TGSL SMD

[daluka]

post nr. 33

A little bit big for 4024 smd to dip
[ATTACH]41721[/ATTACH]

This version has a mistake, IC 4024 pin 2 and 7 must be connected to gnd.

[ripsdevala]

Just add jumper/link for 4024 gnd, the layout missing it, Im remove diode labeled spare 4148.
If u have trouble like me, just change BF245 with another type, if not working try add the mod above post.
I use 10uf BP instead pair of 10uf for c14 and c17, more deep with it.
My current parts
Lf353=Ne5532
Bf245=J201, previously 2n5458, mpf102, afer i put J201 the chatter come without add 470k resistor Mod, if u add it it will chatter more and annoying.
I will try DD coil now.... Good luck

[BKY1337]

Can you please tell me what was wrong in the layout?
Can i use it as it is?

Good Luck!

[ripsdevala]

Eh... yes pin2/6 with 4, my bad.... Solved, time to box it

Addition, i add jumper with switch as blobber mod to get a little more deep when necessary.
And add 1m betwen pin1 u106 to pin5 u107

[dbanner]

If you are getting chatters without 200k then I suppose thats good, whatever works.

[dbanner]

I just looked at my tgsl board, seems like I put 470K between pins 2/6 and pin 4 of U106. Pins 2 and 6 are electrically connected. Also I put 200K for R38. Look R38 on schematic here that I used for my tgsl build.
470K goes between pin2/6 and pin 4 not pin 7. can't seem to find the thread where it is discussed.

[ripsdevala]

Nice! Add 470k between pin 2 and 7 u106 show the chatter, and increase the deep to 26cm clear, 30cm trtt trtt..... There us no R38 in this smd board, if i add 220k to pin6 to the gnd the sens will decrease.

[dbanner]

If you are not getting chatters when sensitivity is turned up fully, then you could be loosing some depth. The sensitivity control would normally be adjusted right up to the edge of where the chatters begin. This would give you best possible depth without too much chattering. On my TGSL, I was not getting chatters even when sensitivity was at max, placed a 470K resistor between pin 2/6 and pin 4 of U106, and changed R38 from 1k to 200K, then I was able to turn sensitivity up to the point of chatters, and got greater depth.
I got these changes from somewhere on TGS thread. I was trying to find it again, but that thread is 225 pages long.

[ripsdevala]

My best is 27cm with v3, never get 30cm before, idk.
Some tune... 23cm clear beep... Need more

Tell me how to proper phase shift with scope, what probe to connect, timing base, im not sure what im doing

[Koala]

Still sounds a bit short. I built the Bandido. Which is very similar. From memory my smallest coin about the size of a little finger nail starts at 7" and I know I can just pick up UK pre decimal coin in the ground at 10" and around 12" in the air. That's with a 5.5" coil.


Yes when the sense is fully up and the coil isn't in motion it chips a bit. Not that I ever ran the machine on full sensitivity.

[ripsdevala]

Now all fine, GB ok, null from dmm 0.019v Detection deep only 20cm with medium brass coin.... Strange no chatter at all, its should be noisy.... Maybe a little more tune somewhere.
And the silver...let me check
Silver rings is detected

[dfbowers]

Progresss. ...
I csn get 25cm air deep now, BUT! can't GB!.. meeh

A little trick I use when building my coils - I have a simple DVM that can measure frequency. I adjust my windings so that Tx runs at 14.5kHz. Then... attach your Rx coil to the oscillator and adjust winding to 13.9kHz (just for tuning purposes). When you put everything back, it should be perfect every time! You should be able to set the GB pot somewhere midrange then.. AND, make sure that you can still detect thin silver in disc and AM modes. If not, your problem is not with the coil. I may try the TGSL SDM as my next project as well.
Don..

[ripsdevala]

Progresss. ...
I csn get 25cm air deep now, BUT! can't GB!.. meeh

[ripsdevala]

I bet your problem is in coil as always Vpp on Tx is 15V and it is correct. But the phase shift is really strange. I made only 2 concentrics in the past, but always had 200° phase shift. You have something like 345-350°. Do you get double tone when target is present? Did you try swap Rx cables?

No double tone, swap rx make double tone.

what voltage are you getting. Anything under 200mv should be good. If the phase is too far out it will affect depth on certain metals. Have you tried lead aluminium silver gold and so on. Are they all bad.?

Yes its under 200mv but its to easy, something not right, and i dont get chater noise at all like the ussual, and you right aluminum is not detected in all metal mode...

[dbanner]

Here is even better video https://www.youtube.com/watch?v=TVrISTKtxAw