CREDO DDM Metal Detector, User Manual

Page: 9 / 17

9
Full Manual Set-Up
Firstly, ensure that no metal is in close proximity to the coil. It is also
advisable to carry out the tuning and setting up of the CREDO DDM
away
from other metal detectors or potential sources of electronic interference.
Turn the CREDO DDM
on. A tone will be heard and the DDM meter will
flash. The tone will fade and the meter bar will settle after a few seconds.
To check the condition of the batteries, turn the Battery Check toggle
switch up. After the battery check is been done turn the toggle switch down
to enable the DDM to indicate metal targets. Keeping the DDM indicating
the battery condition continuously will drain the batteries fast.
Holding the CREDO DDM
with the coil well above ground level, adjust the
Sensitivity control knob to minimum. Adjust the Threshold knob to obtain a
minimal (faint) tone setting. Adjust the Volume knob to set a comfortable
level (remembering to set any adjustable headphone volume control to
MAXIMUM). Lower the coil to the ground and sweep side to side slowly to
ensure that there are no metal targets in the place you are tuning the
detector When you are satisfied proceed as follows.
Position the coil about 3
” above and parallel to the ground surface. Raise
the coil gently to about 10” (250 mm) above the ground and lower back to
3
” (75 mm) above ground several times. Note whether the threshold tone
remains the same or if it increases or decreases in intensity while raising
and lowering the coil. If the tone rises when LOWERING the coil towards
the ground, then adjust the
Ground Balance knob slightly in the clockwise
direction. If the tone rises when LIFTING the coil away from the ground,
then adjust the
Ground Balance knob slightly in the anti-clockwise direction.
Repeat this procedure to check and if the tone remains constant, the
ground balance is set properly.
IF THE GROUND BALANCE IS INCORRECTLY SET THE DDM METER
WILL INDICATE FALSE SIGNALS FROM THE GROUND MINERALS.
To achieve the best ground balance tuning, it is essential that the coil be
held parallel to the ground surface at all times during the procedure.
The next setting is to adjust the
sensitivity to suit the site conditions. From
the minimum setting of the Sensitivity knob (set at minimum in the initial
ground balancing procedure), adjust the control clockwise to increase the
sensitivity. Repeat the procedure of raising and lowering the coil between
3
” (75 mm) and 10” (250 mm) above the ground surface, as for ground