A 52.2 KB PDF with the lowercase name 2sc4938, indexed under schematics. The part number is the sole detail. JIS/JEITA numbering assigns 2SC to NPN bipolar transistors, so this should be the component datasheet rather than a circuit drawing. Technicians use such a sheet to identify the device by marking, check the pin assignment for its package, and read ratings such as collector-emitter voltage and collector current. Confirm the case style on the board before choosing any substitute.
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.