Component sheet for the 2SD1191, delivered as a 143 KB PDF and categorised as a schematic, though the name suggests a datasheet for a single part. In JIS terms, 2SD means an NPN bipolar transistor for low-frequency circuits. Inside you should find absolute maximum ratings, electrical characteristics and the package dimensions. Before replacing the device, confirm the pin order printed in the sheet matches the board footprint, and check any equivalent on voltage, current and power rating.
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.