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LEDs on the power supply unit

This topic provides information about various power supply LED status and corresponding action suggestions.

The following minimal configuration is required for the server to start:

  • One processor in processor socket 1

  • One memory module in slot 7

  • One power supply

  • One HDD/SSD drive or one M.2 drive, or one 7mm drive (if OS is needed for debugging)

  • Six system fans (with one processor)

The following table describes the problems that are indicated by various combinations of the power-supply LEDs and the power-on LED and suggested actions to correct the detected problems.

Figure 1. Power supply LEDs
Power supply LEDs
1 Input status
The input status LED can be in one of the following states:
  • Off: The power supply is disconnected from the input power source.

  • Green: The power supply is connected to the input power source.

2 Output status
The output status LED can be in one of the following states:
  • Off: The server is powered off, or the power supply unit is not working properly. If the server is powered on but the output status LED is off, replace the power supply unit.

  • Blinking green: The power supply is in zero-output mode (standby). When the server power load is low, one of the installed power supplies enters into the standby state while the other one delivers entire load. When the power load increases, the standby power supply will switch to active state to provide sufficient power to the server.

    To disable zero-output mode, log in to the Lenovo XClarity Controller web interface, choose Server Configuration > Power Policy, disable Zero Output Mode, and then click Apply. If you disable zero-output mode, both power supplies will be in the active state.

  • Green: The server is on and the power supply unit is working normally.

3 Fault LED
  • Off: The power supply unit is working normally.

  • Yellow: The power supply unit has failed. To resolve the issue, replace the power supply unit.