Hmm, good point...so it's a physical disruption of some part or other,
you say...any idea which wire?? Well, hopefully it's the adapter,
somehow...though the lil' brick looks fine...I'm going to borrow a
voltage meter at work tomorrow and see how that goes...do you think
it's an either/or situation -- either the adapter or the keyboard, or
that it could be both?

Damn, sure wish I had electronics shop class in high school!

Others have already suggested the solution multiple times. Either the wire
is broken in the adapter cord, something broke within the adapter itself, or
the power jack on the keyboard got yanked and cracked the solder there.
Anyone with basic soldering skills can fix this for you, if you take the
whole mess to a shop it should be under 100 bucks and it'll be good as new.