IDX-PRO+VDI

[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?

[h9361]

Those capacitors make the signal cleaner. Reconnect the pin point and adjust the pot trimmer to barely audible and leave the setting like that. You could also replace the input number 5534 with AD711. As for the sound Karl I know he will give you good advice. My suggestion is to put an 8R speaker and relax the mpsa13 transistor by replacing it with a bst 52 or similar.

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

[Carl-NC]

Is it possible to help me how to increase its audio in speaker?
I tested it with 15, 25, 150R speaker.

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.

[Orbit]

Dear Orbit
I changed position of two capacitors, as you told.
No change to depth.
But i changed IC brand, now my depth for the coin is near 42 cm.
I made your dc convert voltage, it works very nice.
Thank you.

Those capacitors make the signal cleaner. Reconnect the pin point and adjust the pot trimmer to barely audible and leave the setting like that. You could also replace the input number 5534 with AD711. As for the sound Karl I know he will give you good advice. My suggestion is to put an 8R speaker and relax the mpsa13 transistor by replacing it with a bst 52 or similar.

[h9361]

The RX resistance matters very little. The higher TX resistance will add a small amount of phase rotation that is removed with the ground calibration. The resistances you have will work, and are not the cause of your lower sensitivity.

Hello dear carl.
Please forgive me, i have a request.
Please see IDX schematic audio part, post #4378.
Unfortunately its audio level in speaker is very low.
Is it possible to help me how to increase its audio in speaker?
I tested it with 15, 25, 150R speaker.
Thanks

[h9361]

To connect the capacitors as shown in the diagram! Not going into the details of the pcb because I've never used that pcb.Just place the capacitors as I mentioned and as you moved them on the scheme you posted and let me know if there are any improvements..

Dear Orbit
I changed position of two capacitors, as you told.
No change to depth.
But i changed IC brand, now my depth for the coin is near 42 cm.
I made your dc convert voltage, it works very nice.
Thank you.

[Aleks85]

This describes a simple test of operational amplifiers, everything is in Russian, anyone who needs it can translate it. Just look at the oscillogram and it will be clear which microcircuit is normal and which is defective.

[pechkata]