RAR package for the FIC TY640 board at revision 0.3, which the name associates with the STI 1462 system built on this First International Computer design. About 1.30 MB, it likely contains schematic pages. STI sold machines using ODM boards, so service data is indexed by the FIC code. Extract with WinRAR or 7-Zip and use the drawings to trace power rails and signal paths. Confirm the TY640 marking and Rev 0.3 on the PCB before trusting component values.
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 @IT_SERVICE_WORLD. 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)