Part documentation for the 2SC3661, an 87.1 KB PDF. JIS naming assigns the 2SC prefix to NPN bipolar transistors, and the name offers no model, board or revision, so treat it as a datasheet despite its schematic category. The file should cover maximum ratings, electrical characteristics and package dimensions. Repair technicians use it to validate replacements and to read the pinout for in-circuit checks; verify the package and printed marking of the part 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.