Printer Model: Sidewinder X2
MCU / Printerboard: Sidewinder X2 / RPi3b
klippy.log …
klippy.zip (1.3 MB)
Never had this before… after printing 2+ hrs (of a 3 hr print) Klipper died. OctoEverywhere reported… X2 Print Error 
Error: Klipper Disconnected
I could not get it to restart without unplugging the RPi.
For the error see Timeout with MCU / Lost communication with MCU
[mcu]
serial = /dev/ttyACM0
Although not related to your error, this is not the recommended way to do it, since this can change on each new connection of the printer board. See Installation - Klipper documentation
Help Please!
It just crashed again after not printing for 2+ days – after only 3 mins. A few days ago I did multiple prints including three 4 hour prints in a period of 2 days, 2 of them back to back.
Please help me figure this out…
@Sineos I changed that setting, definitely not the issue 
As you have experienced yourself: This often is an intermittent error and hard to pin down. As stated in the link above, it always traces back to some hardware instabilities. Unfortunately, I cannot give any more meaningful advice.
@Sineos Happened again today. This has to be a bug in Klipper… this never happened for the first few months I used Klipper but not for the past month or so I get random disconnects, no error, just disconnected. And since Klipper doesnt have any way to easily restart (I dont know why it doesnt just log where it was a we can simply say ‘start from last log entry’) I’m hosed
I’ve printed 12+ hours, multiple prints, without an issue then boom, poops the bed.
To my best knowledge, all related cases that have eventually been solved have been caused by external influences and not by a bug in Klipper.
If there was a systematic bug then most likely this place would be full of similar reports that cannot be solved.
As it is not the case, I still assume that is is something related to your setup.
Please give more details about your printer/setup.
Is the printer modded?
What is connected to the RasPi?
What else except for Klipper is running on the RasPi?
Do you maybe have another µSD-card and time to set up a new Klipper instance from scratch?
Are all cables from and to the RasPi good and do not have a loose contact?
Do you use the original RasPi power adapter or is it maybe connected via a buck converter to another power source?
Is cooling of the RasPi and the MCU sufficient?
This is still a mystery but has not happened since my last post. While troubleshooting I change many things…
– power supply unit (tried several)
– USB plug gong from RPi to Sidewinder X2
– moved web cam usb to different port
– unplugged LED light from X2’s USB port, put on dedicated usb phone charger
After all those changes it still happened SO I changed everything back to the way it was prior to the problem starting… it is not happened for a while and I during that ‘good period’ there have been several Klipper and other software component updates. I think it was something software related.
Maybe it looked like hardware but I do not think it was since i’m back to the same exact setup which ran for 6 months on Klipper and never failed until a week or so before I posted here.
I’m now back to the exact same hardware config… and its been 2+ weeks of printing without a disconnect.
Nothing changed in Klipper that would influence this.
A charger is always a bad advice when it comes to constant power delivery.
A charger is a … charger. Nothing more.
Have you tried short and high quality USB cables with ferrite beads?