TESORO GOLDEN SABRE

[ivconic]

Or brand new metal detector!
I do suggest XP Gold Maxx Power.
End of a story!
No more troubles with damn TGSL!
Cheers!

That is good suggestion.But right now dont have enough funds for such buy.
Plus I study this circuit well.Spend much time and efforts.Don't wanna leave now.Just have to make one good working device.Your results are great.Will be good if I get near.So will use hammer on this device and make another one.

I also can not afford XP...at least for now. But it is first that i am gonna buy as soon as possible! Hopefully this summer!
....
About TGSL...no,
i am joking, do not give up!
Not at all!
TGSL is worth of every efforts! You will make it excellent, for sure.
Just be patient.
I also lost my nervs many times, torturing myself with damn coils!
Eh!
I posted here only my success so far.
My fiascos are countless!
Shame to talk about!

[Ultimate_Haze]

Or brand new metal detector!
I do suggest XP Gold Maxx Power.
End of a story!
No more troubles with damn TGSL!
Cheers!

That is good suggestion.But right now dont have enough funds for such buy.
Plus I study this circuit well.Spend much time and efforts.Don't wanna leave now.Just have to make one good working device.Your results are great.Will be good if I get near.So will use hammer on this device and make another one.

[ivconic]

The only solution now is to buy an oscilloscope.

Or brand new metal detector!
I do suggest XP Gold Maxx Power.
End of a story!
No more troubles with damn TGSL!

Cheers!

[Qiaozhi]

Ok..never mind the mmeter.

All what have you done and wrote so far leads me to suspect that something on pcb is not good at all. Some component or some track...or..? Tough to guess, really.

The only solution now is to buy an oscilloscope.

[ivconic]

Ok..never mind the mmeter.

All what have you done and wrote so far leads me to suspect that something on pcb is not good at all. Some component or some track...or..? Tough to guess, really.

[Ultimate_Haze]

Ok.
Thanks.I will buy the same.

[ivconic]

First thing, when bought it, i checked residual voltage at original "Brown" Tesoro coil with Eldorado. Reading with this mmeter was exactly 4mV - by the book. Than i made my own handmade coil and nulled it at about 6mV (couldn't achieve less). That coil is working excellent until nowdays (sold to one old "customer"), 1e in air at 34cm with TGSL (BD140 version)...
Than i also made ..maybe 10 more coils (some of those couldn't null below 15mV) and nulled with this instrument. So far i had no problems with it..

[Ultimate_Haze]

Ivconic,
What multimeter do you use?
I will try to get the same.
But I cant get better sens with only coin.So might be everything.
Now changed cable with normal coaxial.Just using two.
Can null much lower.But still sens is the same((((

Qiaozhi,
I try and can reach 0V.But still same sensitivity.

[ivconic]

It is dark and damn camera is poor. But here it is!

"VC9805A+" model....??? With backlight!

Not expensive much..but not cheap also, some 30 euros!

But it is splendid tool for nulling coils! So far most accurate!

http://www.warf.com/electronic-products-4327.html

[ivconic]

No, really; it is hammered several months ago!
Because i had same readings as you and could'nt managed to null coils with it at all!
First one i had was good, than came one friend to me asking and i gave it to him as present.
Second one was exactly the same as yours ......hammmered!
And third one i am having now is COOL !

[ivconic]

Hi,
When in 2V i read 0,015.Then in 200mV lower value I can reach is 115.
Those are taken from LF353 pin.7
When I null directly from RX to 00,4 in 200mV.No detection at all.

So you have that funny multimeter (i had in the past) also!??
That's why i bought new one! And old one .....hammered!

[Qiaozhi]

Hi,
When in 2V i read 0,015.Then in 200mV lower value I can reach is 115.
Those are taken from LF353 pin.7
When I null directly from RX to 00,4 in 200mV.No detection at all.

If you do not have a scope then try this ->

1. Set the ground balance pot to its middle position.
2. Set the discriminate pot to minimum.
3. Connect the multimeter to the source pin of J107 (as shown by the red dot in the image below) and measure the DC voltage.
4. Adjust the coils to give 0V DC at that position.

Get as close as you can by positioning the coils, as you will still be able to adjust this with the ground balance pot.

[Ultimate_Haze]

Hi,
When in 2V i read 0,015.Then in 200mV lower value I can reach is 115.
Those are taken from LF353 pin.7
When I null directly from RX to 00,4 in 200mV.No detection at all.

[ivconic]

And how about trying to null coils without any multimeter? Just swing coin over coils while nulling those and try to find spot with "deepest" detection in air?

[ivconic]

I made another RX 6,13mH this time/which is one turn less/.Nothing change.
I now that 0,27 shouldn't be a problem.
Thanks
Should I try less turns?
Those are shielded coils.So I cant change No. of turns.

Nothing changed? Than you have some serious problem on your pcb! Because with RX=6.23mH and 15nF in parallel you will have approx. +2kHz off resonance from TX, exactly optimum from previous calculations.
Are coils nulled well now? Is residual voltage between 4mV and 7mV?