My ARTY works well when powerd by USB port(J10 connected, J13 set to USB).
But it can not power on when I plugin a 12V adaptor into J12(J10 not connect, J13 set to REF).The voltage between J13 REG pins is 0V and voltage around R245 is 12V. No chips fever.
I tested some voltages on around the IC12 with the 12V adaptor plugined in, as the following.
My ARTY is a new one, maybe the IC12 damaged?