Printer Disconnects Mid-Print

What is the problem?

Octopi disconnects from the printer mid-print

What did you already try to solve it?

changed from 2.5a to 3a power supply, new high quality usb cable, reflash sd card

Complete Logs

octoprint.log, serial.log or output on terminal tab at a minimum, browser error console if UI issue ... no logs, no support! Not log excerpts, complete logs.)

see line 436
octoprint2.log (3.1 MB)
Error: SerialException: 'device reports readiness to read but returned no data (device disconnected or multiple access on port?)'

Additional information about your setup

OctoPrint version, OctoPi version, printer, firmware, browser, operating system, ... as much data as possible

Running the newest Octopi version as I just reflashed it today and the issue persists. Running an Ender 3 with stock firmware and Pi 3B. I start a print and the Pi will disconnect from the printer, sometimes after a few minutes, sometimes after a few hours. The only thing that changed when the issue started is I had moved the printer from my house to the garage

That's unfortunately a common thing with some Ender 3s. Those printers are prone to EMI.
Since you already got a quality usb cable I can only suggest to check for other devices that could emit EMI. That could be for example a microwave, a washing machine or vacuum cleaner.
I had also good results with tin foil - wrap the mainboard box in it (but don't cover the fan venting holes)

1 Like

Are you saying to wrap the Pi in foil, or the Ender's board? The garage has a minisplit heat pump, mini fridge, and fluorescent lights. I tried moving the printer to the opposite end of the garage with no change. I'm gonna move it to the house and see if it changes anything but will ultimately need to find a solution for the garage for noise reasons

The enders board.

for me it was them. Every time I turned them off the connection was interrupted

I've finally narrowed down the problem. I unplugged my mini fridge and my Pi will now stay connected to the printer. I'm guessing the fridge draws too much power or creates interference somehow. Now, is there a way I can remedy this? I've already tried using a UPS with the Pi unsuccessfully. Would a UPS HAT for the Pi work better?

Electro Magnetic Interference, EMI is the most likely cause. A shielded USB cable with ferrite cores could possibly help. A UPS for the RPi and the printer also could possibly help.