When you tried using a ROM SIMM, you needed to remove the jumper next to the ROM socket. Did you do that? I'm not sure it would work, even so, as I've never heard of anyone using a ROM from an earlier model in the IIci. Nevertheless, that's a reasonable way to test whether the traces to the on-board ROM chips have problems.

Hmmm. Come to think of it, was the jumper *installed* when you tried it without the ROM SIMM? That jumper needs to be in place.

I agree with the earlier poster who said to try it with no hard drive connected. At this point you just want a good bong and a gray screen with a flashing floppy image and question mark. You don't need a hard drive or a floppy drive for that.