An 88.0 KB PDF for the 2SD1838, a Japanese-registered NPN bipolar transistor, best treated as a datasheet even though it is indexed as a schematic. It is useful for confirming pinout, collector-emitter breakdown voltage, current capability and gain while repairing amplifiers, power supplies or switching stages. Test the suspect part out of circuit for leakage or shorted junctions, then use these ratings to pick an equal or better replacement, checking the case marking and suffix first.
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.