LOOKING FOR GOLDSCAN 4 Schematic.

[mschmahl]

Now the Goldscan is working.
The deep is not so good (only 10 cm for 1 Euro) but the test-coil only have 350 uH and 1,4 Ohm.
Next step is to build a coil with 400uH and 3 Ohm or change PCB for a dualcoil.

[bernte_one]

means:
i´m happy to see another working detector from forum member in germany
lean back now and drink a beer and i dance towards my lcd screen

if i have time next weeks i will follow you good work until here
sure you can improve it

regards bernd

[Alexismex]

Good work MSCH, Now you must adjust( the damping coil first) well all the stage because 1 Euro is for 20 cm at least... and with your another coil (400uH) you still had the same result because GS4 is not adjusted...

[mschmahl]

Good work MSCH, Now you must adjust( the damping coil first) well all the stage because 1 Euro is for 20 cm at least... and with your another coil (400uH) you still had the same result because GS4 is not adjusted...

Thanks for the hint Alexismex. I had it adjust all but not with damping first. Thanks.

[satdaveuk]

Hi all
I been reading through the 4 pages of this thread, am I right on the understanding that this machine is only good for beach detecting like so many other PI detectors.
Im in know rush to build this one yet because still working on my minipulse 3.
I have read from a couple of uk detectorists that Garrys PI design handles minerals quite well on open land, dont know how far its true but worth the build just to see because its quite stright forward by the looks of the circuit, anyone here built one?

All the best boys and girls

[mschmahl]

I hope it will be good for german fields. there are a lot of iron junk. and the gs4 can differentiate between iron and and other metals. Mineralisation isn´t a big problem there.

I´m very busy, so i make the changes at the weekend.

[maikl]

means:
i´m happy to see another working detector from forum member in germany
lean back now and drink a beer and i dance towards my lcd screen

if i have time next weeks i will follow you good work until here
sure you can improve it

regards bernd

Can you get a link to the German forum?

[Jose]

Hello to All
I built the GS4, the PCB used is different from what we see here, is one face that I found on another forum.
At first it was very unstable and impossible to adjust, the cause was the noise.
This noise had two origins. One is the PCB, perhaps because of poor design, and the other originated in the source of 5 volts, corresponding to the circuits 555 and associated components.
I replaced the 555 by 7660, the scheme copied from HH1, and the noise decreased considerably.
Make bridges on the PCB, which corresponds to GND, and make a shield to 5534.
It's working well, is very sensitive, and fully rejects iron. Be careful with discrimination, which can reject bronze coins larger.
There are different circuits GS4 in the forum, with different values of some components.
What worked for me are:
R49 and R50 are 470K.
Potentiometer 10K GND must be
Apparently lack a capacitor between the legs 6 and 7, U13: C, as shown in the original photos posted in the forum.
I put nf 220.
Hope this helps.
A Warm Welcome
Jose

[mschmahl]

Adjust gs4

Good work MSCH, Now you must adjust( the damping coil first) well all the stage because 1 Euro is for 20 cm at least... and with your another coil (400uH) you still had the same result because GS4 is not adjusted...

Hello all,

I have managed the problem with my coil, now i use the dual-military-coil from schiebel (AN/PSS-12) with TX coil 236 uH 0,9 R and RX coil 447 uH 2,6 R.

I have a problem with adjust RV6. Have i adjust it to zero and must Pin 10 of U13 be zero?

[Jose]

Hello all,

I have managed the problem with my coil, now i use the dual-military-coil from schiebel (AN/PSS-12) with TX coil 236 uH 0,9 R and RX coil 447 uH 2,6 R.

I have a problem with adjust RV6. Have i adjust it to zero and must Pin 10 of U13 be zero?

Hello Mschmahl
This is how I adjust RV6, please correct me if I'm wrong.
Hold or make adjustments bridge during the key "Reset".
Place SW1 in position 2 "All Metall" (RV6 is canceled).
Adjust RV5 to 0 volts, leg 7, U13: B.
Adjust RV7 to 0 volts, leg 8, U13: C.
Place SW1 in position 1 or 3 (RV6 is enabled).
Adjust RV6 to 0 volts, leg 8, U13: C.
Jose

[mschmahl]

Hello Mschmahl
This is how I adjust RV6, please correct me if I'm wrong.
Hold or make adjustments bridge during the key "Reset".
Place SW1 in position 2 "All Metall" (RV6 is canceled).
Adjust RV5 to 0 volts, leg 7, U13: B.
Adjust RV7 to 0 volts, leg 8, U13: C.
Place SW1 in position 1 or 3 (RV6 is enabled).
Adjust RV6 to 0 volts, leg 8, U13: C.
Jose

Hello Jose and all,

Deep is now good, but i can´t eliminate iron.

Must it be leg 1 of u13 to adjust RV5 to 0 V instead of leg 7?

How had you adjust RV1, RV3 and RV 4?
I have adjust RV1 leg 7 u12 to 0 volt, RV3 leg 1 u12 to 0 volt and RV4 leg 10 u12 to -7mVolt.
Which position have SW1(always 2 "All Metall") to adjust RV1-RV8?

Here is a Scopeshot of first sample.
bottom-line is Output of NE5534
upper-line is U5 pin6/11

First picture 5V/15uS
Second picture 5V/5uS

[Jose]

Hi mschmahl
SW1, position 1 "OFF" is a common detector, does not discriminate, (does not remove iron).
SW1, position 2 "ALL METAL" is a ground effect detector does not discriminate, (does not remove the iron).
SW1, position "SEL 1" and "SEL 2" if it discriminates, (removes iron).
Use "SEL 1" for discrimination tests.
If ...., adjust RV5 for 0 volts at pin 7, U13: B; (This recommended "Gurus" elsewhere in the forum).
The other settings:
SW1, position 2, potentiometer "GND" to a minimum (side of R52).
Pulsar "RESET".
Adjust RV1 to 0 volts, leg 7, U12: B.
Adjust RV3 to 0 volts, pin 14, U12: D.
This mode setting RV3, I conducted to ensure that the voltages are equal at the ends of potentiometer "GND". In this way, does not affect the set "Threshold" as you move the cursor to "GND".
I found it easier, make some adjustments when RV1 and RV3, conform to 5 millivolts negative, instead of 0 volts.
RV4 adjustment is different from those described in the forum, maybe because I did not get the J113, and I use one on a replacement.
Try adjusting this way:
Release control "RESET"
After adjusting RV1 and RV3, switch SW1, to the point 1 "OFF".
RV4 adjustment at a point where the sensitivity decreases sharply.
This control back until you feel that the sensitivity increases, this can usually notice a slight instability or increased noise in the speaker, use maximum sensitivity, or a small metal object for testing.
From the point of maximum sensitivity and the gain drops sharply where is the best point. I have my doubts on this method, but is the only one that worked for me GS4 homemade.
You may need to repeat the settings for RV5, RV6 and RV7
The image of the oscilloscope, looks good.
Excuse my English, which is the product of the translator.
Jose

[mschmahl]

Thank´s for all your help.
Now the deep is good. But i can´t fix the problem with the iron.

I bought an original goldscan. So i can compare both.

I have changed the original GS4 so that i can use the military-coil with seperat tx and rx.

Are there other mod´s?
I have read something about a "single-tone-mod" and "high conducter and low conducter switch" from reg on the GS5 and GS4.
Does anyone knows more about it?

[Jose]

Thank´s for all your help.
Now the deep is good. But i can´t fix the problem with the iron.

I bought an original goldscan. So i can compare both.

I have changed the original GS4 so that i can use the military-coil with seperat tx and rx.

Are there other mod´s?
I have read something about a "single-tone-mod" and "high conducter and low conducter switch" from reg on the GS5 and GS4.
Does anyone knows more about it?

Señlales check for the integrator, in the channel of iron.
Deputy scheme GS4, home made.
Jose

[ABDW9]

Hello Jose and all,

Deep is now good, but i can´t eliminate iron.

Must it be leg 1 of u13 to adjust RV5 to 0 V instead of leg 7?

How had you adjust RV1, RV3 and RV 4?
I have adjust RV1 leg 7 u12 to 0 volt, RV3 leg 1 u12 to 0 volt and RV4 leg 10 u12 to -7mVolt.
Which position have SW1(always 2 "All Metall") to adjust RV1-RV8?

Here is a Scopeshot of first sample.
bottom-line is Output of NE5534
upper-line is U5 pin6/11

First picture 5V/15uS
Second picture 5V/5uS

hi thanks for all
I want to see this work The Video