TESORO GOLDEN SABRE

[junko]

Now I have solved the problem with the coil and cable.
On the table i have good result more of 25 cm 1 euro .
And a more big mass 40-60 cm.
All Ok.....
I have try to check on the real soil on the seaside .
It' s like a bed of nails....
Too echo totally indistinguible.
I have put a potentiometer in geb regulation for a fine according but no result.
My shelding it' s good i thinks.
I will try to change the fet Bf 245c versus Bf245a
i suspect spikes and a bad demodulation.
Bye
Junko

[Legaucho]

TGS

Hi,
not big difference. I found that A and AN versions are little better on mine... but cannot say it's always better choice... you have to try them on real circuit to say.

It's about the same.... but if you can find e.g. AN version try it... some are really good on TGS... and only way to know about is trying them on TGS.

Kind regards,
Max

Many thanks for your informations
Kind regards
Legaucho

[Max]

??? I havent seen a,b,c versions so far???

I am using LF353p always...

Hi,
not A, B, C... but there are versions like "A", "AH", "AN", "N" or "P" etc by various manifacturers.

I've tested A, AN, N and P so far... all about the same and no big differences... just found a couple of AN that give better response to targets and without losing stability there. Maybe depends on manifacturing process at factories... don't know... but just some are little better than others medium kind.

I think is not a great issue... anyway... these things are now really obsolete stuff and difficault to find.

Good alternatives could be e.g. MC34002AP or similar stuff.

PS: BH kind exist but I don't know about it... never saw one... is TO-78 thing. "B" and "C" only instead I think were never produced.

Kind regards,
Max

[Max]

Sorry for my mistake, I don't know why I put this, I want just to know Which one is better: BF245A,BF245B or BF245C

Many Thanks

Same of above....

No big differences.

Kind regards,
Max

[Max]

Hi all
I had build the TGS and it work fine but I would like to know which type of lf 353 I can use for the better result: LF353A , LF353B or LF353C
Many thanks by advance

Hi,
not big difference. I found that A and AN versions are little better on mine... but cannot say it's always better choice... you have to try them on real circuit to say.

It's about the same.... but if you can find e.g. AN version try it... some are really good on TGS... and only way to know about is trying them on TGS.

Kind regards,
Max

[Legaucho]

BF245 on TGS

??? I havent seen a,b,c versions so far???

I am using LF353p always...

Sorry for my mistake, I don't know why I put this, I want just to know Which one is better: BF245A,BF245B or BF245C

Many Thanks

[ivconic]

Hi all
I had build the TGS and it work fine but I would like to know which type of lf 353 I can use for the better result: LF353A , LF353B or LF353C
Many thanks by advance

??? I havent seen a,b,c versions so far???

I am using LF353p always...

[ivconic]

"..Have you read the mistake that i found missing 1n4148 near ic7 ?.."

Cant say is it more stabile with it? It is present at TGSL pcb already.
I made first TGS on larger pcb and it is working fine, but i already put that diode than.

[Legaucho]

About LF 353

Hi all
I had build the TGS and it work fine but I would like to know which type of lf 353 I can use for the better result: LF353A , LF353B or LF353C
Many thanks by advance

[ivconic]

Hi Ivconic,I had build the TGS,but I have a question,please help me.
when nulling, i use osciloscope connect to the RX coil,I only got 40MV VPP.
can't get more lower. as you said you get 0.08-0.015V,is that voltage are VPP?
I detect 10eur-cents from 17cm in all metal, on air. It's very poor.
my DD coil,23.5cm form,TX 110 turns,RX 118 turns.frequency 14.3KHZ.
and almost can't detect gold.
Ivconic, what sounds did you hear when power on?
I don't know where the errors in.
Regards and thanks for your support.

No i balanced coils using multimeter in 200mV range, and it showing usually 0.08-0.015V when coils are nulled...
Later i used osciloscope to check phase shift. Since my scope is old,obsolete i cant see accuratelly vpp. You can see some photos of that scope in previous pages.
Your coil must be not balanced well.Try again.

[zzy]

vpp

Hi Ivconic,I had build the TGS,but I have a question,please help me.
when nulling, i use osciloscope connect to the RX coil,I only got 40MV VPP.
can't get more lower. as you said you get 0.08-0.015V,is that voltage are VPP?
I detect 10eur-cents from 17cm in all metal, on air. It's very poor.
my DD coil,23.5cm form,TX 110 turns,RX 118 turns.frequency 14.3KHZ.
and almost can't detect gold.
Ivconic, what sounds did you hear when power on?
I don't know where the errors in.
Regards and thanks for your support.

[junko]

Hi Max and Ivconic
I have the standard gold sabre I suppose the 1M ohm is in right
position.
(this night i check this )
I have mod the 33k to 2k2 with good result in audio.
Have you read the mistake that i found missing 1n4148 near ic7 ?
For me it caused a lot of instability .
I have see a lot of picture of mounted pcb without this 1n4148.
In the next day I will try to fine tune this good detector.
A lot of thanks
Bye
Junko

[Max]

When you said detect a coin at 28cm or more you listen a big sound or only a Tik?
sorry for the stupid question.
I am a beginner i don't have a metaldetector for reference.
bye
Junko

Hi,
if you use the 1Mohm mod at comparator you have a big sound even at maximum depth.... but stability issue is important if you use it.

If you don't use that mod you'll have just weak sound a big depth,

BTW 18cm for 1eur is not good on TGS... you can do much better!

So... if circuit is ok... coils are wrong. Do not put capacitors there... as Ivconic told you... use them on PCB only... no need of them on coil housing...no need to change anything.
Also frequency matching is OK with provided data... be sure of your wire is 30AWG and not anything else; made same formers etc.

Kind regards,
Max

[junko]

When you said detect a coin at 28cm or more you listen a big sound or only a Tik?
sorry for the stupid question.
I am a beginner i don't have a metaldetector for reference.
bye
Junko

[ivconic]

I am not sure that you can use USB cable there. Better find some more proper cable. Dont put capacitors in search head.Leave those on pcb.
Here on these pages you can find proper coil wirements, producing no falses at all. And of course, ballancing is crucial.
Regards