Mysterious "Lost communication with MCU 'mcu'" error began occuring out of the blue
Hey Klippers,
I have a v-core 3.1 500 that was operating flawlessly for ~200H of printing, when I began getting the "Lost communication with MCU 'mcu'" message mid-print, with no accompanying klipper / mainsail error message in the console. After about halfway through this entire past week of troubleshooting, the error would occur while the printer was sitting idle. A time or two the Mainsail console reported "Internal error on command:"G1"".
Here is a brief description of my initial config, followed by the troubleshooting steps I've gone through to no avail.
Dedicated 30A 110v circuit to printer, for 4x 500w heater pads powered via SSRs, 24v PSU
BTT Octopus 1.1
rPi 3 v B powered via UART from the Octopus, connected to the Octopus via USB
Standard Klipper / Mainsail install from rPi imager, using Mainsail OS and then updating everything through Mainsail
My initial thoughts were that the rPi was undervolted as I previously experienced issues with the canakit AC adapters, so I started with the following:
Began with Orcaslicer, tried prints with Cura and Superslicer to the same result (not a slicer/gcode issue)
Installed dedicated 5V PSU for the rPi
Installed new "gold plated" USB A to C cable for the rPi > Octopus
Installed new high quality 64gb Sandisk microSD cards for both the rPi & Octopus
re-imaged the rPi with Mainsail OS, without updating Klipper
re-imaged the rPi using KIAUH
Flashed the MCU via USB
Flashed the MCU via microSD technique
Replaced rPi 3 v B with another known working rPi 3 v B
Replaced Octopus 1.1 with another brand new Octopus 1.1
Isolated the 24v & 5v PSUs for the rPi / Octopus on a separate dedicated 20A circuit
Additionally I should note that I have fans on the stepper drivers, Octopus, & rPi.
But I am still getting the random Lost communication with MCU errors! I am at my wit's end. I am hoping I am overlooking something simple here.
Any insight would be greatly appreciated. A few klippy & moonraker logs attached.
2 Replies
Any resolution on this? I've began to experience the same after about 2 years of running without such an issue
Kind of wondering if it's symptomatic of a board that is about to die?
I had such an issue when I added a separate PSU for RPi. My EBB36 would regularly loose connection. I fixed it by connecting all ground terminals between PSUs and wiring a ground to the USB cable (which I did not have before).