PDF datasheet of 185 KB for the 2SD1509 transistor, indexed as a schematic. Under the Japanese JIS scheme, the 2SD prefix marks an NPN bipolar device for low-frequency applications. Only the part number appears in the name, so check the marking on the board for the exact variant. The file size points to characteristic curves as well as ratings tables and a package drawing. Repairers use that data for substitution decisions and correct pin identification.
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.
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