If the power supply unit LED does not light up or the System Status is displaying a failure, it may indicate that there is a problem with the power supply.
Perform the following to identify where the problem lies :
IMPORTANT : Ensure all the necessary safety precautions are taken before working with electrical components.
NOTE: When you are looking at the left and right power supply status' under the "System Status" page,left and right is referenced as if you were looking at the device from the front panel. So when you are looking at the power supplies physically from the back the left and right will be swapped. See the below images as a visual representation of the explanation above.