A 90.4 KB PDF describing the 2SA1423, identified only by part number. By Japanese JIS convention the 2SA prefix marks a PNP transistor. Even though the index type is schematic, expect a component data sheet giving limits such as collector-emitter voltage, collector current and dissipation, plus gain ranges and a pinout drawing. Technicians use it to confirm lead identity before measurements and to vet substitutes, matching polarity, package and ratings rather than relying on look-alike markings.
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.