Named 16TTS-S, this 109 KB PDF is catalogued as a schematic, but the name looks like a discrete semiconductor code with a suffix, not a board identifier. No model, board number or revision is stated. Part numbers of this pattern are associated with International Rectifier thyristor products, and the suffix commonly marks a package variant, so treat it as a datasheet. It helps confirm ratings, gate data and footprint when replacing a part; match the exact marking and package on the component before ordering.
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.