I have a screeching belt noise.

replaced belt - quiet for a week. then came back, replaced both idler pulleys even though all rotating pulleys seemed fine. cheap enough. noise still there.

then I used my stethescope and thought maybe it was the alternator. ( the noise was coming from that section anyway. ) replaced alternator - noise still there. I am thinking I need to replace the tensioner assy complete -

PS: AC compressor was changed a year ago and noise is the same ac on or off.