Sony laptop schematic, an 891 KB PDF whose name refers to MBX-239 and MBX-240, suggesting one document covering two closely related VAIO mainboards. MBX codes are Sony's internal board identifiers found on the PCB. When both variants share a diagram, check the notes or BOM options to see which parts are fitted on your version. Open it in a PDF reader to follow the power path from the adapter, verify regulator outputs, trace power-on sequencing and find where a short on a rail originates.
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 @cyberlanelectonik. 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.