(03-Apr-2021, 10:28 PM)voodoo614 Wrote: Not sure what you mean by HR? But you can check to see if the ground pin is shorted with the 3.3V in the MCU. Also look for solder bridge or burnt component on the FC.

sorry, i meant FC, I was wrong

on the FC there are no punctured components and I checked that all the ground are grounded and the 5V have energy and it seems to me everything is fine, I can't explain it. The only thing that is really out of place is the MCU which always gets hot even when attached to the pc with cable without its battery and even if it is without ESC.

(05-Apr-2021, 11:32 AM)gianlucafava Wrote: sorry, i meant FC, I was wrong

on the FC there are no punctured components and I checked that all the ground are grounded and the 5V have energy and it seems to me everything is fine, I can't explain it. The only thing that is really out of place is the MCU which always gets hot even when attached to the pc with cable without its battery and even if it is without ESC.

I am asking you to check the ground and 3.3V on THE MCU itself. Not the supply voltage. MCU usually take 3.3V, so you also need to check the 3.3V regulator. if you are checking supply. But it is likely getting power because it is getting hot. Again, a hot MCU is a dead MCU.

Since its already dead,

grab your USB microscope, and probe the MCU power, reset etc pins. Usually its the 5V LDO that dies or ceramic cap.

Next grab BGA flux, apply generously, and with 700C on hot air gun, reflow components on the board.

If that doesnt work, and you are sure no shorts, hot air remove and replace MCU from donor board.

Easy.

(06-Apr-2021, 04:45 AM)romangpro Wrote: Since its already dead,

grab your USB microscope, and probe the MCU power, reset etc pins. Usually its the 5V LDO that dies or ceramic cap.

Next grab BGA flux, apply generously, and with 700C on hot air gun, reflow components on the board.

If that doesnt work, and you are sure no shorts, hot air remove and replace MCU from donor board.

Easy.

since I don't have these tools and skills, I prefer to buy a new FC so I avoid problems.

Thank you so much for helping everyone