The 2SC4673 is described in this 124 KB PDF, which the catalogue lists as a schematic. Japanese JIS designation assigns 2SC to NPN bipolar transistors, so a component datasheet is the likely content. Only the part number is given in the name. Technicians open it to confirm base, collector and emitter pins, check ratings and gain, and pick a suitable replacement, verifying package outline and marking against the failed part before soldering in a substitute.
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)