Part document for the 2SC1050, a 192 KB PDF filed as a schematic, the name giving only the part number. Being a JIS 2SC designation, it describes an NPN bipolar transistor, with ratings, characteristic curves and package information typical for such sheets. Use it to identify the leads, test junctions out of circuit, and check that any substitute matches collector voltage, current and dissipation. Any PDF reader opens it; older parts may come in metal cases, so compare the case style and marking on the board with the drawing.
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.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.