CREDO DDM metal detector User Manual
Table of contents. 1. 2. 3. 4. 5. - 6. 7. 8. 9. General description – page 3, 4 Assembly & Preparation – page 5 Controls – page 6, 7, 8 DDM – Definite Discrimination LED Meter – page 6 Discrimination Control – page 6 Ground Balance Control – page 7 Threshold and Auto Mode Control – page 7 Sensitivity Control – page 7 Volume Control and Power On/Off switch.
10. Troubleshooting – page 15, 16 General Description The CREDO DDM is an Analogue Induction Balance (IB) metal detector that operates in the very low frequency (VLF) range and it is designed for use on all Inland Sites and Tidal Salt Water Beaches. It may be used in any of the three basic modes of operation - Auto, All-Metal or Discriminate. The CREDO DDM is designed to be a general-purpose metal detector, capable of finding both small and large targets at extreme depths.
- 13"DD at 6kHz General search coil designed for higher detection ratio of small, medium and large targets in normal search conditions. It exhibits greater depth than any other DD search coil made by other competitive brands. It detects 18mm coin at 28 cm with very loud signal responses. Due to large search area it will find more targets for shorter period of time compared to smaller search coils. Not suitable for mineralised conditions due to high probability of producing multiple signal responses.
and experiment in order to obtain the best possible results on any particular site. All sites and soils are different and settings that will give good results on one site may be less successful if used elsewhere. The CREDO DDM is designed to detect the very deepest of targets and operates near to the limits of what is achievable with induction balance.
MAXIMUM and use the CREDO DDM Volume knob on the control box to set the volume level. Controls The CREDO DDM has six rotary control knobs and three toggle switches (two located on the front panel of the control box and one underneath the control box). DDM – Definite Discrimination Meter The DDM meter is based on LED technology and provides a reliable visual discrimination analysis in All-Metal Mode and Iron Rejection Mode. The bar will light RED for non ferrous targets and will not indicate Iron targets.
as low as is possible; to avoid masking the smallest and deepest desired targets. Ground Balance This knob is used to set the balance of the CREDO DDM to suit the soil conditions on any given site. Threshold and Auto Mode This knob sets the level of the threshold tone. The CREDO DDM may be operated in silent mode, with no audible background tone or with this tone set to give a slight tone level.
Mode Toggle Switch Located under the control box and accessible from the hand-grip, this toggle switch is used to change operating modes. When pushed to the left, the CREDO DDM operates in Discrimination Mode. In the right position, the Nexus Standard Mk II operates in All-Metal Mode. Battery Test Toggle Switch. This is located on the front panel of the control box.
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.
balancing. If there is no change in tone while doing this, then the sensitivity may be increased further. For best results, the setting should be at the maximum possible while maintaining a stable threshold tone. At maximum sensitivity settings, a slight tone change may be noted when both raising and lowering the coil. This will not adversely affect the operation of the CREDO DDM, providing that the coil is kept at a reasonably constant level above the ground surface and parallel to it while detecting.
In All-Metal Mode, both ferrous and non-ferrous targets will give the same audio response (unless the Multitone function is turned on) by a sudden increase in the intensity of the threshold tone. A strong response indicates a large or relatively shallow target and a weak response indicates a small or deep target. Any audio signal in All-Metal Mode may be analysed by using the DDM meter. To analyse a signal with the Meter observe its light response.
to reduce their interference, is similar to that used for Discriminating Ground Minerals. To remove the hot rocks and/or metallic ores from the audio signals turn on the Iron Rejection Mode using the toggle switch under the control box; this switch is move to the LEFT. Start swinging the search coil over a sample of the specific type of a hot rock or ore piece that you wish to be removed from the audio responses, positioned as you would detect them during normal searching.
Note: Gold nuggets and all small targets are best detected at the standard ground balance setting in All Metal Mode. This procedure is only recommended in severe contamination or bad mineral conditions. As setting the detector in this way will result in a high discrimination setting, while rejecting all large targets, there will be also a loss of depth for the remaining small targets as much as 50%. Discriminating Against Small Targets and leaving only larger metal objects.
It must always be remembered that no detector can find what is not there – nor can any detector give a signal unless the coil is passed directly over that target! There will always be sites on which any single detector does not work to peak efficiency.
Guarantee The CREDO DDM metal detector is guaranteed for a period of 24 months from date of purchase against all manufacturing defects. The Control Box is sealed and contains no user-serviceable parts Opening the Control Box will invalidate the Guarantee. This Guarantee does not cover: Damage due to dropping, impact or accident Damage due to improper use or care of the detector Damage resulting from leakage of batteries Damage to the coil or coil cable In the event of any problem, please contact us.
Troubleshooting 1. The detector does not turn on. Check the batteries. If they are old replace them with new. Make sure the batteries are properly inserted into the battery holder and have a good electrical contact. 2. The detector is giving too many false signals. If this happens first turn the Sensitivity to 0, minimum level. Check the Ground Balance if it is adjusted correctly according to the ground balance procedure.
