Anybody have any experience with batteries working just fine but the DC power adapter NOT working at all? It was working fine earlier today on a shoot, but suddenly only the battery was working. Tests seem to indicate that the DC adapter has power (batteries charge fine and power plug shows 12.2 volts at the end of the plug), but my camera won't recognize the power/plug and only runs on batteries?? Anybody have any ideas? This is a huge inconvenience for me as I'm in the middle of a feature film shoot!

Have you tried running the camera from Sony charger? this will tell you if the power port still works

12.2v sounds pretty close to a cut off voltage imho, maybe the camera has decided that there isn't enough voltage for it to operate safely on.