LOOKING FOR GOLDSCAN 4 Schematic.

[mohandes]

thanks jose
but if u have time please certain the error on pcb and put it here the correct

[Jose]

Mohandes, No error on the PCB.
If have, design problems.
These design problems, causing noise and instability.
The problems can be overcome in various ways, depending on the judgment and experience of the person building the detector.
For example i found that the main cause of noise generated in the power supply of 5 volts, at 555. The solution I found is to replace it by a 7660 built, removing some components and adding others.
The same is done with the NE5534, which fits two-stage preamp with NE5532.
Both schemes were copied from HH2.
Also cut some PCB tracks and make shorter connections in different parts of the power supply and GND, trying to reduce the oscillations and noise.
The work is cumbersome.
Is not I have the PCB with the corrections. That's why I do not recommend.
Jose

[lucafa]

Hello Jose.

Very interesting what you say about: " The same is done with the NE5534, which fits two-stage preamp with NE5532.
Both schemes were copied from HH2."
Please write in link of HH2 to see this schematics.
Regards.

[amarasha]

salam mohandes
in borda be dard kar herfei nemikhore ye foto fanai dare be mror ashna baiad beshi!
takhasoset chie? koja kar mikoni? ta hala chikar kardi?

[Jose]

Lucafa, HH2 is the hammer. For modifications to the source, see page 8, post # 191. It's the same pattern I use.
For the front stage, NE5532, see drawing.
Attached is a picture of my GS4 Mod
Jose

[Qiaozhi]

salam mohandes
in borda be dard kar herfei nemikhore ye foto fanai dare be mror ashna baiad beshi!
takhasoset chie? koja kar mikoni? ta hala chikar kardi?

Please read the forum rules and make your posts in English -> Basic Rules of the Forums

[6666]

Jose did you use C24 on your preamp, that cap is not supposed to be there.

[Jose]

6666, Apologies, I forgot to correct.
Install in place 15 pf.
Jose

[ivconic]

Mohandes, No error on the PCB.
If have, design problems.
These design problems, causing noise and instability.
The problems can be overcome in various ways, depending on the judgment and experience of the person building the detector.
For example i found that the main cause of noise generated in the power supply of 5 volts, at 555. The solution I found is to replace it by a 7660 built, removing some components and adding others.
The same is done with the NE5534, which fits two-stage preamp with NE5532.
Both schemes were copied from HH2.
Also cut some PCB tracks and make shorter connections in different parts of the power supply and GND, trying to reduce the oscillations and noise.
The work is cumbersome.
Is not I have the PCB with the corrections. That's why I do not recommend.
Jose

It's been a while, this topic faded out, so it seems!
Winter, snow, annoyance... so i start listing old and interesting topics here (new topics are so annoying... painfully annoying and far away from being inventive).
Gold Scan always attracted my attention but i never really tried to think more seriously about it.
Now reading some posts i find it amusing.
Jose you did quite job there, indeed.
But i think that you wasted your time trying to solve the stability issues at your GS made on that pcb.
Power supply stage is generating all the noise and it should be excluded from main board, just as on original GS.
That pcb is esthetically nice, indeed, but from designer's perspective it is not good at all.
It's actually a horror, referring the signal&power paths, gnd loops and interferences.
So, either draw better pcb, either exclude power stage from it and transfer it on another pcb.
Not only that; also try to correct some of the ground paths and put them all close and with together endings.
Maybe this is not possible on existing pcb draw, not sure.
There are some notes on one of the existing schematics, explaining which gnd's should be put together at the same spot.
So, custom pcb for handmade GS should be draw very carefully and with a lot of attention.
That is the only possible way to make it stable and accurate.
I'll see, i might give it a try this winter, will see, depends on my free time.
Cheers!

[kt315]

I still thinking Eric Foster has to set down writing a big book on PI theory and with all schematics he did. this is my opinion. if he refuses... there will be ivconic, kt315,
mohandes, GS, and another noobies in this field of blunt copying.
not winter and not snow had made GS4. but hottie climate and hard soil of Australia. mine cheers too.

[Koala]

Are then any good independent review of the original detector. Found a few via Google but they are more in the line of yes I have one and they are great.

[Koala]

found a review of the GS2

[kt315]

thanks Koala.... keeping in archive... I following Eric, what his state... http://www.findmall.com/read.php?34,1959675

Hi Guys,
a friend of mine was at a Rally in England recently and was told that Eric Foster had passed away! Is this a rumor or is it True? Anyone know about this?

Cheers
Al

[Jose]

Hello Ivconic.
You played very well what I meant in the previous post, on the issues related to instability in the GS4.
I do not try to make the PCB, because I have not enough experience to take over.
I am willing to build another GS4, if they make the PCB, although the current, it's working reasonably well.
I would ask you please to try.
If anyone cares to experiment, here's one mods for tall drivers I'm rehearsing in, SEL2 mode.
Regards
Jose

[ivconic]

Hello Ivconic.
You played very well what I meant in the previous post, on the issues related to instability in the GS4.
I do not try to make the PCB, because I have not enough experience to take over.
I am willing to build another GS4, if they make the PCB, although the current, it's working reasonably well.
I would ask you please to try.
If anyone cares to experiment, here's one mods for tall drivers I'm rehearsing in, SEL2 mode.
Regards
Jose[ATTACH]27346[/ATTACH]

I hate to promise something and later not to fulfill it, so this time i will not promise, but be sure i will try my best to draw another pcb for GS.