Identified solely as 2SC3420, this 180 KB PDF is filed under schematics. In the Japanese JIS registration scheme a 2SC number is an NPN bipolar transistor, so expect a datasheet listing ratings, characteristics and package dimensions. It helps when a stage has failed and you need the correct pinout to test junctions or a reliable set of limits to choose a substitute. No further details appear in the name, so confirm marking and case on the actual part.
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.
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