Can't seem to find a solution to this problem. Tightening the screw doesn't help. I have two 70s-era basses and by no small coincidence, those are the only instruments I have that don't hold their tuning for very long. I would like to keep the original tuners if you know a hack to keep them from slipping. Any way to restore them to their former glory? Otherwise, I will have to get replacement vintage-style tuners. Thanks in advance!