acer 250.....bump coil head on the ground and the unit beeps...

Ok, lots of ideas here but here is the botom line.

First off make sure your cable is wrapped firmly around the search pole, or it can cause this problem.

Yes, in (some) soils the Aces (and other Garretts too) WILL sound off sometimes when reacting to high iron content AND being bumped or rubbed on the ground. They aren't designed to be used that way anyway. Additionally they were NOT designed to be used in high iron soils. They were designed for the mild soils in most of the Eastern US soils and the weaker European soils. A few other detectors from mid 80's and prior will respond that way too. This is why Compass Metal Detectors invented autotrac. Yes, Compass invented it. DD coils and auto retune too.

Remember that the Aces use very antiquated circuitry with bells and whistles attached. But that bumping problem happens only on really HIGH magnetite or hematite soils, or, also for another reason that I'll tell you about, and why. There is another possibility, that the coil windings inside the coil cover have become dislodged from being banged around. This dislodging disturbs the magnetic field concentricity. If it hadn't been dislodged the magnetic field DOES NOT CHANGE.

If sliding the coil is your cup of tea remember that in doing so - that you lose a lot of depth doing this and will also lose good discrimination and good cherry-picking abilities too. The Aces already are handicapped in this regard so why push the inadequacies to the very limit? It just doesn't make any sense. NEVER, NEVER, NEVER scrub your searchcoil on the ground!

Read George Payne's engineer's notes about this and see why 1-2" off the ground is IDEAL! He'll tell you why too.

I've written SCROLLS about this here and on other sites too, but some people still don't understand how searchcoils work and they continue this practice anyway. A searchcoil has two polarities - Neg on top and Pos on the bottom, with an overlapping of both in two big patterns resembling two 4+ ft beachballs back-to-back with radiating field lines comprising it. Since Garrett has seen your machine already then you need to send some of your soil along with the detector and have them adjust the soil to your detector's internal ground balance. I'm quite sure that they have already checked for a loose winding, but if they screwed up you can do that too by shaking it while running. If shaking it changes the sound then your searchcoil is loose and you need another searchcoil. Actually, just buy a cheap Tesoro and it will be a superior machine to start with. Or get a Minelab or Fisher or White's and put a smile back on your face.

LL
 

Well in 4 years, mine has never done that...My Land Star does from time to time, but not my Ace...Seems like it might be a bad coil.........I am one of those scrubbers, it is a wonder I have a coil left at all as hard as I am on it...
 

Correctly designed coils with efficient faraday screening and cable shielding will not signal when bumped or brushed over wet or dry grass.
This was a problem with very early metal detectors until shielded cables and Faraday screening was introduced to protect the coils from external electrostatic charges that build up as the coil is scraped across the ground or grass and in particular, wet grass.

Also if the coil is not held extremely firmly within the coil housing (totally unmoveable) then a signal is generated every time the coil is bumped because the electromagnetic balance of the coil is altered when the windings move in relation to each other.

Even with properly screened,shielded and potted coils false signals are sometimes generated when the coil is bumped, I am not sure why this is but it may be because the sudden shockwave that travels through the coil epoxy potting and the windings may be sometimes strong enough to move the windings minutely in areas where the potting material may not have set solidly around the windings thus allowing them to move enough to produce a signal. In this case the only fix may be a new coil.

Adrian SS
 

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