2000 Chevy Blazer "Clicks"

I appear to have a "clicking" sound under the hood of my truck. Thebest way i can describe it is it sounds like someone took a baseball card and stuck it in their bike spokes. I put my ear over the Alt. and rev'd the engine and it appears to be coming from that. It is def on the top passenger side of the motor and seems to be cmoing from the Alt. The only thing i can think of is a bad bearing, or a bearing going bad on the Alt. There are 2 weird things though:
1 - the sound goes away after 5 mins of driving
2- the volt meter on my gauge cluster is stable @ 14v
any idea?
A failing alternator bearing doesn't mean the alternator won't put out proper voltage. My old taurus has a bad alternator bearing and it just made a racket but worked fine otherwise. Take the belt off and spin it by hand, see if it feels or sounds funny.






