The 2SB1406 transistor is the subject of this 70.7 KB PDF, listed under schematics but best treated as a datasheet. No other information is encoded in the name. Japanese JIS numbering assigns 2SB to PNP bipolar transistors aimed at low-frequency circuits. Before swapping a failed part, compare its voltage, current and dissipation ratings with the candidate, and confirm the lead order, since equivalents in the same package can still differ in pinout. Any standard PDF viewer opens it.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @cyberlanelectonik. Enginerys does not host this file.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.