[462ron]

One trick that I have used successfully to find where a plate might be touching or shorting out will require you to disconnect any wires connected to the tuning gang. Charge up an electrolytic and connect it to the frame and the other lead to the stator. Then in a darkened room, rotate the tuner and if there is a short or some debris between the plates, there will be a spark, helping you to locate where exactly the problem is. Also, using this method, I've had the discharge of the electrolytic actually clear the problem, sometimes! YMMV

Ron