I need help with idx pro silverdog red pcb!!

[Koala]

That's one of the problems im facing Koala, i have this little Whites made 8 inch coil that is a perfect little coin shooter, Air test, i used to get at least 14 inches easy with a nickle, now i can barely hit 8 inch, if that was in the ground i would be lucky if id get 3 or 4 inches deep, where before that same little 8 inch I have dug things up 6 inch plus with a very solid tone.

I take is a genuine Whites coil on the outside of the left lug there should be something like 6B stamped into it.


Whats there ?

[Tibuck19]

Once again, i want thank you all, for all and any suggestions you have made or can make, i am willing to try any suggestion you guys have. I know for a fact how well the IDX works in the field, and i am willing to try just about anything to make it work as it was.

[Tibuck19]

12" and maybe a bit more on dry sand is normal for this detector on larger coins. If there isnt much junk in the fields and you run the detector hot

8" is an easy solid loud tone on most things




to get the best out of it you need Good headphones and run very little discrimination. You need to be where your digging some forged nails bent at 90 and horseshoes. Most of the iron giving a broken tone.


on my lawn. With in the field settings I can't hit a Vicky very thin half penny at 10". I can if I Crank it up a bit.

but with in the field setting on a Bandido I can. As does a Fisher 1265x


in the field settings = discrimination at a point where not too much iron is dug, Sensitivity is where it runs stable and threshold where you can still get the depth proportional volume

hot = threshold and sensitivity cranked up and discrimination reduced.

That's one of the problems im facing Koala, i have this little Whites made 8 inch coil that is a perfect little coin shooter, Air test, i used to get at least 14 inches easy with a nickle, now i can barely hit 8 inch, if that was in the ground i would be lucky if id get 3 or 4 inches deep, where before that same little 8 inch I have dug things up 6 inch plus with a very solid tone.

[Tibuck19]

I respectfully greet you all


I wasted my time for a year and came to this conclusion:


- the problem is due to the sensitivity of the integrated circuits buy several quality units NE5534, LF347N / NOPB, LM393N / NOPB and check with the oscilloscope each signal,
- and as a signal the return of the coil at the output NE5543 should not be higher than 100mV.


Gaby

For all but the NE5534, that was exactly what i done i spent just shy of 70$ with digikey in IC's and a pot for the sens, i replaced every single ic and swapping one for another, the NE5534 i basically used the ones i already had, due to the fact a few because most of the Pi detectors projects on Geotech pretty much uses one. i will re-prob the ne5534 for mv. Thanks for the suggestion.

[Tibuck19]

I am wondering if to problem is not in the detector circuits but maybe in the coil or coil connections.

3 coils, all 3 show a drop in performance just the same when i started noticing there was a depth lost, i had suspected a connector problem which is why replaced the detectors connector and checked the connectors on all 3 coils, Nice suggestion just the same, i wish it was something that simple.

[gaby_sult]

I respectfully greet you all


I wasted my time for a year and came to this conclusion:


- the problem is due to the sensitivity of the integrated circuits buy several quality units NE5534, LF347N / NOPB, LM393N / NOPB and check with the oscilloscope each signal,
- and as a signal the return of the coil at the output NE5543 should not be higher than 100mV.


Gaby

[waltr]

I am wondering if to problem is not in the detector circuits but maybe in the coil or coil connections.

[Koala]

I might have believed that, had i not been using it for the last two years and collected thousands of coins and other buried treasures lol deepest being a 1850 Upper Canada penny almost 12 inches deep, i am not ready to give up on it just yet, there has got to be an explanation for this.

12" and maybe a bit more on dry sand is normal for this detector on larger coins. If there isnt much junk in the fields and you run the detector hot

8" is an easy solid loud tone on most things




to get the best out of it you need Good headphones and run very little discrimination. You need to be where your digging some forged nails bent at 90 and horseshoes. Most of the iron giving a broken tone.


on my lawn. With in the field settings I can't hit a Vicky very thin half penny at 10". I can if I Crank it up a bit.

but with in the field setting on a Bandido I can. As does a Fisher 1265x


in the field settings = discrimination at a point where not too much iron is dug, Sensitivity is where it runs stable and threshold where you can still get the depth proportional volume

hot = threshold and sensitivity cranked up and discrimination reduced.

[Koala]

Yes, I had the same problem. Only I didn't solve it ... I also changed everything ... As a result, I put Whites in the archive and assembled another device. Somewhere there was information that the problem was in the GB variable resistance, but I did not check it.

ground balance will be okay if ferrite is rejected around the POT centre position

[Tibuck19]

I might have believed that, had i not been using it for the last two years and collected thousands of coins and other buried treasures lol deepest being a 1850 Upper Canada penny almost 12 inches deep, i am not ready to give up on it just yet, there has got to be an explanation for this.

[SWL]

Yes, I had the same problem. Only I didn't solve it ... I also changed everything ... As a result, I put Whites in the archive and assembled another device. Somewhere there was information that the problem was in the GB variable resistance, but I did not check it.

[Tibuck19]

Not yet, however i am working on it. I have replaced everything but the resistors, i am now in the processes of redoing all the connections to the pots and connectors... and going over each solder joint. Am i to assume you re also having the same problem? i'm hoping you went throw this and have a suggestion of something i missed?

[SWL]

Tibuck19, have you solved your sensitivity problem?

[Tibuck19]

what size target

I might be wrong. I seem to remember 35cm on a vicy penny

you could tune the RX capacitor to 50cm however thats only in an air test. Going too far from a standard coil makes it unstable on field.
It quite difficult to get consistent testing. Very small differences in sensitivity, threshold and discrimination adds or looses a cm or two
I also found depth altered with the headphones I used. Again from memory it was mainly the all metal mode

I am not sure what size a Victorian penny is, I am testing with American Nickles , and both Canadian and American silver coins and pennies which is what is mostly found here, Which i do get the 35 cm , however, it use to be closer to the 43 to 45 cm, i just find it odd all of a sudden it dropped so much and in proportion with every coil and coil size i have, I did noticed something after replacing Each and every Poly Cap on the board, The nickle use to get discriminated out at around 5K on the 10K pot now its more like 8K before it drops, I also tried with both the speaker and head phones both give the same results, What cap vales would you suggest to help bring back some of the sens? The RX Caps would be the 220n and the 680p? the ones along side the 5534. Again i thank you all for your insights and suggestions.

[Koala]

I hate to have to ask for help yet again, however, I have no clue what to try next, My IDX was working great, hitting 42CM on air test with a 10 inch coil, Detecting with it was fun and getting good depth, digging out quarters 10 inches deep. Around the end of summer, i notice the detector was not performing and was also getting more noisy, than it used to be. Now the max it is getting on air test is 34Cm, I replaced the Caps around the NE5534 the 5534 itself, i bought replacements for all the ic's. For the 347 i got a LF347n, Lf347bn and a LMC6484ain(LMC6484 reduced depth by half), Replacing it has made the idx quite again however still no change in depth, I also replaced all the 393 with 393pe4's no change, i also replaced those with lm2903p's Again no change, i replaced all the 358's with lm358n and i tried lm358an. I have 3 coils and all three coils are showing the same amount of depth lost, between 5 to 8 Cm. is it a TX problem or an RX? i also replace every transistor and diode. i would appreciate any clue as what i can do next to being this detector back to how it was.

what size target

I might be wrong. I seem to remember 35cm on a vicy penny

you could tune the RX capacitor to 50cm however thats only in an air test. Going too far from a standard coil makes it unstable on field.

It quite difficult to get consistent testing. Very small differences in sensitivity, threshold and discrimination adds or looses a cm or two

I also found depth altered with the headphones I used. Again from memory it was mainly the all metal mode