The new box fan I bought rattles, but only when it's set to a lower speed. If I have it on full blast it's fine.
It came with a little card that says if I have any problems I should contact them, the manufacturer, rather than returning it. Is this even worth the effort or should I resign myself to having it on full blast (which is a bit much) or not at all, or just dealing with the rattling
Should I try opening it up and tightening things? Apparently this kind of rattling can be caused by things not being perfectly balanced, in which case there isn't much I can do.

I tried some of the obvious things like making sure it's on stable ground and steadying it/feeling if there's any obvious shaking that can be stopped by me holding things in place. No dice.