Reference sheet in PDF format, 137 KB, for the 2SD1840 transistor from the 2SD family of NPN bipolar devices; despite the schematic label, expect datasheet content. It lists electrical limits, typical characteristics and pin assignment, all needed when swapping a damaged part or confirming that a substitute can handle the circuit's voltage and current. Make sure the pin order in the package drawing matches the footprint on the PCB, as similar-looking cases can use different lead layouts.
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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The standard format for schematics, block diagrams, power-sequence charts and service manuals.