TESORO GOLDEN SABRE

[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

[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]

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]

Ok.
Thanks.I will buy the same.

[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.

[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]

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!

[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]

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!

[Dennis the Mennis]

I'm not going to say, "told you so".

Looking at the values for your coils and the tuning caps used, I have calculated your TX frequency to be 14.5KHz, which you have confirmed is correct. However, your RX circuit is tuned to 19.7KHz, which in my opinion is too high, as Tesoro circuits are usually off resonance by around 9%. In this case you should be using a calculated capacitor value of 15.5nF to tune the RX to 15.8KHz. I would suggest trying a 15nF cap instead of the 10nF and see if there is any improvement.

I totaly missed the part of 'off resonance , thanks for reminding me that .
I will experiment with the Rx part , I can remember that when I placed a 22 nF cap (somewhere around that value) in the Rx part a huge signal appeared compared to the 10nF but i chose for the 10 nF' because I've had the lowest residual voltage ...
I've learned this lesson

regards Dennis the Mennis

[Dennis the Mennis]

Darn, Qiaozhi. You beat me to it.

LTspice shows almost 3x increase in received signal voltage by changing to 15n, with a 6.53mH receiver coil.

Sorry about the wild goose chase, Dennis.

Never mind Porkluvr ,

I would never know what happened if I didn't change the caps ...
Perhaps it's a part of the solution , I'm going to try to tune the rx part.
If the sens increases as LTspice shows ...

regards Dennis the Mennis

[Dennis the Mennis]

" ..Nulling on pin6 input LF353 (coil connected to pcb to compare with firdt video):
http://www.youtube.com/watch?v=AyK02Zk1PLY .."

I guess those "notches" (kind a distortion in sinus) are caused by bad quality of RX cap ?
Because i usually have there perfect sinus without any distortions...

I am using PP caps at TX and RX whenever i can find proper ones.

I will check this also , right now I've got so many caps I'm going to open my online second hand capacitor shop

regards

Dennis the Mennis

[Dennis the Mennis]

" ...Is there a possibility that when even the nulling seems fine , the sensitivity is poor ?..."

"Nulling seems fine" but you must understand that coils nulled well on one frequency are not nulled well on another (different) frequency. Residual voltage rised if frequency changed.

I think Qiaozhi already gave here good hint. Keep RX coil resonance within +1.8 - +2kHz than TX coil.
And use pp caps.

BTW thank You very much on your effort making those clips!
Best Regards!

You're welcome ,

I hope anyone can use them for future use whenever there is something to make clear.
Those clips will stay there .
Whenever I get this 'thing' to work I will post the correct video's ( of a working TGS ) or I will make an online manual or something like that.

regards ,

Dennis the Mennis

[Dennis the Mennis]

Yes, this is what I meant.
It's Dennis' scope picture the one I posted...
Am I correct that the right nulling is achieved at position 0:11 of the first video that he published? (11 s after the start is the only way I can find to refer to that position... ), but that phase is anyway reversed in polarity...

Later on my photo- and video session I've changed the polarity off the rx coil so you are right , I've wanted to gain the pictures as posted on page 57.
I've made this photo for the voltage compare this was the lowest value I could reach , I was not really shure about the phase shift ...

regards

Dennis the Mennis

[ivconic]

You're welcome ,

I hope anyone can use them for future use whenever there is something to make clear.
Those clips will stay there .
Whenever I get this 'thing' to work I will post the correct video's ( of a working TGS ) or I will make an online manual or something like that.

regards ,

Dennis the Mennis

That's the right spirit!
Ehh, if there were more people thinking like you!
Hopefully others will follow your example!
Regards!