Short 54.7 KB PDF for the 2SD1991A, an NPN bipolar transistor going by its JIS 2SD prefix. The index lists it under schematics. The A suffix indicates a variant of the base 2SD1991 type, and the E after it is not explained by the name. Check the case marking on the board before relying on the data. Repairers use sheets like this to find the base, collector and emitter pins, confirm voltage headroom and compare gain with a candidate substitute.
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.
Any PDF readerSumatraPDFFirefox / ChromeFlexBV (links PDF to boardview)