MCU lost communication - Creality 4.2.7 + RPi Zero 2W

Basic Information:

Printer Model: Ender 3
MCU / Printerboard: Creality 4.2.7
Host / SBC: Raspberry Pi Zero 2W
klippy.log:
klippy (2).log (2.2 MB)

After getting another ender 3 I thought I would save some money and go for the RPi Zero 2W rather than another RPi 4. I’ve never had any issues with the Pi 4’s.

For whatever reason I seem to be having some serious problems. It performs exactly like the RPi 4, only using about 4% of the CPU and never more than half the ram, yet I have MCU lost connection issues.

The disconnects behave really weirdly. Sometimes I’ll try print the same item several times and the printer will disconnect at a similar place. Then it will last longer on another print etc.

It disconnects even when idle, but its hard to say how often.

Sometimes I’ll try a fix and it will be better, but then it will start happening again.

Thing’s I’ve tried:

  • Wiggling the cable and checking if it disconnects (It doesn’t)
  • Complete reinstall of Klipper + Mainsail
  • Tried with a different printer, also running a 4.2.7 board
  • Swapping from by-id to by-path in the serial section of the config.
  • Masking Modem manager
  • Reflashing printer firmware

Removing modem manager seemed to fix it for around 12 hours, and I thought it was all sorted, but it’s back again.

I just cannot wrap my head around what could be going on. It’s definitely a Pi issue, the printers work fine with the other Pi’s.

I would really appreciate some help. The RPi Zero 2W seems great, it’s much cheaper and plenty powerful so I’d love to be able to use it.

Thanks.

You’re getting the error

b'Got EOF when reading from device'

Try the suggestions outlined here:

I have read through this guide, but I’ve tried every one of those bullet points.

Everything is brand new. The cable is short, the connections are solid.

I have wiggled the cable pretty thoroughly while the printer is printing with no issue.

So I’m not quite sure how it could be a problem with any physical connections.

The one thing you haven’t mentioned is power.
How are you powering your Pi Zero 2W?

As in, What is the power supply rating and how it is connected?

I’ve got the standard raspberry pi power supply designed for this board, also brand new.

It’s a 5.1V 12.5W power supply. I have the cable away from everything to avoid any interference.

The usb cable I have is a usb micro to usb micro.

https://www.pbtech.co.nz/product/CABSTT3131591/StarTech-UUUSBOTG8IN-USB-OTG-Cable---Micro-USB-to?qr=GShopping&gad_source=1&gclid=Cj0KCQjwu8uyBhC6ARIsAKwBGpTpbkuIZOFYCearT0X_IuM1v1X0wbUVkvxabWwzkdGP6GYhcJjT_ZIaAqTCEALw_wcB

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