LOOKING FOR GOLDSCAN 4 Schematic.

[ivconic]

look attachment post #407

Pito, I will definitely measure the power of the TX one of these days and let you know.
I'm too tired to do any work now. I'm going on a short rest from this.
The thing I didn't mention here is this: the pcb layout I used to do this is based on the original GS4 from Eric.
But that Sprint Layout file was drawn by someone, I don't know who, who made a dozen mistakes, there are some missing links, there are some mistakes, and even extra components that are not on the original.
The first time it was turned on, it didn't work at all, one horror.
So I worked really hard for a couple of days to locate all the mistakes, correct them and note down everything I found that was bad. So that process made me very tired.
Give me time to rest and these days I will measure everything you are interested in and post it here.

[ivconic]

One thing I can confirm here; the schematic by Alex, in post #408 is definitely correct and accurate.
Because I compared the Sprint file with it and thanks to that schematic I successfully corrected all the errors on the Sprint pcb layout.
With one small note; R49 and R50 on schematic do not exist on Sprint pcb layout.
I believe it's either one of Eric's revisions... or Alex himself added it to the schematic.
In any case, it is not wrong, because by adding those resistances, the detector will get "slow motion" behavior.
Only that I would set both resistors to be 470k.
I haven't put them on my work yet, but I plan to include them as an option.
That's it for now... I'm falling from fatigue, I'm in rags!
Cheers!

[Alexismex]

Hello ivconic,
I have the equipment lying around, it worked perfectly, if you want to have it, I will send it to you by international DHL, you pay me for the transportation only through Pay Pal, you have to give me your exact address and telephone number. So I will be happy that you check the schematic because its creator was very stingy in giving something!!!
Nice day ,Saludos from México.

[ivconic]

Hello ivconic,
I have the equipment lying around, it worked perfectly, if you want to have it, I will send it to you by international DHL, you pay me for the transportation only through Pay Pal, you have to give me your exact address and telephone number. So I will be happy that you check the schematic because its creator was very stingy in giving something!!!
Nice day ,Saludos from México.

Thanks for the good will!
I respect that!
But there is no need.
The total shipping costs would exceed all logic.
And there is no need, I already have 5 pcb done in JLPcb.
I don't know what to do with the other 4.

[ivconic]

Ok here is what I was talking about.
It is Eric's original pcb design.
To make less clutter on the desk; I combined both pcbs into one file, so that in JLPcb they would do it as one pcb.
But I left a "perforation" between both pcbs, in case I want to separate them.
In the end, it turned out that the detector works in an unprecedentedly stable and calm manner, which can be seen on the video.
Plus is powered by a very old bench power supply and not by a battery.
So my amazement is all the greater that the detector works so stably, calmly and cleanly!

[ivconic]

But make no mistake, the previous file has errors, which I didn't know at the time.
Here is the file with all the mentioned errors.

[ivconic]

[ivconic]

And finally, a couple of very important notes for those who would like to make this!
Forget gemranium diodes, total nonsense!
I guess Eric had a lot of those in stock, so he wanted to use them!

Not only are they a bad solution, but they also cause a big problem for the operation of the device and precise adjustments.
To fit all the different diodes I put a BAT86. On each diode place!
Instead of J113, which I can't find in local stores; I put J112.
All quads are TL064.
All other transistors are BC547/557.
The mosfet is IRF840.
All other passive components are of original values.
All other ic chips are according to the original schematic.
I adjusted the trimmer potentiometers according to the schematic provided by Alex.
Everything is 100% correct.

[ivconic]

[ivconic]

"...gemranium diodes..."

[ivconic]

Coil from video is 18-19cm diameter, 0.43mH/2.9 ohms...
After 40 minutes of operating the IRF840 gets only a bit warm but never hot, no need for heatsink at all.
For the whole video duration; the delay is at minimum (don't have a clue about exact value).
PPS is at maximum, I guess it is 550pps as on Alex's schematic.
I don't pay attention on such side details, my focus was only on GEB and "Disc" behavior for now.

[ivconic]

I ordered several types of pcb in the same package.
The original GS4 design, then Alex's pcb design, which I like better, but I haven't decided to build on that pcb right away, because of the SMD resistors on the bottom, until I get them all...
and a couple more pcbs for some of my other devices .
JLPcb minimum quantity is 5 pieces, so I had to order 5 of each.
I don't have the conditions to ship abroad without it all making sense in terms of shipping costs, so don't ask me for a pcb.
Because it doesn't make sense.
It is much cheaper to order directly from JLPcb yourself and with the Fedex shipping method, it ends up being cheap and very fast, within a maximum of 10 days it arrives at your home address.

[ivconic]

Alex did a great job!
Obvious.
I went a step further and added a ground plane to his pcb design.
In order to improve the S/N ratio even more.
I tried to make sure there were no mistakes, but I can't guarantee that I didn't make at least one.
This should be checked though.
But I like this pcb design a lot more and I think it is a better choice for those who want to make it.
...
Alex's choice to put all resistances on the bottom layer is a particularly good move!
Makes a lot of sense!
Because resistances are certain noise generators, depending on where they are located and the role they play.
An additional good thing is because the SMD 1206 resistors are smaller in size, smaller "antennas" that emit noise...
but the 1206's are large enough to easily solder to the solder pads.
A very intelligent choice indeed!
It reminds me of my way of thinking when designing a pcb.
A very smart move, which I liked right away.
I also like the footprints for most of the components better than Eric's choice.
Eric used 2.5mm for capacitors and 5mm for resistors!!!
More than once I mentioned Eric's name in the process of soldering components in that excruciating way!

[ZOUjiarui]

People always like to release pcb without inspection

[ivconic]

In most cases, I tend to believe that, there is no bad intention.
But is more likely about the fact that we are all living human beings of flesh and blood, whoever works makes mistakes.
Only those who do nothing do not make mistakes.
In this case, I am even grateful for those mistakes, because that way I was forced to go deeper into the essence of the project and to understand things better.
If there were no errors, I would have simply replicated that detector and would not have been too keen on going into details.
Because by nature I am very lazy and inert. And I'm at an age when I'm increasingly losing motivation for further "endeavors"...