TESORO GOLDEN SABRE

[Unregistered]

To Max

Hello,
Thanks IVCONIC I will try!
What about the capacitator near BC517?What is its VALUE?Its not marked!

[Unregistered]

To Max

Hello,
Max!
I will try but cant understand:

you can use a normal electrolitic near tis75

part???
tis75?
Thanks for your HElp

[Leto]

To unregistered

part???
tis75?

tis75 transistors are substituted with BF245c transistors..
Beter still to use tantalium cap..

I suggest you check out the shematic..

[Unregistered]

Hi

Thanks Leto!
Why is so important?
I cant find TANT!
Will this afect my circuit?
And also there is one capacitator which
have no value?
Why?
What shell I use?
Thanks

[Unregistered]

Leto

Did you make Metal detector with meter discriminating ,by Sasho Varna BG?
I am working on that PCB!
Its look like very good ****!

[Leto]

ahh..

That unmarked cap. is 100nF..
Tantaliums are pretty common capacitators you should find them right-away.
This >tant< cap is part of negative power supply witch is not "state-of-the-art" in this project.. But as Max proposed - you CAN try with electrolitics.

I wanted to make PCB for Sashos detector - but I will NOT: because you are already on the work..

[Unregistered]

to Leto

Ok!
But you have to promiss that you will help!?!?!?!??!!?
Because You have made whit sucses unless ONE!
And I am more than beginer.

[Unregistered]

which type should capacitators be?In Volts?

[erolunall]

golden sabre

Hello
I changed bc517 tansistor with mpsa13.But mpsa13 is heating and voice is
downing not same( bc517 is high volume). I made coil with 0.3 mm copper wire .its about 23 ohm.I dont use 10 mf tantalyum cap but normal 10 mf cap.
I used 5.6 and 86 pf capasitor (not 5 p and 68 p farat)
but performans is not good.İt is signalling cigarrete packet about 10 cm.
if an am radio put on battery it giving a bit more performans by changing radio signal.
any idea will be good?
best wishes
Erol Ünal

[erolunall]

golden sabre

Hello
I changed bc517 tansistor with mpsa13.But mpsa13 is heating and voice is
downing not same( bc517 is high volume). I made coil with 0.3 mm copper wire .its about 23 ohm.I dont use 10 mf tantalyum cap but normal 10 mf cap.
I used 5.6 and 86 pf capasitor (not 5 p and 68 p farat)
but performans is not good.İt is signalling cigarrete packet about 10 cm.
if an am radio put on battery it giving a bit more performans by changing radio signal.
any idea will be good?
best wishes
Erol Ünal

[Unregistered]

to Leto

Hello,
I have difficulties whit this PCB!!!
It's look harder than I told,but I will keep pushin!!!
Will you help whit some advices?
???

[Leto]

To unregistered

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[Sean_Goddard]

Maybe this has been covered, BUT........

I have found from experiments with this type of oscillator used that the FET part is an "auto level control". It also seems to affect the purity of the Tx signal.

When you find a large target, the level of the Tx will dip slightly, not sure why Tesoro feel the need to compensate for this but at least I assume that is what they are doing, maybe also to compensate for different sizes of coil.

The 4.7 BiPolar Electrorytics are there FOR A REASON. I have found using any other type of cap will affect performance. Maybe its the ESR of electrolytics they are after and they MUST be BiPol due to the large pos/neg swings on different types of target?

[Max]

I have found from experiments with this type of oscillator used that the FET part is an "auto level control". It also seems to affect the purity of the Tx signal.

When you find a large target, the level of the Tx will dip slightly, not sure why Tesoro feel the need to compensate for this but at least I assume that is what they are doing, maybe also to compensate for different sizes of coil.

The 4.7 BiPolar Electrorytics are there FOR A REASON. I have found using any other type of cap will affect performance. Maybe its the ESR of electrolytics they are after and they MUST be BiPol due to the large pos/neg swings on different types of target?

Hi Sean,
I don't know for sure but seems that the FET there is , as you stated, a feedback component. I think it serves to stabilize and keep osc working also with important variations on osc current. They maybe noticed that an overload on osc (due e.g. to a big target) causes sometimes the osc to shut-off so maybe the FET keep it running varing polarization network parameters also if big masses are near coil.
If it is so, without the FET if osc shuts off the detector will lose negative voltage rail and so all need resetting far away metal to recover it again.
This way there's maybe no danger of locks at osc sections even if big metals are near the coil.
About caps I think that caps loss due e.g. to electrolytic fluid is no good in this kind of detector. There would be asymm between the two sections and partial reversal if just one electrolytic is used (instead of antiparallel config) so there could be problems. I've tested single and antiparallel config and found that there is some bleeping on output due to this wrong component(s).
Replacing with bipolar caps partially solved that and now I have much less bleeping in search field conditions on bandidoII.

Best regards,
Max

[Unregistered]

NOT Unregistered

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REASONS:
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So please register.

Hi are you admin or?
I am registered,just forget to logg!
Why you are asking?
I am having a very buisy,hard days lately and cant think for logging and etc.
But if you are on it I will!