PDF document for the 2SK1847, catalogued as a schematic but by its name most likely a component datasheet. Under the Japanese JIS naming system, the 2SK prefix marks an N-channel field-effect transistor. The 74.4 KB file should hold ratings, the package outline and pin assignment. Use it to confirm gate, drain and source before probing or replacing a failed part. When choosing a substitute, compare voltage, current, on-resistance and package against the original, and match the part marking first.
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.