonky”. A micro-usb cable requires some force and wiggling to come free, and depending on the quality of the board, some solder-points could come loose which could make the connection break depending on different “pull” or pressure on the cable.

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Robo 3D determined that an entire batch of Raspberry Pi 3B computers (a hundred or so) came in with microUSB power connectors that were quite loose, for what it's worth. By this, I mean that any plug put into them would be loose.