Schematic PDF for a Lenovo mainboard numbered NM-A251, a pattern used by LCFC, the Lenovo-owned design and manufacturing arm. The file name carries no laptop model or revision, so match the NM code on the PCB to confirm compatibility. At 4.86 MB it should cover full circuit pages, useful for tracing power rails, finding the charger and VRM circuits and following signals during diagnosis of no-power or no-display faults. Any standard PDF viewer opens it.
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 @schematiclaptopramkushwaha. 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.