Under the JIS semiconductor scheme the name 2SJ464 refers to a P-channel FET, and this 320 KB PDF, although indexed as a schematic, should be its datasheet. No device, board or brand is mentioned. A technician reads such a sheet to identify leads, check maximum drain-source voltage and current, and review gate threshold and switching behaviour before testing the part with a meter or installing a replacement. Verify that the package and suffix printed on the original transistor correspond to the sheet.
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.