Part reference sheet in PDF form for the 2SK663, carrying a 2SK prefix that under the Japanese JIS system denotes an N-channel FET. Although filed under schematics, the 30.3 KB size points to a brief component datasheet. It is useful for identifying pin functions, reading breakdown voltage and drain current ratings, and checking a suspect transistor for shorts between terminals. When substituting, match package, polarity and ratings rather than relying on the number alone, and confirm the marking on the actual part.
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.