Chapter 4 Troubleshooting the Installation
Identifying Startup Problems
4-4
Cisco Catalyst 4900M Switch Installation Guide
78-18350-01
Step 2 Verify that the LEDs on the front panel are lit:
• The STATUS LED flashes yellow during diagnostic boot tests. It is green
when the switch is operational (online). If the system software is unable to
start up, this LED stays orange.
Tab l e 4-1 Power Supply LED Meanings
LED and Color Meaning
INPUT OK (AC)
Green
Red
Off
This LED should turn green immediately when power is
applied to the supply and the power switch is set to ON.
AC input voltage is greater than 80.5 +/- 4.5 V AC.
In a dual power supply configuration (alternate unit
powered) the AC input is less than 73 +/-3V, or the power
supply is turned off.
In a single supply configuration, signals that AC input
voltage is less than 73 +/-3V, or the power supply is turned
off.
INPUT OK (DC)
Green
Red
Off
This LED should turn green immediately when power is
applied to the supply.
DC input voltage is greater than -38.25 +/-2.25V.
In a dual power supply configuration (alternate unit
powered) the DC input is less than 33 +/-3V, or the power
supply is turned off.
In a single supply configuration, the LED shall be off to
signal that DC input is less than 33 +/-3V, or the power
supply is turned off.
OUTPUT OK
Green
Red
DC output voltages are within the normal operating range.
Output voltages below the minimum or above the
maximum will create an output fail alarm and cause the
LED to illuminate red.