AC belt chatter on 4.8 engine

[beardedx5]

Hi everyone. I've searched a bit for answers and I'm running out of ideas. Have an 08 with the n62 engine that has a belt chatter issue from the ac belt. When I inspected it, the belt was shredded on the side and misaligned on the pulleys. After a bit of work, my 3 year old son and I got it changed and properly aligned. He probably also learned a few new words I'm sure his mom will love after dealing with that tensioner. Anyway, fired it up, and the chatter noise returned. New belt didn't seem to change anything. I'm wondering if maybe the tensioner is bad. Any ideas? I'm not really sure what else it would be. Noise is there both with ac on and off. Thanks in advance!