F75 5" Coil Overload Signal Could Actually Be a GOLD RING?

[David53]

I purchased an F75 around two weeks ago. I took off the Stock Coil and replaced it with a 5"DD Coil. Then I conducted several air tests before I went to a school to do some detecting. During these Air Tests as long as my Sensitivity was at least 30, I receive an Overload Signal Sound 100% of the time whenever a Nickel or to my surprise a Gold Ring touched the Coil or was less than an inch from the Coil. If I lowered the Sensitivity to 29 or less no matter what process I used, I did not receive an Overload Signal when I placed a Nickel or Gold Ring up against the Coil or in very close proximity to it.

I experienced the Overload Signal later while detecting at the school when my Sensitivity was set on 60 and Instead of walking away, I checked to see what had produced the Overload Signal Sound. Sure enough, it was a Nickel located on top of the ground. Had I not conducted the Air Tests, before, I would have never have checked to see what was causing the Overload Signal Sound. Instead, I would have assumed it was a trashy target and walked away $.05 poorer or if the Nickel had been a Gold Ring, I would have ignored it as well possibly missing the find of a Life Time.

 

[REVIER]

My F70 doesn't really do that on any sense setting even maxed in disc or all metal.
I have used that same coil a ton and don't remember any overloads on any coins...even on the surface.
Just checked that, got the Sharpshooter mounted now but even scraping the nickel on the entire coil no overload nor have I noticed anyone else with an F75 mentioning this.
On a coin or anything else small like that.

Could be normal on an F75 but I would check into that.

 

[dfmike]

Never experienced this with my F5 or F19 either no matter what coil I use and I do have the 5 inch round coil.

 

[David53]

I received several overload signals today once again while detecting with my F75 and while using the DD 5" Coil that turned out to be sometimes coins and sometimes trash when the targets I was detecting were less than an inch from the Coil. I was using a sensitivity of 60 in the Default Process Mode.

 

[David53]

Today I also received the Overload Signal when any coin or metal target was within an inch from my F75 5" Coil. This happened very seldom though because most of my targets I dug up were no less than several inches deep.

 

[REVIER]

Something is not right.
These will overload but over targets that will logically trigger it, large cans shallow, big pieces of other metals close to the coil, etc.
Yours overloads way too much on targets way too small...something is wrong.
If it does this on the small coil only and not the bigger coil that would be a clue.
If it does it on both the electronics are suspect.

Was this bought new or used?

 

[David53]

I bought it new about 2.5 weeks ago. It is the first Fisher I have ever had. I also use a Compadre, Lobo, AT Pro, Sovereign GT, and CTX. None these other detectors produce the overload signal like the small coil on the F75 does. I will have to send my 5" coil back in for an exchange since it is still under warranty. Before I do, I will make sure the Stock Coil doesn't Overload the same way as the 5" Coil. Thanks for the heads-up.

 

[vlad]

on a CZ will overload on larger shallow coins.

 

[David53]

I tried the Stock Coil and it also overloads when a Gold Ring or Platinum Ring is placed against the Center of the coil, but not as often as with the 5" coil?

 

[REVIER]

I tried the Stock Coil and it also overloads when a Gold Ring or Platinum Ring is placed against the Center of the coil, but not as often as with the 5" coil?

Before you do anything else CALL Fisher and talk to them.
Tell them what is happening...they could have changed something recently on the newest ones so it could be normal, I doubt it but you never know.
If they want you to send it back you need an RMA number anyway so a call is in order either way.

A hassle, but even though it's rare a few lemons can escape from the factory.
Fisher will make it right, for me hunting with all those overloads would be a real drag.

 

[BarryL]

couldn't stand it any longer did a check on all my coils 5 inch concentric, NEL Sharpshooter, 11inch DD coil I just got and also the 6x3 coil . put a Nichol on the floor and passed each coil over the Nichol at about 1 inch no overload but touched the Nichol or within 1/8 of an inch every coil would overload signal . So I would say your coils are good , with that being said I would say the coils are so sensitive this will happen , Sensitivity was set at 33 for this test . Also went back and lowered Sens to 20 and no overload even with Nichol touching coil with movement . !

 

[Dave J.]

The rule on overload is "back off!" unless you already know what's causing the overload.

 

[David53]

I called Fisher and they said the overload signals I was getting were normal as well. If small targets produce Overloads more than an inch from the Coil then I would have a problem. The person I spoke with gave me some tips such as going into all metal mode and setting the threshold to -5, then going back into Discrimination Mode and setting the Sensitivity as high as possible and the detector is supposed to run more smoothly due to the threshold being set to -5. I am definitely going to try this out. He said the Default Mode is the most stable Process to use. He also indicated that the newer Nickels produce less consistent VDI #s than older ones produce. Lower sensitivity means less depth, which can sometimes come in handy if you're looking for small Jewelry that may not be deep.

 

[Cal_Cobra]

The engineer that designed the F75, gave you the best advice possible above

I called Fisher and they said the overload signals I was getting were normal as well. If small targets produce Overloads more than an inch from the Coil then I would have a problem. The person I spoke with gave me some tips such as going into all metal mode and setting the threshold to -5, then going back into Discrimination Mode and setting the Sensitivity as high as possible and the detector is supposed to run more smoothly due to the threshold being set to -5. I am definitely going to try this out. He said the Default Mode is the most stable Process to use. He also indicated that the newer Nickels produce less consistent VDI #s than older ones produce. Lower sensitivity means less depth, which can sometimes come in handy if you're looking for small Jewelry that may not be deep.

 

[Oldguy]

The same thing happens with my F75. The solution is to simply raise the coil up from the ground and continue sweeping it. The small target too close to the coil will give a good reading with the coil several inches up from the ground, the aluminum can or large iron will quickly reveal itself this way.