PDF reference for the 2SA1807 transistor, 43.9 KB, listed as a schematic but in practice a component datasheet. Following JIS naming, the 2SA designation means a PNP bipolar device. The sheet gives the figures a repair technician needs: maximum collector voltage and current, dissipation, gain grouping and lead layout. That information supports in-circuit testing, identification of an unknown part and selection of a compatible replacement. Confirm the body marking first, since abbreviated codes on tiny packages can mislead.
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.