I've looked at many sources that talk about truss rod adjustment, and I learned that it's a lot easier to do that when the adjusment nut is located at the headstock. The adjustment nut on my Yamaha is located at the base of the neck, and I've heard that some bass guitars with this layout such as the older Fender precision bass must have the neck completely removed in order to adjust the truss rod. I tried adjusting mine with an allen key, but the nut doesn't seem to turn and I'm afraid if I apply any more pressure, I'll damage it. To fix the action, I tried lowering the string height on the bridge, and this worked for a while, but it looks awkward and the strings buzz occasionally at the lower frets. The curve of the neck seems to be the most severe near the headstock. Can anyone tell me if I have to remove the entire neck of my bass guitar to adjust the truss rod? Or am I not looking at the situation correctly?