One of my friends has bought a used 17-85. The seller told, it has only a broken cable, otherwise is ok.
– the flex cable from the IS module was broken
– the IS module’s adjustable lens was forced, 2 of the excentric pins broken, one ose not there at all, therefore the lens group moves in the plane.
– internal screws were not tighten
– the brush contact for the zoom (from the outside accesible, covered with an adhesive tape) was forced, bended
– the former changed flex cable for the aperture module was visible bended, the adhesive tape for it was not glued well (probably mounted on a dirty surface)
– soldering on the aperture was very made very poorly
As this lens is not possible to be repaired, he has bought on another one.
Seller told him, it’s in perfect condition, only the front lens has a small scratch.
– the brush contact for the zoom was forced, bended (as I see, this is a common problem: people didn’t know, how they should start disassembling)
– the aperture cable wa mounted in a very strange, modified way, without the small brass metal plate (it was flickering in the air) bended.
– wrong soldering, aperture molded a little bit by soldering
– internal screws not tightened
– some dirt in the inside of the lens
– and the most beautiful thing: the plastic mounting plate beyond the bayonet mount, which should be mounted with 5 screws, was fixed with only 2 (!!!) – but that one, wich is under this, and should be mounted with 3 screws, was mounted with 6….
Now, I have to bring together one lens from these two. Plus a new aperture cable.
So, don’t be afraid, buy used lens from any unknown person. Sellers will tell You always the truth.
But buy immediately two pieces instead of one.