TGSL Tuning & troubleshooting

[sdesic]

On schematics disk pot is 10k
my is 100k ... I am looking at TGSL - Eduardo schematics

[Davor]

What about minus voltage?
Also what chips did you use?

[sdesic]

-6V on ICs pin 4

Silverdog supplied kit...
TL071CN x2
LM393p x2, LF353N x1, LM358AN x2, HEF4024BP

[Davor]

OK. Do you get the minus voltage immediately, or it builds up till the 50 second limit?

[sdesic]

instant power up -6V
as 12V

[sdesic]

Before I glued coils together I was able to move one of them and then it woul'd detect other coil and work before 50s.

Čudno zar ne

[Davor]

Možda i nije

There might be some things related with such time delays, but the most obvious ones are related with large capacitors. We've gone through the most obvious ones, and I guess the solution will pop up eventually. For the time being you can perfect the features of your rig up to the limits of your abilities, and the delay causes will most probably show up in due course.

Just have fun

[Fabian]

Hello everyone. I read in a previous post of Sdesic that "do not get the 50 cm" in TGSL-EDU ... Am I confused or just a few on the forum have achieved these results? I think with a 35-38, maybe 40cm he should be happy (I speak about detection)
On the other hand, I think that many forum members purchased Silverdog kits or manufactured own but did not read the threads complete of each project; without this knowledge it is very difficult for a detector to operate properly. And generally, the problems appears with the coils, which is essential part of building a detector that almost made me angry of frustration more than once,
but the calibration and tuning of the coils is complex and slow. Be patient!

Thoughts ...

regards

[sdesic]

Davor,

I would be happy with this king of detection and 50s delay in powering up detector in case if I had notch capabilities...
but I don't ... my Surf Pi Pro thanks to ApBerg, Jose and all others is working better than this TGSL EDU

Where to start ...
1. will try to made new coil
2. will try to find oscilloscope to rent or to buy (USB one)
3. will try changing ICs ot transistors
4. Anyone selling their coil ? with average 30 cm range ?
Offering to take one from you.

I was in Zagreb few days ago do you have time to look into this maybe ?


Fabian
I wish I had problem with not reaching 50 cm in depth ... If I had just 35
my TGSL and others only detect 1 EURO coin at 15 cm

[Davor]

My problem is that my "lab" is not where I live, and it takes extra time and effort to get there and do something constructive. Without some essential lab equipment it is difficult to do much good. Unfortunately.

I bought a used CRO at njuskalo.hr for under 1000kn, while the USB scopes of any real value start over 1200kn. I think CROs are much better options for amateurs, as they are virtually indestructible, repairable, and do not require soon-to-be-obsolete drivers to work.

I used a soundcard scope before, so you could also give it a try. It is OK if you know and appreciate it's drawbacks.

BTW, you'll hardly get depths beyond 30cm for nowadays coins. Croatian coins of 1, 2 and 5kn contain 23.2% Ni, while coins below 1kn have a steel core and stick to a magnet. See here: http://www.kunalipa.com/katalog/kovanice/1-kuna.php
Euros are not much different, as they are also multi-layered crap money.
You'd get much more depth with real coins made of real materials, which means every coin minted prior to 1990. You'll easily get over 40cm with silver coins. Pay closer attention in the future when observing videos of detectors bragging about great depths - they all use real money, not the nowadays crap.

[sdesic]

Today I rechecked my wire diameter and it is 0,27-0,28 with non conductive layer

USB scope is OK, soundcard scope is better cheap
Don't have any other use for it other than this. Will try to find data about it.

I have found 0,05 KM coin at about 12 cm with my Surf Pi Pro...
coin is 17mm in diameter .. like 50 lipa coin
I am using EURO as comparison... must use silver next time or roman bronze

I was going to say I can leave or send you my TGSL as I am not able to do much with it.
My brother is in Zagreb so no problem with waiting, if you have time and willing to help with it.

[sdesic]

Found soundcard scope but I don't see what is needed (hardware) - probes
http://www.zeitnitz.de/Christian/scope_en

and DIY probe
http://www.ladyada.net/library/equip...udioprobe.html

[sdesic]

Poor Man's Oscilloscope http://www.ledametrix.com/oscope/

[sdesic]

Done first two and now I have some kind of scope. Soundcard scope.

Here is screenshot.
Fist test without anything connected


Tested output from speakers - loop - sound generator from this fine software
Triangle from signal generator


What to test first on MD ?
Where are test points ?
Looking at TGSL 101 from Don but don't know what are safe points for my audio card scope.

[Davor]

You must find points with low impedance to avoid loading your device with a long cable and low impedance.

Start with Tx, but make a 1:10 or so attenuator, just reverse the resistors as seen in http://www.ledametrix.com/oscope/

Next connect a scope (with 1:1 probe) to output of preamp, and re-do coil nulling.

The most important thing is to supply your device with batteries, as a PC PSUs are not famous for their isolation.