Sony MBX-223 circuit diagram for the M960 and M970 projects, L model variant, revision SA, provided as an 843 KB PDF. A related H model uses the MBX-224 board, so check the MBX number printed on your mainboard to avoid working from the wrong set. The schematic helps trace DC-in and charging, CPU and memory power, and signal connections between chips, and identifies components near a short. MBX codes are Sony's internal mainboard designations, while the design itself is often made by an ODM.
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 @smschematics. 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.