Catalyst 2950 shuts down

[James May]

I have a Catalyst 2950 switch that will run for a little while and then power down. 

The fan is functional, no sounds or slow RPMs.  Seems to be operating fine and the unit doesn't feel warm.

I have to unplug it for a few minutes and then plug it back in to turn it back on.

Then it will repeat the process after awhile.

Any thoughts on this?

Thanks kindly,                  

[glen.grant]

   You have some kind of heat related failure or the power supply. Replace it ...