A 121 KB PDF named 2SK2170, listed among schematics but most likely the datasheet for that single device. In Japanese JIS/EIAJ notation, 2SK marks N-channel FETs, and nothing else about the part is stated. Small-signal and power FETs share this prefix, so read the ratings inside before assuming an application. Technicians use the pinout and limit values to test the device out of circuit and to confirm any replacement matches its voltage, current and package.
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.
Any PDF readerSumatraPDFFirefox / ChromeFlexBV (links PDF to boardview)