Okay, it seems I have a power problem. This may merit a new thread but I'll try this one, first.
1. I had been reading my multi-meter wrong, looking at the wrong row of numbers. What I though had been 5v was slightly more than 1v. Not enough to power the TB, so no wonder Windows wasn't finding it.
2. When I read the supplied harness coming off the I-pac pins (for the optipac) it reads nearly 8v (more than 7, anyway). But as soon as I hook it up to the optipac, or directly to one of my P360s, it again drops to between 1-2v.
3. Here's the really weird part: when I put my multimeter black sensor on an Ipac GRND terminal, and the red one on ANY OTHER screw terminal, I'm seeing almost 8v. I'm thinking this is a problem.
I'm at a loss here. Any advice?