TGSL Tuning & troubleshooting

[BKY1337]

My Tracks are all connected , it's the PCB from silverdog. It worked before.
Can someone show me the test points from the PDF at the PCB?

[ripsdevala]

Im afraid u must disamble the pcb and trace dead part or unconnected track, or find all voltage reading by each components to find the error. Or ur speaker just dead

[BKY1337]

It's the same with coil. I think the coil is ok. Measured the resistance of the coils: 25 Ohm and 26 ohm.
Pin 7 Voltage (Null Voltage) is 0,77V -> Does this mean that the coils are coiling?

I got constant 2,5V or -2,5V at the speaker with speaker attached.

1,8V at the BC547 Base. (Control Point 13-Audio) , doesn't change with target, always 1,8V.

[BKY1337]

Hello, i have a problem with my TGSL . I think my internal speaker detached and caused a short curcuit.
The Coils are not coiling and the speaker doesnt make a sound.

Should i check the Pin 4 Voltages from my Op amps? Can i do this without coil?

Edit: I got 0.605 V at Pin 4 from every 8 Pin IC without coil.

[ripsdevala]

Let me do some test tomorrow, i got a better deep after change lm308 with can type and mpf102 as bf245. Thanks davor

[Davor]

Viscous soil GB is solved for PI devices, but not the most popular ones like Surf. Single frequency VLF has no such mechanism available, so it will be useful for you on easy soils, and you'll benefit from discrimination there.

[ripsdevala]

Yes, my soil is not friendly with most vlf detector, especially at mountain area, i know how to gb like quasar, but useless there, or maybe my built is wrong, out of vulcanic zone all is ok

[Davor]

If your detector is properly ground balanced to your soil, and it has resistive components due to the moisture and salt content, or due to the viscous behaviour, it is expected to behave like that with a pure reactive ferrite.
Do you know how to ground balance your detector?
BTW, coming from Indonesia, your soil must be very red from volcanic composition of the soil. It most likely has also viscous magnetic properties as well. If that is all so, you'll hardly find a simple solution for ground balance, and your conditions will change a lot. Thus you'll have to learn how to adjust GB often.
PI with ground balance will give you much more depth.

[ripsdevala]

Is that okay? Only for ferrite not others target.

[Davor]

Everything that causes phase to reverse causes double beep. If you reverse a coil, every target gives double beep. If you over-tune a GB phase, it appears as reversed signal, and gives double beep.

[ripsdevala]

Hello all, what cause ferrite make double beep?

[homefire]

Yes, Having more electronics skill makes life easier, eaa? Those little DSO 150 scopes are down to like $20.00 USD now.

[Hyena]

LOL, Acually the TGSL is a quite Simple VLF detector to build. There is nothing in the line of Alignment to do other then the coil. Nothing is adjustable without changing component values.

LOL, of course it is easy PCB to built it only with DMM, but if you want to make good coil, you should get at last DSO chinese oscilloscope. For example my DMM is able to measure 14-16V on Tx, but it is very unstable when it comes to lower voltage and totally unusable under 1 volt...

SKilled electronic enthusiast with good DMM can troubleshoot it anyway, but TGSL often buid amateurs and I think it is bad idea to tell them that they can do it only with DMM well (because they always have crappy DMM).


IF you want more than so-so working TGSL with your own coil and you are electronic amateur, do it with dmm. If you intent to make TGSL with depth 30cm and more and be able to troubleshoot it in future, you NEED oscilloscope.

[homefire]

LOL, Acually the TGSL is a quite Simple VLF detector to build. There is nothing in the line of Alignment to do other then the coil. Nothing is adjustable without changing component values.

[fekemil]

I spent a couple of hours with my good friend and his oscilloscope. We measured the important things on the circuit, it seems that working well. Then we set the overlap of the coils. And voilá! Now everything works just the way it should be. Ferrite rejection, discrimination OK. Sensing distance is 35 cm with 1€ in the air.


I'm not saying it's impossible to set the TGSL right without an oscilloscope, but I did not know. And as I watched the oscilloscope chart, it must be very lucky for someone to perfectly adjust the overlap without the device.
With a cheap multimeter you can not measure exact voltage at such a high frequency. And debugging will require an oscilloscope.
This is really not a beginner project, it's not enough to make the circuit and the coils well.




Thanks to everyone who helped, especially to Hyena!