I figured out what's wrong with the power tuning. The plastic gear on the end of the shaft coming out of the motor separated and broke in three pieces, allowing the motor to turn inside it without actually moving anything. I might try to glue it on there with some kind of heavy duty epoxy or something, but I don't have anything like that on me, I'll have to make a trip to the hardware store tomorrow. Here's a pic.
http://www.audiokarma.org/gallery/sh...ze=big&cat=503 You can see the upper part separated from the lower part on the shaft. It's not visible, but the lower part is also separated into 2 pieces.