I was using a Raspberry Pi Model 3B in my smart home system for about half a year now, which means it was powered around the clock - without any issues.
Yesterday, both of my living room lights (one of them controled using a relay) went crazy and randomly turned on and off. I immediately unplugged the Pi from the power grid and waited for a minute. Then I re-powered it and both lights went crazy just in the same moment when I plugged the power adapter to the grid, which is obviously caused by a faulty GPIO interface.
Then I realized a smell of hot plastic and saw smoke - the power cable of my Pi was melted (well, my power supply has a current limit of 4-5amps and I should have attached a fuse in series to it, I know...).
I almost burnt my fingers when I tried to hold the Pi in my hands and the processor and SD card slot were too hot to touch. The SD card cracked and when plugging it into another Pi, it also produces so much heat that you can smell it.
The curious thing about it is, that when using another SD card, the Pi still works (I get screen output and it even boots up), but the processor gets so hot just 2-3 seconds after powering it (you can not put your finger on it), even without an SD card, so it is not caused by the processor load.
I read much about overheated and cracked SD cards but now, but this time, it is probably not just an SD card, but also a faulty Pi.
Did anyone of you experience this problem? Does your Pi 3B get hot without having an SD card inserted?
And do you have any ideas how to prevent this fault in the future? This seems very dangerous to me as the cable could have cought fire and I even read about burning SD cards (with appropiate power supplies).