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M120 Power Supply LEDs


The LED on each power supply faceplate indicates the status of the power supply (see Table 1, which applies to the AC and DC power supply). The power supply status is also reflected in two LEDs on the craft interface (see Power Supply LEDs on the Craft Interface). In addition, a power supply failure triggers the red alarm LED on the craft interface.

Table 1: M120 Power Supply LED






No power applied to power supply.


  • Power supply blinks for 5 seconds after initial power on.

  • Power supply is installed, but not powered on.

  • Input voltage is invalid.

  • Power supply has failed.

On steadily

Power supply is functioning normally.