Backlight circuit page from the Samsung SM-A30S schematic, stored as a 4.29 MB PDF. It covers the display lighting driver, typically the boost converter, inductor, diode and enable lines feeding the panel backlight. Repairers use it when the phone works but the screen stays dark, checking the boost output voltage, the enable signal and parts that commonly short after liquid damage. Opens in any PDF reader; compare part positions on the drawing with the actual Galaxy A30s board.
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 @phoneSchematics. 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.