I got a very dirty IIc locally. The initial memory test showed a bad RAM chip, which I've replaced. The self-test now reports "System OK," which is great! The only problem is that after replacing the chip, the keyboard (which worked before) now does nothing. No keys register, and the cursor sometimes either blinks VERY fast or shows an "alternate" character, a cross in reverse color, which isn't even supposed to be in the IIc's character set. Any thoughts? I've piggy-backed a keyboard encoder chip with no change. Maybe a bad character generator rom?