I have built my prusa i3 clone and everything was working fine. until I saw some problem on Y axis endstops. I have mounted the endstops by inserting the screw in one of hole in the endstop. when I clicked the home button the axis came toward the endstops and sorted the endstop pin with the screw to the ground. and suddenly a lot of smoke came out of the endstop. I immediately unplug the power. but when I tried to connect the printer through USB it stopped recognizing it. what can be the issue? how can I trouble shoot it?