Indexed as a schematic, this 107 KB PDF refers to the 2SK1440, and the name states nothing beyond the part number. Under JIS coding, 2SK identifies an N-channel field-effect transistor, so expect a data sheet. Typical uses include pin identification before in-circuit measurement, checking breakdown voltage and on-resistance, and cross-referencing an equivalent when the original is unavailable. Match the marking and package on the board to the document before relying on any value.
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.