What is wrong with my F75 ?

[WKyfisher]

I just got a brand new f75 SE black edition. Today I took it out for my 4th hunt using it.
Went to a school playground , the kind filled with brown pea gravel. The problem I am noticing is the pinpoint depth is way off. Coins 1-2 inches deep will pinpoint at 5 inches or more. I found several coins today all 2 inches or less in the gravel and every one of them pinpointed at 5 inches or more. I even rolled over a shallow zinc penny that gave me the double beep which means it's on the surface or extremely shallow. It pinpointed at 5 inches. All 4 hunts and 4 different locations this machine has acted this way. Also the vdi doesn't lock on like it should on these really shallow targets. My f70 will lock on and rarely move on shallow targets. My f75 is a lot more jumpy. Also the audio is not as clean ,loud ,and crisp as it is on the f70 on these shallow coins. I have not seen it pinpoint anything at less than 5 inches yet. Today's settings were factory default. Machine has been reset several times. Using the 11 inch DD factory coil. Baterries are brand new alkaline. Does anybody have any experience like this ? Could I have a faulty coil ?

 

[SueK]

I've had my F75SE for over a year and have not had that problem. Sounds like something that might need to go back to the factory for repair. Sorry it's not working right....I love my machine, and I hope they fix yours so you'll love it, too!

 

[FindandDetect]

Is it only doing it in the gravel?

 

[WKyfisher]

Is it only doing it in the gravel?

No it does it in dirt too

 

[FindandDetect]

Yup... I'd send it in. Sorry to hear that...

 

[WKyfisher]

I'm hoping it's something simple like a bad coil. I've only had this machine about 2 weeks

 

[ohiochris]

How far above the gravel/soil are you holding the coil ? I get baffled about way off depth readings with my at pro sometimes too until I remember I sometimes hold the coil an inch or two above the surface in some areas....and since the depth indicator on any detector isnt 100% accurate , its more of a general suggestion , the 1 to 2 inches above the surface plus a inch or two depth into the soil can easily look like 5 to 7 inches deep on the display. You have to factor in the distance from the coil to the ground and remember its not rare for the depth reading to be off a couple inches as well.

 

[WKyfisher]

How far above the gravel/soil are you holding the coil ? I get baffled about way off depth readings with my at pro sometimes too until I remember I sometimes hold the coil an inch or two above the surface in some areas....and since the depth indicator on any detector isnt 100% accurate , its more of a general suggestion , the 1 to 2 inches above the surface plus a inch or two depth into the soil can easily look like 5 to 7 inches deep on the display. You have to factor in the distance from the coil to the ground and remember its not rare for the depth reading to be off a couple inches as well.

I'm holding the coil just high enough so as not to scrape the gravel. On a coin that's 2 inches deep in the gravel my coil is 2-3 inches total above the coin. Not the 5 to sometimes 8 or 9 inches that the depth indicator tells me. I threw a coin on my grass on the surface and pinpointed it with the coil directly above the coin almost touching it. It said 5 inches deep. My f70 never acted like this. I'm starting to think more and more it's a coil issue

 

[CoiltoSoil]

Does it do it in all modes? DE, JE, etc?

 

[WKyfisher]

Does it do it in all modes? DE, JE, etc?

I've only used DE mode so far. But it shouldn't be doing it in any mode

 

[ohiochris]

I'm holding the coil just high enough so as not to scrape the gravel. On a coin that's 2 inches deep in the gravel my coil is 2-3 inches total above the coin. Not the 5 to sometimes 8 or 9 inches that the depth indicator tells me. I threw a coin on my grass on the surface and pinpointed it with the coil directly above the coin almost touching it. It said 5 inches deep. My f70 never acted like this. I'm starting to think more and more it's a coil issue

If your coil was 2 inches above the ground and the coin was 2 inches under the soil its not really uncommon many detectors to read the 4 inches total as 5 to 7 inches or so. Depth readings are commonly atleast a couple inches off and could be more under certain ground conditions.


One more possibility , sometimes shallow targets cause some type of overload and many detectors will give crazy depth readings. Just a suggestion since I dont know much about that particular detector , I would try turning down the sensitivity a little and see if that has any effect , seems like less sensitivity might aleviate overload if there was any. Probably a good idea to test it on known deeper targets as well , maybe something about 6 inches deep and see if that depth reading is way off as well. Just suggestions that might help determine what could be going on with it. But I am not familiar with this detector , only going on what seems common for many detectors , so take it for what its worth

 

[WKyfisher]

If your coil was 2 inches above the ground and the coin was 2 inches under the soil its not really uncommon many detectors to read the 4 inches total as 5 to 7 inches or so. Depth readings are commonly atleast a couple inches off and could be more under certain ground conditions.


One more possibility , sometimes shallow targets cause some type of overload and many detectors will give crazy depth readings. Just a suggestion since I dont know much about that particular detector , I would try turning down the sensitivity a little and see if that has any effect , seems like less sensitivity might aleviate overload if there was any. Probably a good idea to test it on known deeper targets as well , maybe something about 6 inches deep and see if that depth reading is way off as well. Just suggestions that might help determine what could be going on with it. But I am not familiar with this detector , only going on what seems common for many detectors , so take it for what its worth

I don't think that's it. There's prob 3 inches between my coil and the coin that's 2 inches deep. 1 inch of airspace and 2 inches of depth but it will pinpoint at 5 inches or more. 5 inches is the shallowest it has pinpointed anything. Some of these 2 inch coins pinpointed at 8 and 9 inches

 

[Captain Silver]

Never mind the 2 inch deep coins...how does it work on targets 6" deep or better? The F75 LTD/SE comes new with with a 11" and a 5" coil, how does that one work? Have you tried the coil off the F70?

 

[Bonefish101]

How far above the gravel/soil are you holding the coil ? I get baffled about way off depth readings with my at pro sometimes too until I remember I sometimes hold the coil an inch or two above the surface in some areas....and since the depth indicator on any detector isnt 100% accurate , its more of a general suggestion , the 1 to 2 inches above the surface plus a inch or two depth into the soil can easily look like 5 to 7 inches deep on the display. You have to factor in the distance from the coil to the ground and remember its not rare for the depth reading to be off a couple inches as well.

Thanks for that, I'd never have thought of that. That right there is a great help to me (clueless rookie), I was wondering why the depth readings always seemed a bit off, makes perfect sense now.


Sent from my iPad using Tapatalk HD

 

[WKyfisher]

Never mind the 2 inch deep coins...how does it work on targets 6" deep or better? The F75 LTD/SE comes new with with a 11" and a 5" coil, how does that one work? Have you tried the coil off the F70?

I haven't hit any deep coins with it yet. Took it to a couple playgrounds to get the feel for it. Yes my next step is to try some different coils on it before contacting fisher. There is definitely an issue with it though. Or I should say it doesn't pinpoint near as precisely as the f70 does. With the f70 it will pinpoint these 2 inch coins at 2 inches sometimes 3 not anywhere between 5 and 9 inches like this 75 is doing

 

[Captain Silver]

Definitely try the other coils and seek out some deep targets with it. Let us know how you do...

 

[WKyfisher]

Definitely try the other coils and seek out some deep targets with it. Let us know how you do...

Will do. It's back to the grind tomorrow of 12 hour dayshifts so I'll experiment with some different coils next weekend. I'm hoping someone chimes in and says hey my f75 did the same thing and the problem was "this" and I had to do "this" to fix it

 

[metaladdict]

I could pinpoint with the stock coil on my f70 way easier than the 11inch ddcoil.
Hope you get your f75 fixed.

 

[graybeard]

In stones or hard packed ground, the depth reading is usually off. Most of the time I don't squeeze the trigger or push a button to pinpoint, because the amount of trash that I am hunting in. When a target is found, you determine if you want to dig it or not. The depth reading being off would not bother me at all.

 

[WKyfisher]

In stones or hard packed ground, the depth reading is usually off. Most of the time I don't squeeze the trigger or push a button to pinpoint, because the amount of trash that I am hunting in. When a target is found, you determine if you want to dig it or not. The depth reading being off would not bother me at all.

For the most part I agree with what you are saying. But a fairly accurate depth indication is an important clue in what the target may be, especially when hunting for old coins. My F75 is very inconsistent with these depth readings. Like i said it has never indicated anything at less than 5 inches. Even a surface coin it reads at 5 inches. The pinpoint audio is inconsistent also. Some of these 1 or 2 inch coins the pinpoint audio will give me the high pitch squeal of a shallow target but the screen will read 5 inches or more. Other shallow coins have given me the lower tone pinpoint audio of a deeper target and the screen reads 5 inches or more depth and the coin would be 1-2 inches.

Something else I noticed yesterday. I dug a crusty zinc at 1 inch that read 5 inches. I tossed it on the surface of the gravel and passed the coil about 1 inch above it. With the coin directly under the sweet spot of the coil the pinpoint audio was silent. If i moved the coil to the left where I could see the coin between the spokes on the coil I would get audio. When I moved the coil to the right where the coin was between the spokes on that side there was no pinpoint audio. That seems very strange that the audio would not sound with the coin directly under the sweet spot and would only sound if the coil was moved to the left. It's like one side of the coil is not working if thats even possible. I dont know. I need to do some more experimenting