Do me a favor, put your machine in all metal and see if your menu go's from threshold back up to program, not to tones and then notch. I called Fisher and they said send it in. Got a call from a tech and he said that's the way it is suppose to work and that my machine checks out OK? I feel stupid but seems like they could have explained this when I called ?. I was relic hunting going back and fourth from all metal to discrimination when I noticed I could not change my tones. Well if this is true it's a lesson learned for me.