so, if we assume Ryan is correct, you can verify this by putting about 5 volts into the barrel connector on the Arduino and then verify that there’s no voltage on any of the small pins of the regulator. be careful not to bridge the pins when you measure voltage on the regulator or you could blow it up…
if leslie is correct, you can measure resistance across the yellow fuses. it should be near zero.
the way I troubleshoot this when something shorts is to put correct voltage into the input (Green connector). measure voltage at that point (and current if you are able), make sure it’s in spec. then move to fuses, then look at the diode just past the fuses. and start working your way through the circuit to see where voltage goes away.
things that tend to die for me in rough order are: arduino regulator, arduino diode connecting the regulator to usb (at least, I think it’s a diode), ramps fuses, ramps diodes that bridge boards (its underneath the x axis driver). and, to find it, as I said, I chase the voltage around the board to see where it quits.