I have a fan that I was trying to plug into my Raspberry Pi 4 (4gb) (Deskpi lite addition from "Geeekpi")
I was plugging it in, but didn't realize I accidentally plugged the red/positive wire into the "GND" pin, and then the black/negative wire into the "5v" pin.
I turned on the Pi after I plugged it in, thinking I would be done. I didn't hear it spin to life so I turned the device back off. I changed the connection to red to 5v, and black to GND, and turned it on.
The fan spun to life, the lights on the pi did the blinking they normally do, everything looked normal. It showed the "splash screen" that says "Welcome to the Raspberry Pi desktop" on my display for a couple seconds, changed some words in the bottom left like it were to boot up, the screen went off and then back on to a black screen and stayed like that. (You could tell the monitor went off but came back because even if it's black it still emits light)
Could the fan "failed modification" be the problem? I'm really worried, I just got this Pi a few days ago, not sure if warranty would cover it...
Thanks for any help.