Schematic in PDF form, 1.39 MB, for the X55C laptop motherboard; the name gives the model and the RG tag, used on ASUS repair guide schematics, but no revision. A circuit diagram like this helps you work through the power-on sequence, find which regulator drives a missing rail, trace a short to ground and check connections between the chipset, memory and connectors. Open it in any PDF viewer, and since the revision is not stated, compare the board number on the PCB carefully with the title block.
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 @Motherboard_Repair_Guide. 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.