The 2SC4250 transistor is documented in this 347 KB PDF, listed among schematics in the index. The name carries only the part number, so details such as maker and document revision are found inside. In JIS numbering, a 2SC part is an NPN transistor of the high-frequency class. The sheet lets you confirm pin order, check breakdown voltage, current and dissipation, and review gain grading. Match the case marking, typically C4250, and the package type on the board before installing a replacement or cross-reference part.
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.