Fisher "F" Series Forum

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Fisher F-75 LTD malfunction
Posted by: comisoas
Date: February 05, 2019 11:05AM
Wonder if anyone else has experienced this problem. I have not used my detector in several months and fired it up the other day. I had 2 horizontal lines where the numerical readout is. There were lines marking out numbers above as though I set notch discrimination (which I never do). After about 5 second the detector nearly goes blank with a low growl. I tried another set of batteries, same thing happened. The coil cord is tight. Batteries are put in correctly. I tried the detector factory reset, same thing happened. Detector off, push Menu and toggle outward at the same time, turned detector on, for reset. Same symptoms. I called Fisher and they may have me send it in. I am going to buy fresh batteries and try one last time. Any insight would be appreciated.

Re: Fisher F-75 LTD malfunction
Posted by: Snap On Man
Date: February 05, 2019 12:10PM
Where was it stored? Humidity might have built up on the circuit board.

Re: Fisher F-75 LTD malfunction
Posted by: Mike Hillis
Date: February 05, 2019 12:49PM
Dead batteries make detectors do all sorts of weird stuff. Only takes one or two bad cells to mess it up.

Hopefully fresh batts will solve your problem.


Currently own and use:
***** Fisher F75 LTD w/DST ***** Whites V3 ***** Minelab E-Trac *****Teknetics ETPro ***** Makro Gold Kruzer *****Tesoro Golden Sabre II ***** Tesoro Compadre ***** Garrett ATPRO *****

Re: Fisher F-75 LTD malfunction
Posted by: comisoas
Date: February 05, 2019 01:20PM
I had it in the trunk of the car for a couple weeks, but it was cold here in NC during that time. No heat or humidity. Fisher said that should not have caused any problems. I will buy some fresh batteries and try.

Re: Fisher F-75 LTD malfunction
Posted by: WV62
Date: February 06, 2019 09:17AM
Check for corrosion on the battery contacts before you give up and send it back.

Ron in WV

Worked and lived in the Huntington West Virginia area all my life, retired 2010
US Air Force Vietnam Veteran (68-69 & 70-71)
Started getting into metal detecting around 1975

Re: Fisher F-75 LTD malfunction
Posted by: jd88047
Date: February 09, 2019 08:47PM
I hunt in a pretty rough environment. My F75 still hunted and it was in pretty bad shape when I sent it in. Fisher replaced coil and main box. I also upgraded the detector when the option came available. Mine never did that. If it dont hunt, send it in.

Re: Fisher F-75 LTD malfunction
Posted by: comisoas
Date: February 18, 2019 07:46AM
Good news. Mike Hillis is right. Apparently it was the batteries I used. I finally was able to access a fresher set of batteries that I previously have used in the detector and it worked fine. I just had used some mixed up batteries that had different charges and conditions apparently. I got all in a huff for nothing. We just finished moving so everything got all mixed up, including me, and my batteries as well. Thanks for all the comments!

Glad to hear all is well
Posted by: therover
Date: February 18, 2019 09:42AM
Yup, a mixed set of batteries can always be the culprit. Been there done that. Finally bought a battery tester and whenever I am ready to go out on a hunt, test the batteries I will be using.

I usually have a whole bunch lying around. I have now mustered up the courage to throw out batteries that test as low. Even though I know I can possibly salvage a few more hours on them, it's not worth the hassle.

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