Light path diagnostics

Light path diagnostics is a system of LEDs on various external and internal components of the server that leads you to the failed component. When an error occurs, LEDs are lit along the path of the front panel, the operator information panel, then on the failed component. By viewing the LEDs in a particular order, you can often identify the source of the error.

When LEDs are lit to indicate an error, they remain lit when the server is turned off, provided that the server is still connected to power and the power supply is operating correctly.

Before you work inside the server to view light path diagnostics LEDs, read the safety information Safety and Handling static-sensitive devices.

If an error occurs, view the light path diagnostics LEDs and look at the operator information panel on the front of the server.

If the check log LED is lit, it indicates that an error or multiple errors have occurred. The sources of the errors cannot be isolated or concluded by observing the light path diagnostics LEDs directly. A further investigation into IMM2 event log or system-error log might be required.

The following illustration shows the operator information panel on the front of the server.

Figure 1. Operator information panel

The following table describes the LEDs on the operator information panel and suggested actions to correct the detected problems.

Follow the suggested actions in the order in which they are listed in the Action column until the problem is solved.
If an action step is preceded by '(Trained technician only)', that step must be performed only by a Trained technician.
Go to the Lenovo support website at the Lenovo Support Portal to check for technical information, hints, tips, and new device drivers or to submit a request for information.

Table 1. The suggested actions to correct the detected problem for each LED light.
Three column table for documenting the LED, description, and action.
LED	Description	Action
System locator (blue)	This LED is used as a presence detection button. You can use Systems Director or IMM2 to light this LED remotely.	Use this LED to visually locate the server among other servers.
Check log (yellow)	An error has occurred and cannot be isolated without performing certain procedures.	Check the IMM2 event log and the system-error log for information about the error. Save the log if necessary and clear the log afterwards.
System-error (yellow)	An error has occurred.	Check the light path diagnostics LEDs and follow the instructions. Check the IMM2 event log and the system-error log for information about the error. Save the log if necessary and clear the log afterwards.

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