RK07 Manual Dual Port?

[Jay Jaeger]

After seeing an M7706 on eBay (and realizing I already have a spare),
but no dual-port card (M7730), and reading instructions in the
maintenance manual regarding placement of a single M7706 drive interface
card in either slot, depending upon whether A or B is selected I began
to wonder...

Is there any reason one cannot do a manual dual port on an RK07 by
having both M7706 slots populated, but then only ever selecting A or B
using the buttons on the RK07?  Has anyone ever done that?

The existence of two separate wire list pages in the schematic, and a
quick look at the M7706 diagram output signals suggests that this would
*not* work - that the output lines of the two M7706 cards are wired
together on a single-port drive and driven by ordinary TTL, and that a
dual-port drive had different wiring on the backplane, even though the
card cages are the same and the backplane itself is the same.

JRJ