NEC schematic in PDF for a design labelled AF1, an internal project or model code. The name states no board number or revision, so look at the title block inside and compare with the label on your mainboard. Such drawings show power input and charging circuits, system rails, chipset and memory wiring and connector pinouts. Technicians use them to measure voltages, trace signals and find the cause of shorts or no-power faults. It opens in any PDF viewer, at about 1.1 MB.
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 @ITHINKHS. 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.