SD2100 Threshold

I have just recently aquired a SD2100v1 when trying to setup the detector I am having trouble with the threshold control, when I turn this knob it does not seem to adjust the level of the background hum and is really loud and can not turn down.

Is this a problem with the detector or more learner user error

Sounds like there seems to be a problem, If I were you I would get it checked out by Minelab.
The Threshold when adjusted should reduce and increase in sound.
Perhaps try another coil and or battery narrow what maybe a problem ( I am assuming that you are trying it away from built up areas with all the EMI around towns and cities.

thanks for the response, i am trying it away from town, I will try another coil and see how i go. If not will send of to minelab for further investigation

Stuart,
Maybe your machine is in "overload" if you are testing it in suburbia. Get out of town and see how you go.

Stuart I just checked the schematic,its possible there is a bad/broken connection or solder joint to the pot(threshold control)as there is a +5v on one side and a -5v 0n the other,this allows a ref voltage to the ic's and would cause the problem so mentioned,it may pay to have a quick look behind the panel.I'm guessing the threshold gets a bit of use and may even have taken a knock at some point.You could verify with a meter if your handy.There is also a 3.3m resistor from the centre of the pot that may have gone high.