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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.

The following illustration shows the light path diagnostic LEDs for the server, which are located on the operator information panel.
Figure 1. Front operator panel
Table 1. Light path diagnostics: LED status and actions
1 Power button/LED (green)

  • Off: No power supply is properly installed, or the LED itself has failed.
  • Flashing rapidly (4 times per second): The server is turned off and is not ready to be turned on. The power-control button is disabled. This will last approximately 5 to 10 seconds.
  • Flashing slowly (once per second): The server is turned off and is ready to be turned on. You can press the power-control button to turn on the server.
  • Lit: The server is turned on.
Press the power button to turn the server on and off manually.
2 Network activity LED (green)

LED on: The server is transmitting to or receiving signals from the Ethernet LAN.Use this LED to identify network connection status.
3 Identification button/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 (yellow)

LED on: An error has occurred.
  1. Look for other error LEDs lit in the system (fans, DIMMs, power supplies, etc).
  2. Check the identification LED and check log LED and follow the instructions.
  3. Check the Lenovo XClarity Controller event log and the system-error log for information about the error.
  4. Save the log if necessary and clear the log afterward.