Okay, the opera continues.
I found a flaky socket on the CPU card. The machine was showing some intermittent behavior. It would work fine for a couple of hours then .. not .. for a few more hours. During the trouble shooting I grabbed the 8212 whilst putting a scope probe elsewhere, then it worked fine. However, as soon as I let go the 8212, it would play the fool. It took an iteration or two before I caught on but eventually realized there was an issue with the 8212. Pushing it one way, it worked .. the other way it did not. So I replaced the socket. Now it works more reliably.
I'm not going to claim it's fully functional yet. But it's closer.
Stay tuned ..
(Does this sort of thing only happen to people that live out in the woods where every little part needs to be shipped in and handled by local hillbillies for the final delivery [read - painful process], or has everyone had these troubleshooting experiences? It also seems the trouble index is proportional to the square of the cost.)
(Oh, BTW, I am actually enjoying this. Really.)