The name 81CNQ035A on this 233 KB PDF identifies a rectifier part code in the International Rectifier dual Schottky family rather than a board, so although it is filed as a schematic, the contents are most likely a datasheet. The trailing A marks a variant of the base number. Open it in any PDF viewer to read pin configuration, case outline and limit values when diagnosing or replacing a failed diode. Verify the full part marking matches before ordering a 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.