Toshiba Satellite M55 repair material packed as a 2.01 MB RAR file and tagged with board number LA-2721. LA codes belong to Compal, which manufactured this motherboard for Toshiba. The archive contents are not stated, though schematics are the usual payload at this size. Use the drawings to follow the power-on chain, measure the expected voltages on each regulator, and find components around a suspected short. Before relying on any value, compare the board code and revision printed on the PCB with the title block.
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.