[Elecraft] Noisy KPA100 Fan

[Phil Wheeler]

I've recently noticed a very soft, but eventually annoying, "frying" 
noise in my shack.  It's source was vague with my monoral hearing.  But 
I finally tracked it down to the fan in my KPA100.

I don't recall this sound being there early on, but maybe I'm wrong.  I 
do know that I have not put enough hours on the PA to wear anything out.

Has anyone else noticed such a (hard to describe) sound from a fan? 
 Sort of a new fan (I should not need one this soon), any thoughts on 
how to eliminate it?

73, Phil