However, a little investigating quickly showed that even the most basic ten-word TTY check program would not deposit or run. In fact, when depositing or examining sequential locations I found the address display would increment from 0200 to 0001. 0577 would increment to 0400, etc. So something is wrong with address bit 4. I pulled all the boards from the backplane except the CPU set and it still does it. Now I've got to fix the hardware! Sigh.