Start TGSL built

[BKY1337]

Hello, i bouht a TGSL EDU Kit and it came today.

The Board is almost ready. But i saw that i got TL081CN GR926 OpAmps instead of LM308.
Is this the same?

And one LM393 is a LM393P and the other one is a LM393N.
Which one belongs to which Place on the PCB?

[Toros]

It seems that Silvardog experiencing problems with the delivery of the components (IC).
LM308 is very old operational amplifier, which is no longer produced. Usually for replacement used NE5534. It is possible scheme to work with 081, but I think enegy consumption will increase.
The letters after LM393 indicate the temperature range in which the scheme operates.
D - up to 97 degrees Celsius
P - up to 85 degrees Celsius
Since you will not heat detector to a temperature such that I think you can calmly ignore these differences.

[kt315]

this is not same concerning tl081 but subs. lm308 is obsolete and you have to find more modern opamps around.
you have to choice best one.

[BKY1337]

Okay, i have finished soldering now.
But no sound appears when i connect the battery.

I dont have Coils , just the board with components on a battery (8xAA)

Is this okay?

The board was out of stock and andy from silverdog made a custom one for me.

[Hyena]

Yes it is correct, you need to connect coil, otherwise colpits oscilator wont work and you can not hear anything.
I used TL071 instead of LM308.

Always check power consumption, without coil it is 120-150mA (not sure if it can harm something). With coil and propper circuit is about 30mA.

[BKY1337]

Yes it is correct, you need to connect coil, otherwise colpits oscilator wont work and you can not hear anything.
I used TL071 instead of LM308.

Thanks!

[BKY1337]

Why is it more without coil?
I have just finished my mold for the coils.
Will test the consumption tomorrow.

[BKY1337]

I have finished RX Coil without any measuring and got 16,16 kHz connected to TX.
Is this okay?

And i got the battery sound with connected coil. Everything seems to work.

My consumption is about 15 mA without coil.

[ripsdevala]

I have finished RX Coil without any measuring and got 16,16 kHz connected to TX.
Is this okay?

And i got the battery sound with connected coil. Everything seems to work.

My consumption is about 15 mA without coil.

Wrong, you should have 13.9khz on TX, 16khz is with 15nf Rx caps.

[Toros]

People these frequencies are suitable for tesoro Lobo. For TGSL frequencies are much lower.

[BKY1337]

What? The PDF says that i need 6,5mH , 107 Windings, for RxCoil and Resonance should be
16,1 kHz with 15nF capacitors.

I have made 107 Windings, not sure about resistance and inductance but i got 16,16 kHz with one coil.

I think you have meant the TX Coil. I mean the RX coil connected to TX connectors.

And i think Toros means the IGSL not the TGSL.

[ripsdevala]

Yes, tx connector on board as measurement.
Tx 14.5khz
Rx 13.9khz

Rx with 15n = 16.1khz
Let me know if you have success build, good luck.

[BKY1337]

Tx connector on board has 15nF right?

So i should have 16,1 with my Rx coil connected to it.
I have just finished my Tx coil.
I will connect it to Tx and it should be 14,5 kHz right?

With both coils connected the resonance of Rx should be 13,9?

Can i test the metal detector without shielding?

Can i test the resistance from the coils with a multimeter?

[ripsdevala]

Tx have 220n and 22n
Rx have 15n

Yes you can without shielding
Yes you can use dmm

[BKY1337]

Okay, i have made my second coil, but i got wrong resonance ->> 15,88 kHz and the other one is now running at 16,04 kHz.

Depht is without tuning at about 16cm with a 1 Euro coin.

I have changed nothing on the potentiometers.

The PDF says that i have to make 98-99 Windings, but i need less kHz at the same connector . then i think i have to make more than 107
because i have more than 17 kHz at TX connector. I think less winding means more kHz.

Does the shielding change much in depht?