11'' commander mono

I just brought myself an 11'' mono and I was really happy with the sensitivity of it, but every time i bumped a little rock it went off its head I gather that there is an issue with this coil as it should not be doing this,
the one thing I can say is that the skid plate will last forever as I cannot hit any rocks with it no matter how soft it is bumped.
am I right in thinking that I should send this back and get a replacement?

cheers

koeh

I have a small elip that does the same. Sometimes if i uplug it, redo the twist around the shaft, Use heaps of velcro around near the head so the lead doesnt move it goes like a champion. You could use it as an axe without it going off. But sometimes its hard to sort it out to stop it being bump sensative and i feel like throwing it across the paddock...
I have spread the pins in the plugs and that also helped a little.. Remember the vibration goes up the shaft so check the top lead where it goes into the CP.
Worth a try b4 u send it back...

Yes, you should send it back. Before you do make sure that it isn't the cable or plug moving when you hit something or the detector rising upwards (glancing upwards off what you hit making the detector react to the ground). What I suggest is that you rest the coil on the ground and whilst holding pressure on the coil shaft so nothing can move, hit the side of the coil with a piece of wood to see if it reacts. If it does make a noise without anything moving then the windings are loose and it will give nothing but trouble in the future...

a fellow member i know had this problem with the same coil.

if everyone elses suggestions doesn't help, then it may be a faulty coil. if this is the case send it back to minelab. if you can get a video of the unit making noise (and this might just be as simple as putting a small amount of pressure on the coil with your fingers) upload the video to youtube and send the link to that youtube video to minelab so they can see for themselves how touch sensative your coil is.

sounds like a fault to me.

Thanks guys for the quick replies, I will give them all a try before I make a phone call.

Cheers

koeh

what do you guys think of this?

https://youtu.be/E4wX58DfKA4


cheers

koeh

hard to say. the one i saw did the same thing with less pressure.... is the noise only coming from that one side of the coil, or does it do it on the other side as well.

Does it do that if you used a piece of wood or something insulated? The reason I ask is that sometimes a static build up in the body can be detected when touching the coil. Seems to me from what I saw was maybe the downward pressure of squashing the coil may move the foam in the coil making the squeal. Tomorrow I will try that with my coil and report back tomorrow night....

Ismael wrote:Does it do that if you used a piece of wood or something insulated? The reason I ask is that sometimes a static build up in the body can be detected when touching the coil. Seems to me from what I saw was maybe the downward pressure of squashing the coil may move the foam in the coil making the squeal. Tomorrow I will try that with my coil and report back tomorrow night....

That would be great if you could Ismael i would appreciate it, I couldn't find a stick when I went out as i didn't take a torch with me, but I did stand the detector up vertical and just the weight of the detector on the coil made the thing squeal.

Goldbait,

When I pushed on the other side of the coil it did make noise aswell.

cheers

koeh

koeh wrote:

Ismael wrote:Does it do that if you used a piece of wood or something insulated? The reason I ask is that sometimes a static build up in the body can be detected when touching the coil. Seems to me from what I saw was maybe the downward pressure of squashing the coil may move the foam in the coil making the squeal. Tomorrow I will try that with my coil and report back tomorrow night....

That would be great if you could Ismael i would appreciate it, I couldn't find a stick when I went out as i didn't take a torch with me, but I did stand the detector up vertical and just the weight of the detector on the coil made the thing squeal.

Goldbait,

When I pushed on the other side of the coil it did make noise aswell.

cheers

koeh

Sounds like a faulty coil. No coils should make a noise when hitting an object when swinging unless they have a sudden "lift or Glance" upwards from the ground sending the detector suddenly out of balance. Years ago I bought a little Coiltek "Joey" coil that did the same and I thought nothing of it. I lent my detector to a mate and after the trip they commented that the coil was rubbish. They did a comparison with another mate's joey coil and it was way below par on sensitivity. I sent it back to coiltek and knowing the 2 Johns at the time they said there was nothing wrong with it but replaced it all the same... The new joey was miles better and never made the "Twang" when hitting an object. Even my homemade coils only suffer from the dreaded twang when the coil or windings can move even if only .25mm. That is why if you ever look at a coil when pulled apart, the manufacturers generally enclose in an epoxy or varnish type paint around the coil after being "spun". It stops any of the coil from moving. I would take it back...

As an after thought make sure you properly balanced as this will make a coil do the "twang" so double check that also...

Ismael wrote:

koeh wrote:

Ismael wrote:Does it do that if you used a piece of wood or something insulated? The reason I ask is that sometimes a static build up in the body can be detected when touching the coil. Seems to me from what I saw was maybe the downward pressure of squashing the coil may move the foam in the coil making the squeal. Tomorrow I will try that with my coil and report back tomorrow night....

That would be great if you could Ismael i would appreciate it, I couldn't find a stick when I went out as i didn't take a torch with me, but I did stand the detector up vertical and just the weight of the detector on the coil made the thing squeal.

Goldbait,

When I pushed on the other side of the coil it did make noise aswell.

cheers

koeh

Sounds like a faulty coil. No coils should make a noise when hitting an object when swinging unless they have a sudden "lift or Glance" upwards from the ground sending the detector suddenly out of balance. Years ago I bought a little Coiltek "Joey" coil that did the same and I thought nothing of it. I lent my detector to a mate and after the trip they commented that the coil was rubbish. They did a comparison with another mate's joey coil and it was way below par on sensitivity. I sent it back to coiltek and knowing the 2 Johns at the time they said there was nothing wrong with it but replaced it all the same... The new joey was miles better and never made the "Twang" when hitting an object. Even my homemade coils only suffer from the dreaded twang when the coil or windings can move even if only .25mm. That is why if you ever look at a coil when pulled apart, the manufacturers generally enclose in an epoxy or varnish type paint around the coil after being "spun". It stops any of the coil from moving. I would take it back...

As an after thought make sure you properly balanced as this will make a coil do the "twang" so double check that also...

When I did have it on my detector I did balance it a few times to see if it did make any difference but it didn't.
I ended up calling minelab today and told them the problem I was having with it and they told me to send it to them as it could be faulty.
I dont know if i mentioned it before but if you put the coil on the ground and lifted the detector to the vertical position the weight of the detector on the coil was enough to make it squeal like a pig, I will post the outcome once I hear back from minelab.

thanks all for your input.

cheers

koeh

What Ismael has posted is correct. I recently brought a new 11"mono commander for my 4500. It runs like a charm and is pretty bomb proof unless you do as Ismael suggested and raise the coil while your detecting and bump or knock the coil in which case it gives off a sound like a target. But once i am back and detcting nice and smoothly again there are no ptoblems.
Cheers Steve.

I got my coil back yesterday from minelab, I have not had a chance to test it since it has been repaired but hopefully everything is all good.
According to the repair sheet from minelab it was incorrectly wired/assembled, I actually rang minelab on monday and they said that they had to cut it open to fix the insides, I am pretty happy with the service from these guys a big pat on the back from me.

cheers

koeh