Originally Posted by anarchipur
after tuning my Yamaha BB424 bass I noticed that on the E string the notes on the frets around the 12th fret have a shift about a quarter of a tone higher than the note should be.
How should I adjust the bridge to get the right notes on the higher frets without distorting the overal tuning?
"Overall tuning", as in, affecting other strings? Changing the saddle on one string will do nothing to the others unless the bridge is one piece with no adjustment (it only slides forward and back).
If the bridge saddle is as far from the bridge pickup as possible and the spring over the screw is compressed between the saddle and the end of the bridge where the screw head is, it's possible that the saddle was installed backward and the break point for the string isn't able to move to the correct position. Can you post a link to a photo of your model, with the same bridge?