Skip to main content

Power-supply-unit LEDs

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

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

  • Servers without Compute Complex Neptune Core Module

    • One processor in processor socket 1

    • One memory module in slot 7

    • One power supply unit

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

    • Three system fan-packs (Fan-packs 1, 2, and 3)

  • Servers with Compute Complex Neptune Core Module

    • Two processors

    • One memory module in slots 7 and 23

    • One power supply unit

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

    • Four system fan-packs (Fan-packs 1, 2, 3, and 4)

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

Figure 1. LEDs on a CRPS Premium power supply unit
Power supply LEDs

LEDDescription
1 Output and fault status (bi-color, green and yellow)
The output and fault 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 LED is off, replace the power supply unit.

  • Slow blinking green (about one flash per second): 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.

  • Fast blinking green (about five flashes per second): The power supply unit is in firmware update mode.

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

  • Yellow: The power supply unit may have failed. Dump the FFDC log from the system and contact Lenovo back-end support team for PSU data log reviewing.

Zero-output mode can be disabled via Setup Utility or Lenovo XClarity Controller web interface. If you disable zero-output mode, both power supplies will be in the active state.

  • Start the Setup utility, go to System Settings > Power > Zero Output and select Disable. If you disable zero-output mode, both power supplies will be in the active state.

  • Log in to the Lenovo XClarity Controller web interface, choose Server Configuration > Power Policy, disable Zero Output Mode, and then click Apply.

2 Input status (single color, green)
The input status LED can be in one of the following states:

  • Off: The power supply unit is disconnected from the input power source.

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

  • Blinking (1Hz): The input power is unhealthy.

Figure 2. LED on a CRPS PSU (1)

Figure 3. LED on a CRPS PSU (2)

1 Power-supply-unit LED (bi-color, green and yellow)
StatusDescription
On (green)The server is on and the power supply unit is working normally.
Blinking (green, about two flashes per second)The power supply unit is in firmware updating mode.
On (yellow)When the power supply unit is lit yellow:

  • Scenario 1: one of the two power supply units has powered off or is unplugged from the power cord, and at the same time, the other one has power on.

  • Scenario 2: the power supply unit has failed due to one of the issues listed below:

    • Over-temperature protection (OTP)

    • Over-current protection (OCP)

    • Over-voltage protection (OVP)

    • Short circuit protection (SCP)

    • Fan failure

Blinking (yellow, about one flash per second)The power supply unit is showing warnings, indicating over-temperature warning (OTW), over-current warning (OCW), or a slow fan speed.
OffThe server is powered off, or the power supply unit is not working properly. If the server is powered on but the LED is off, replace the power supply unit.