@Abou27:
On the rev 3.0 and 3.1 A3640 boards, the C105, C106 & C107 capacitors are powered with reversed polarity which will eventually result in leakage so that could be the source of the corrosion on your board.
Read this page about that problem and what to do about it:
Amiga A3640 CPU Board RepairGood luck!
/Patrik
