To those who have had problems. Does this sound familiar?

[Idaho-Marke]

Hi all:

I've been trying to ignore these symptoms and making excuses for this behaviour since I got my machine, but today at a lake with no electrical interference (and no back up MD!!!!) my F-75 lost it's mind.

I was running at 85, disc 9, 3H and DE and was digging some deep ones and having fun. Then I decided to cut out the foil and jumped disc to 20. Then the numbers started rolling. Bouncing all over the place. I turned it off and started in default. Made adjustments to where I had it and the numbers kept on flashing by. Turned it off and started in default a few times before it settled down. Left disc under 10. Was able to hunt some more. It acts like this when my vibraprobe is on which is why I am looking for a new pin pointer, but the pin pointer wasn't on. Later, it started acting up again. When I would lay my machine down to dig something numbers would start rolling and sounds would also be jumping all over the place. If I placed it this way or that way it didn't matter so it wasn't something in the soil.

Eventually, I lost confidence in the readings and drove 75 miles back home with three hours of sunlight and half a beach left.

This is not operator error. I have an MXT and also use a friends CZ20 for water hunting and have been MDing for years now. My MXT also hits deeper which people on this forum say shouldn't be happening.

I'm planning to drive 8 hours to a gold field in a few weeks to try out the F-75 with the dealer I bought it from, but now I don't know if I want to make the trip with a machine I have lost confidence in.

Before I send it in, I wanted to hear if this is the reason others have sent their machine in. If so, maybe Fisher can get it back to me in time. Please advise.

Thanks and HH

 

[jimmyk]

I hear having a cell phone on you can cause problems. I don't carry one when I detect, so I can't speak to that particular issue from personal experience. Just a thought.

jimmyk in Missouri

 

[Chris(SoCenWI)]

Idaho-Marke,

In DE mode for some reason when discrimination is set between 5-19(I think these are the numbers) it kicks the machine into a lower gain/pre-amp/somethein? mode. You might be able to crank the sensiitivity up high in this range but once below 5 or above 19 you may need to back the sensitivity way off. I've seen this many times when I've been detecting and once you know what the problem is it is easy to avoid.

99% sure this is the problem.

Chris

 

[Tinfoil]

n/t

 

[jbow]

I have found that I can run mine with the disc on 0 and the sens high in DE if Ikeep it in motion. Swinging it over the ground will calm it down but when you stop it will go crazy. On this setting it will respond to everything in the groung, including the ground. When you find something you want to investigate all the erroneous signals will disappear when you pinpoint.

The F75 really is an amazing detector.

J

 

[jbow]

It will do the same thing if you have anything notched in above 20 or below 5.

It is easy to accidentally have something notched in. If your F75 seem's unstable, reset it. Someone, Mike I think, said that they consider the factory reset to be just another function of the machine and so do I, I use it regularly. I find that sometimes after using higher disc or notch and then going back to regular 6 or 10 disc and no notch, somehow it does not completely come back and remain's a bit unstable. That is when I reset and it make's a world of difference.

Julien

 

[jbow]

cell phones only seem to cause a problem when there is not a good signal, like way out in the boonies and it is trying to reach out and touch a tower. Then it will cause a bunch of chatter. If I have a good signal, (five bars), then i have no problem from it. I never hunt without my cell phone. If it cause's me a problem then I switch it off but I keep it with me in case I need it. I also always call and tell my wife exactly where I am going to be. You cannot be too careful or, as they say, an ounce of prevention is worth a pound of cure.

J

 

[Mr.Bill]

A few things come to mind when I read your post. No disrespect meant, but perhaps you should re-read the owners manual. Take it with you in the field. It's tough to try and remember every bit of info printed in the book. With experience comes knowledge, and this also apples to the F75.


First thing, you had not found out if it was interference caused by something other than your detector. Did you try switching to another frequency to see what happens ?
They are 7 frequency's to choose from, and you would do this to help correct from outside interference.

I would have turned down your sensitivity a bit. Did you do this to see if it helped ? It certainly sound like the sensitivity was cranked up a bit too much from what your explaining.
After changing the discrimination settings I would have re-ground balanced over clean ground. Changing the discrimination on the F75 does have a way of changing the sensitivity, so having a sens. setting of #85 with a disc. of #9, and changing to a disc. #20, may have required a re-setting of the sensitivity, ground balance.

If you need any questions answered in person, please feel free to contact me by email, or phone me at my shop, 508-457-4805

Have a nice day

 

[Mr.Bill]

I would say your happy with your unit now. I guess things straighten up ?