Boardview for the U8C main board, marked MB with revision B, in a 278 KB RAR archive. Once extracted, the layout file opens in a viewer such as OpenBoardView or FlexBV. It shows where each component sits, how nets connect and where test points are, on both sides of the board. That makes it fast to locate a shorted capacitor or probe a specific signal. Confirm that the PCB carries the U8C code and revision B before relying on the placement data.
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 @cyberlanelectonik. 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.
7-ZipWinRARThe Unarchiver (macOS)