Excalibur II Coil

[FloridaGoldDigger]

I have been having heavy falsing with my Excalibur II. I tried turning down the sensitivity all the way down and also set it on Auto. With a slight, very slight turn of the coil in the salt water it would false. I know my machine and knew the coil must have water intrusion.
I purchased the machine new in 2012, and about a year later the coil separated in the center. I appled a nice layer of epoxy to the coil and I guess the coil finally failed after a total of 5 years. I just sent it away to Kelly Co.

I took the coil apart due to curiosity and found that when I cut the coil cord, the copper was very clean, nothing was black. I opened the coil up and found the main copper coils running around the coil were also very clean. I was like "oh no". Is it something else. I then found a single wire that was black that went across the top of the coil in between the factory epoxy and the plastic coil. In one spot the wire was missing and where it should have been was just green corrosion. Seems like a defect or bad design, that all the coil wire is mainly set in epoxy but this single coil was more exposed causing failure.

You can see in the pictures how clean the copper is, except for the single wire running across the top of the coil. You will see the green corrosion where the wire was and black copper wire that connected to it.

Left picture black copper wire set outside of epoxy, nice clean wires set in the epoxy, middle shows green corrosion, last picture is general view. Look closely and you will see the damage. The single wire on the top of the coil is black and damaged, in the center of coil you will see where the copper wire runs to the side of the coil where there was corrosion and the wire was gone.

 

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[dewcon4414]

My opinion of some of these coil issues. First off the head on the lower shaft and those washers are to soft. That allow a lot of wear.... then we like to tighten them down pulling those ears in putting pressure on the two parts of that coil bottom. Some of those coils arent completely full of epoxy either. Them to contribute to it........ we love to lean on our machines..... bad idea. So if there are any wires not properly sealed when this separation takes place.........

 

[Treasure_Hunter]

Your coil leaked from the delamination on the bottom, most likely let salt water in before you found it and sealed it and caused it to rust and fail. Delamination is usually cased by not using a coil cover.

Coils should routinely be closely inspected for the first sign of delamination and fixed before it is allowed to leak into the coil, and cables should be inspected for cracks.

 

[FloridaGoldDigger]

Your coil leaked from the delamination on the bottom, most likely let salt water in before you found it and sealed it and caused it to rust and fail. Delamination is usually cased by not using a coil cover.

Coils should routinely be closely inspected for the first sign of delamination and fixed before it is allowed to leak into the coil, and cables should be inspected for cracks.

The bottom of the coil separated like you said, however I have always and still do use a coil cover.

I'm sure it was too late.

I heard they had some issue 's with the slim line. Hopefully the new coil is better. It would have made sense to seal the entire coil in epoxy.

Time will tell.

 

[FloridaGoldDigger]

My opinion of some of these coil issues. First off the head on the lower shaft and those washers are to soft. That allow a lot of wear.... then we like to tighten them down pulling those ears in putting pressure on the two parts of that coil bottom. Some of those coils arent completely full of epoxy either. Them to contribute to it........ we love to lean on our machines..... bad idea. So if there are any wires not properly sealed when this separation takes place.........

You hit the nail on the head...

If you don't replace the black rubber between the coil and the shaft in time, The shaft will dig out the plastic of the coil. It's important to replace them every year or so, depending on use. If not, you just continue to tighten the plastic wing nut to make the coil stable, making it worse.
I do at times lean on the metal detector shaft when digging, it's a bad habit but natural.

I just wish they had completed sealed the coil with epoxy. Didn't makes sense that the one wire was not sealed causing failure.

Any one else have the same problem?

 

[Treasure_Hunter]

The bottom of the coil separated like you said, however I have always and still do use a coil cover.

I'm sure it was too late.

I heard they had some issue 's with the slim line. Hopefully the new coil is better. It would have made sense to seal the entire coil in epoxy.

Time will tell.

It is usually caused by no coil cover but not all are. I agree all the windings should be covered with resin and most coils are but every now and then one has a bare wire exposed.

 

[FloridaGoldDigger]

It is usually cased by no coil cover but not all are. I agree all the windings should be covered with resin and most coils are but every now and then one has a bare wire exposed.

Thank you for taking the time to respond. I'm about to head out with the new Excalibur. It was a good excuse to purchase another one, can't be without one during repairs...lol.

Heavy overcast with rain,calm Gulf, and low tide at 6pm...perfect day for detecting.

Last week I picked up three gold rings, followed low tide in the same target line of heavy objects. Thank you Mother Nature!

 

[cudamark]

Good time to install a big coil, like the NEL Attack or WOT, and get the PP mod.