I finally got the rebuilt industrial PC shipped back to Seattle earlier this week but not without a small worry at the end. The PC has two digital I/O boards: one has 8 I/O; the other has 20 I/O. While testing the 20 I/O board, the inputs had a strange behaviour. The 20 inputs are read as sequence of three bytes and the lower nibble of each of those bytes were always zero.
After some head scratching, I finally went and checked my notes from the first rebuild project. And right there, plain as day, is a note that the new SBC has on board I/O which has a port conflict with the 20 I/O board. The solution is to disable the SBC's I/O in the BIOS.
So the lesson for the week is, if you make notes, why not use them? ^_^