Schematic PDF of 1.01 MB for the board identified as 71R-NH4SU4-T850, with a note marking it as compatible (compatível), suggesting it applies to related board variants as well. The 71R prefix numbering is common on boards from the Chinese laptop makers supplying budget brands, but the name does not state the laptop model. Use it to trace power rails, check circuits around the charger and PWM controllers and find signal paths. Verify the code printed on the PCB, since a compatible schematic may differ in minor 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 @oficinacomputadores. 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.