Fisher CZ-3D manual GROUND control with your thumb

"BOBBING" THE SEARCH COIL METHOD

1.Set as in the “Turn-On” procedure, making sure the DISC control is at AUTOTUNE and the SENSITIVITY control is set so you can just barely hear a threshold hum. Hold the search coil parallel to and 6 to 12 inches over the ground and at least three feet away from any metal objects. Do not use the PINPOINT button during any part of this procedure.

2.Lower the coil to an inch or two above the ground and then quickly raise it. Note that as you lower the coil, the tone disappears, then gets louder as you raise it and finally returns to normal when you stop it 6 to 12 inches above the ground. Conversely, if you set the GROUND control to 1, the threshold hum will get louder as you lower the coil and disappear when you raise it.

3.Your objective now is to adjust the GROUND control so that there is no change, or only a minimum change in the threshold hum, as you move the coil up and down. Start by lowering the GROUND control to 9. Lower the coil and raise it again. One of three things will happen to your theshold hum:

A It will fade again as you lower the coil and increase as you raise it. Continue to lower the ground balance setting in small increments until the threshold hum remains the same (or changes very little) as the coil is lowered and raised.

B It will get louder as you lower the coil and go silent as you raise it. Increase the ground balance level (rotating the control counterclockwise) in small increments until there is little or no change in the threshold level.

C The hum will remain the same, or if it changes slightly, the change is the same whether you lower or raise the coil. Your CZ-3D is properly ground balanced, and you are ready to begin your search. You have gone past the correct ground balance setting.

4.With a little practice, you should be able to ground balance quickly by “bobbing” the coil up and down in a continuous movement as you adjust the

GROUND control with your thumb. 9