Dell Precision 7920 Rack Owner's Manual

Power supply unit indicator codes

AC power supply units (PSUs) have an illuminated translucent handle that serves as an indicator. The indicator shows whether power is present or a power fault has occurred.

This image shows AC PSU status indicator. — Figure 1. AC PSU status indicator

Table 1. AC PSU status indicator codesThis table describes the AC PSU status indicators and what condition is the PSU when the power indicator light is green, blinking green, blinking amber, and when it is not lit.
Power indicator codes	Condition
Green	A valid power source is connected to the PSU and the PSU is operational.
Blinking amber	Indicates a problem with the PSU.
Not illuminated	Power is not connected to the PSU.
Blinking green	When the firmware of the PSU is being updated, the PSU handle blinks green. CAUTION:Do not disconnect the power cord or unplug the PSU when updating firmware. If firmware update is interrupted, the PSUs do not function.
Blinking green and turns off	When hot-plugging a PSU, the PSU handle blinks green five times at a rate of 4 Hz and turns off. This indicates a PSU mismatch with respect to efficiency, feature set, health status, or supported voltage. CAUTION:If two PSUs are installed, both the PSUs must have the same type of label. For example, Extended Power Performance (EPP) label. Mixing PSUs from previous generations of Precision Workstation is not supported, even if the PSUs have the same power rating. This results in a PSU mismatch condition or failure to turn the system on. CAUTION:When correcting a PSU mismatch, replace only the PSU with the blinking indicator. Swapping the PSU to make a matched pair can result in an error condition and unexpected system shutdown. To change from a high output configuration to a low output configuration or vice versa, you must turn off the system. CAUTION:AC PSUs support both 240 V and 120 V input voltages with the exception of Titanium PSUs, which support only 240 V. When two identical PSUs receive different input voltages, they can output different wattages, and trigger a mismatch. CAUTION:If two PSUs are used, they must be of the same type and have the same maximum output power. NOTE:Ensure that both the PSUs are of the same capacity. NOTE:Mixing PSUs (even the PSUs that have the same power rating) from previous generations of Precision Workstation is not supported. This results in a PSU mismatch condition or failure to turn the system on.