LOOKING FOR GOLDSCAN 4 Schematic.

[lucafa]

Thanks ABDW9 and jose.

Wery well.

Good job jose.
One question, have you tried to use graphite spray for the screen?
Metal grid great screen with a reduced signal transmission and reception.
If you use graphite, 10 ohm cm have a perfect shield, but not metal.
Use in this way.
Building coil as you want, paper tape wrapped around the coil, 1x1 cm piece copper (recovers from pcb) with welded wire 5 or 10 cm, glued with hot glue a piece of copper tape, spray graphite thin layer and wait until dry. Measure resistance per cm, if not 10 ohms make another layer of spraying.
When good results, connect the screen to shield wire coil.
The 10 ohm as a guideline, try resistivity is high and excellent result.
For example VLF coils have resistivity screen from 3 to 7 kilo ohms.
regards.

[Jose]

Jose.

Thank you very much for your explanation.
I imagined strange things, while he was a simple thing .
A question, you can measure how diameter of only one conductor and how many individual small wires is composed ?
I want to be sure to use the same material to compare the results.
If you write me also cable serial number would be perfect.
Regards.

Lucafa
The cable is known as UTP or CAT5 for computer network, consists of four twisted pairs, eight in total, and the diameter of each conductor is 0.5mm.
Cat6, the driver is alrrededor diameter of 0.6, with a little more insulation, the two works well. Cat5 is easier to work for its lower section.
Attached is a photo, where observed the cable insulation with Scotch tape No. 24, makes a shield.
In the photo is a single coil, you must perform two coils with 2 laps each with diameters of 20 and 30 cm., connected in series as shown in the post above.

[ABDW9]

Welcome back lucafa
Number of small individual wires 7
diameter of only one conductor about 0.05 cm
Thanks for helping me

[lucafa]

Hi all.
The L4 is 330 millihenry NOT 330 microhenry for piezo use.
If no correct value defect is low sound.

[lucafa]

Jose.

Thank you very much for your explanation.
I imagined strange things, while he was a simple thing .
A question, you can measure how diameter of only one conductor and how many individual small wires is composed ?
I want to be sure to use the same material to compare the results.
If you write me also cable serial number would be perfect.
Regards.

[ABDW9]

ABDW9
Where problem?
If new construction controls FET J113 when mounted correctly.
Check pin 8 U12C, if VOUT is always ZERO, control calibration setting or TL064 failure.
Check fault on DIODE OA85 (gate Q10 and GND).
Check proper functioning RESET button.
Regards.

Thank you very much
Brother lucafa I will review these
You greetings

[lucafa]

ABDW9
Where problem?
If new construction controls FET J113 when mounted correctly.
Check pin 8 U12C, if VOUT is always ZERO, control calibration setting or TL064 failure.
Check fault on DIODE OA85 (gate Q10 and GND).
Check proper functioning RESET button.
Regards.

[ABDW9]

Peace to all of you
I have been asked several questions, but I did not see any answer
And now I have only one question
I have a problem in the RESET key does not work Is it possible to explain where the problem
Knowing that the device works perfectly ..
Greetings Abdo

[Jose]

Jose
How much uH for the two coil? what is CAT6?
More info please.

Lucafa.

Lucafa
The total inductance is 380 uH.
Cat6 is computer network, cable consists of 4 twisted pairs, 8 conductors in total, conductor section is slightly larger than that used in CAT5.
Can be used CAT5, the total resistance is greater than 2 ohms, but will work equally well.
This type of coil is more sensitive to small objects.
All the details are in the scheme.
Regards

[ABDW9]

Dear Brothers
Hello everyone


sw1-A SW1-B SW1-C
How to deal with it during operation
Warmest congratulations

[lucafa]

Maikl, this dual coil, works best for small items like gold earrings. The scope is larger and is more intense signal, the values of the damping resistors are what worked well in my GS4, but may vary depending on the characteristics of the MD used.
Jose[ATTACH]22445[/ATTACH]

Jose
How much uH for the two coil? what is CAT6?
More info please.

Lucafa.

[ABDW9]

Peace to you all
Good morning
My dear porkluvr I hope to be in perfect health
Today I will fix the problem on the 12V-and the problem was that the installer is not well-connected with the PCB thing that made me do Bmrajhh full board for the third time ..
Only porkluvr still problems found:
1 / voice is still weak.
2 / earpiece not working
3 / Can be sound you hear is it pulses the U4 Altaymr 555 and has nothing to do with the rest of the circle, because he is very weak
4 / also noticed that there is an impact on the radio with a widening AM when you round search coil L1 Is this a sound
Thank you all
Sorry very beloved honored I am that I did not identify myself to you ...
I Abdo From Sudan pleasure coexistent with you a lot and I hope that benefited from you Thank you

[porkluvr]

...
How do I increase my sound audio output is very weak and there is no output in the earpiece HP What should I do

If I understand you correctly, you have a problem that causes -12V to be very wrong. That is the very first thing you must repair. Fix that, and only then should you attack other problems.

[ABDW9]

Maybe my "original drawing" is messed up (I've been guilty of messing up perfectly good work before) but I see a potential problem with the charge pump in my previous post.

Apparently, the maximum voltage that can be obtained with -12V input is only about +3V. Doesn't matter what diodes are used, 3 Volts does not make a good input for LM78L05.

I think that 555 duty cycle (dc) (about 95%) is the boogeyman. My LM555 model is not exactly same as the specified TC555, but it should make a reasonably valid point.

The original circuit is simulated at "A". The bottom trace is voltage output. The top trace is diode current, (zoomed in at about 5ms).
************************************************** *******

In "B" I made changes in the 555 circuit to obtain ~50% duty cycle. It requires adding one diode and changing two resistor values. Those R values should give close to the same 555 output frequency as before, but with a more symmetrical waveform.

Now the charge pump can drive to +11.4V in about 22ms.

Well, er, I also changed R11 and R12 to 4.7kΩ at "B". That reaches peak output more quickly, but 10kΩ will work fine. (oops, but not a big oops)

edit: OF course the idea for adding the 1N4148 diode to modify dc is not my own. Look at Eric Foster's CS6PI circuit and you will see the same scheme used in the tx oscillator. There is another common method for getting symmetrical 555 output (look at the Tesoro LOBO circuit) but that would require a little more PCB modification. And for that matter, it is not necessary to drive a charge pump symmetrically, but I think it helps.

Peace to all of you
My dear
porkluvr
You greetings you have done a simulation of the Department of fallow
The results were illogical to some extent I do not know, but units 7912 and 7905 and 7805 when do I connect each one battery results are as they are in the sense -12 and -5 5 but when gather them as the circle original voltmeter does not read the results as in the first case gives -5 -4 3 Are these results are required or what should I do
The second thing
Reference back me Palmhaki of you are as intended to have a left Altaymr NE555 as in the picture below



All of which he was already talking about the emulator and unfortunately I find it difficult to speak in English a recurrent Voadhirona if responses I have I will not mindful of the bug I do not know are good in English
The device was operated work, but I want to know how can I prepare the device before starting operation


How do I increase my sound audio output is very weak and there is no output in the earpiece HP What should I do
And you love and respect
Congratulations

[petoco]

Thanks for ilustrating it Porkluvr
I have the 470k resistor in both channels, r49 and R50 with a switch to change a 4,7 M, because in post 119 I think, said made more stable the detector in case of use of larger coils, In one hand I am happy to know is not neccesary the ring guard, for the other I still trying to see wath happen with the coil and why is not active apparently, hope this is the problem and not in other part,
The problem with the -12V that dropps to -8V I solve only with wider path, was maybe to narrow but thanks to your tip now this is no longer a headache.
thanks friend!