Named 30LJQ150 and filed as a schematic, this 51.4 KB PDF looks like the datasheet for a discrete rectifier, with 150 plausibly indicating a higher voltage grade than the 045 and 100 versions in this set. No board or device is referenced. A technician would consult it to verify ratings and package outline when repairing a power supply section. As with any part datasheet, match the exact marking on the original component and confirm the replacement meets or exceeds its voltage and current limits.
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.