IBM 5100 Restoration in progress

Hi All, Long time reader, first time poster. I am in need of some assistance in trying to revive an IBM 5100. It is a Basic 32k version that was in rough shape. You can see pics here: http://vintagecomputer.ca/ibm-5100-before/ I've been able to clean it up but when I fire it up I see a single "A" on screen. I can't seem to get into any diagnostic modes. The single "A" indicates an issue with the F2 Base I/O card. Some of the ICs do have some rust on them but I'm wondering if it might be the "bridge connectors" between the Base I/O and Controller (CPU) card. Are they directional or can then be swapped or turned around? I may have not kept them in the correct orientation but I don't see any mention in the Maintenance manual. I, pretty much, need someone who has one to take a picture of the top of their Base I/O and Controller cards. Any help is much appreciated. If someone happens to know a common issue that would make the "Bring up Program" stop at A, I'd love to hear about it. Thanks in advance, Santo