- If you are looking trough front ventilation holes, just below the left (blue) USB port, you should see a LED. This LED is located on the board bottom side. Verify that the LED is illuminated.
- If the LED is not illuminated, check if the Power Supply isn't disconnected. Try to connect replacement Power Supply, however be aware that NUC may reach 230W at full power consumption.
Be aware that the Standby LED has low light intensity. Please verify that in dark environment you can't see light illumination on the board bottom side (just below the front blue USB port).
Verify also that you have power in the wall receptacle. And yes, try to use other Power Supply Adapter.
If still your NUC will not power ON, probably the Power Input Circuit failed and you need open request to RMA in order to replace your NUC under warranty: https://supporttickets.intel.com/warrantyinfo?lang=en-US
We found another support ticket where you describe the same issue reported on this thread. It seems that the unit was replaced and the new unit is up and running.
If you need further assistance, please let us know.
Intel Customer Support Technician
A Contingent Worker at Intel