Tesoro Eldorado on the bench

[juankarlosnv]

The circuit does not work, and to change the NTE312 FET MPF102, the LM308 TL081 also change, then change the TL082 to TL062 and nothing my little sound of speaker is very low is nothing I declare myself defeated I declare myself defeated by this detector or may not work



change errors of 1 transistors nothing wait the coils unhardened. I have not even aluminum, are just flossing this is right?

[juankarlosnv]

I followed the tracks compared diagrams, other forums in other languages, and it does not work, I think it's time to let go
Revised Ics, Transistor changed,
The only thing I wonder is if it really works

[ivconic]

I followed the tracks compared diagrams, other forums in other languages, and it does not work, I think it's time to let go
Revised Ics, Transistor changed,
The only thing I wonder is if it really works

Look back; first page here: post #8 - that's the one i guarantee is working 100% right.
I made few of those so far; works very nice.
I am not sure if that is the version you made?
I can't guarantee for other versions, haven't tried.
Cheers!

[juankarlosnv]

Hi ivconic, is the same pattern you gave us, if parts are correct and change TL082, TL062 and TL062 for LM308 BF245 - MPF102 what my error.
The feed I use, perhaps the low corrienrte but already connected to 12 volts of car batery

[ivconic]

"...Hi ivconic, is the same pattern you gave us, if parts are correct and change TL082, TL062 and TL062 for LM308 BF245 - MPF102 what my error.
The feed I use, perhaps the low corrienrte but already connected to 12 volts of car batery..."

Let's clear this up; TL082 and TL062 are DUAL (two in one package) opamps, while LM308 is ONE opamp in one package... HUGE DIFFERENCE!
You can't replace TL062 with LM308!
MPF102 and BF245 are having different pin assignments, as i recall quite oposite they are (DSG - GSD), so take care about their orientation on pcb.
Wall power supply (from your photos) is very low profile, low filtered and suspiciously inaccurate voltage source for testing such sensitive device as metal detector.
And last; Eldorado will not work if coil is not properly connected to it. Without coil ti will remain silent.

[juankarlosnv]

sorry for the mistake to write for LM308 TL081, TL062 not

feeding if I'm wrong, I'll get a battery for this


You guide me with the coil please. thanks



I connect the coil

[Davor]

It is always good to try initial tests with batteries. That also reduces a possibility of bad PSSR influencing your judgement on the device noise. Once you are convinced it works with batteries you can switch to something else. But honestly - you are going to use this rig on batteries anyway.

[ivconic]

sorry for the mistake to write for LM308 TL081, TL062 not

feeding if I'm wrong, I'll get a battery for this


You guide me with the coil please. thanks



I connect the coil

Yes that's alright.
...
What about MPF? Have you checked it's orientation on pcb?

[juankarlosnv]

Hi, MPF102 out. BF245A of fairlchild install and put this:

[juankarlosnv]

Sorry I'm late, spend the weekend away from home

[juankarlosnv]

Ivconic Hello, could you tell me which is the orientation of the 3 transistors - BC327
and BC337?

[Davor]

You may try this link: http://lmgtfy.com/?q=BC327&l=1

[juankarlosnv]

I meant in the circuit but thanks

[Derx]

How to about last bench today?

[dgm]

Hello, my name is Maurizio from Rome, Italy, I wanted to ask you of the forum, I have built a treasure MD eldorado, when it does not work always sounds in both metals in all discrimination, and warms up the pnp transistor BC327 in push-pull you located close to the CD4024, I checked all the solder connections but nothing, it always sounds. Thank you for your response.