The 2SC3894 NPN bipolar transistor is covered by this 84.5 KB PDF, labelled a schematic but named only by a JIS part number, where 2SC denotes NPN devices, so it is most likely a datasheet. Expect a pin diagram, maximum ratings, electrical characteristics and package dimensions. In repair these figures support in-circuit junction testing, correct orientation during replacement and selection of a cross-reference part with enough voltage margin. Verify the marking on the board before use.
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.