Schematic for a G31MX motherboard as a PDF of about 1.03 MB; the name gives no brand, design code or revision. G31 refers to the Intel G31 chipset used on many entry-level desktop boards. The document can help locate the regulator behind a missing voltage, check the CPU power phase components, and follow chipset links to the BIOS chip, Super I/O and ports. Look at the title block inside for the maker and revision and compare it with the PCB silkscreen, since similar names cover different designs.
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 @Datalvela_servicios. 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.