Jim--
My Craftsman DP looks kinda-sorta like yours.
I have an unlocking lever that comes out about the
same place as what looks like the end of a bolt in
your pictue #4 (underneath the pulley closest to
the motor). Is there a lever on the Left side?
I'm guessing that's the speed selector knob on the
front (??) attached to the linkage and I'm guessing
that you've fiddled with it to make sure it's fully
engaged and not between positions?
And last - there's not a diagram on the inside of
the lid is there?