TESORO GOLDEN SABRE

[nelson]

Max, have you tried any GS coils? HOw where your experiencies?
Can you post your coils details to compare my expirencies with you.
Now i m working on the TX coils, same has Ivconic, but i ll have to take turns away to get correct values. Don´t know the reazon of why if i use same dimensions, same coil form, same wire, i don´t get the results of 21 ohms and 6.7 ohms has Ivconic. No dubs on this, everything was cheked and is ok. But my mesures are still diferent. So for that i ll made the coils to match correct values, and this means for example for my tx coil only 85 turns instead of 120.
120 turns give me 11.43 mH and 30.2 ohms, not correct, double cheked with diferent instruments and results are the same. Also if i calculate the values with software, gave me also very close to 85 turns ( see my previus report).

Perhaps this troubles, it´s a very nice detector to experiment and learn.

Best regards
Nelson

Hi Max, yes i think this is the hardest part of the project.
Anyway i ll keep traing until i get good results.
Yes i agree in this case that inductance is not to important. I just discover that if you made the coil to match impedance btw 19 and 22 ohms, you are geting closer and then if you mesure inductance you get the correct values (21.6 ohms and 5.9 mH for TX coil). Now why this detector must mach 19 to 22 ohms of resistance?
Has a hamradio hobbist, i learn that most of radiotransivers use 50 ohms of impedance, so antenns must match this impedance. Is the principle of adjusting coils the same has used for antennas.
Thanks Max and friends.
Best regards
Nelson

[tiktak]

Max,
When I try to null with multimeter and conect only TX without shields THIS NASTY SOUND IS STILL THERE!!!
Its look like I reach right value!
Can I try now just to conect two RX windings start and end point to RX place on PCB just to test?
Or this is not good idea?
Thanks

[tiktak]

In this case I should conect TX start point to pcb point V and TX end to U point.No shields/or with shields?/?And I will use 1k resistor,but which capacitator will be good?Electrolitic,ceramic?Whit what value?I have 4,7 mf electrolitic and 15n ceramic?I should put the multimeter in 1-10v range in AC
Thanks

[Max]

Thanks
Man I will try and then ask stupid and boring questions.
Just have made 3 projekts and cant get non working as I wish,so when first time saw thi GS project I have told myself this will work!!!!
Thanks

I'm sure at end will work!

[tiktak]

Thanks
Man I will try and then ask stupid and boring questions.
Just have made 3 projekts and cant get non working as I wish,so when first time saw thi GS project I have told myself this will work!!!!
Thanks

[Max]

How should I null the coil?I were thionking to use ivconics method.Conect to G Sabre and move untill get best point/deepest reading/!!
What will you advice me?
Thanks.
How to acive this?

test if voltage levels change at output of op. amps. when you near some
metal to coil?

And can the problem be in coil?
Only?

Hi,
oh man! Yes could be...
Ok. If your coil isn't nulled you get too much signal into first op. amp. and then it saturate easy.

So, first of all, you need to carefully null the coil. Look at previous posts:
you can do with multimeter too... be sure you get the minimum signal on rx coil at nulling. Then reconnect rx leads to PCB and go ahead with testing.

Ivconic uses that method cause he knows what he do... I mean he get the coil near to nulled and then adjust for maximum sens... he have experience with homemade coils...but if you try yourself... without making any preliminary adj on coils positions... with scope or multimeter... well you'll never get this stuff working!

So got the null first!

Best regards,
Max

[tiktak]

Hi

How should I null the coil?I were thionking to use ivconics method.Conect to G Sabre and move untill get best point/deepest reading/!!
What will you advice me?
Thanks.
How to acive this?

test if voltage levels change at output of op. amps. when you near some
metal to coil?

And can the problem be in coil?
Only?

[Max]

Have you nulled the coil right ???

[Max]

Ok,
So, I have to put -of multimeter and according ivconics schematic to check all elements starting from this 15n cap afther RX points on pcb?

I have just tryed with ac/dc adapter only louder sound!
So I will keep testing with two paralel 9V batteries for now.
Which element is the last in this testing?So I can imagine all!

Hi,
start at capacitor... and end at speaker!
No... just joke!

You need reach the last LM358... the one you removed. Between rx pads and it would be the mistake or mistakes. I think that could be a wrong component value or soldering.

If you can, test if voltage levels change at output of op. amps. when you near some metal to coil... just to know if they are blocked (saturated) or not.
A good test if you could see where thing starts becoming frozen...

Best regards,
Max

[tiktak]

Hi

Ok,
So, I have to put -of multimeter and according ivconics schematic to check all elements starting from this 15n cap afther RX points on pcb?

I have just tryed with ac/dc adapter only louder sound!
So I will keep testing with two paralel 9V batteries for now.
Which element is the last in this testing?So I can imagine all!

[Max]

I have remouved this transistor and switch on no sound.switch off put 358 on place and switch on still that nasty sound~!

Hi,
ok now we know that battery-checker is not involved.
So resolder TR10 in place (bf245).

OK. Possible fault is in signal path. You must check PCB following schematic from RX coil pads ahead till you find mistake.

Long work... I know, but only way to know what's wrong.

Check connections, check diodes orientations, check capacitor terminals of polarized ones orientations, check for short-circuits due to soldering ...

Problem is that your last op. amp is in saturation and something before it cause that problem. So your detector keep screaming... cause output stage is always in saturation.

Best regards,
Max

[tiktak]

hi

I have remouved this transistor and switch on no sound.switch off put 358 on place and switch on still that nasty sound~!

[Max]

How to mesure the current drawn by circuit ?
If I conect in series 2 9v batteries?
Will 18 be to high?
Or just two week 9B batt. in series around 12?Just to test?
If the batteries are to week coud circuit react like mine?
Thanks again for your attention!

Hi,
you could use the 9v batt in series gettin 18volts that are fine as input to 7808... but you must consider that these batteries could provide few current and last few so aren't so good for long testing. You could use an ac-dc adaptor e.g. like the ones that supply some computer equipment or old phone's chargers... but be sure you got something from 12V to say 24V dc.
What's important is that you get at least that 12volts... so use 8AA cells or whatever suits.

OK- leave current measure out for now... you could burn multimeter if not skilled in it.

Best regards,
Max

[Max]

Sorry for boring questions but you mean this 358 and this transistor?

Hi,
yes they are: TR10 is the bf245 related to batt-checker.

Best regards,
Max

[tiktak]

How to mesure the current drawn by circuit ?
If I conect in series 2 9v batteries?
Will 18 be to high?
Or just two week 9B batt. in series around 12?Just to test?
If the batteries are to week coud circuit react like mine?
Thanks again for your attention!