Cause - Improper plug-in procedure and/or the DC-In pins of the External Power Supply have become recessed
1. If the PC will not turn on but the External Power Supply's LED is lit (green or blue), first ensure the unit is being plugged in correctly. The safest way to plug in the PC is to plug the DC end of the External Power Supply into the unit, followed by the AC end from the wall into the External Power Supply.
2. If this process is being followed and the unit still will not turn on and/or the machine is turning off at random, check to ensure the 4 pins on the DC end of the External Power Supply do not seem recessed. For normal operation these pins should be almost to the top of the connector, but just barely below it (PSU FIX2.JPG).
3. If it seems the pins are further down than those in the picture, adjusting them so that the pins are in the right position is required. Take the DC-IN connection in one hand, and the choke of the External Power Supply in the other. Simultaneously pull down on the DC-IN locking connector while pushing up on the choke until the pins are correctly aligned. Please see PSU FIX.JPG for an image of this process.
4. If the pins are properly aligned to the DC connector, try a different External Power Supply to see if the issue remains with the unit or follows the External Power Supply.