For a PCM at the front of the card cage, the green LED is to the left of the yellow LED. At the back of the card cage, the LED positions are reversed and the green LED is to the right of the yellow LED. See Table 9-3.
When the yellow LED is lit, a fan or a DC output has malfunctioned. Each modular power supply contains two fans and three DC supplies (+3.3 VDC, +5 VDC, and +2 VDC).
The green LED indicates that the DC supplies are operating, but does not guarantee that the DC outputs are within specification.
Table 9-3 Modular Power Supply LED Codes
Green |
Yellow |
Condition |
---|---|---|
Off |
Off |
No AC input or key switch is turned off. |
On |
Off |
Normal operation. |
On |
On |
A fan has failed or one or more voltages are out of specification. |
Off |
On |
One or more DC outputs have failed, or the voltages are out of specification, or the system is in the low power state. |
The PCMs operate in redundant current share mode. If a module fails, the remaining modules may or may not provide enough current to continue system operation. The system's ability to continue operations depends on the total demand for current.