Stop in for a cup of coffee

Honda pilot. Noisy bearing. Tensioner pulley,loud buzz. Replaced,comes with tensioner and an idler too. Still buzzing.
And its louder than the alternator. Unplug alt, buzz goes away. Wtf?
Its charging fine. I may test it,see if its putting out like it should,and see if a/c is getting through a diode.
Rav 4 tomorrow, alternator may be also going bad.