The 2SB857 transistor is covered in this 42.0 KB PDF, the same size as the 2SB858 file and probably from the same document series. By JIS convention the 2SB prefix denotes a PNP device for low-frequency circuits. No maker, revision or package code appears in the name. Use the sheet to read the collector ratings, gain range and pinout when testing the part out of circuit or sourcing a replacement. Match the outline and markings to the original component before installing anything.
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.