Why the Cisco 2960S Randomly Reboots

Having a strange problem, my catalyst Catalyst 2960 switches keep randomly restarting. They are stacked and are running IOS version 12.2(58) SE2. I also can't find a crash log file in the flash directory after they randomly reboot.

                 

Ive checked the show version with no avail, but it does indicate a possible power issue:

System returned to ROM by power-on

System restarted at 09:11:13 PAC Tue Nov 15 2011

System image file is "flash:/c2960s-universalk9-mz.122-58.SE2/c2960s-universalk9-mz.122-58.SE2.bin"

Im not too sure, but the switch WS-C2960-48TT-L is connected to a ups, that a few other switches are also connected to and they did not go offline during the time the switch did.

I am not sure whats going on, as I have nothing to base it on.

The solution:

Try changing the power lead or connecting it to a different source.

The line "System returned to ROM by power-on" usually means that the switch thinks it reset due to power loss.  So you may have a power issue, or possibly the power supply in the switch is bad.  Can you swap the stack master roles so the other switch is master?  It's unlikely that both switches have bad power supplies, so with the other switch running the stack, you should be able to look at the logs and see if the first switch looses power alone, or if both switches go down and come back up at the same time.

You may also try moving the switch to a different port of the UPS.