Component document in PDF for the 2SK2555, filed under schematics although the part number points to a discrete semiconductor rather than a board. Under the Japanese JIS naming system the 2SK prefix marks an N-channel field-effect transistor, so expect a datasheet with pinout, package outline and ratings. At 42.7 KB it is a short file. Use it to confirm gate, drain and source pins before testing a suspect FET in a power stage, and compare the marking on the package with the number here before ordering a substitute.
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.