Lenovo E40 circuit diagram as a 1.38 MB PDF, whose name states the model alone. Board number, designer and revision should be read from the pages, and a similarly sized copy exists under another name. Technicians use schematics like this to check the charger and main regulators, follow enable signals through the power sequence, trace display and USB lines and find shorted parts. Another E40 drawing lists the HM55 chipset, so confirm which board your laptop uses before relying on 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.