Hi- Can anyone tell me what would cause the needle on a meter just start bouncing all over the place just when sitting still. No metal around. Starts doing it shortly after I turn the detector on. Checked all the connections and can even turn down the sensitivity to nothing and same thing. Also chatters. It's a Garrett Master Hunter CX. I can still detect with it but it's hard without the meter and constant chattering to know if I have something. Any ideas would be greatly appreciated. Thanks Chuck