Schematic for the MSI MS-7399 mainboard marked version 4.0, supplied as a PDF of roughly 1.1 MB. MSI labels its desktop motherboards with this MS-plus-four-digit number. Opened in a PDF reader, the diagram lets you follow the CPU and memory power circuits, check the standby rail, and locate the parts responsible for a dead or shorted line. The board appears in several versions in this index, so confirm that the PCB is printed with 4.0, because values and component placement can change between versions.
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 @pepeelectronica. 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.