I need help with idx pro silverdog red pcb!!

[waltr]

Did you measure the supply Voltages?

[Tibuck19]

Morning Waltr, i have all the voltages to the ic's are at 8V, but just to be sure, i replaced the Voltage regulator and the electrolytic caps, i have not measured the millivolts out to the coil as im not sure how to do that, nothing is getting warm, everything works as it should no problems with discrimination ... just what i feel is a huge depth lost, which is why i like the IDX so much more in comparison to the TGSL, before it was double the depth of the tgsl and now it is around the same. i will hook up the X and Y to my oscope to see if the detector is reading targets even if i cant hear them? i am almost tempted in replacing every single poly cap just in case one of those are the reason, At this point i'm Gutted, these days financially has not been the best for anyone, I spent a little over 70$ in replacement chips and caps hoping it will fix it but at this point i feel i only brunt money i dont really have. and i have bought a 15inch coil for this detector.

[Qiaozhi]

I've never built the IDX, but I was under the impression that (compared to the TGSL) the extra depth was due to coil tuning. i.e. The TX and RX coils were tuned closer to resonance. Perhaps a tuning capacitor value or the coil inductances have drifted over time. That's of course the main problem with resonance tuning. It wouldn't take much to throw it completely out of wack.

[kt315]

he has 3 coils George. you have to read whole story. i grasp something with pots.
if in a pot leak dirty/salt water wait a problem. also maybe a wear of brush and coating of pot.

[Tibuck19]

Good morning George, Hope all is well? as well as can be these days anyways, i replaced most of the poly film caps that seem to be connected to both TX and RX line, the only two i have not replaced, however i have tested is the 220 picofarad and the 100 puff that is connected to the 393 u8. I have never made a coil for this detector, one of the coils, Don had made for me and the two others are Whites made coils Which all worked perfectly till the end of the summer, there is a very very good chance your assumption is correct, idk why i somehow feel something that is connected to the 393 u4 or the 347 u3 is out of wack?

[Tibuck19]

he has 3 coils George. you have to read whole story. i grasp something with pots.
if in a pot leak dirty/salt water wait a problem. also maybe a wear of brush and coating of pot.

Good day KT, I was suspecting the same thing also, which is why i replaced all of them, i even went as far as buying a fancy BOURNS 16$ 100K from digikey for the sens, the only one that has not been replaced is the GB which i am waiting on a new multi turn to show up.

[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

[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.

[SWL]

Tibuck19, have you solved your sensitivity problem?

[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]

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]

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.

[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

[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.

[waltr]

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