Covering the 2SK2603, this 410 KB PDF is indexed as a schematic but carries only a component number, pointing to a datasheet. The 2SK prefix follows the JIS system and marks an N-channel FET. Open it with any PDF viewer to read gate, drain and source pin positions, voltage and current limits and switching data. That information supports diode-mode testing of a suspect device and choosing a replacement with equal or better ratings. Confirm the physical marking matches the number 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.