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.