White 3900D

[dbanner]

For whatever reason, Q3 and Q5 were left out together with the surrounding components. However this circuit (Q3,Q5) is part of the original 3900, so maybe I'll try to stick it in somewhere on this layout if I can find the space.

[gurdal]

Hello

[MartyJ1963]

Hi DB,,,,Think I found a missing track as well,,,From the Cap to the SP output. Regards,,,Marty

[MartyJ1963]

@DB,,,,Can a 'jumper' just be used in place of the '0.2r' resistor?,,Thanks, Marty

[dbanner]

@DB,,,,Can a 'jumper' just be used in place of the '0.2r' resistor?,,Thanks, Marty

I think they meant to limit the full stop of the tune pot on one end to a voltage slightly higher than the negative rail, not sure why. But I think this calibrates the tuning range for the audio chopper.

Thanks for spotting that missing track on pcb

[sayan1345]

3900ِِِِD

picture of detector and coil

[dbanner]

Hello

Very good, but where is the big iron pliers waving across the coil to demonstrate the discrimation? The implication here is that the coil is not properly phased and the circuit will not discriminate.....nice try!

[gurdal]

hi
yes you're right, coil hard work.

[kt315]

Very good, but where is the big iron pliers waving across the coil to demonstrate the discrimation? The implication here is that the coil is not properly phased and the circuit will not discriminate.....nice try!

this VLF is not different that other. big iron pliers also gives good unferrous signal. this is sure normal situation.
in real conditions in ground rust shell around the target will reinforce the signal and kill all disc you wait from this detector.
we are back returning to HALLO/gallo effect matter, our loving melancholy winter time discussion.

[Nandor]

Very nice work Gurdal, PCB looks very good!
It's a good static discriminator detector.

[kt315]

picture of detector and coil

[ATTACH]48278[/ATTACH]

[ATTACH]48279[/ATTACH]

chinese MD-5012/MD-5008 is more progressive than 3900. https://www.geotech1.com/forums/show...73-MD-5008-PCB
here is not for me what to do if i want to build the non-motion detector. i had see MD-5012 in real work and
you can buy it 'for repair' without problem on ebay. that will decrease your time much to result getting without resource.

[dbanner]

this VLF is not different that other. big iron pliers also gives good unferrous signal. this is sure normal situation.

Nonesense, a standard size iron pliers is surely REJECTED! Who can say what coil is in the video? Can anyone undersatnd the language?
https://www.google.com/url?sa=t&rct=...LXoul7T0D8KhEs

And here:https://www.google.com/url?sa=t&rct=...Q4UgWp25shWN6L

[dbanner]

Very nice work Gurdal, PCB looks very good!
It's a good static discriminator detector.

Pcb is very nicely done. I think it is a copy of this one.

If we can make the correct coil with proper phasing, we will have a very good coin and relic hunter!

[gurdal]

Pcb is very nicely done. I think it is a copy of this one.

If we can make the correct coil with proper phasing, we will have a very good coin and relic hunter!

white's jvn(jonny van norden) special edition

[gurdal]

https://www.ebay.ie/itm/Jv-N-Metalld...-/283628505129