TESORO GOLDEN SABRE

[Max]

Actually, it seems very strange and very interesting!
In All Metal mode, already mentioned problem occurs ONLY WHEN
APPLY COIN TO COIL FROM GREAT DISTANCE AND CLOSE TO POINT WHERE
IS JUST ABOUT TO DETECTION OCCUR!?
But when move coin in the zone and accurate detection no problem at all.
Detector makes "beep-beep" and than stops normally like in Disc mode.
So let's repeat;
it cant stop beeping ONLY if coin is approximated to coil from zone out
of detection,slowly...first "beep" occurs and no matter if coin is
removed, beeping continues until switched OFF or I HAVE TO PUT HAND ON
COIL OR EVEN HELPS WHEN I TOUCH THOSE 3 WIRES WHICH CONNECT PCB WITH
DISC/ALL SWITCH...OR IF I RANDOMLY TOUCH SOME PART (BUT NOT EVERY) ON
PCB...IN THOSE CASES IT WILL STOP WITH BEEPING.THIS IS THE CASE ONLY IN
ALL METAL MODE, IN DISC MODE ALL IS WORKING PERFECT!
Also if i move coin from a side into "sure detection" zone, let's say
10-15cm away from coil surface (must be much louder signal than) than
device is working normal,same as in Disc mode, no beeping more when
coin is removed from zone of detection????
Today i tried somehow to dig what is all about - but no results.
Coil is prefect, no doubts in it. Cable wirements from coil to device is
also good - no mistakes, no twisted pair effect, absolutely stabile,no
false signals....nothing!
I put sort of "gnd cage" over those switching fets - still the same...
it seems fets are not problem here despite a lot of noise they producing.
I changed that 15pf, replaced...tried even without it...- same...!?
Coupled LM393 supply pins with 0.1 to gnd...- same...?
Damn!Damn!Damn! This thing is making me crazy! It is not a big deal to
have detector working perfect in Disc mode but not in All Metal mode.
I can live with this.It is working so good in Disc mode so i dont mind
about beeping in All metal mode at all. Besides i am not using All Metal
mode anyway...
But from constructors point of view this thing is interesting me much!
I just would like to understand this better.
I would like to see others opinions on this! Sean,KT315,Carl...others!
Please come here and help us to solve this thing!
What should be a problem here?
Regards!

Hi Ivconic and all,
...sorry I referred one of my previous post about TL062 that some of you haven't on TGSL, cause you haven't notch mode there! So just people having that notch, so building original TGS can refer to the change with e.g. TLC2262.

About problem of bleeping:

I haven't the same problem ...at least I cannot notice it and detector sound or be quiet even slowly moving a coin e.g. above the detection range area... then putting it near it's detected... but need a fast movement and sound isn't loud without the 1Mohm resistor at D12.

Don't know why.

Only I know that if you have it working ok in disc... you actually have it quiet when the shift network related to disc phase angle is from the LF353/LM393 action on disc side and not from the fixed delay network (fixed delta-phase)100k/15pF of all-metal.

I start thinking you have some kind of problem there, but cannot figure out what could be... and why you have that problem and I haven't.

Now it's a real mistery.

Best regards,
Max

[Qiaozhi]

Actually, it seems very strange and very interesting!
In All Metal mode, already mentioned problem occurs ONLY WHEN
APPLY COIN TO COIL FROM GREAT DISTANCE AND CLOSE TO POINT WHERE
IS JUST ABOUT TO DETECTION OCCUR!?
But when move coin in the zone and accurate detection no problem at all.
Detector makes "beep-beep" and than stops normally like in Disc mode.
So let's repeat;
it cant stop beeping ONLY if coin is approximated to coil from zone out
of detection,slowly...first "beep" occurs and no matter if coin is
removed, beeping continues until switched OFF or I HAVE TO PUT HAND ON
COIL OR EVEN HELPS WHEN I TOUCH THOSE 3 WIRES WHICH CONNECT PCB WITH
DISC/ALL SWITCH...OR IF I RANDOMLY TOUCH SOME PART (BUT NOT EVERY) ON
PCB...IN THOSE CASES IT WILL STOP WITH BEEPING.THIS IS THE CASE ONLY IN
ALL METAL MODE, IN DISC MODE ALL IS WORKING PERFECT!
Also if i move coin from a side into "sure detection" zone, let's say
10-15cm away from coil surface (must be much louder signal than) than
device is working normal,same as in Disc mode, no beeping more when
coin is removed from zone of detection????
Today i tried somehow to dig what is all about - but no results.
Coil is prefect, no doubts in it. Cable wirements from coil to device is
also good - no mistakes, no twisted pair effect, absolutely stabile,no
false signals....nothing!
I put sort of "gnd cage" over those switching fets - still the same...
it seems fets are not problem here despite a lot of noise they producing.
I changed that 15pf, replaced...tried even without it...- same...!?
Coupled LM393 supply pins with 0.1 to gnd...- same...?
Damn!Damn!Damn! This thing is making me crazy! It is not a big deal to
have detector working perfect in Disc mode but not in All Metal mode.
I can live with this.It is working so good in Disc mode so i dont mind
about beeping in All metal mode at all. Besides i am not using All Metal
mode anyway...
But from constructors point of view this thing is interesting me much!
I just would like to understand this better.
I would like to see others opinions on this! Sean,KT315,Carl...others!
Please come here and help us to solve this thing!
What should be a problem here?
Regards!

Hi Ivconic,

Have a look at the wire-ORed outputs of the LM339 comparators when the detector starts beeping continuously. It's possible that the comparators have gone into oscillation. If so, then you may have a layout problem, and/or you may need to add some hysteresis to the comparators.

Also have a look at the attached Application Note, especially the section entitled "Comparators with Hysteresis".

[ivconic]

Rotten tomato!


Problem is solved!
Before i tell you what was the problem, first let me add few more things;
In the past when i made original TGS on that large pcb, i had no problem
with it at all. Sens.pot....hmm! At the time i was able to adjust sensitivity
linear in both modes: Disc and All M.
But now at present, when i noticed this All M. mode problem, forgot to examine
Sens. stage more detailed. So, few hours ago i checked all over again and noticed
that Sens. pot does not have much of influence of depth and overall behavior!?
In the past (large pcb) i could adjust Sens. in both modes to avoid erratic
working od device. Now not!?
So i started to checking arround that part. So...all the problems came with
adding that famous 1M resistor parallel to 1N4148!!!!!
I resoldered it and detector started to working without any problem!!!!
Now, when switched in ALL M. Mode, i can stop bleeping by lowering Sensitivity
a bit with Sens. pot! Does not affect depth to much....you may say - not at all!
Depths remains the same...O.K. maybe 5% worse, but detector is working excellent
in All M.mode same as in Disc. mode!!! HUUUURRRAHHHH!!!!!
Yes audio now is not loud all the time but variabile - depending of the signal
strenght....When very small coin put at the edge of detection, audio is weak..
When approximated bit by bit, audio becomes louder and louder.....
So...conclusion:
Yes...in a way i was very right when suggested 1M resistor as optional BUT
ACTIVATED (WHEN DESIRED) ONLY WITH A SWITCH! NOT INCLUDED ALL THE TIME IN
WORKING CIRCUIT....
My mistake was because i soldered it over diode and included it all the time
in detector activity...Not good! Lost of All M.mode in that case!

Sheeeesh! I really exausted my self last few hours.....
All started when KT315 suggested that 1M at the first place...!?
So i should take some rotten tomato and hit dear KT315's nose!!!
Ha,ha,ha,ha,ha,ha!!!! I am only joking here...of course! Mistake was only mine!
Best regards!
Got to sleep few days.....


P.S.

I am not gonna examine this further...to exausted.But last year i had same situation with Minelab Musketeer Colt. It was impossible to work with it in All M.Mode when Sense turned to maximum....simillar isnt it!?

[ivconic]

!

Quiaozhi...in a way you are right also!
Adding that 1M resistor caused to many offsets in overall design....to much for device to work linear in all modes...
Thank your for .pdf...Interesting for me much!
Regards!

[erolunall]

Hello all
I am reading every day discussion about TGS .I built one TGS but
I thing it not working properly. Giving a constant saund like düüüüt
and sound changing very close to coil near a metal.İt was not giving this sound before .it was giving like tik tik but I thing some IC is burned,
I changed 4024 and lm358 saund changed to Tic Tic but very short time
its turned Düüüt again .disc and all metal mode looking like same.
Which IC I Have to change? Because I changed all transistors.
I made a small coil about 16 cm.18 ohm but it s same performance whith 22 cm coil,
İf a shortwave radio antenna near the 4024 I can hear a good sound from radio.This way İT detecting about 40 cm For 10 cm metal object.
Which IC' s I Have to change?
Best Wishes
Erol Ünal

[Max]

Hello all
I am reading every day discussion about TGS .I built one TGS but
I thing it not working properly. Giving a constant saund like düüüüt
and sound changing very close to coil near a metal.İt was not giving this sound before .it was giving like tik tik but I thing some IC is burned,
I changed 4024 and lm358 saund changed to Tic Tic but very short time
its turned Düüüt again .disc and all metal mode looking like same.
Which IC I Have to change? Because I changed all transistors.
I made a small coil about 16 cm.18 ohm but it s same performance whith 22 cm coil,
İf a shortwave radio antenna near the 4024 I can hear a good sound from radio.This way İT detecting about 40 cm For 10 cm metal object.
Which IC' s I Have to change?
Best Wishes
Erol Ünal

Hi,
you have built TGS first PCB ? if so...

if you have "bleeping" meaning some beep-beep erratic from it at max sens you have to change the TL062 with something better like TLC2262 cause I noticed that TL062 is not good cause of that bleeping at max sens.

There could be also other, many, causes as example I remember you have to clean the solderside of PCB very well after soldering cause all these circuits have great amplification and some hi-impedance input op. amps... that don't like e.g. solder flux and similar "contamination" that makes conductive paths appear between pcb tracks.

There are other causes that could be related to e.g. coil wiring... you have to use separate conductors in your cable for e.g. ground of each coil.

You need also a good shield on them to avoid picking up too much electrical noise at 50 or 60Hz depending which is electric network frequency in your country... other noise from intermodulation between mains frequency and e.g. electric apparatus could interfere with your detector... also on-state TV sets that emissions are in 10s KHz range could give you false signals indoor, same for fluorescent-lamps, motors etc etc

Causes could be so many that's impossible make a remote analysis of your problem and you'll have to discover yourself which or where is the problem... but check what I've said...often cause is easy to find.

Best regards,
Max

[Qiaozhi]

Hello all
I am reading every day discussion about TGS .I built one TGS but
I thing it not working properly. Giving a constant saund like düüüüt
and sound changing very close to coil near a metal.İt was not giving this sound before .it was giving like tik tik but I thing some IC is burned,
I changed 4024 and lm358 saund changed to Tic Tic but very short time
its turned Düüüt again .disc and all metal mode looking like same.
Which IC I Have to change? Because I changed all transistors.
I made a small coil about 16 cm.18 ohm but it s same performance whith 22 cm coil,
İf a shortwave radio antenna near the 4024 I can hear a good sound from radio.This way İT detecting about 40 cm For 10 cm metal object.
Which IC' s I Have to change?
Best Wishes
Erol Ünal

This will be extremely difficult to fault find remotely. As Max rightly says, you will need to discover the problem yourself. But first you will need an oscilloscope. Without one you will have an almost impossible task.
First check that the power supplies are ok, and that they're connected where they should be. Next check that the transmitter circuit is oscillating and that it's working at the right frequency. Failure of the oscillator will mean that the negative supply rail will be zero volts, since the oscillator drives a diode pump circuit via a divider. If all's well with the power supplies and the transmitter, then check the following:
1. Signal across receive coil.
2. Output of preamp.
3. Sample pulses at the gates of the FETs for the GEB and DISC channels.
4. Filter outputs for both GEB and DISC channels.
5. Audio osc output.
6. Headphone amplifier.

Somewhere along the way you should be able to identify the problem.
Good luck.

[Max]

weight considerations

Hi all,
I think I'm ready for the final TGS assembly with new coil... but I'm a bit puzzled about weight.

I'm going to use spare parts from here and there... cause I haven't any good ready to made assembly.

With my actual parts I'll assemble I have the following (about) weights:

battery (12V 1.2Ah gel-type) : 450gr

circuit (with wirings, pots, screws etc) : 200gr

Control box (without circuit inside) : 300gr

Pole/stem (alluminium made with kind of handle) : 600gr

Estimated Coil weight (at now can only estimate) : 350-400gr

So with data of above I'll get about 2Kg of total weight of detector:

what do you think ? too heavy assembly ?

I can change easy the gel-type battery with 10 NiMh e.g. 700mAh saving about 200gr that's about 10% of weight but other parts are a problem cause I cannot find at now more light ones.

Any suggestion welcome.

Kind regards,
Max

[Max]

Damn !

I saw some "coiltek" (for minelab's) coils at
http://www.detectordepot.com/coiltek_search_coils.htm

and see that a 11'' round ("the ripper" model) has a weight of 1.6lb = about 0.72Kg

For me is really heavy for a 11'' fabric made coil !

Tesoro's originals are much less heavy.

These stuff are good for body-building !

Considering that a Tesoro's Tejon Pro weight is about 1.5Kg total my 2Kg aren't so much more... but I still think I have to reduce weight.

What do you think ? Any idea ?

Best regards,
Max

[Max]

uhm...

I see Minelab Musketeer Advantage Pro with 10''coil that weight about >2.4Kg so more than what I'll get from my homemade with spare parts!

Damn !
Isn't it heavy ?

Kind regards,
Max

[dino]

For Ivconic and Max

Hello, well i finaly made my GS and i can say its wery good. Sensitivity is wery good, golden ring detect on 27cm, and im wery pleased with that, but i have some problem, its when i start GS on i keep get a tone in 6 to 7 seconds interval and then it disapier. Tone on detection over 10cm is wery weak, and i use NF MPSA13. Coils are made 255x137 RX 105 TX 100.Bipolar cond. 4,7mF 100V originaly. For TL062 i use LM393 and i have beter results. Batery 12V 8AH. Speaker 8ohm with added resistor 10ohm. Voltage +8V -6,27V. As on Tesoro Bandido for wich i have shematic power is +5V, would GS be beter with that?

Regards Dino

[Max]

Hello, well i finaly made my GS and i can say its wery good. Sensitivity is wery good, golden ring detect on 27cm, and im wery pleased with that, but i have some problem, its when i start GS on i keep get a tone in 6 to 7 seconds interval and then it disapier. Tone on detection over 10cm is wery weak, and i use NF MPSA13. Coils are made 255x137 RX 105 TX 100.Bipolar cond. 4,7mF 100V originaly. For TL062 i use LM393 and i have beter results. Batery 12V 8AH. Speaker 8ohm with added resistor 10ohm. Voltage +8V -6,27V. As on Tesoro Bandido for wich i have shematic power is +5V, would GS be beter with that?

Regards Dino

Hi Dino,
congratulations... yes, it works good.

First tone you ear everytime you switch it on is battery checker... if you ear no-sound or bleeping sound at start battery isn't good... but cause you use 12V 8Ah it'll require years to discharge... but is very heavy for field use !

It last for 3-4 seconds... you can stop this behaviour pulling out the fet that go from the op. amp. output to the audio section transistor bc517/mpsa13 by a 1K resistor. Just pull the fet out of pcb or you can mount an e.g. jumper like in computer cards to disable/enable battery checker.

Follow Ivconic's posts about.

For testting is ok. Do you thing using it on the field ?

For me it's really heavy... about 6Kg or more.

I suggest you use a 12v 0.8Ah or 12V 1.2 Ah gel-type or 10 Nicd or NiMh cells with at least 700mAh capacity.

-6.27 V is what we expect there, good.

I've built bandidoII and the mark with -5V is wrong, as Carl already stated somewhere as I remember, ... actually theoric limit is -4V on -V rail... but it works with something around -3.2v on -V rail.

It's good for it cause of special components. TGS have similar performances but the 2 design are different about components and some other things... like notch that bandidoII haven't and all-metal non-motion that TGS haven't ...though similar for other things.

TGS need more about -6v at -V rail cause of components.

Best regards,
Max

[nelson]

Hi Max.
Yesterday on field test, i experimented with GEB setting. When i set up geb to a level where ground balance was ok, TGS detect all coins, but when you try to detect a bigger pice of metal, like 10 by 4 cms. this detection was at about 4 cms. Then when you set back geb to it´s original position you can detect it at about 35 cms, but ground balance not good, losts of noises. Do you know anything about this or should i experiment with geb to the rest of it settings, cause this whas tested to a half of pot geb setting.
I m also purchasing 125 LM308 at 45 cents each.
Regards
Nelson

Hi Dino,
congratulations... yes, it works good.

First tone you ear everytime you switch it on is battery checker... if you ear no-sound or bleeping sound at start battery isn't good... but cause you use 12V 8Ah it'll require years to discharge... but is very heavy for field use !

It last for 3-4 seconds... you can stop this behaviour pulling out the fet that go from the op. amp. output to the audio section transistor bc517/mpsa13 by a 1K resistor. Just pull the fet out of pcb or you can mount an e.g. jumper like in computer cards to disable/enable battery checker.

Follow Ivconic's posts about.

For testting is ok. Do you thing using it on the field ?

For me it's really heavy... about 6Kg or more.

I suggest you use a 12v 0.8Ah or 12V 1.2 Ah gel-type or 10 Nicd or NiMh cells with at least 700mAh capacity.

-6.27 V is what we expect there, good.

I've built bandidoII and the mark with -5V is wrong, as Carl already stated somewhere as I remember, ... actually theoric limit is -4V on -V rail... but it works with something around -3.2v on -V rail.

It's good for it cause of special components. TGS have similar performances but the 2 design are different about components and some other things... like notch that bandidoII haven't and all-metal non-motion that TGS haven't ...though similar for other things.

TGS need more about -6v at -V rail cause of components.

Best regards,
Max

[ApBerg]

Ground adjustpotmeter

Hello Nelson.

Look at what happens to silver if you adjust the ground pot.
When wrong adjusted you can not detect silver coins !!

Look at post no: 986 open the PDF

The scope shows the fase shift for the goundpot in relation to the transmit signal.

Succes.

Ap

[Qiaozhi]

Hi Max.
Yesterday on field test, i experimented with GEB setting. When i set up geb to a level where ground balance was ok, TGS detect all coins, but when you try to detect a bigger pice of metal, like 10 by 4 cms. this detection was at about 4 cms. Then when you set back geb to it´s original position you can detect it at about 35 cms, but ground balance not good, losts of noises. Do you know anything about this or should i experiment with geb to the rest of it settings, cause this whas tested to a half of pot geb setting.
I m also purchasing 125 LM308 at 45 cents each.
Regards
Nelson

The GEB sounds like it's working as expected. GEB stands for "Ground Exclusion Balance" and that's what it does. It is used to set the sample pulse for the GEB channel at a position where any response to the ground is excluded. i.e. it does not produce a signal when the coil is raised or lowered with no metal present. If you do this test in the air, then the correct sample point is at the zero-crossing of the RX signal measured at the input to the sample gate. If you don't have a scope then you can use a piece of ferrite to find the correct position. In reality the ground may contain some mineralization, and the GEB control will need to be adjusted slightly.
The GEB is really only another discrimination control that is used to discriminate against ground, and incorrect adjustment will produce lots of false signals.
Hope this helps.