A 77.6 KB PDF titled 30LJQ100, catalogued among schematics, but the name reads as a semiconductor part number, so expect a single-component datasheet. It belongs to the same LJQ series as the 045 and 150 files indexed here. Datasheets like this provide reverse voltage, current rating, thermal data and mechanical outline, which are needed to choose a valid replacement for a shorted or open diode. Confirm the marking on the board part, and check orientation against the package drawing before soldering.
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.