A 41.1 KB PDF titled with the part number 2SC1980 and an _E suffix, catalogued among schematics. Because 2SC follows the JIS designation for NPN bipolar transistors, this file is most likely a short component datasheet. Open it in a PDF viewer to look up terminal order, absolute maximum ratings and hFE classes when a stage fails or a substitute is needed. Since the name names no manufacturer or package, compare the outline drawing and marking with the part actually fitted on the board.
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.