Circuit diagram for a Sony laptop mainboard identified as GD1A, supplied as a PDF of about 733 KB. Neither the VAIO model nor the MBX number appears in the name, so match the board code and revision on the PCB before you rely on it. A near-identical GD1B file also exists, most likely a sister variant of the same design. Technicians use such drawings to trace voltage regulators and signal paths and to identify the components around a short. Any PDF reader opens it.
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 @alischematics. 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.