The name carries only a part number, 2SD1905, which points to a semiconductor datasheet even though the entry is filed under schematics. In JIS numbering, 2SD identifies an NPN bipolar transistor for low-frequency applications. The 112 KB PDF opens in any standard reader. Use it to verify the base, collector and emitter layout, voltage and current limits and gain grouping before swapping the device, and compare against the marking on the failed part, since package variants can differ in pin order.
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.