Sony mainboard schematic for MBX-237, version 030 according to the name, delivered as a 2.68 MB PDF. No laptop model is given, so link it to the device through the MBX label on the PCB. The sheets support tracing power rails, checking voltage regulators, locating test points and identifying components when chasing a short or missing rail. Sony uses MBX numbers for VAIO boards made by various ODMs; confirm the board version matches before using component values.
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 @schematicslaptop. 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.