I just picked up a IIc. ROM 255. When you power it on, you get a changing pattern:
If I hit ctrl-reset, it will give me a normal boot screen, and then display the "check disk drive" message. If I hit ctrl-reset again, it will reboot to the garbled screen. When it does try to boot from the drive, I get the "check disk" message, regardless of whether I've got a disk inserted.
Occasionally, if I hit ctrl-reset rapidly, I'll get an Applesoft prompt. But even at that point, if I hit ctrl-reset (no apples held), it will reboot to the garbled screen. When I manage to get an Applesoft prompt, the keyboard is fully working.
Any suggestions on where to start?