AC input

NOTE:

In the following subsections, the system status LED collectively refers to both the system status LED on a 5120 EI switch and the power LED on a 5120 SI switch.

If the system status LED is off, an AC input failure has occurred. Verify the following items:

•The AC power cord is securely connected to the switch, and the AC-input power receptacle on the switch and the connected AC power outlet are in good condition.

•The external AC power system is correctly working.

•The operating temperature of the switch is in the normal range, and the power module has good ventilation. Over-temperature can cause the power module to stop working and enter the protection state.

RPS DC input

If the system status LED or RPS status LED is off, an RPS input failure has occurred. Verify the following items:

•The switch is securely connected to the RPS.

•The RPS is correctly working.

•The operating temperature of the switch is in the normal range, and the power supply has good ventilation. Over-temperature can cause the power supply to stop working and enter the protection state).

Concurrent RPS and AC inputs

1.If the system status LED is off, the AC power supply and the RPS both have an input failure. Verify the following items:

{The AC power cord is securely connected to the switch, and the AC-input power receptacle on the switch and the connected AC power outlet are in good condition.

{The external AC power system is correctly working.

{The switch is securely connected to the RPS.

{The RPS is correctly working.

{The operating temperature of the switch is in the normal range, and the power supply has good ventilation. Over-temperature can cause the power supply to stop working and enter the protection state.

2.If the system status LED is on but the RPS status LED is steady yellow, an AC input failure has occurred.

Verify the following items: