The 12v goes from the power supply threw the 5a poly fuse threw D1 to the mega via the Vin pin
On the mega it goes threw the voltage regulator to generate 5v.
Firstly check you have D1 installed (its hiding under the X and Y pololu modules)
But most likely you have killed the 5v regulator on the mega, as its easy to do, plugging in your 3 pin endstops in backwards will do this every time.
To test this simply remove the ramps and power the mega from the dc input jack 7-12v, and check your getting 5v on any 5v pin.
Edited 1 time(s). Last edit at 08/28/2016 01:53AM by Dust.
