Tesoro Eldorado

[Max]

OK i was restless to see if this gonna work. So i delayed some more important things to be done first and few minuteas ago i finished with Eldorado and tested it. Not working!
It was expectable not to work at once. I expected simillar problems.It is always like this when man staring new project, never done before.
Well...after switching it ON some "dashed" tone appears. But fast "dashed".
There is no noticeable detection or any kind of reaction on metal in coil vicinity.
Voltages are 7.8V abd -6.23V on very start and in few seconds drops to 5.8v and -4.7v....!? Nothing burns, nothing hot,nothing even warm. Audio is not very loud it is medium but good audible.
When TL072 (all 3 of them) pulled out of sockets (later included, cant be seen on posted photo) voltages rises a bit. If i turn pots and loose audio than voltages rises to expectable values. But even with audio and without TL's voltages are almost normal - expectable. Since i dont have proper opamps right now i took first simillar to check. So i put 4558x3 instead TL's and situation was the same as with TL's...?!
I used TGS coil already proven as excellent. So...?
What drains voltage here!?
I am very occupied with few other designs at the same time so i cant really follow and retrace this accuratelly.But it is very possible that i made some mistake drawing pcb....or schematic is not accurate!? Which one of those!?
It will take some time me to retrace this and recheck all over again.
Meanwhile if somebody of you do that faster and spot something i missed please do post here so i can have less job.Also will help to others here.
Regards!

Hi,
the positive voltage drop is not good stuff... and have nothing to do with voltage converter unless there's some strange error on transistors there...make another test too...

TRY THIS:

disconnect output pin of 8V regulator and look for current drawn by device... connect amp-meter before give power to device... better if analog kind of meter there... and look how much current drain there is and how behave startup of device (initial peak ? etc).

Then post here informations:
look ! if your regulator , 7808 (right ?) , have 2 volts drop there you maybe probably have bad supply (too low I mean ...not 12V) or you have something that drain too much current on circuit... but really much current ! 7808 is rated 1ampere ...and I think can't be this way cause with so hi current you'll have regulator running really hot and some part in the circuit burns... etc

Maybe your powersupply doesn't give enough real "voltage" to 7808 to work properly ? You need at least 11volts there... otherwise you cannot have real 8V at output under real conditions of load.

If you test with batteries be sure they are charged well and don't drop under 11volts during operations...otherwise you know what will happen... your regulated voltage will drop too really easy under 8volts cause of internal dropout.

Kind regards,
Max

[Leto]

Hi Ivconic,
thanks for nice PCB, I also wanted to re-design big Italian .dxf board but you beat me to it good thing.
About device not working - no idea. Shematic looks OK - did you compared it with that one published with .dxf files?
What about voltage regulator - its a big voltage drop (2v) from nominal, did you try replacing it? How big is the current draw?
As you have the negative supply - oscillator is probably working, whats the frequency?
Is there any induced voltage measuring across Rx coil?
If the rainy days continue, I'll try to check your PCB..

[OSTIN]

Nice pcb ivconic !
I am want to make Eldorado too. On mounth ago I have desing pcb too. But your pcb look more easy. Maybe, my pcb with mistakes.
Goodluck!

[tragac3]

pitanje

Hi.A kad bi zamenio kondenzatore u Tx od 470n sa 220n i 47n sa 22n kao i u Rx 33n sa 15n?pozdrav

[Geo]

OK i was restless to see if this gonna work. So i delayed some more important things to be done first and few minuteas ago i finished with Eldorado and tested it. Not working!
It was expectable not to work at once. I expected simillar problems.It is always like this when man staring new project, never done before.
Well...after switching it ON some "dashed" tone appears. But fast "dashed".
There is no noticeable detection or any kind of reaction on metal in coil vicinity.
Voltages are 7.8V abd -6.23V on very start and in few seconds drops to 5.8v and -4.7v....!? Nothing burns, nothing hot,nothing even warm. Audio is not very loud it is medium but good audible.
When TL072 (all 3 of them) pulled out of sockets (later included, cant be seen on posted photo) voltages rises a bit. If i turn pots and loose audio than voltages rises to expectable values. But even with audio and without TL's voltages are almost normal - expectable. Since i dont have proper opamps right now i took first simillar to check. So i put 4558x3 instead TL's and situation was the same as with TL's...?!
I used TGS coil already proven as excellent. So...?
What drains voltage here!?
I am very occupied with few other designs at the same time so i cant really follow and retrace this accuratelly.But it is very possible that i made some mistake drawing pcb....or schematic is not accurate!? Which one of those!?
It will take some time me to retrace this and recheck all over again.
Meanwhile if somebody of you do that faster and spot something i missed please do post here so i can have less job.Also will help to others here.
Regards!

Hi Ivica. How are you??
Again the same problem with you......
You have problem with the First time, i want to believe not with all things
Anyway i am sure that you will find the problem(s) because the Eldorado maybe it is the best Tesoro detector.
I want to wish you Good luck with the eldorado and with YOU.
Best Wishes

[Max]

OK i was restless to see if this gonna work. So i delayed some more important things to be done first and few minuteas ago i finished with Eldorado and tested it. Not working!
It was expectable not to work at once. I expected simillar problems.It is always like this when man staring new project, never done before.
Well...after switching it ON some "dashed" tone appears. But fast "dashed".
There is no noticeable detection or any kind of reaction on metal in coil vicinity.
Voltages are 7.8V abd -6.23V on very start and in few seconds drops to 5.8v and -4.7v....!? Nothing burns, nothing hot,nothing even warm. Audio is not very loud it is medium but good audible.
When TL072 (all 3 of them) pulled out of sockets (later included, cant be seen on posted photo) voltages rises a bit. If i turn pots and loose audio than voltages rises to expectable values. But even with audio and without TL's voltages are almost normal - expectable. Since i dont have proper opamps right now i took first simillar to check. So i put 4558x3 instead TL's and situation was the same as with TL's...?!
I used TGS coil already proven as excellent. So...?
What drains voltage here!?
I am very occupied with few other designs at the same time so i cant really follow and retrace this accuratelly.But it is very possible that i made some mistake drawing pcb....or schematic is not accurate!? Which one of those!?
It will take some time me to retrace this and recheck all over again.
Meanwhile if somebody of you do that faster and spot something i missed please do post here so i can have less job.Also will help to others here.
Regards!

Hi Ivconic,
I read your post... and I think I know what's happened there... the voltage converter is inefficient thing on all these Tesoro's expecially at lower frequency like in the BandidoII range (10KHz) and Eldorado... if I remember well... is one of those with weak converter power.

The fact you have first full voltage means that at startup your current drawn is less than after few seconds... and I think there's effect from some saturation of op. amp. there that make your thing waste too many energy ending with so low voltage at converter output.

I think you have to change some things:
- change the 2 resistors of 5K1 at base of transistors of converter with 1K

if not enough...

- change also the 3 TL072 with something lower current like TS27M2 or TS27L2 if you can find them ... I suggest those cause I already know you cannot find the TLC2262 things at your place: these are more easy to be found... e.g. recovering from stuff.

Let me know...

Kind regards,
Max

[ivconic]

OK i was restless to see if this gonna work. So i delayed some more important things to be done first and few minuteas ago i finished with Eldorado and tested it. Not working!
It was expectable not to work at once. I expected simillar problems.It is always like this when man staring new project, never done before.
Well...after switching it ON some "dashed" tone appears. But fast "dashed".
There is no noticeable detection or any kind of reaction on metal in coil vicinity.
Voltages are 7.8V abd -6.23V on very start and in few seconds drops to 5.8v and -4.7v....!? Nothing burns, nothing hot,nothing even warm. Audio is not very loud it is medium but good audible.
When TL072 (all 3 of them) pulled out of sockets (later included, cant be seen on posted photo) voltages rises a bit. If i turn pots and loose audio than voltages rises to expectable values. But even with audio and without TL's voltages are almost normal - expectable. Since i dont have proper opamps right now i took first simillar to check. So i put 4558x3 instead TL's and situation was the same as with TL's...?!
I used TGS coil already proven as excellent. So...?
What drains voltage here!?
I am very occupied with few other designs at the same time so i cant really follow and retrace this accuratelly.But it is very possible that i made some mistake drawing pcb....or schematic is not accurate!? Which one of those!?
It will take some time me to retrace this and recheck all over again.
Meanwhile if somebody of you do that faster and spot something i missed please do post here so i can have less job.Also will help to others here.
Regards!

[ivconic]

Yes i will do that soon. Like i said it is not finished yet. Expect to finish it in a few days and than perform usuall testing. I will post results than here.
Regards!

[aft_72005]

Hi Ivconic
Please explain about Eldorado testing.
How much detection range for 2cm dia coin in air?
Also discrimination and …..
Regards.

Eldorado

Hello Ivica.

Nice work !! The eldorado is also a very good detector. As I remember it has some more sens. for smal coins than the golden.

Regards.

Ap