Part documentation for the 2SK2731, a 113 KB PDF placed in the schematic category. JIS naming assigns the 2SK prefix to N-channel field-effect transistors, so the content should be a datasheet listing maximum ratings, typical characteristics and pin arrangement. A second copy with a 1-5 suffix is also indexed. Technicians refer to it when testing a suspected shorted FET, confirming gate, drain and source positions, and comparing replacement candidates by drain-source voltage, current and on-resistance.
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.