Tesoro Eldorado

[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

[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

[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!

[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..

[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

[nakky]

Hi Ivconic ,I have check schematic but can"t find mistake.Grt Nakky.

[ivconic]

Friends,friends! What could i do without you!?

Damn accu.!!! It is brand new, just bought it! Never checked it!
Voltage is 10.15V not 12V!?
Right now is hooked up on charger and it is charging.
I used another one and tested Eldorado with it;
it is working, yes....but working bad. Frequency is 11khz. Voltages are now 7.9V and -6.00 volts. Does not drop when detection occurs.
Current drain is 42mA without sound and 60mA with sound at full detection.
Right now it can detect Cu plate 10x10 at 15-20cm distance...bad, not good.
But also it works only in Disc mode, in all metal mode device is dead!? Not reacing at all.
I rejected that 100pF from 8. pin of LM308, earlier added as trying to be smart a.s.s.! No need for it, LM works pretty good at that place without any external compensation.
Right now i cant pull right conclusions since LF442 are replaced with TL072. Until buy proper opamps...
But still something is not right.
I still have doubts about my wirements. Need to check that again.
Nakky you said you checked schematic, did you checked my pcb or just schematic?
If you checked my pcb and there is no mistake than must be in wirements or it is possible that i put some bad component there....or schematic is not accurate? Dont know what to think?
Also that negative voltage worrrys me. At Tesoro Golden Sabre, same setup gives me -6.30 Volts and here only -6.00 volts.
OK must be cose of those TL072..
Leto i did exactly what you suggested me; i changed 0.47 to 0.22, 0.047 to 0.022 and RX to 0.015 and frequency rised as expected.
Same detection...no progress..
But for now i will keep these changed capacitors. I like more idea to work on higher frequency.
OK...i am returning to check all over again.
I'll inform you if any news.

Thank you all!
Regards!

[Max]

Friends,friends! What could i do without you!?

Damn accu.!!! It is brand new, just bought it! Never checked it!
Voltage is 10.15V not 12V!?
Right now is hooked up on charger and it is charging.
I used another one and tested Eldorado with it;
it is working, yes....but working bad. Frequency is 11khz. Voltages are now 7.9V and -6.00 volts. Does not drop when detection occurs.
Current drain is 42mA without sound and 60mA with sound at full detection.
Right now it can detect Cu plate 10x10 at 15-20cm distance...bad, not good.
But also it works only in Disc mode, in all metal mode device is dead!? Not reacing at all.
I rejected that 100pF from 8. pin of LM308, earlier added as trying to be smart a.s.s.! No need for it, LM works pretty good at that place without any external compensation.
Right now i cant pull right conclusions since LF442 are replaced with TL072. Until buy proper opamps...
But still something is not right.
I still have doubts about my wirements. Need to check that again.
Nakky you said you checked schematic, did you checked my pcb or just schematic?
If you checked my pcb and there is no mistake than must be in wirements or it is possible that i put some bad component there....or schematic is not accurate? Dont know what to think?
Also that negative voltage worrrys me. At Tesoro Golden Sabre, same setup gives me -6.30 Volts and here only -6.00 volts.
OK must be cose of those TL072..
Leto i did exactly what you suggested me; i changed 0.47 to 0.22, 0.047 to 0.022 and RX to 0.015 and frequency rised as expected.
Same detection...no progress..
But for now i will keep these changed capacitors. I like more idea to work on higher frequency.
OK...i am returning to check all over again.
I'll inform you if any news.

Thank you all!
Regards!

Hi,
if you want more current (so more voltage out) from converter try lower the resistors at base of the two transistors... as I wrote before.

You can lower to 1k5 or also 1K if needed... you'll get them saturate more easy and so some bit efficiency more there... but expect also more noise on supply rail... BTW the actual value for them is good BUT for original components there... not your stuff... TL072 and the like I mean.

About depth I think if you use the TGS coils you need some extra care on front-end... first op. amp. and, more important, disc section tuning with right components values I think could be something wrong about values there... better checking with scope at sampling pulses if you get so bad detection of copper with it. Try also swap the RX coil leads.

Current drawn seems good for it.

Best regards,
Max

[ivconic]

Yup, i performed detailed checks yesterday. All Metal mode doesnt work. When i switch to it detector dies at once. Again nothing burn,warmed or hot.
I noticed also that Disc and Geb pots doesnt make any difference in Disc mode? Threshold and Sense and Gaind works, makes differences in sound and sensitivity. I unsoldered every suspectable component and measure it, one by one. All accurate!? I would rather expect md not to work at all in Dsic mode but not in All Metal mode???In my case it is oposite???
It is detecting in Disc mode but does not disriminate at all...
It is not detecting in All Metal mode and does not produce sound?
When switched ON and works in Disc mode, when switched to All Mode it literally act as it was switched Off??? I checked and checked....sheesh!
Nothing yet. My eyes get very used on present situation on schematic and wirements draw, so if is there any mistake, right now i am not able to spot it.
I will need day or two to rest my mind and than to take another "fresh" look on it. Maybe than i will see where is mistake.
I am sure in one thing; either i made mistake in pcb, either schematic is not accurate? About components i dont have any doubts any more.
Yes Max again you are right, i am using TGS coil.Logically it must work here. Oscillator is the same,RX is almost the same, frequencies at Eld. and GS are pretty close. No reason why shouldnt work, and why coils wouldnt be exchageable.Ok small differences i can accept, but not this.
Another thing, when it detects in Disc mode that Cu plate, sound is a bit "wider" than at TGS but still it is not nonmotion sound, looks more on motion sound yet? You know what i mean? Instead "teeeeeeeeeeet" i got "teeet"?
Very confusing situation.
I think even with these TL072 it must work so so in all modes.Not great but must work. So main reason seems is not cose i put TL072 instead LF442.
I never doubted at W.Lahr's traces. All of those turns to be very accurate so far. Again great tribute to W.Lahr. But when i do agains checks on my pcb, and if no mistakes, i would start to suspect that must be some unintentionall mistake there, on schematic. Or maybe other guy, one who posted it made intentionall mistake??? Who knows? I dont..
Regards!

[nakky]

Hi Ivconic,I checked pcb with schematic but not the wirements.I don"t no how the wirements must be,that is always a problem for me.Grt Nakky

[OSTIN]

there are no mistakes at pcb, i have just checked too. Maybe is better use resistors 5k1 near 12 pin 4024

[ivconic]

So you are saying my pcb has no mistakes? Right?
Thank you very much Nakky! You saved me waiting day or two and recheck myself again...
Best regards!

P.S.
Wirements are simplier than on TGS. Draw on schematic pretty logically.
Maybe there is mistake? I rechecked those several times, yesterday.
I obeyed schematic completely. Still confused?

[ivconic]

Thanks Ostin. I will change it later afternoon and see differences.

[nakky]

If we don't make the same mistake,pcb is right.

[Max]

Yup, i performed detailed checks yesterday. All Metal mode doesnt work. When i switch to it detector dies at once. Again nothing burn,warmed or hot.
I noticed also that Disc and Geb pots doesnt make any difference in Disc mode? Threshold and Sense and Gaind works, makes differences in sound and sensitivity. I unsoldered every suspectable component and measure it, one by one. All accurate!? I would rather expect md not to work at all in Dsic mode but not in All Metal mode???In my case it is oposite???
It is detecting in Disc mode but does not disriminate at all...
It is not detecting in All Metal mode and does not produce sound?
When switched ON and works in Disc mode, when switched to All Mode it literally act as it was switched Off??? I checked and checked....sheesh!
Nothing yet. My eyes get very used on present situation on schematic and wirements draw, so if is there any mistake, right now i am not able to spot it.
I will need day or two to rest my mind and than to take another "fresh" look on it. Maybe than i will see where is mistake.
I am sure in one thing; either i made mistake in pcb, either schematic is not accurate? About components i dont have any doubts any more.
Yes Max again you are right, i am using TGS coil.Logically it must work here. Oscillator is the same,RX is almost the same, frequencies at Eld. and GS are pretty close. No reason why shouldnt work, and why coils wouldnt be exchageable.Ok small differences i can accept, but not this.
Another thing, when it detects in Disc mode that Cu plate, sound is a bit "wider" than at TGS but still it is not nonmotion sound, looks more on motion sound yet? You know what i mean? Instead "teeeeeeeeeeet" i got "teeet"?
Very confusing situation.
I think even with these TL072 it must work so so in all modes.Not great but must work. So main reason seems is not cose i put TL072 instead LF442.
I never doubted at W.Lahr's traces. All of those turns to be very accurate so far. Again great tribute to W.Lahr. But when i do agains checks on my pcb, and if no mistakes, i would start to suspect that must be some unintentionall mistake there, on schematic. Or maybe other guy, one who posted it made intentionall mistake??? Who knows? I dont..
Regards!

Hi,
I've made a mistake...sorry!


Kind regards,
Max