Vin connected to 9V and USB cable connected to PC, and then I've made a mistake and got a short circuit between 5V Output and GND. The short circuit is still there, even if I cut off the power supply. I thought the Voltage Regulator (LM2734) or some Diode might be damaged because of the overload, but I am not very sure about it, hat someone got the same experience?
I shorted my Mega and blew the regulator. Take a close look at it and see if you see any signs of damage.