The 2SC3040 appears in the name of this 107 KB PDF, which is indexed among schematics and probably holds that part's datasheet. In Japanese JIS numbering, the 2SC prefix marks an NPN bipolar transistor intended for high-frequency service. Use it to confirm lead assignment, absolute maximum ratings and hFE bins when replacing the component or comparing a cross-reference part. No maker or package is stated, so match the body marking against this number before relying on the figures.
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.