Hey Bill
You are going to like that little Bandit, it has a high gain cirquitry, Ed 120 discrimination and a 3 and half turn ground ballance.When you get it just drop a 9v battery in the back. For an initial tune................go outside turn it on,put it on full sensitivity, turn you discrimination on minimum, flick the right switch to autotune,flick the left switch to allmetal, thumb the left switch to retune and release it . Now listen to the treshold hum(use headphones) adjust(threshold on upper right side knob) to a low level that you can hear. Then raise coil to about 8 to 10 inches above the ground. Thumb left switch to retune and release, now quickly lower coil to ground. If the threshold gets louder as coil approaches the ground, it is set too positive,turn ground balance knob counterclockwise, if the threshold goes silent(null) it is set too negative, turn ground balance knob clockwise. I adjust mine to where it is set nuetral , that is , the hum stays the same as you raise and lower the coil. Just remember to thumb and release the retune switch (left switch) each time you lower coil to ground to check ground ballance. It sounds complicated untill you have done it a few times, it only takes me a minuite or so to GB a Tesoro...........Hope this helps............Hombre PS: after the ground ballance set the sensitivity to where the machine is stable, and set the Disc to reject a common rusty square nail, and get with it!!!!!!!!