So here's a first: I might have killed my RPi 3.
I was working last night on a GrovePi robot and I left my RPi 3 plugged into the wall socket overnight.
In the morning I discovered it had shut down. So I rebooted...
I have a USB power meter attached to the USB cable power source and it was showing high current draw, over1.5 Amps and it was very very hot. I re-image the SD card thinking the OS might have crashed somehow.
It now booted but it was instantly very hot and after a few minutes it shutdown to protect itself. I used a IR thermometer and found that it was actually the power circuit that was overheating and not the CPU itself, it was over 100 Celsius.
Even booting without anything plugged(no sd card) in it still heats up like crazy.
Now, I read about polyfuses and that once blown the resistance goes up like crazy and maybe this is what is happening, it would explain the high current draw, I guess. But the voltage drop over PP3 and PP7 is 4.93 V so pretty normal?
Also, where is the fuse located on the RPi 3? I see a fuse marked F1 on the back, near the microUSB port.
Checked the voltage again and it's 4.38 now so it sounds like a blown fuse?