Got a call from Good Guys ... my Karma is on its way home. They ended up replacing it. Duh.
Neal did everything he could for me ... like too many great workers, he's often better than the company for which he works. When I brought my Karma in, he checked out the repair history for that model, called service, and said "look, every single one of these ends up being replaced, why don't you let me save us all some time by replacing this now." They said no. More than a month later, they let me know their conclusion: it needs to be replaced.
So thanks to Neal for trying. Nice to know my Karma will be back soon! I never really got a chance to mess around much with the Zen Xtra that Robin got for me ... now it's up to Sara to tell us how it is, since she's going to get it, now.