questions about TGSL

[ShinyGoldPT]

Hi all, im building this metal detector because i found a lot of information about it (components used OC placement and so on), but i have no formation in electronics. I study geology in Portugal so im facing some "small" problems with this project, so i started this topic so to be able to share my questions and maybe get some answers. So my questions are:

1- I got a bit confused by the Farad units by looking at others TGSL and comparing with the components pdf (see attachment)

1_a- Im 99% sure that the value of the blue caps is 100 pF am i right? The same goes for the green ones, 0.022 uF caps?

1_b- The pink one is either 15 pF or 0.015 uF and the grey one is the other one.
1_c- Could i use the BF245A instead of the BF245C? I tried to read the datasheet but i can't understand if i could replace the BF245C but i saw somewhere that would be ok, also the J111 is a possible substitute?

That's it for now, i have a couple more questions, but will leave them for later. "Det.jpg" is what i have done so far.

Thank you all.

[homefire]

Pink .1uf

Blue 100p

Green .22uF

Yes on the BF245A

That PCB is a bit different then the one I have.

[kt315]

also the J111 is a possible substitute?
---
maybe but where you see them to buy? source?

[Tibuck19]

Hi all, im building this metal detector because i found a lot of information about it (components used OC placement and so on), but i have no formation in electronics. I study geology in Portugal so im facing some "small" problems with this project, so i started this topic so to be able to share my questions and maybe get some answers. So my questions are:

1- I got a bit confused by the Farad units by looking at others TGSL and comparing with the components pdf (see attachment)

1_a- Im 99% sure that the value of the blue caps is 100 pF am i right? The same goes for the green ones, 0.022 uF caps?

1_b- The pink one is either 15 pF or 0.015 uF and the grey one is the other one.
1_c- Could i use the BF245A instead of the BF245C? I tried to read the datasheet but i can't understand if i could replace the BF245C but i saw somewhere that would be ok, also the J111 is a possible substitute?

That's it for now, i have a couple more questions, but will leave them for later. "Det.jpg" is what i have done so far.

Thank you all.

Did you buy the TGSL board from Silverdog or a board you made yourself?? there seems to be a few version of this board out there , if its a black board the parts placement photo u have is not the right one, you will need Version 3 I believe. EDIT: Sorry just seen the photo of the board.

[ShinyGoldPT]

Hi all,

For some reason i can't quote anything.
Tibuck19, i got my files from this google drive: https://drive.google.com/drive/folde...mc4YkRXMGdLS1U
kt315, there is a store called mauser (https://mauser.pt/) that sells that J111 and since is near my college (FCUL, Lisbon) i usually buy them some pieces (the ones i don't buy from China).homefire, if the pink is .1uF why is not the same size has the 0.1nF (just want to understand why)so im still left with a 15pF and a 0.015nF acording to the partslist, idea where they go?


Thank you all.

[Nandor]

That's a mirrored PCB, it wont work!

[Tibuck19]

Hi all,

For some reason i can't quote anything.
Tibuck19, i got my files from this google drive: https://drive.google.com/drive/folde...mc4YkRXMGdLS1U
kt315, there is a store called mauser (https://mauser.pt/) that sells that J111 and since is near my college (FCUL, Lisbon) i usually buy them some pieces (the ones i don't buy from China).homefire, if the pink is .1uF why is not the same size has the 0.1nF (just want to understand why)so im still left with a 15pF and a 0.015nF acording to the partslist, idea where they go?


Thank you all.

I bought a board from Silverdog , a side from some transistors that had to be installed backwards it also worked first shot! perhaps it be worth getting yourself one, I really enjoy the it out in the field .

[ShinyGoldPT]

Hi all,

Nándor, thank you for remind me of that Yes i've inverted the circuit and i noticed that when i started to drilling the holes so i inverted all pieces in order to fix that, hope i can continue.

Tibuck19, i wanted to do the pcb my own so i could learn something and to have some fun (im because im a student and im low on $$), plus i want to buy either surf pi or barracuda from Silverdog.

maybe next thursday im gonna get all the pieces i don't have so i can finish the whole thing.

I still don't understand why the .1uF in that help diagram is so little compared to the others 0.1uF caps. Plus, where im going to put the 15pF cap that is listed in the BOM.pdf (components list). If anyone knows please tell me

Thank you all.

[homefire]

1 C11 478-4845-ND CAP CER 15PF 100V 5% NP0 C 11

[Tibuck19]

I recently Changed a GB wire that goes to the GB pot, I don't know if it as anything to do with it but I seem to have lost some depth on the TGSL, If I mesure the frequency of the LM393 near the GB, (14.50) and on the RX side I have 15.50. should I change the Cap on C6 if so how do I get the value for the replacement cap ? EDIT I re measured the freq and the TX and RX measures the same are the LM393 14.6543, however a USA quarter , A dime a Nickel and a Spanish real silver coin is not being detected at 8 inches in the ground, The nickel is but only when im not in discrimination, I need it to detect at least 8 inch for the silver coins, How can I fix my TGSL for those depths with discrimination on ?????

[ShinyGoldPT]

Hi all,
homefire, you were 100000% right.. but you might know, im still really fresh in this scene to not notice that 15 pF is the same as 0.015nF.

I've soldered everything (without the coils + power supply) and i noticed some holes without informations (see attachment), the ones who have the same color i guess are from the same component the other ones i have no idea. Can anyone tell me what components are missing (in those holes) and the values of the pot's.

Thank you all.

[Tibuck19]

Hi all,
homefire, you were 100000% right.. but you might know, im still really fresh in this scene to not notice that 15 pF is the same as 0.015nF.

I've soldered everything (without the coils + power supply) and i noticed some holes without informations (see attachment), the ones who have the same color i guess are from the same component the other ones i have no idea. Can anyone tell me what components are missing (in those holes) and the values of the pot's.

Thank you all.

Not the same version but it should still be the same pinout I would think. one is a On Off On toggle switch the other is a 100K pot for the Discrimination

[homefire]

[ATTACH]42935[/ATTACH]

Not the same version but it should still be the same pinout I would think. one is a On Off On toggle switch the other is a 100K pot for the Discrimination

[ATTACH]42935[/ATTACH]

LOL, Wish I had that about a month ago !!!!

[ShinyGoldPT]

Yeah... My bad... Tibuck, that seems correct, can anyone verify it please?

[Tibuck19]

LOL, Wish I had that about a month ago !!!!

you should of asked about a month ago loll