When I connected my brand new Ender 3 v2 into my PC via USB port ( printer was turned off a spark came out usb?? There was also a humming sound so I quickly removed the cable, what do I need to do so this doesn't happen again???
Turned it off immediately and messaged here to see what I did wrong as well as to get help for what I should be doing???
Your printer was turned off and you connected to your PC via USB? In this case the 5V voltage of the PC tries to power the printers main board but does not deliver enough current via the USB. This can result in such sparks and humming noise. So I would turn on the printer before connencting to the PC. In addition to this I would recommend to isolate the +5V line of the USB cable. Some do it but here you need some experience with electronic devices...
If your printer was turned ON before connecting the USB but still you will get sparks and humming noise I would say there is a problem with your power grounding in your house. I don´t know where you are living but in Europe it is possible to turn the 230V power plug 180°. This often solves the problem with the sparks but however does not solve a possible grounding problem!
That you this information was very helpful, my printer was turned off and both items where plugged into different grounded powerboards, in Australia and the house is 50 years old so not having my hopes up about having decent grounding from these Power points