A 42.7 KB PDF datasheet for the 1N5391 diode, listed here as a schematic although it covers a single component. Being the first number of the 1N539x series, it likely shares content with the full family sheet. Reference it for reverse voltage, forward current, surge rating and outline drawing when testing or replacing a rectifier in a power stage. Open it with any PDF viewer, confirm the package fits the PCB footprint, and install the new part with the cathode band oriented as on the board.
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.