Part reference for the 2SC4987, provided as a 110 KB PDF and filed under schematics. No model, board or revision is stated in the name. Under the JIS/JEITA system a 2SC code identifies an NPN bipolar transistor, so the contents are most likely the device datasheet. Open it in a standard PDF viewer to read absolute maximum ratings, hFE ranges and the package drawing. Check the pin assignment carefully, since layouts vary between packages, and choose any replacement with ratings at or above the original.
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.