How To Tell if Your Metal Detector Coil Is Bad (4 Signs)

If something seems off with your metal detector out in the field, it can be difficult to know which part of the tool isn’t working properly. Often, the problem is with the coil, as the coil is one of the most essential parts of a metal detector.  

You can tell if your metal detector coil is bad if it is chattering a lot, there’s water underneath the coil cover, your metal detector targets only shallow depths, the detector can’t detect silver or copper.

In this article, I’ll discuss four potential faulty metal detector coil symptoms, so you know what to look out for. I’ll also explain how to repair a metal detector coil so you can get back out in the field detecting. Let’s get started. 

1. Your Metal Detector Is Chattering a Lot

One potential sign of a bad metal detector coil is if your metal detector is suddenly doing a lot of chattering. A noisy metal detector is not enjoyable for the user and wastes lots of time because you’ll end up digging up trash instead of your desired objects. 

If you’re out in the field, most of the time, you can briefly fix a faulty metal detector coil by giving it a quick whack with your hand. I also recommend removing the coil cover to see if any dirt or water is caught underneath. If there is, the debris moves around while you’re using the detector, which can cause all the chattering. 

However, if your metal detector is chattering a lot, don’t automatically assume it is a defective coil. Sometimes, metal detector coils frequently start chattering because the sensitivity is set so high that the coil picks up everything in the ground instead of your desired objects. The coil in this scenario is actually working too well.  

If you’re a beginner or determined to make a find, you might be tempted to turn up the sensitivity on your metal detector as high as it can go so you don’t miss out on anything. This method is not good because your detector will respond to everything, even little bits of trash underground. Instead of cranking up the sensitivity, I recommend adjusting your settings according to the material you’re looking for.  

The following table outlines the recommended sensitivity settings for various materials: 

Material Sensitivity 
Silver 7 kHz 
Copper 7 kHz 
Brass 7 kHz 
Gold 15 kHz 
Iron 10 kHz 
Nickel 8 kHz 
Aluminum 8 kHz 
Zinc 10 kHz 

If you don’t have your sensitivity settings turned up and your metal detector is chattering more than usual, that may be a sign of a faulty coil. 

2. The Coil Has Water in It 

Another possible sign of a faulty coil is if there is water trapped in the coil. Even waterproof coils can get thrown off by excess water, so check underneath the coil and see if there’s a buildup of water that you need to clear out. If you’re metal detecting at the beach, it may not be the water itself that’s the problem but the sand and debris in the water. You should also be wary of metal detecting in grass drenched in dew. 

There’s no reason to be paranoid about getting a metal detector wet, though. Most of them are waterproof, at least up to the control housing. If you want to metal detect in the rain, I recommend purchasing a rain cover.

I suggest this UproMax Store Metal Detector Rain, Dirt, Dust Cover from if you have a Garrett or Minelab Equinox metal detector. This waterproof cover features transparent PVC film that makes it easy to still see all the controls, and it’s designed so you have easy access to the headphones jack, the connector to the coil, and the buttons cover.

If you don’t want to invest in a rain cover, you can use a plastic bag instead. Just ensure that there aren’t any holes in the bag and that you wrap it tightly around the detector so it doesn’t catch on things as you’re detecting. I suggest using electrical tape to seal the bag around the protector. This method isn’t as convenient because your visibility will go down the more water drops there are on the bag, but it’s a good solution in a pinch. 

If you have been metal detecting in the rain, remove the coil cover as soon as you’re in a dry space to clear out any moisture that’s gathered underneath. By being proactive in this way, you can prevent any coil trouble in the first place. 

3. Your Detector Is Only Detecting at a Shallow Depth

If you know that your metal detector can detect objects buried deep underground, and then suddenly you’re only picking up objects with five centimeters (2 inches) or less of depth, your coil probably has a broken wire inside.

If you aren’t sure whether or not you’re experiencing this problem, you can test your metal detector by digging a hole and burying a metal object. Then, try running your metal detector over the area. If the detector can’t identify that there’s a target there, your coil is probably malfunctioning in some way. Most working metal detectors can reach objects up to 45 centimeters (18 inches) underground, and specialty detectors can go even further. 

Metal detector coils send an electrical current through a wire to create a magnetic field. This magnetic field creates an opposing current when it reaches a metal. Therefore, if the metal detector isn’t sensing any opposing currents, it is a sign that something has gone wrong within the coil and isn’t working properly. 

4. Your Detector Can’t Find Silver or Copper

Silver and copper are the two most challenging metals for a metal detector with a faulty coil to pick up. These are two relatively common and desirable metals, so you’ll probably notice if suddenly your detector isn’t finding anything made of these materials. 

Before you jump to the conclusion that your coil is defective, though, check your settings to make sure everything is set up correctly. If you’re looking for silver or copper coins, I recommend checking out my article on the best settings for coins: These are the Best Metal Detector Settings for Coins

How To Repair a Metal Detector Coil

Now that you know the signs of a faulty coil, you need to learn how to repair it to get back out and metal detecting again. 

The method for repairing your metal detector coil varies depending on the brand and type of metal detector you have, but in general, you’ll follow these steps: 

  1. Loosen the cable gland with a pair of pliers.
  2. Cut out the glue holding the coil cover using a sharp blade. 
  3. Separate the slide covers so you can reach the cable. 
  4. Locate the wire resting on top of the cardboard on the flat part between the covers. 
  5. Ensure the wire is still connected to the outside of the cable. If it isn’t, reconnect it. 
  6. Put tape over the wire to hold it in place or glue it down.
  7. Reassemble the covers. 

Sometimes, repairing a cable isn’t enough, and you’ll need to do a complete replacement. You should buy a replacement coil that will fit and work with your metal detector, as they vary in shape and compatibility.  


Metal detector coils occasionally stop working for various reasons, and when this happens, there are several signs that something has gone awry with your metal detector coil. These signs include constant chattering, water inside the coil, the inability to detect objects deeper than five centimeters (2 inches) in the ground, and the inability to sense silver or copper. If you notice these signs, you may need to repair or replace your metal detector coil.

Alexander Picot

Alexander Picot is the principal creator of, a website dedicated to tips on finding and collecting precious items. Inspired by reading countless adventurer reports from the oldtimers, Alex is passionate about discovering hidden treasures and loves to share his experience with the rest of the world.

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