1989 GMC s15 -- tensioner bouncing

[vikasintl]

I know if tensioner is bad ...it can bounce while engine running

but can it be any other reason ....like something wrong with belt?

I checked all other pulleys and they dont have any play...

but tensioner is bouncing so I am trying to figure out if its tensioner or it could be something else?

 

[98trck]

start with the simple things
replace the belt
my 98 with the hood open and engine running had a pulsing whining noise
there must have been a bad section of the belt
I replaced it , no more noise