Datasheet for the 2SD814 NPN transistor, a 42 KB PDF whose _E suffix probably indicates an English edition. Japanese JIS nomenclature uses the 2SD prefix for NPN low-frequency transistors, and parts of this kind appear in many power and audio circuits. The sheet gives the pinout, electrical limits, gain ranks and mechanical outline a technician needs when testing junctions, tracing a faulty stage or choosing a replacement. Confirm the case and lead order on the board before soldering in any substitute part.
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.