I have a Dell Latitude E5570 that will charge on my docking station and the battery will hold a charge. However when I plug in the power supply directly into the laptop the LED light turns off. I have opened up the laptop and disconnected the power port and plugged in the power supply, the LED light remains on. It turns off when I reconnect to the circuit board. I have replaced the power supply. I have updated the BIOS, ran diagnostics and all has passed. Is it possible the motherboard could be bad if all diagnostics have passed and it works just fine on the docking station and on the battery as long as it is charged? I am hoping there is an easy fix.