One of the larger sheets in the set at 271 KB, this PDF is named after the 2SD2498 and serves as a transistor datasheet. JIS naming assigns the 2SD prefix to NPN bipolar transistors for low-frequency applications. A technician uses it to read collector-emitter breakdown voltage, collector current, dissipation and gain classes, and to locate each terminal on the package. Before substituting, confirm the package matches the footprint and that the original marking corresponds to this exact number.
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.