Chapter 3: Installing Fans and Power Supplies
22
Determining Power Supply Status
When the amber power supply failure LED on the front of the chassis turns on, determine which
power supply is defective by checking the three status LEDs on each supply. Each power supply has
three LEDs that both indicate whether power is supplied to the power supply and the health of the
power supply. The LEDs are ordered top to bottom on each power supply. Table 3-1 illustrates the
states indicated by the three LEDs.
Table 3-1. Power Supply LEDs
Power Supply Status
PWR
(Green)
(Top
Position)
PFAIL
(Amber)
(Middle
Position)
FAIL
(Amber)
(Bottom
Position)
No AC power to any power supplies Off Off Off
No AC power to a specific power supply Off Off On
AC present / Standby output on Blinking Off Off
DC outputs on and okay On Off Off
Power supply failure Off Off On
Current limit On Off Blinking
Predictive failure On Blinking /
Latched
Off
