Seagate ST43401N/ND, ST43402ND user manual LED indicator Function

ST43401N/ND, ST43402ND User’s Manual, Rev. B			45
Table 6. LED functions for ST43401N/ND drives
LED indicator	Function
Drive control board
Ready LED	This LED flashes during the power-on sequence until
(green)		the discs are up to speed and the heads are loaded.
	It is on steady with power-on complete, assuming that
	there are no fault conditions.
	It flashes during a power-off sequence. This occurs
	when the drive receives a Start/Stop Unit command
	after it has once been started.
Heartbeat LED	This LED blinks when the SCSI controller is operating
(green)	properly.
	If the LED is constantly on or off, it indicates one of two
	things:
	•	The SCSI controller is not functioning properly.
	•	The SCSI controller is executing diagnostics and
		should be ready in a few seconds.
Active LED	This LED socket is provided for units which do not use
(socket)		the optional bezel. When the active LED is inserted
	into this socket, it indicates SCSI command activity.
	When it is on, the drive is executing a SCSI command.

When it is off, the drive does not have a SCSI command to execute.

Optional bezel on drive Active LED

(color unspecified)

This LED indicates command activity by the drive. When it is on, the drive is executing a SCSI command. When it is off, the drive does not have a SCSI command to execute.