I have recently revived 2 Amiga 4000 motherboards from the dead(well, I have done more but these were especially tricky) and I can now savely say that no matter how bad the corrosion is or how busted the Amiga 4000 motherboard looks it can be brought back to live 100%.
But these things do need some work though. What I always do first is replace all electrolitic capacitors with new ones because those are either flakey or dead already. Then fixup the battery area which might mean 1 or more of the clock chips might need replacing also and then I measure all traces around the battery area because you can get a trace cut at the weirdest places.
Then it's time for any of the larger chips.
