Tesoro Eldorado

[Sacchetti]

Hi ivconic, i almost finish my metal detector tesero eldorado made in you circuit and i ask you what capasitor you put on pin 8 lm308

Hi Kelt,
use 100pf to compensate frequency.
It is necessary only if you use LM308, instead if you use LF353 or TL081 for example then you can remove it.

[ste]

They are similar, some changes regards only the oscillator and some minor parts as battery check, for example.
The result as depth is the same.

Thank's you!!

[MaverickITA]

hello, I'm new to the forum. I'm going to build a tesoro eldorado. I have seen that there are many variations of PCBs, which do you recommend? you have a pattern more up to date? thank you!

They are similar, some changes regards only the oscillator and some minor parts as battery check, for example.
The result as depth is the same.

[ste]

hello, I'm new to the forum. I'm going to build a tesoro eldorado. I have seen that there are many variations of PCBs, which do you recommend? you have a pattern more up to date? thank you!

[kt315]

......analogi TIS75.txt

[emoxristov]

Friends analogue TIS 75 ??

[Davor]

Easy. Use just about any PNP small transistor. BC327 is a better choice.

[emoxristov]

how can I replace 2N2907

[ivconic]

Here are both pcb versions i done than.
Both are working good (as i recall).

[ivconic]

Hi ivconic, i almost finish my metal detector tesero eldorado made in you circuit and i ask you what capasitor you put on pin 8 lm308

Oh it's been long time ago, i can't be sure. I am listing now my files to check.
There are two pcb's i done. At first one i put 100pf and on second one seems i omit capacitor?
LM308 usually need external compensation and usually it is 100pf.
But right now i am not sure to tell you why there is no cap at all at my second pcb!??

[kelt]

Hi ivconic, i almost finish my metal detector tesero eldorado made in you circuit and i ask you what capasitor you put on pin 8 lm308

[lanzi]

hi Ivconic.
I need your help for a very some question.
Please contact me
I am french and my name is florian
[email protected]
Merci beaucoup

[arion]

Please help. How to prepare the coils? What are the correct parameters? What is the diameter of the coils? How to turns the transmitter and the receiver coil?
What is the inductance and resistance? Which is better, the DD or OO? Sorry for the bad English. Thank you.

[sadowski25PL]

Hello again,

Now, some updates about building My Tesoro Eldorado

First photos:

Eldorado No.1:




Eldorado No.2:




For coil I use a tensometric cable, HBM CABA2 with double shield ( main shield and pair shield).
In Eldorado No.1 use TL081
In Eldorado No.2 use LM308H

[sadowski25PL]

Hello,

I have big problem with My eldorado...

Before I try another cable, I use a LIYCY 6x0,25 cable with copper shield.
On that cable in air test for 2cm coin I have some about 32cm, Discrimination works very good.
But when I try VGA cable from computer monitor...

Tx voltage fall down from 15V to 8,3V o.O
Receiver works fine, but Transmitter dead.
Max in airtest is 10cm for beer can ( full ).

Can you tell me where is the problem ?