PDF schematic for the Lenovo B490 laptop, 1.95 MB in size. The file name gives no board number or revision, so open the title block on the first pages to see which ODM board it describes before trusting it. Technicians use such diagrams to follow power sequencing, locate the charger and VCORE circuits, and check signal paths around the EC and chipset. Any PDF viewer opens it, and text search for net names speeds up tracing a rail or a missing enable signal.
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.
Any PDF readerSumatraPDFFirefox / ChromeFlexBV (links PDF to boardview)