A 74.3 KB PDF classed as a schematic and named only after component 1SS311. The 1SS prefix comes from the Japanese JIS scheme for small-signal diodes, a range Toshiba manufactures extensively, suggesting a datasheet for a single part. It is useful for confirming anode and cathode pins, reading reverse voltage and forward current ratings, and decoding the marking on a tiny SMD body. Any PDF viewer opens it; match the board part marking and package against the sheet before replacing anything.
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.