Sony schematic in PDF form, 1.17 MB, labelled only with the MS01 project code and no model or MBX board number. The device it belongs to has to be confirmed from the title block and page headers inside the document. Once matched to the PCB, such diagrams help a technician trace power rails, follow signals between the chipset and controllers, and find the parts on a shorted line. Compare any board number and revision on the PCB carefully, as project codes alone can be ambiguous.
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.