Below are patterns for the altered scale in B at different positions on the mandolin neck. The mandolin in these examples uses standard tuning (G, D, A, E open mandolin strings lowest to highest).
The horizontal lines in the patterns represent the mandolin strings, where the lowest string is at the bottom. The vertical lines are the frets and the fret numbers are at the top of each pattern. The tonic of the scale (the first note) is in white. The dominant of the scale (the fifth note) is in gray. Note that the altered scale is the Locrian scale with a flat fourth (the Eb in this example). Both the fifth note (the dominant) and the fourth note (the subdominant) in this scale are not a perfect fifth or a perfect fourth, but a diminished fifth and a diminished fourth. The perfect fifth and fourth of the tonic B are actually F# and E, but the altered scale uses F and Eb.
These scale patterns can be transposed to other positions on the neck to produce other altered scales. Also, since not all of the patterns below start on the tonic of the scale the same patterns can produce other modes of the altered scale (e.g., the melodic ascending minor scale).