Power Led Is Off - Allied Telesis AT-9448Ts Installation Manual

Power LED is Off

Check the PWR LED on the front of the switch. If the LED is off, indicating
that the unit is not receiving power, do the following:
Make sure the power cord is securely connected to the power source
and to the AC connector on the back panel of the switch.
Verify that the power outlet has power by connecting another device to
it.
Try connecting the unit to another power source.
Try using a different power cord.
Check that the voltage from the power source is within the required
levels for your region.
AT-9400 Stack Installation Guide
85