Identifying a failed power supply

The power supply unit uses an LED that indicates whether the unit is working as expected. The location of the LED is shown in the following figure:

Figure 1. Power supply LED
The following table indicates the potential problems that can occur with the power supply:

Power supply condition LED state
Normal work Green
No AC power to all the power supplies Off
AC present / Only 12VSB on (PS off) or PS in CR state 1 Hz Blink Green
AC cord unplugged with a second power supply in parallel still with AC input power 0.5 Hz Blink Green
Power supply warning events where power supply continues to operate: high temp, high power, high current, slow fan 1 Hz Blink Red
Power supply critical event causing a shutdown, failure, OCP, OVP, Fan Fail Red

Parent topic: Power Supply Replacement Instructions