Ender 3 V2 - Fried Mainboard via USB (?!)

hi all,

i'm pretty new to the 3d printing world and don't know what to do... i just seemed to have fried the mainboard on the ender 3 v2.

i connected my PC via USB to the ender and boom - the printer restarted, beeped and i only got a black screen. a bit of smoke (and stink) came from the mainboard area.
i've now read that this is "common" for this printer when you use buck converters and connect the usb cable that has a 5V line. learned something for the next time and will cut the 5V line from the usb cable.

still, i have a fried mainboard at hand ;)
- is there an easy fix? just a cheap part, maybe even just a fuse to replace?
- otherwise, i'd need to buy a new mainboard. does it make sense to buy a version 4.2.7 (now 4.2.2)?
- is is usual for this particular event that other parts got fried in the process? - maybe my screen, too?

maybe you can help me. i really want to print again, soon ;)

thanks and cheers,
narf

ok, bought a board for a premium price with premium shipping which came today. installed it - smoke... f.ck :/ that hurts...

does anybody know this error better? what usually breaks, too? there must be a short somewhere. i won't do many trials because it gets too expensive for my taste -.-

I have had problems like this in the past, though I was lucky it only rebooted my computer.
Can not explain exactly why this happens. Most likely a voltage differential or a floating ground.

Though found that if you plug the USB into the 3D Printer controller when powered on this can happen.
However if you plug in the 3D Printer Controller then power on the 3D Printer it does not happen.
OR
If you use a laptop that is on battery this never happens.

thank you for your reply. and yes, i already stripped a usb cable of its 5V line, so that won't happen again. right now, i'm having a defect printer that needs repair and i'm not sure where to start. a new mainboard was destroyed instantly (without usb), so there's another device that has a short circuit. is it the display? is is the PSU? is it one/all of the stepper motors, is it CR-touch, ... is it a combination? i'm pretty close to just buying a new printer -.-

hi all,

just a quick update for everyone that may search for similar incidents: my printer is now working again. the problem was my display.

you could feel it when you open up the display box. (remove power cable first.) for me, the top left corner was pretty warm (maybe like 50 degrees) after a few seconds of power.

after i changed that for a used one, everything worked again. well, "everything".. i figured that not only my printer was destroyed but also all the onboard usb connectors on my pc. luckily, the rest of the mainboard was left intact. so i just bought an external usb controller (for pci-x).

soooo, in conclusion: never ever plug your 3d printer to any other device by usb, unless you've cut the 5V wire first. and the destroyed parts fall under warranty, so you get them from the manufacturer - when you have time to wait a month for shipping from china :)