IDX-PRO+VDI

[eduardo1979]

Thanks.
I have a problem, i used two tones pcb ( attached).
First, i remove ferrite in one tone mode using GB pot.
Then, i switch to two tones but i can not remove ferrite in this mode.
I think GB is not working on two modes and it is very very unstable on ground and we have Continuously IRON tone!
I think schematic of the two tones is not correct and need to be edited.
Has anyone been able to solve this yet?

First, did adding the 4.7V Zener diode solve the overload problem? The PCB layout corresponds to the IDX PRO 2 TONES schematic, except for the CD4060, which performs the same function as the CD4024. If this schematic doesn't suit you, you can use the CLASSIC 3-2 TONES schematic.

[pechkata]

Thanks.
I have a problem, i used two tones pcb ( attached).
First, i remove ferrite in one tone mode using GB pot.
Then, i switch to two tones but i can not remove ferrite in this mode.
I think GB is not working on two modes and it is very very unstable on ground and we have Continuously IRON tone!
I think schematic of the two tones is not correct and need to be edited.
Has anyone been able to solve this yet?

There should also be a third tone—a background sound.

https://www.youtube.com/shorts/H6ZfXZA6NHg

[h9361]

Hi.
A large part of this problem is solved by adding a 4.7V Zener diode in parallel with resistor R22, connecting the diode's anode to pin 1 of U3 and the diode's cathode to pin 2 of U3. Let us know how it goes.
I have attached the diagram with the modification.

Thanks.
I have a problem, i used two tones pcb ( attached).
First, i remove ferrite in one tone mode using GB pot.
Then, i switch to two tones but i can not remove ferrite in this mode.
I think GB is not working on two modes and it is very very unstable on ground and we have Continuously IRON tone!
I think schematic of the two tones is not correct and need to be edited.
Has anyone been able to solve this yet?

[eduardo1979]

Hello dear Carl
My IDX is working nice with my coil but there is still a problem.
Audio of My IDX will be cut off if i close any medium or big size targets to coil (5-10cm)!
For exp, i have not any audio for a 10 cm (diameter) steel bowl from 10-12cm distance.
I checked it on scope, i have a big overload.
Do you have any suggestion for solving this?

Hi.
A large part of this problem is solved by adding a 4.7V Zener diode in parallel with resistor R22, connecting the diode's anode to pin 1 of U3 and the diode's cathode to pin 2 of U3. Let us know how it goes.
I have attached the diagram with the modification.

[irmasirmas1234]

Skema PCB metal detektor IDX pro 2 tone

[Carl-NC]

As Orbit says, all detectors will overload at some point. Normally, the gains of the various stage are set up so that nothing overloads on the worst expected ground. After that, reducing the RX gain just reduces sensitivity. If you are not overloading on ground then I would leave the gain as high as possible. If a target overloads it, just lift the coil.

[pito]

check what going on on U6 output and Q3 base when sound is despairing

[h9361]

What you described is normal for idx! Even factory idx devices with the original coil have an overload effect on targets that are 10cm and larger near the coil! This is absolutely normal behavior for Whites idx Clasic 3, Whites ID.. Don't worry about it!

Thanks.
I think this overload distance is very high.
For exp, i have an overload for smoke foil from 10cm distance.
Do you think i should decrease Gain preamp?

[Orbit]

Hello
Dear Orbit
Do you have any suggestion for #4398 post?
Thanks

What you described is normal for idx! Even factory idx devices with the original coil have an overload effect on targets that are 10cm and larger near the coil! This is absolutely normal behavior for Whites idx Clasic 3, Whites ID.. Don't worry about it!

[h9361]

The current of the collector should be a little higher in the case of bst 52 is 1A darlington so that the transistor absolutely does not overheat and the speaker does not break. But I think Karlo's proposal might be better..

Hello
Dear Orbit
Do you have any suggestion for #4398 post?
Thanks

[h9361]

-VB

Dear Carl
Do you think the overload is because of more gain in preamp (R2/R1=180)?
Do you think i should decrease this to lower like 150 or 120?

[h9361]

-VB

Hello dear Carl
My IDX is working nice with my coil but there is still a problem.
Audio of My IDX will be cut off if i close any medium or big size targets to coil (5-10cm)!
For exp, i have not any audio for a 10 cm (diameter) steel bowl from 10-12cm distance.
I checked it on scope, i have a big overload.
Do you have any suggestion for solving this?

[Carl-NC]

In your LM386, gnd is the pine 7 or _VB?

-VB

[Orbit]

Thanks
You right, my noise is low by the changing.
I can not understand bst 52.

The current of the collector should be a little higher in the case of bst 52 is 1A darlington so that the transistor absolutely does not overheat and the speaker does not break. But I think Karlo's proposal might be better..

[h9361]

An 8-ohm or 4-ohm speaker might be louder. However, the speaker is DC-coupled and you run the risk drawing a lot of static current. Here is a simple circuit I used in ITMD3 projects:


In your case, VTX is Vbatt, VCC is your "+" supply, and Q3 (your Q4) can remain as an MPSA13 although a non-Darlington NPN might give a little more loudness.

Very thanks dear Carl
GND is generated in IDX by u7-pine 7.
In your LM386, gnd is the pine 7 or _VB?