The 2SJ609 is documented in this 30.0 KB PDF, listed under schematics but named in the manner of a component datasheet. JIS part codes with the 2SJ prefix are P-channel field-effect transistors. The sheet should help a technician identify pins, check absolute maximum ratings and judge on-resistance when picking a replacement. Because the name contains only the part number, without brand or package, verify the marking and footprint of the device on the board 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.