RAR archive for the Dell Inspiron 3520 with Wistron board number 11280-1; the name also carries the DV15 MLK platform tags. Dell outsourced this design to Wistron, whose numbers follow the five-digit-plus-revision pattern seen here. Extract it with 7-Zip or WinRAR to check whether it holds a schematic, boardview or both. Such files help trace power rails, find test points and locate shorted components. Before use, verify that the 11280-1 number printed on the motherboard matches, since Dell models can use several boards.
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 @alischematics. Enginerys does not host this file.
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.