So my new theory is that it's the MBox (either the
backplane, the
boards, or the wiring from it to connectors, etc) that is the difference
between the KL10-A and the KL10-B.
So I wuz confused; the second backplane is not the MBox (which is apparently
on the main CPU backplane), but an 'I/O backplane'. The one in the KL10-B is
different+larger and holds the RH20s, etc.
Noel