Reference sheet for the 2SK2739 in PDF format, 146 KB, indexed in the schematic section. The 2SK code follows JIS convention for N-channel FETs, so expect a single-component datasheet with ratings, characteristic curves and outline dimensions. A variant file with a 1-5 suffix exists too and may be another edition. On the bench this helps confirm which pin is the gate, verify that a candidate replacement meets the voltage and current requirements, and interpret diode-mode readings on a suspect 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.