Named 20MT40KB, this 127 KB PDF is classed as a schematic, though the name does not identify any device, board number or revision. The format of the code points to a component designation and not a motherboard number, so open it first to see what is covered. Any PDF reader works. Reference sheets like this help when checking pin functions, measuring a suspected failed part or choosing an equivalent. Check the full marking on the original part before ordering, since a single letter can change the variant.
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.