TESORO GOLDEN SABRE

[Fabian]

hello, i have problem with my TGSL. Detecting distance is very poor (15cm with 1 Euro).
Inductance are 6.5mH and 6.04mH.
I did some measuerments with oscilloscope and everything is seems OK.
Could it be the metal connector problem. It is placed in coils !


Can you help me please !?!?!

Hello Juka vk. Re-read #889 Ivconic's post, it's very explanatory. My experience says that is always about the coils. It isn't hard to achieve, but needs some practice.

I hope this can help you.

Best regards

Fabián

[xXx]

Hello!

Sorry for my English but I use the translator. To recommend the use of probes TESORO Firewire cable 6 / 4 works well. It selected a dozen of others have used a home-made probes at my ELDORADO.

http://imageshack.us/photo/my-images...102011002.jpg/

Best regards !

[Max]

Check how you have installed Q3, the marking on the SilverDog PCB (maybe all PCBs from the same Layout file) is reversed.
Firstly I have to say that I have not had a PCB in my hands with this problem of the Q3 transistor, when I built mine, I put the transistor in backwards according to the legend (the correct way for most transistors, but maybe not all!!), but I would guess that the -6.2 volts will be completely wrong, maybe only 3 volts or so if the transistor is placed as the component placing dictates......

Measure the -6.2 volts first, I believe relative to 12 volts ground/minus.....(my PCB is not quite finished!)

If true:- If the -6.2 volts is bad, it will affect the correct operation of the following Op amps:- U1a, U6a, U4a, U7a, U7b, U8a, U12 and U5a. Probably they will just work still, but with drastically reduced gain…..it’s worth checking up on that point.

Its a simple matter to check.

Metal in the search coil area, connectors for example, will reduce the overall sensitivity, I never use more than a soldered connection with heat shrink tubing for insulation. I cannot say exactly how the connectors will affect things, but if they were added AFTER nulling, you may have found your problem already......

Not getting a good null will also affect the sensitivity, how did you actually "null" the coils? Full and exact details in short sentences.

Is your main 12 volts good? Have you checked it with a scope for noise?

I am not a TGSL or IGSL expert - yet anyway , only Ivconic is.....Simon is pretty good too, read and carry out anything they suggest....Don Bowers knows the normal TGSL well, has also written helpful documents.....coil construction for example....See TGSL part 1 and part 2.

regards

Andy

"null the coils" means you got about 0 mV signal (peak-to-peak) at RX coil in REAL conditions of working MD on the bench (sometimes the concept is quite more complex as you need nulling in average soil conditions... but with TGSL/TGS and similar is not the case)

said so you need balance TX flux and counter-flux (nulling coil) to get exactly 0 mV at RX in working conditions (read it, as if it is connected to primary amplifier etc of detector): actually Ivconic's way of doing so is looking at output of preamp during nulling phase, plus some other tricks to null the signal

Said that some people here look for small not-null value (few mV p-p) cause coils can be slightly overnulled to gain increase in stability, but, usually, you can't get much lower 1mVpp when nulling a VLF coil in any case, unless you use tricks that ar not just geometric properties and align of coil but also "dump" magnetic flux somehow in some hot spots, e.g. using tiny pieces of Aluminium foil at coil bottom and/or adding some conductive substance (e.g. graphite) to the epoxy/putty of coil to both shield from static charges the coils and absorb some magnetic flux due to small eddy currents flowing inside this stuff...

read Ivconic's posts about, it's all there

[johnsmith77]

Hello everybody I am the new one in this forum, but not a newbie in the electronics. So i made TGSL. This is my first homemade MD in my life. I have never had any commercial MD also before

My results: 1e coin 29cm, disc mode. Measure at home. I have Dfbowers mod in sensitivity pot.

All metal mode: tunned gb pot, so small ferrite can detect only about 3cm.

Disc mode, disc pot min; big pliers detects at 20cm. As i said 1e at this adjustement is 29cm.
If i turn disc pot more to middle or to max, detection range to iron is bigger.

What is your opinion about gb and disc adjustements?

Thank you

[dfbowers]

Hello everybody I am the new one in this forum, but not a newbie in the electronics. So i made TGSL. This is my first homemade MD in my life. I have never had any commercial MD also before

My results: 1e coin 29cm, disc mode. Measure at home. I have Dfbowers mod in sensitivity pot.

All metal mode: tunned gb pot, so small ferrite can detect only about 3cm.

Disc mode, disc pot min; big pliers detects at 20cm. As i said 1e at this adjustement is 29cm.
If i turn disc pot more to middle or to max, detection range to iron is bigger.

What is your opinion about gb and disc adjustements?

Thank you

I just did a quick check on one of mine - TGSL Eduardo's version.. With disc set at a minimum (in disc mode), I can still detect a HUGE pair of pliers. If I turn disc up to just reject small bits of foil, the TGSL is quiet on iron as well... nothing at all..

That's the stong point of the TGSL, assuming phasing is set correctly. It should still reject fairly large pieces of iron. Discrimination is excellent!!

Try adjusting the GB to completely reject ferrite, in the A.M. mode. Then, make sure that you can still detect quarters or small silver in the disc mode. That will tell you that the GB trimmer is set correctly.

You can easily misadjust the TGSL. The GB trimmer can sometimes be set on the wrong side of the "quiet spot" while rejecting ferrite in the A.M. mode.

Hope this helps..

Don

[ivconic]

"..You can easily misadjust the TGSL. The GB trimmer can sometimes be set on the wrong side of the "quiet spot" while rejecting ferrite in the A.M. mode..."

Thats true and i experienced that many times.
But that also depends mostly on coil.
Not a big deal, as long as you can achieve null in trimmer range.
Along with achieved null (tested on ferrite) do test it also on tiny piece of Al foil.
It may happen tiny Al foil to be fully rejected (even in AM) , meaning the coil is "overnulled" a bit. Try to compensate by turning back a bit GEB trimmer.
It really doesn't matter if detector starts to make short "cracks" responses on ferrite, because it will remain calm and GEB-ed nice on real soil.
In the past i insisted on full ferrite rejection, which was mistake in a way.
Later i realized that there is no need for that.
That's why (in meantime) i replaced ferrite (as "reference" when nulling coils) with few pieces of hotrock and old Roman clay.
But apart that, best solution would be GEB preset at front panel.
So each time when start searching; operator to "pump up" the coil toward soil and manually readjust GEB.
That's how best performances will be assured each time.

[johnsmith77]

I checked now.
I all metal mode foil accepted, iron accepted. GB trim allmost at the end CCW.
Previously with a little different coil (1 turn more on Rx and 1nf plus on 0.022 oscillator capacitor C2) i managed trim GB to reject ferrite at a little ccw from middle position. This position is stated in tgsl tunning manual, if i correctly remember.

Main thing:

In disc mode, when disc min: iron rejected, (not deep as i want, but rejected), foil accepted, ferrite accepted.
When i turn disc pot more, foil rejected, iron accepted.

If discrimination rejected higher response phase metal (at this example-foil); it should reject also lower response phase metal (iron).


Am i correct?

[ivconic]

I checked now.
I all metal mode foil accepted, iron accepted.

In disc mode, when disc min: iron rejected, (not deep as i want, but rejected), foil accepted, ferrite accepted.
When i turn disc pot more, foil rejected, iron accepted.

How it can be?

Have you readjusted GEB trimmer to see if there is difference?

[johnsmith77]

Have you readjusted GEB trimmer to see if there is difference?

Yes, seems GEB trimmer does not affect DISC mode at all. Not sure with silver (i have only silver chain), but at first try no difference with ferrite, foil, iron.

[ivconic]

Hello everybody I am the new one in this forum, but not a newbie in the electronics. So i made TGSL. This is my first homemade MD in my life. I have never had any commercial MD also before

My results: 1e coin 29cm, disc mode. Measure at home. I have Dfbowers mod in sensitivity pot.

All metal mode: tunned gb pot, so small ferrite can detect only about 3cm.

Disc mode, disc pot min; big pliers detects at 20cm. As i said 1e at this adjustement is 29cm.
If i turn disc pot more to middle or to max, detection range to iron is bigger.

What is your opinion about gb and disc adjustements?

Thank you

I am analyzing again what you posted earlier.

"...so small ferrite can detect only about 3cm..."

Not a big deal. Maybe will need slight readjustment and maybe you can leave it like that.

"...Disc mode, disc pot min; big pliers detects at 20cm. As i said 1e at this adjustement is 29cm.
If i turn disc pot more to middle or to max, detection range to iron is bigger..."

Maybe you reversed Disc pot wires?
Even so; definitely your Disc circuitry is not working.
Maybe you wired it up wrong? Check again Disc pot leads and A/D switch wires.
And last (but not least) - coil?
If everything on pcb is correct, than all the troubles are starting and ending with coil.

[johnsmith77]

I am analyzing again what you posted earlier.

"...so small ferrite can detect only about 3cm..."

Not a big deal. Maybe will need slight readjustment and maybe you can leave it like that.

"...Disc mode, disc pot min; big pliers detects at 20cm. As i said 1e at this adjustement is 29cm.
If i turn disc pot more to middle or to max, detection range to iron is bigger..."

Maybe you reversed Disc pot wires?
Even so; definitely your Disc circuitry is not working.
Maybe you wired it up wrong? Check again Disc pot leads and A/D switch wires.
And last (but not least) - coil?
If everything on pcb is correct, than all the troubles are starting and ending with coil.

Seems correct. Tx measured in oscillator circuit 14,5 khz. Rx in oscillator circuit - 13,78 khz.
Recalculated because C 20nf to 15nf: will get 15,9 khz. And after that i took off 1 turn. So almost ideal frequencies.
Shielded, with gaps. No double beeps. Usb 2 cable. Oscilograms like in the page 57 of this forum. Only have 1 channel scope, but checked with 2 channel pc scope.
Ps: I have usb socket connected usb cable to coil and to pcb, grounded. Can it affect?

Strangest as i said discrimination works only by one metal. If reject foil, then accept iron and contrary.

[ivconic]

Seems correct. Tx measured in oscillator circuit 14,5 khz. Rx in oscillator circuit - 13,78 khz.
Recalculated because C 20nf to 15nf: will get 15,9 khz. And after that i took off 1 turn. So almost ideal frequencies.
Shielded, with gaps. No double beeps. Usb 2 cable. Oscilograms like in the page 57 of this forum. Only have 1 channel scope, but checked with 2 channel pc scope.
Ps: I have usb socket connected usb cable to coil and to pcb, grounded. Can it affect?

Strangest as i said discrimination works only by one metal. If reject foil, then accept iron and contrary.

Hmmm!?
Again (maybe annoying) try to recheck all the pots and switch wires.
It happened to me few times that i reversed wires and also put viper wire on wrong place on pcb. So i got than pretty strange behavior too.
Also once i mixed up those 3 wires for A/D switch and behavior was also very strange.
Other thing... coil, again coil!
It doesn't matter if you read proper freq, because if coil is not nulled well; it can cause such and similar behavior.

[johnsmith77]

Hmmm!?
Again (maybe annoying) try to recheck all the pots and switch wires.
It happened to me few times that i reversed wires and also put viper wire on wrong place on pcb. So i got than pretty strange behavior too.
Also once i mixed up those 3 wires for A/D switch and behavior was also very strange.
Other thing... coil, again coil!
It doesn't matter if you read proper freq, because if coil is not nulled well; it can cause such and similar behavior.

I checked. All looks ok.

But hope i found mistake. Hope it is the reason of my problem.

In TGSL_101 documentation i found usb cable connection: J2-1 (U101a pin 5 not inverted) goes to ground in coil head.
In the forum, i see J2-2 (U101 pin 6 inverted) should go to ground in coil head.

Is there a mistake in that manual or in forum?
Think manual has mistakes Also found some others in it.

Later i checked your manual and see J2-2 goes to ground. Vuolia!

Because of this mixing i thing Rx signal was not inverted so GB channel should act as DISC.

Still not checked, it is morning and i don't want wake up my sleeping family with TGSL loud beeps

Thanks

[johnsmith77]

I turn disc up to just reject small bits of foil, the TGSL is quiet on iron as well... nothing at all..

That's the stong point of the TGSL, assuming phasing is set correctly. It should still reject fairly large pieces of iron. Discrimination is excellent!!

Don

Please tell how big rejection distance is for iron pliers, small bits of foil in DISC mode (min, middle, max DISC pot positions?)
Does totally rejected? 0cm or there are gap?

Thank you

[der_fisherman]

Broken links

Wonderful work @dfbowers !

Here you have an eBook written by Vinvent J. Ginger about a DIY Plastic Vacuum Forming Machine, which may be of interest to those who would want to build there own Coil Housing.

Also, thank you very much to all who have participated in Designing and Refining the Tesoro Golden Sabre Metal Detector.

Excellent Job!

The Refined and Working Finished Project by @Ivconic can be found here:

TGSL - Complete Details, posted by @Qiaozhi's and Designed by @Ivconic:
http://www.geotech1.com/forums/showthread.php?t=15710

And here you have the eBook:

Secrets of Building a Plastic Vacuum Forming Machine - By Vincent R. Gingery (1999)



* Author: Vincent R. Gingery
* Publisher: D.J. Gingery
* Number Of Pages: 106
* Publication Date: 1999-07
* ISBN / ASIN: 1878087223
* EAN: 9781878087225
* Binding: Paperback
* Manufacturer: D.J. Gingery
* Format: PDF (OCRed)
* Size: 4.13 MB

Description by Vince Gingery:

Geez... you should see the samples of vacuum forming Vince sent me! I can show you a photo but until you hold the formed sheet in your hand you don't know how powerful this thing is. It's professional quality. And you can build it for far less than you can buy a machine. And since Vince will reveal his experiences, you should be able to adapt the design and scale it up or down. The best way to describe the machine is to let Vince do the talking:



"The machine is built almost entirely of angle iron and flat bar. Construction is simple, with some welding being required. Being built on wheels makes the machine easy to move from place to place. It has a unique clamp frame that works very well and the adjustable work surface (platen) is a real asset. The machine has a 12" x 15" forming area, and I have formed ABS plastic up to 3/16" thick with it. I believe the machine would form 1/4" as well. Of course, thicker plastic takes longer to reach forming temperature.

The machine operates on a 20 amp 120 volt circuit using a 1500 watt, 120 volt heating element. Temperature is controlled by an infinite range switch mounted in the control panel. Everything required to build the machine is easy to find except for the 120 volt heating element. It's an oven replacement element, and ... will sell for around $30.00 plus shipping...



The vacuum for the machine can be supplied by either an air venturi pump or electric vacuum pump in conjunction with two storage tanks. I am mentioning the air venturi pump as one alternative because it's so cheap. Only $12.99 through Harbor Freight and it pulls 4.2 cfm per minute taking about 4 minutes to pull a 25 kg vacuum on my two 11 gallon tanks. Not too shabby for the price. In order to use it though, you need to have an air compressor capable of maintaining 90 psi.. The other and better alternative is an electric vacuum pump. The electric pump I have pulls 6 cfm taking about 2 minutes to pull a 25 kg vacuum. Although twice as fast, the electric pump costs close to $300.00."

You oughta have a copy of this... for your reference library if nothing else!

Note by @Cyclonite:

You can also use an old Refrigerator Motor as Vacuum Pump, connected to a Buffer Cylinder for fast release of Vacuum Pressure. These Refrigerator Motor Pumps work slow, so you will have to suck a Buffer Cylinder vacuum (empty CO2 Fire Extinguisher etc.) for use with large cavity suction products. The faster you can suck a vacuum, the less heat you will have to expose your plastic forming material to.

Download (RARed 3.80 MB):

Secrets of Building a Plastic Vacuum Forming Machine - By Vincent R. Gingery (David J. Gingery Publishing LLC - 1999) 56s (d).pdf

iFile.it Download Link:
http://ifile.it/td75bo4

or (optional)

MegaUpload Download Link:
http://www.megaupload.com/?d=JP2EVEO7

No Password Required !

Enjoy !

Robert

It may be me, but I think all the links are broken due to "age"...... Could you post the actual document here so that it stays? Or is it simply too big?

If I could get hold of a copy from you, I could cut it up into pieces that Geotech will allow to be posted if you wish.....

I could send you my proper email address via the Geotech message service to make that easier if you wish.

Thanks for your help

Regards

Andy

Thanks in advance.