I think he meant that he tried ROMs from machines that had chimes of death, etc.. and no chime on the IIci.

I am thinking damaged traces to the ROM address/data lines. If you look how bad that oscillator is, all the ROM traces run right underneath it. Even if it looks clean, the acid/corrosion could have been absorbed in the solder mask, or the PCB itself and causing a "leakage" current between all the traces in the bus, resulting in this system. And jumpering out the select line between DIPs/SIMM isnt going to fix that issue, as the databus is the databus.