TESORO GOLDEN SABRE

[waltr]

Taddaaaa I finally got it
when i was checking the U101 input and output , i realized that the pin 7(the original pin 1) and pin 8 are shorted!!!
i noticed the chip(LF353) is getting too hot , but i thought it is normal(yes i'm being dumb sometimes)
after refreshing all the solder joints i carefully followed the traces around inputs and output and find out that the stupid PCB manufacturer has joint the pin 7 and 8 !!!
because these two traces are a bit close to each other but not out of spec of the manufacturer, they told me they can etch down to 0.25mm at minimum , and my design was about 0.5mm !
the joint was extremely thin and somewhere very unreachable...
i ruined my 100k pot when i was trying to change it, it's a bit touchy but i saw the correct waveform for a second and i'm sure it's okay now, but couldn't capture it
i'll buy a new one tomorrow and test everything, hopefully it'll be fully functional, i'm pretty confident

so yeah fortunately it fixed, well thanks to you great people , i've learned a lot here just within a few days
truly you guys are some of the must helpful and useful people on earth, thank you very much for lessons
regards

Excellent. Very happy you found the problem and got it fixed.
Now waiting to hear how your TGSL performs.

[Mr.Jaick]

hello friends
i'm back again ,sorry
i can't reject ferrite with my tgsl
i've done whatever i know that could be effective
everything just looks perfect

take a look at these
scope set up for all pics: 2v/div , 20us t/div

1- pin 7 U102(gate of tr5) , GB pot min


2- pin 7 U102(gate of tr5) , GB pot max


3- mid leg of disc pot(min)


4- mid leg of disc pot(max)


5- Gate TR4 disc set at min


6- Gate TR4 disc set at mid range


7- Gate TR4 disc set at max


8- TX vs RX(output of pre-amp U101)
TX 2v/div and RX 0.5v/div

as you can see nothing is wrong here, i don't know where is the problem... i've tried many different null positions for coils, but nothing
the project looks at my eyes, smiles and says "that's not gonna happen buddy"

[waltr]

Scope waveform look ok but best if two scope traces are used. First on TX and then the other.
This is because ALL are relative to the TX signal and why it is called "synchronous detection'.

What are you using as the Ferrite sample??? There are Many different kinds and sizes of ferrite and not all can be used.
I use small thread cores from RF coil salvaged from very old radios. Some of the larger ferrite I have is never rejected.

Also, the adjustment of the GB pot is very, very sensitive. The tiniest movement can be too much.

What does the Coil RX Null look like?? We need to see RX at output of Pre-amp relative to TX to judge Phase shift and amplitude.
Look at Dbower's TGSL 101.pdf Scope pictures for examples.

[Mr.Jaick]

Scope waveform look ok but best if two scope traces are used. First on TX and then the other.
This is because ALL are relative to the TX signal and why it is called "synchronous detection'.

What are you using as the Ferrite sample??? There are Many different kinds and sizes of ferrite and not all can be used.
I use small thread cores from RF coil salvaged from very old radios. Some of the larger ferrite I have is never rejected.

Also, the adjustment of the GB pot is very, very sensitive. The tiniest movement can be too much.

What does the Coil RX Null look like?? We need to see RX at output of Pre-amp relative to TX to judge Phase shift and amplitude.
Look at Dbower's TGSL 101.pdf Scope pictures for examples.

i use toroid ferrites , new ones for power supply coils ,28mm
the tx vs rx was spouse to be the last pic sir , i forgot to share
here it is

the trigger source in scope is VERT not CH1(TX signal) , is that ok?

[Nandor]

Add 1nF in plus for the Rx circuit and it will shift a bit the Rx. Theoretically the Geb phase shifter can do 45deg of phase shift, maybe your Rx signal is not in the range of that. No component is perfect so it could have only 40deg phase shift that could be a reason, it worked for me.
Read the topic, there are so many informations to learn this is only repetition!

[peyman 74]

hi to all.what is the last version of tgsl?? regards

[waltr]

hi to all.what is the last version of tgsl?? regards

https://www.geotech1.com/forums/forumdisplay.php?18-Silver-Sabre-Bandido-TGSL

[Nandor]

Hi

In my recent build I have used OP07 to replace the LM308, I had no more "free" TL071. Using this opamp the detection distance has dropped about 5cm . I have tried LM741, TL081 TL071 all works fine but OP07 is weak.
Looking at the datasheet it a pretty decent opamp yet it does not perform well in this circuit.
Anybody some ideas? I have bought 10 pcs from Texas insturments they are not fake

[waltr]

Did a quick compare of the OP07 verse TL071 data sheets.
What I see that may cause the OP07 to be not as goo is:
Input bias current is higher (nA vs pA) due to bi-polar inputs vs FET inputs.
Slew Rate and BW lower.

The OP07's best characteristic is Stability & low drift.
It also wants a full +-15V (all spec are for +-15V).

[SWL]

Зачем нужны эти эксперименты --- проще 308 заказать в интернет-магазине

[Qiaozhi]

Зачем нужны эти эксперименты --- проще 308 заказать в интернет-магазине

Please make your posts in English.
Basic Rules of the Forums

[SWL]

Uppss!! Sorry!
Why do we need these experiments --- it's easier to order 308 in the online store

[Nandor]

I think slew rate and band with at 11Hz is not so important. But as you said input bias current is higher and the voltage is lower, didn't even see that.
The LM308 is very expensive here, I prefer to use the TL071, good price and less chatters at max sense.

[green]

I think slew rate and band with at 11Hz is not so important. But as you said input bias current is higher and the voltage is lower, didn't even see that.
The LM308 is very expensive here, I prefer to use the TL071, good price and less chatters at max sense.

Why 11Hz?

[Nandor]

The center frequency of the bandpass filter.