Covering the 2SC3953 transistor, this 40.7 KB PDF is catalogued as a schematic, though a JIS part-number name like this normally denotes a datasheet. The 2SC prefix stands for an NPN bipolar transistor. Use the document to confirm leg order, maximum ratings and hFE grading, which helps when a transistor measures shorted or open and a suitable equivalent is needed. Verify the abbreviated marking C3953 and the package on the PCB against the drawing before substituting.
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.