I got a DOA twin famicom from ebay for cheap as a little "challenge" system. Firing it up basically had nothing happen. I opened it, gave it a good internal bath (it was full of crud). Next I socketed some chips on my dev toaster for a little chip testing fun:
I next started desoldering and socketing the main chips on the twin pcb:
Tested the ppu in my toaster, ran, tested the cpu in my toaster, ran, tested the ram chips, didn't run with this one:
Swapped that ram chip with another one and..
The fds drive on this thing is probably never going to work. I got it to spin but it doesn't read anything. The p1 controller start button didn't work so I just swapped the pcb with the pcb from an original famicom controller (same pcb) and that fixed the start button. The p2 control pad down button barely works but the thing is so yellowed and nasty looking it's not even worth repairing.
*edit*
The case after some much needed cleaning. Still doesn't look perfect but a heck of a lot better than before: