The 2SC4685 is documented in this 186 KB PDF, filed as a schematic though the name is a transistor part number. In JIS designation, 2SC stands for an NPN bipolar transistor, making a datasheet the most probable content. No variant, maker or revision appears in the filename. Read it in any PDF viewer to check package, pinout, gain and absolute maximum ratings, which supports in-circuit testing and choosing a correct replacement when the original has failed.
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)