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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 on the front operator panel on the front of the server, then on the failed component. By viewing the LEDs in a particular order, you can often identify the source of the error.

Operator panel light path LEDs​

The following illustration shows the light path diagnostic LEDs for the server, which are located on the operator information panel.
Figure 1. Operator information panel LEDs Graphic depicting the location of the light path diagnostic LEDs on the server
Table 1. Light path diagnostics: Operator information panel LED status and actions
LEDDescriptionAction
1 Power button and power LEDIndicates power status of the server.Not used for troubleshooting server beyond providing power status. See Front operator panel for additional information.
2 Network activity LEDIndicates activity between the server and the Ethernet LAN.Not used for troubleshooting server beyond providing network activity status. See Front operator panel for additional information.
3 System ID LED (blue)This LED is used as a presence detection LED. You can use Lenovo XClarity Controller to light this LED remotely.Use this LED to locate the server among other servers visually.
4 System-error LED (amber)LED on: An error has occurred.
  1. Check the system-locator LED and check log LED and follow the instructions.
  2. Check the Lenovo XClarity Controller event log and the system-error log for information about the error.
  3. Save the log if necessary and clear the log afterward.

Rear light path LEDs​

The following illustration shows the light path diagnostic LEDs located on the rear of the server.
Figure 2. Rear LEDs
LEDs on the rear of the server
Table 2. Light path diagnostics: Rear LED status and actions
LEDDescriptionAction
1 Power supply AC power input LED (green)

Status of power supply AC power input.

See Power supply LEDs for detailed descriptions of the power supply LEDs.

See Power supply LEDs for actions relating to the power supply LEDs.

2 Power supply DC power output LED (green)

Status of power supply DC power output.

See Power supply LEDs for detailed descriptions of the power supply LEDs.

See Power supply LEDs for actions relating to the power supply LEDs.

3 Power supply fault LED (yellow)

Indicates a power supply malfunction.

See Power supply LEDs for detailed descriptions of the power supply LEDs.

See Power supply LEDs for actions relating to the power supply LEDs.

5, 6, 7, 8, 10, 11, 12, 13, 14, 15, 16, 17, 24, 25, 26, 27, 28 Adapter error LEDs

Indicates a malfunction for the associated adapter.

  1. Check the Lenovo XClarity Controller event log and the system-error log for information about the error.
  2. Save the log if necessary and clear the log afterward.
4, 9, 18 Riser error LEDs

Indicates a malfunction for the associated riser or an adapter installed in the riser.

  1. Check the Lenovo XClarity Controller event log and the system-error log for information about the error.
  2. Save the log if necessary and clear the log afterward.
19 Power LED (green)Indicates the power state of the server.Not used for troubleshooting server beyond providing power status. See power supply LEDs (1, 2, and 3) for additional information.
20 System ID LED (blue)This LED is used as a presence detection LED. You can use Lenovo XClarity Controller to light this LED remotely.Use this LED to locate the server among other servers visually.
21 System-error LED (amber)Indicates an error has occurred.
  1. Check the system-locator LED and check log LED and follow the instructions.
  2. Check the Lenovo XClarity Controller event log and the system-error log for information about the error.
  3. Save the log if necessary and clear the log afterward.
22 3v fault (system battery) LED

Indicates a malfunction or low voltage for the 3V system battery (CR2032) in the I/O tray.

  1. Check the Lenovo XClarity Controller event log and the system-error log for information about the error.
  2. Save the log if necessary and clear the log afterward.
23 I/O-board fault LED

Indicates a malfunction for the I/O board or an adapter installed in the I/O board.

  1. Check the Lenovo XClarity Controller event log and the system-error log for information about the error.
  2. Save the log if necessary and clear the log afterward.
  • Power supply LEDs
  • System-board LEDs
    The following illustration shows the location of light path diagnostic LEDs and light path diagnostic switch on the system board. These LEDs can often identify the source of an error.