This 145 KB PDF carries only the part number 2SC2884 in its name and is filed as a schematic. Following JIS conventions, a 2SC code refers to an NPN bipolar transistor, so the document is most likely its datasheet. Open it in any PDF reader to check pin arrangement, absolute maximum ratings, gain classes and package dimensions. Such data guides the choice of a substitute when the exact part is unavailable. Confirm the physical marking on the failed transistor, as abbreviated codes on small packages can be misleading.
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.