2SC4317 is the sole identifier in this 468 KB PDF, listed as a schematic but most likely the component datasheet. JIS part numbers beginning with 2SC denote NPN bipolar transistors, and the device itself is typically labelled C4317. Read the package drawing to confirm lead order before testing in circuit, and use the maximum collector voltage, current and dissipation figures, along with gain and frequency data, when deciding on a substitute for a failed 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.