Motherboard burned down after Plugging in a second Printer into Rasberry Pi 4
here comes a strange one and I really do not know why that happened.
Here is the scenario:
I was running a Creality Sermoon D1 and an Anycubic Mega S on the same Rasberry Pi 4 RepServer for quite a while without any problems.
Today I exchanged the Anycubic with a Creality CR10 V2 and got some nice firework and smoke from the Sermoon D1.
The Sermoon was plugged in and running, the CR10 was powered on when I plugged in the USB cable into the Pi (that was not a problem with the Mega S before).
I have disassambled the Sermoon and found that the burning had started on the mainboard where the USB was attached. The Pi is running as there was no problem at all and the CR10 is also performing from SD Card.
Now my question? Why? How can the CR10 send so much current via USB cable, through the unharmed Pi into the Mainboard of the Sermoon D1 sothat it burned down?
Can anybody help? Because now I am affraid to attach any of the systems to my laptop or the Pi again.
Thank you in advance for any suggestions.
The only thing that is connected through all devices is mass signal. I once fried a usb port due to having phase on mass (defect in PSU). Since the D1 is the old one working for a time I would normally guess the error comes from the new CR10, also it might just be bad luck. Anyhow back to mass - all need to have potential. If no power plug has ground and they are all in same phase that would normally not happen I think. I would check with a multimeter how much voltage your usb on cr10 has plus vs mass. Also eventually check for cables having contact to printer mass (housing) and housing having contact to usb connector.
I'm no electrican, so can not say how good this idea is, but I know that some printers had contact to ground that should not exist. Be it a loose cable or badly wired. And since you had some wrong voltage on one printer it must come from something. Once you measure a wrong voltage between mass and 5v in one combination I'm quite sure you have the problem and just need to find where it comes from.
Don't think that is the problem. But did you install a new printer firmware on the new board? Also depending on your config, the port name might be different if it was by id.
Question is if the driver module is not loaded or just port does not see it (defect from last burnout?)
So first check if the usb is working. Unplug und run
then plug in and run again. It should then show a new device you connected. If so usb port should be ok and you know what hardware it uses.
With that you might be able to google which driver should appear in
and if it does not you can add it with insmod. Then serial should show up.