A schematic diagram for Dell hardware. Shared as “DELL_3421_screen_dark_screen_backlight_does_not_light_up_maintenance.pdf” — a .pdf file, 447 KB.
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 @bartonarquivos. 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)