3com 3848 User Manual

Page of 72
46
C
HAPTER
 4: P
ROBLEM
 S
OLVING
Solving Problems 
Indicated by LEDs
If the LEDs on the Switch indicate a problem, refer to the list of suggested 
solutions below.
The Power or Power/Self Test LED does not light
Check that the power cable is firmly connected to the Switch and to the 
supply outlet. If the connection is secure and there is still no power, you 
may have a faulty power cord or an internal fault. Check the power cord 
by:
Testing it in another device
Connecting a working power cord to the ‘problem’ device
Then contact your supplier for advice.
On powering up, the Power/Self Test LED lights yellow for about ten 
seconds after which it starts flashing green (Switch 3848 only).
On powering-up, the Self Test LED lights red (Switch 3812 and 
Switch 3824) or Power/Self Test LED remains yellow (Switch 3848)
This indicates one of the following:
A port has failed and has been automatically disabled. You can verify 
this by checking that the Port Status LED is flashing Green/Yellow 
(fast). This could be due to a loop back failure. If a port fails the Switch 
passes its Power On Self Test and continues to operate normally.
An internal fan has malfunctioned. If a fan has stopped spinning, 
power off the unit and check the air vents for obstructions. If this 
situation occurs, the fault LED will light red (Switch 3848 only).
The internal PSU has failed and power is being supplied by an external 
Redundant Power Supply (RPS). Although the Switch has a fault it will 
continue to operate normally.
On Powering up, the Power/Self Test LED lights yellow for about ten 
seconds after which it starts flashing green. This is normal and does not 
indicate any of the above conditions. (Switch 3848 only)
A Port Status LED is flashing green/yellow
The port has failed and has been automatically disabled. The Switch 
passes its Power On Self Test and continues to operate normally, even if 
one or more ports are disabled.
dua1740-0aaa03.book  Page 46  Thursday, December 23, 2004  9:23 PM