你是不是panning那個小knob鎖死了？

手冊上說：

Mud or salt water shouldbe lightly rinsed off with fresh water and then thoroughly dried. DO NOT submerge the ballhead when washing and do not direct a high-pressure stream of water at the ballhead.

All the knobs are captive, meaning they cannot come off without damaging them so do not attempt to remove the knobs. If fine sand/grit fouls the knob, simply run a gentle stream of water around the knob while rotating it one-half turn back and forth.

我用BH-55至少有4-5年了，還真沒有遇到像你這個難題，希望你能早日解決。