TESORO GOLDEN SABRE

[ivconic]

I will take this advice.5kg.hammer will do the job just fine!Bang.
So this must be the reason why I cant null those coils.They just refuse to go lower then .200/2V AC.
Today I will make some new coils and inform you here about the results.Pity that I almost destroy this nice pcb.Solder and desolder all the time various components.And it were wrong L all the time.
Regards.

Not only that but all the time you've been kept on your mind wrong values. Horrible situatuion. I should know that very good cose i "wandered in a fog" for sometime. Until hammer did pretty nice job! Now with new multimeter things simply came on their places.
All the calculations with old values are now pointless.

[Ultimate_Haze]

I will take this advice.5kg.hammer will do the job just fine!Bang.
So this must be the reason why I cant null those coils.They just refuse to go lower then .200/2V AC.
Today I will make some new coils and inform you here about the results.Pity that I almost destroy this nice pcb.Solder and desolder all the time various components.And it were wrong L all the time.
Regards.

[WM6]

.Also my LC meter is wrong too.It shows 6,35mH on one winding and this new multimeter shows 6,75mH.

Not necessarily wrong.

Measurement result depends on the measuring frequency of L-meters.

Closer than this frequency is to the operating frequency of MD, more correct are results.

[ivconic]

I just got new multimeter.Its VC9805A.Think that its previous version of the one you show.Because dont have backlight.
So it shows quiet different readings.Frequency is with some old coil is 15,2 and old one shows 14,2.Also my LC meter is wrong too.It shows 6,35mH on one winding and this new multimeter shows 6,75mH.
It must be that my units are damaged somehow.
I will make new coil using this VC9805A.Hope that this will solve my problems.

That explains everything...
Now you know why i keep 5kg hammer near me, all the time!

[Ultimate_Haze]

I just got new multimeter.Its VC9805A.Think that its previous version of the one you show.Because dont have backlight.
So it shows quiet different readings.Frequency is with some old coil is 15,2 and old one shows 14,2.Also my LC meter is wrong too.It shows 6,35mH on one winding and this new multimeter shows 6,75mH.
It must be that my units are damaged somehow.
I will make new coil using this VC9805A.Hope that this will solve my problems.

[Ultimate_Haze]

Hi,
Simonbaker.
Sorry to hear this.Wish fast recovery.

[simonbaker]

Hello,
So there is possibility that everything on pcb is ok and still device can't reach good depths?And this is with good coil?
So I will just make another one and see if there are differences.I test every new coil also with two other TGSLs/BD140/and one TGS.
Yesterday I try to null last coil better and I get down to 0.004/200mV.And today switch on the setup as I leave it and read .940/2V.Its not the multimeter.Must be noise from TVs,security radios,cells,etc.
When I tune it were late.And maybe less of those.
I wont quit on this also.

The best that I reached is with BD140 version.With 22cm coil/22cm in air for 1e coin.
Now I remember that you use 4K7 for R13 and R14.I have mount 5K1.I will try now to see is there any change.

SB glad that you are back on this too.
now, cannot participate.
Why?

Unfortunately health problems of wife takes all time for now. But I have not lost desire to get to bottom of intriguing mysteries of TGSL -- especially because my TGSL performed similar to Ultimate_Haze -- but will have to wait for the future now.

Good luck, you may find answers first!

-SB

[Pompey]

When disrimination pot is replaced with 10k sinus on pin1 improves.Sinus on pin1 depends from Tx sinusoide.I tried this.When you put 10k disc pot Tx signal goes weaker and it`s crack at the top disapears -sinus on pin (LF353) improves too.I think that disc. pot must be 10k -in TGS there are 100k and 10k paralel,so 10k is correct I think.

[ivconic]

Does the signal return to a good clean sine wave when you bring a coin towards the search head?

No it stay the same/you mean LF353pin1!/.What makes you think that I over-nulied the coils?I think that there is too much surrounding noise and I miss the null.In same time how chain is affected and show less sensitivity.
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Check C9 (100pF) and replace it with some high quality cap.

Have just check it again.Its 100p.Change with some scraped from old Tv/which looks ok/.No change.
10p again on its place.

Try 50pf (56pf or 68pf) than and scope it... Although i think Qiaozhi is right...

[Ultimate_Haze]

Does the signal return to a good clean sine wave when you bring a coin towards the search head?

No it stay the same/you mean LF353pin1!/.What makes you think that I over-nulied the coils?I think that there is too much surrounding noise and I miss the null.In same time how chain is affected and show less sensitivity.
--------------------------------------------------------------------------
Check C9 (100pF) and replace it with some high quality cap.

Have just check it again.Its 100p.Change with some scraped from old Tv/which looks ok/.No change.
10p again on its place.

[ivconic]

Yes.Its like you describe it.
So generator is ok.
But now I remove this 10p from LF353 and still same shape on pin1.I don't know if this is the right way to check this problem.But think that signal must be near to sinus if this 10p cap were the problem.
Which cap should distort there?15N?

Pin 1. has nothing to do with RX stage!
Return back that 10p.
Check C9 (100pF) and replace it with some high quality cap. Also you may tray to replace it with lower capacitance there...56-86pF.
But 100pF will be just fine if cap is good quality.

[Qiaozhi]

Ok,
I will follow your lead.And search between gates and 358.
But if coil moved over night,why now I cant co lower then .200/2V?Must be noise interface.That make my live hard.
The signal from LF353 pin 1 is not sinus.Its strange.Will make some pictures.Have you check on good TGSL how it looks?

You have most likely over-nulled the coils.

Does the signal return to a good clean sine wave when you bring a coin towards the search head?

[ivconic]

I´m planning make this MD too. Here are some places with lots of hot rocks. Can this be a problem? Can this be eliminated by ground balance?

Tesoro's GEB and DISC are very accurate. I think you will be satisfied.

[SIBI]

I´m planning make this MD too. Here are some places with lots of hot rocks. Can this be a problem? Can this be eliminated by ground balance?

[Ultimate_Haze]

Yes.Its like you describe it.
So generator is ok.
But now I remove this 10p from LF353 and still same shape on pin1.I don't know if this is the right way to check this problem.But think that signal must be near to sinus if this 10p cap were the problem.
Which cap should distort there?15N?