IMSAI 8080 (our show so far...)

Ok. There is a 16 pin ribbon cable between the front panel and the MPU-A card. It has dip headers on both ends and is soldered on the front panel and socketed on the MPU-A. looking at the front panel side, the pins on opposite sides are connected by original traces on the printed circuit board. That is (excuse the bad ASCII art): O O O O O O O O | | | | | | | | O O O O O O O O So I guess that is 1 to 16, 2 to 15, etc. Looking at the MPU-A... WELL SHIT! Sorry, I think I found it... no, that didn't help. There was a single strand from a braided wire resting across pins 7 and 8 on the rightmost N8T97N, however removing it doesn't seem to have helped. Anyway, the MPU-A only seems to have connections to pins 1-8 of the dip socket where the ribbon from the front panel connects. If I plug in the cable reversed, front panel behavior gets worse. That is, strange addresses pop up all over, the EXAMINE switch causes all sorts of odd activity. One odd thing is that the STOP switch still works. Anyway, there are no patches or cut traces on the MPU-A that I see. There are lots of patches on the front panel. Thanks, Bill