coil bleeps when my hand passes over coil

[dejavuband]

is this normal on full power ive checked the earth inside box to coil connector and it was hanging on by 1 single strand of wire so i fixed that but it still does it on full power it also picks up on cheese and tomatoes but i can discim the tommys out,this sounds like a joke but im not kidding it does it on all three of my coils,machine is modded cibola,any ideas lads

[Qiaozhi]

is this normal on full power ive checked the earth inside box to coil connector and it was hanging on by 1 single strand of wire so i fixed that but it still does it on full power it also picks up on cheese and tomatoes but i can discim the tommys out,this sounds like a joke but im not kidding it does it on all three of my coils,machine is modded cibola,any ideas lads

Has this only started happening since the Cibola was modified? If so, what was the mod?
It sounds like there is excessive gain in the receive stage.

[dejavuband]

RE cibola

the mods i done were adding ground balance pot and toggle switch for all metal,you think extra power maybe somehow getting through the coil?ive recently changed over to nimth rechargeable instead of getting .50 of an amp from the 9volt batts i converted it to take aa batts now im getting 15 to 17 amps on a full charge,you think it could be that?

[Qiaozhi]

the mods i done were adding ground balance pot and toggle switch for all metal,you think extra power maybe somehow getting through the coil?ive recently changed over to nimth rechargeable instead of getting .50 of an amp from the 9volt batts i converted it to take aa batts now im getting 15 to 17 amps on a full charge,you think it could be that?

You didn't say whether the detector was working ok before the modifications.

What do you mean "now im getting 15 to 17 amps on a full charge"? How could the current consumption jump from 0.5A to 15A (or even 17A)? Perhaps you meant to say something else.

[homefire]

My bet is you lost some shield wire some place or have a capacitance problem on the input.

[dfbowers]

Thank you for reminding me that my Cibola has a lifetime warranty.. and If I mod mine the warranty will be void too

[Qiaozhi]

Thank you for reminding me that my Cibola has a lifetime warranty.. and If I mod mine the warranty will be void too

Everyone would have assumed you already knew that!

[dejavuband]

You didn't say whether the detector was working ok before the modifications.

What do you mean "now im getting 15 to 17 amps on a full charge"? How could the current consumption jump from 0.5A to 15A (or even 17A)? Perhaps you meant to say something else.

To be honest the detector is working great im just concerned that when its supertuned(full sens and threshold)it picks up on my hand when about 1 to 2" away,with discim turned all the way down it still discrims out large nails and runs stable supertuned,in air tests with the standard web coil i can get 10" on a cut quarter and with the DD coil on i can get 9" on a new 5p coin on 0 sensitivity im getting some fantastic results out the machine,what i meant with the batts was i checked a new 9volt and it was only pushing out .50 of an amp and with the nimth batts im getting 15 amps there about 3 amps each times six AA batts,the checks are done with the batts out of detector with an amp meter that drains current when connected to the batts,hope ive explained a little better now!

[Qiaozhi]

what i meant with the batts was i checked a new 9volt and it was only pushing out .50 of an amp and with the nimth batts im getting 15 amps there about 3 amps each times six AA batts,the checks are done with the batts out of detector with an amp meter that drains current when connected to the batts,hope ive explained a little better now!

OK, now I understand that you are shorting out the batteries with an ammeter. In this case the current is only limited by the internal resistance of the battery, but the current you are measuring in your test is totally irrelevant to the operation of the detector. In fact, your detector will be drawing no more than about 50mA maximum.

[dejavuband]

OK, now I understand that you are shorting out the batteries with an ammeter. In this case the current is only limited by the internal resistance of the battery, but the current you are measuring in your test is totally irrelevant to the operation of the detector. In fact, your detector will be drawing no more than about 50mA maximum.

what do you think could be causing the xtra sensitivity to my hand and some other objects not of metal?could it just be very sensitive when supertuned or do you think that maybe something is not right in the control box someware?and what about what you first said about excessive gain in the receive stage what could cause that?

[Fred]

Do you use a (wedding) ring ? That could explain everything...

[dejavuband]

Do you use a (wedding) ring ? That could explain everything...

No rings no bangle and no watch,do you think its that powerfull its picking up the iron in my blood

[Qiaozhi]

what do you think could be causing the xtra sensitivity to my hand and some other objects not of metal?could it just be very sensitive when supertuned or do you think that maybe something is not right in the control box someware?and what about what you first said about excessive gain in the receive stage what could cause that?

Did this problem only start after the modifications, or was it there before?

[dejavuband]

Did this problem only start after the modifications, or was it there before?

to be honest i did the mods after about two days of having the machine as it wasnt really perfoming that well on the nasty black soil i was detecting on so i did the ground balance mod and it really made the machine a lot better,ive worn a pair of dewalt fingerless gloves when detecting and they have velcro straps on them no metal on them that i could see and whenever my gloved hand was empty it still set the detector off i always thought that there was maybe some mesh or something else in the gloves that i couldnt see as they are heavy duty so your guess is as good as mine

[Qiaozhi]

to be honest i did the mods after about two days of having the machine as it wasnt really perfoming that well on the nasty black soil i was detecting on so i did the ground balance mod and it really made the machine a lot better,ive worn a pair of dewalt fingerless gloves when detecting and they have velcro straps on them no metal on them that i could see and whenever my gloved hand was empty it still set the detector off i always thought that there was maybe some mesh or something else in the gloves that i couldnt see as they are heavy duty so your guess is as good as mine

I think there's 3 possibilities here:

1. There was a mistake made during the modification, possibility a wiring error or wrong component value. This should be easy to check out.
2. The electrostatic shield in the search head is not connected to the screen. It would be worth trying another coil to see if the problem goes away.
3. The maximum sensitivity of the detector is set too high. If this is the case then lightly tapping the coil will also cause an audio response.

The most likely cause is #2.