TGSL Tuning & troubleshooting

[kliner]

P3 P4 IGSL don't seem to do much

Ivconic
Thanks very much for your help, I've got a lot of interference in my workshop so I think I'll have to go out into the countryside and give it another test.
I'd just like to say that I have had a lot of pleasure out of reading your posts and building your detector designs, thanks a lot for all your time and effort

[ivconic]

Here is little check that you may do, using 1 coin (1e for example).
Adjust Senses to maximum and check air depth. It should be at least 30cm (with 25cm DD coil).
Than lower Senses to minimum and check again. Should be now 22-25cm.
If works like that - than everything is alright.

[ivconic]

I've just finished my IGSL musketeer, (nice kit from Silverdog) didn'nt work on first power up, I inversed R40 and R41 and then I had an intermittent fault on the -6v to the 347, it turned out to be a through hole plated jumper not so well plated. All seems to work OK (nice two tones) with a Tesoro Tejon coil except that P3 and P4 don't seem to do anything. I've checked the wiring of the pots, there is 8V on the wiper which varies when the pot is turned but when I measure on pins 4 and 6 and 8 and 11 of the 339 I have zero volts which doesn't change. I've checked my TGSL which works the same way and it's the same thing. If somebody could explain what I've not understood !

P3 and P4 are Sensitivity potentiometers, each one for it's block.
Those do makes differences, but very small. Same at my TGSL's and IGSL's too.
From minimal to maximal values at those pots you can see barely difference in gaining depths, and those can easily be omitted from front panel and put inside as trimmers.
Yet i don't think it would be good idea, because i noticed significant differences later when was outdoor with it, searching.
Lowering Iron Sens will help you in some situations where you are focused only to nonferrous targets and on places where there are lot of irons in soil.
Also, at some soils, which are highly mineralized and trashy, IGSL (same as TGSL or any other Tesoro) can produce occasional "click"'s and false signals.
Especially if there is some high voltage power line nearby.
Than in such situations, those Sense potentiometers will help you a lot, by lowering them you will make IGSL pretty calm and immune on such obstructions.
It may lose maybe just 10% of depths when Sense's are at minimum.
So, there is (must be) difference, only it is hard to notice it in workshop, on the bench.
In case you still can't notice difference at all - than it is strange and must be some problem at your hand made?

[kliner]

IGSL P3 and P4 don't seem to do much

I've just finished my IGSL musketeer, (nice kit from Silverdog) didn'nt work on first power up, I inversed R40 and R41 and then I had an intermittent fault on the -6v to the 347, it turned out to be a through hole plated jumper not so well plated. All seems to work OK (nice two tones) with a Tesoro Tejon coil except that P3 and P4 don't seem to do anything. I've checked the wiring of the pots, there is 8V on the wiper which varies when the pot is turned but when I measure on pins 4 and 6 and 8 and 11 of the 339 I have zero volts which doesn't change. I've checked my TGSL which works the same way and it's the same thing. If somebody could explain what I've not understood !

[johnsmith77]

If you have access to U.S. Nickel, tell us where that discriminates out (min DISC pot position for no response).

regards,

-SB

Sorry, not have.
Furthermore, discrimination works only by one metal. If reject foil, then accept iron and contrary. If reject silver, than accept iron, foil, etc.

[simonbaker]

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

If you have access to U.S. Nickel, tell us where that discriminates out (min DISC pot position for no response).

regards,

-SB

[satdaveuk]

fault

hi bernte
If everything was alright last time you used it then look for the ovious like leads perhaps short circuit or possable dry joins/ fracture on the pcb, dont go to in depth fault finding to start with because you could creat further faults, been there in the past myself, also when I say fracture in the print there very rarely visable to the eye, so you need to check each track with your meter if theres nothing showing up with supply volts testing, who knows you may come accross bad joints that would have give you problems in the fucture.
Anyway let us know how you get on then its another fault to log on here for others.
Regards

[Jerry]

There is always pretty good reason why transistor die!
Not possible to happen without reason, trust me.

Transistors are filled with smoke when they are made. They need this in order to make them work. If you let the smoke out they quit working

Jerry

[habitbraker]

There is always pretty good reason why transistor die!
Not possible to happen without reason, trust me.

hehe Thats what Im saying

I have built/soldered/programmed many circuits/projects and almoast none of them worked at first power up. And guess what - 100% of faults was MINE not mistically faulty componnent

[bernte_one]

hello

many thanks for taking time to answer me
i will follow your advices and take my multimeter out of my toolbox

tgsl run perfectly since i have build it

thats the reasons i suggest that there is a bad component
i have already an idea which parts i have to check

but i dont know the values which are right
but first i will check voltage at the q´s

thx

(p.s. it is not the first time i have burned one part or had a problem with a ic socket)

[Wiltran]

Bernt one, If it happened right after you soldered something in, check for solder bridges, or transistors put in the wrong way because of substitutions, check for proper voltages at IC sockets. good luck!

[ivconic]

Also - 95% of faults happen because of user/conscructor, NOT because components are just bad. Transistors doest burn just for no reason

There is always pretty good reason why transistor die!
Not possible to happen without reason, trust me.

[habitbraker]

Also - 95% of faults happen because of user/conscructor, NOT because components are just bad. Transistors doest burn just for no reason

[habitbraker]

1.Check voltages - positive and negative. If there is no negative, then most likely oscillator isnt working - check it. If Voltages is below +8 and -5 then also it could be short circuit somewhere.
Check if speaker driver - its highest power part of the circuit..

If you cant find fault with multimetter and you eyes, then youll need scope...

Good luck

[bernte_one]

my tgsl is died

hello

at the weekend after soldering something on my new igsl i thougt ok lets go in garden with my tgsl but i gives no more tones when pushing on button no more beep

i have tested battery and coil connection and also headphones somethings coming out from audio but no detector signal like the beeping i love testing also to turn pots checked the cables inside but nothing to see

so where should i start

i know there are some testing points where i could check the current i think one of the transistors is crashed

could anyone give my a troubleshooting list or link one if he knows where to find

thx