The 2SA1734 is the subject of this 183 KB PDF, which carries only the component number in its name. Although listed as a schematic, a file named this way is normally the maker's datasheet for a PNP bipolar transistor, the 2SA prefix being the JIS code for that device class. Typical content includes maximum collector-emitter voltage, current, dissipation and pin assignment. Check the package and pinout against the part on the board, since lookalike packages can swap leads, and verify that any substitute meets or exceeds the ratings.
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.