When viewing the rear panel, PSU 1 is on the left side of the chassis; PSU 2 is on the
right side of the chassis.
Figure 14 S4048–ON PSUs on the rear panel
1. PSU 1
2. PSU 2
Power supply units status indicators
Each PSU has a bi-color (amber and green) LED to indicate power supply status.
Figure 15 PSU LED location
1. PSU 1 LED
2. PSU 2 LED
Table 12 PSU LED behavior
Power Supply Condition
LED State
Output ON and OK
Green
No AC power to both power supplies
Off
AC present / Only 12 VSB on (PSU off) or
PSU in Smart on state
1 HZ blinking green
AC cord unplugged or AC power lost; with a
second power supply in parallel still with AC
input power
Amber
Power supply warning events where the PSU
continues to operate; high temp, high power,
high current, slow fan
1 HZ blinking amber
PSU critical event causing a shutdown;
failure, OCP, OVP, fan fail
Amber
PSU firmware updating
2 HZ blinking green
Dell S4048-ON Switch FRUs
DELL EMC CONFIDENTIAL
Power supply units status indicators
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