OK, I'm pretty sure I know what the diagnosis is, but I just thought I'd run it by you guys to confirm and see if there are any suggestions other than a funeral. I have a (righty) MIM jazz bass that I have around the studio as a loaner. I decided to do a setup on it. Measured the relief (I use a carpenters square and feeler guages) and was surprised to see how far out it was. I usually keep my basses at .008. This was at least three times that. (I didn't bother to get a precise measurement.) I don't remember setting it up when I got it, but I would never have left that much relief in. So anyway I go to tighten the truss rod. I use one of those "rock and rollers" under the seventh fret, push down on the head stock and let the weight of the body take the pressure off the truss rod. Seems to be a tight fit of the rod in the nut. (This model is at the headstock.) Give it a quarter turn. Measure....Nothing. Another quarter turn...Nothing. Once more... Nothing. I gave it a full turn with no visible effect. There is plenty of resistance when tightening and loosening the rod. Feels like it is turning. Just no effect. The neck is firewood, right?