The switch does not have any easily replaceable parts on it. In this Youtube video you get a glimpse of the inside of the switch, and can see that everything is all on one board.  [URL] this sounds like a hardware issue, but you may want to try reflashing the firmware on the switch. [URL] If the switch continues to exhibit this behavior, then it will need to be replaced. 
Ports 13-24 (Circuit 2) on my Dell Powerconnect 5448 are dead with no lights regardless of the connection. Is there any way to have the device serviced or that circuit replaced? Thanks, Will C.
Dead Circuit 2 on Dell Powerconnect 5448