Stability of the F-75

[Lt4ever]

I just got my F-75, and I am trying to get used to it. It seems as long as I do not move it what so ever it is stable. If I tap the rod, control box, or coil, it goes nuts. Is that normal? All of the other detectors I have used were not sensitive to movement like that. I have not had it in the field yet, but it looks like it will go nuts very time I hit a twig, or clump of dirt. Any suggestions on this problem. It might just be Me have inexperience with a powerful machine.

 

[jimmyk]

Are you doing this inside your house? I find it very unstabel inside, but very smooth away from electrical interference, such as light bulbs and electrical appliances.

jimmyk in Missouri

 

[Lt4ever]

I have tried it in the house, and out away from any electrical source, and any vibration still makes it go nuts.

 

[UncleTom]

My 75 is not that way, but in the house forget about it. Check your coil connection.

 

[Lt4ever]

The coil connection is as tight as I can get it, and seated as far as the plug will go.

 

[Charlie P. (NY)]

I found mine to be a bit "motion sensitive",especially to bumps. I played with the coil and found that if I lead the coil wire straight up and then attached to the lower shaft about 4" up but with no tension on the rubber strain relief or coil wire leading off the coil things settled down to normal. Any side tension at the coil outfeed and it was very sensitive to bumps.

 

[Lt4ever]

Tried what you said, no good. Tries the cable tight, loose, and not around the rods at all, and still goes berserk.

 

[Charlie P. (NY)]

Give Fisher a call and tell them you have a coil that you suspect is "microphonic". (Old timers will remember you had to tap the old mics to get the carbon loosened up so they would work). If a tap produces a signal it is because something inside the coil is making an electrical connection. The F-75 seems to be more sensitive to that than most, but tapping the control box and getting a "beep" is a bit overly sensitive.

They'll test it and replace it free if this is the case.

 

[Charlie P. (NY)]

Oh, and what sensitivity setting are you running? Try 30 or 40 and see if that helps.

Sensitivity is like the focus ring on binoculars: too much is no better than too little.

 

[liquid1]

Sounds like your batterys are a bit loose..the new upgrade unless you have a new after febuary built machine is suppose to take care
of this issue..mine will become erratic if I suddenly move from side to side....tap on the top or side of the battery box..I dont know why the springs are so light but they are..I am now very smooth with my F75 and dont have any problems..I even did a air test in my dads log cabin the other day got a sweet 16" on a DR Pepper soda pop can..Now in my stick built house forget about it the machine will go nuts..learn to use low sensitivity around electrical interference, also go up to F7 it seems to help..The F75 is a sweet sensitive machine which is a good thing it will do a good job for ya..I love mine..

 

[Mr.Bill]

Phone up Fisher, and speak with Felix in the repair department. Ask him for a RA# to return the unit for a check over. If your the original owner, it's covered under the warranty if there's anything wrong.

If your not the original owner, speak to them about it. They may work something out with you ????

 

[Scully]

Also talk to the dealer you bought it from, he should be offering you help.

 

[Mr.Bill]

That may do the trick ?

 

[Mike Hillis]

If you bought it new, then I'd try to exchange it for another. Otherwise, its off to El Paso to visit the doctor.

Mike

 

[Scully]

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