Hi Guys
Having an issue with prints cancelling midway
I’ve had my prusa i3 for about 3 months now, and probably 30% of all prints fail due to cancellation. The printer just stops, keeps up the temperature, but i cannot move it in the Host software.
What I’ve done so far:
Plugged into powered USB hub reading 4.85v at arduino, therefore the issue isn’t with arduino lacking power.
Changed host from repetier to octoprint, therefore not a host issue.
Used the same sliced file twice, the first print cancelled, the second didn’t, therefore not a slicing error.
Power supply is Chinese 12v 300w and rarely the fan turns on, therefore not an issue with drawing too much current.
This is the error is recived in the host after the print cancelled:
Unexpected error while reading serial port: SerialException: ‘device reports readiness to read but returned no data (device disconnected or multiple access on port?)’ @ comm.py:_readline:782
Changing monitoring state from ‘Printing’ to 'Error: SerialException: ‘de…’
I’ve Googled everything possible, no conclusive results.
Im running marlin, and i really hope you guys can offer suggestions of what to try next.
Your still loosing the USB signal from the PC to the printer. How long is the USB cable? Even though you are plugged into the powered USB hub that can not guarantee the signal strength or connection.
I am guessing you are using RAMPS. If you unplug the USB the board will still be powered up from the power supply, provided you didn’t remove the diode. I would suggest you try a different USB cable. New would be best but a different one if you happen to have one.
Running at 57600 Baud @Daniel_Fielding
Thanks heaps for the advice @Wayne_Friedt , i have switched USB cable and trying a long print now so we will see how it goes
I don’t tend to use USBs less than 2 feet due to this issue. If you require a long cord, use a microsd card (if your board has a port for that) and run the job on that. No more failed connection.
I had that serial error on my Mendel 90 when the PSU terminals needed tightening. Not sure how your Prusa works but the arduino in the Mendel is powered from the PSU, if it’s powered from the USB on the Prusa then a quality cable will be important as has been said.
I’ve seen appliances plugged in near the printer switching on/off cause enough of a spike in the power to make the USB chip brown out or lose timing or something. I even heard that one person could repeatably get his USB connection to die from the EMP of an old camera flash bulb going off near it (after a family member accidentally caused this to happen while taking a picture of the machine).
@Daniel_Bull may be right about the power terminal. Same error happened to me with the Printrboards but my power terminal was semi burnt, turning it into a weak power connector. The PSU will try to compensate this poor power transfer by pumping more current through the board and my mosfets became scorching hot. I replaced the power terminal with a fresh one and installed a fan to actively cool the board. No problems ever since.
