Tesoro Eldorado problem

[dgm]

Good morning to you all the members of this Forum. I wanted to ask your opinion on a problem I am having with a self-built metal IB treasure eldorado. I made two of these circuits, one of them works perfectly, instead the second one I have a problem with discrimination, I can cut the ferrite in all metals, and as a step in discrimination, with the discrimination potentiometer at zero, I should see all metals less than small iron, but it is not so iron discriminates it and I can only hear 5 cent nickel, gold, and aluminum. the rest of the metals such as copper, silver, are discriminated against. I did several tests but nothing, only by moving the knob of the GB I can find the other discriminated metals, but I lose the ground balance. I tried several coils made by me, once brought in resonance and balanced, I always have the same problem. I have also tried to lengthen the discrimination scale by substituting in the 100 pf capacitor, but nothing in this way moves me forward the regulation of the GB.
Thanks for who can give me a suggestion to solve and understand the problem.

[Artyom]

Good morning to you all the members of this Forum. I wanted to ask your opinion on a problem I am having with a self-built metal IB treasure eldorado. I made two of these circuits, one of them works perfectly, instead the second one I have a problem with discrimination, I can cut the ferrite in all metals, and as a step in discrimination, with the discrimination potentiometer at zero, I should see all metals less than small iron, but it is not so iron discriminates it and I can only hear 5 cent nickel, gold, and aluminum. the rest of the metals such as copper, silver, are discriminated against. I did several tests but nothing, only by moving the knob of the GB I can find the other discriminated metals, but I lose the ground balance. I tried several coils made by me, once brought in resonance and balanced, I always have the same problem. I have also tried to lengthen the discrimination scale by substituting in the 100 pf capacitor, but nothing in this way moves me forward the regulation of the GB.
Thanks for who can give me a suggestion to solve and understand the problem.

As planned, Eldorado does not have black metal in discrima. But there should be foil, without foil you miss a lot of things. In order for it to appear, it is necessary to reduce the 100-peak capacitor in the discriminator node. By decreasing it, lower the scale below for foil targets and the like.
Ferrous metals in El Dorado only in all metals. Why do you have to reduce it, in a seemingly correct factory circuit, because the TX is wound not 0.25 and everyone is trying to add voltage to the TX. Because of this, the impulses to the discrim node are of a larger size. By reducing this pass capacitor, we also reduce the influence of these pulses.

[dgm]

Thanks Mr. Artyom for your answer, I meant that I tried to reduce the capacitance of the discrimination capacitor from 100 to 20 pf, but it only shifts the groun balance, leaving only the metals described above. I don't know where to look for the problem.

[dgm]

After rechecking the eldorado circuit, I fixed the problem, the 15pf capacitor C20 was mistakenly set to 150pf. Now it works perfectly.