Full m/lab SD2000 schematics

[Mechanic]

Hi Orbit,

Define "small", say with grams of lead.
Typically a .22 bullet will be detected at about 4~5", though it has been a long time since I played with/used an sd2000, so my memory is a bit fuzzy on what it used to do! Smaller targets under a gram are harder to detect.

One thing to be sure of is that the coil settles properly before the first sample is taken. If it doesn't settle properly before first sample, this can have a big effect on sensitivity. Also the EF balance would seem wrong. A good way to test a home made coil is to wave a non metallic magnet over it(raise and lower in the center of the coil, only down to about 2" from the coil) and if suddenly the magnet is picked up by the new coil, it indicates that the coil may not have settled in time for the first sample.

Cheers Mick

[ZED]

Lets do a sim of the TX cct

So upon reading some of the posts in this thread regarding the TX cct and its peripheral ccts i thought i would create a sim using LTspice,it shows a working TX cct which for the most
part is the same as the SD2000 schema.I think of particular interest will be the cct involving the 100uf electro and the IRF710.
This will be of help to those trying to understand the wave forms at various nodes around the cct

Now can somebody tell me how to share a LTspice file with the members here.
I have however changed the file extension to ( txt ), To view the file in LTspice just change the file extention back to ( asc )

Cheers...

[Qiaozhi]

Now can somebody tell me how to share a LTspice file with the members here.

Compress the file as zip.

[dbanner]

So upon reading some of the posts in this thread regarding the TX cct and its peripheral ccts i thought i would create a sim using LTspice,it shows a working TX cct which for the most
part is the same as the SD2000 schema.I think of particular interest will be the cct involving the 100uf electro and the IRF710.
This will be of help to those trying to understand the wave forms at various nodes around the cct

Now can somebody tell me how to share a LTspice file with the members here.
I have however changed the file extension to ( txt ), To view the file in LTspice just change the file extention back to ( asc )

Cheers...

Compress the .asc using Winrar. Or any similar Winzip software. Then upload the .zip or .rar file.

[dbanner]

Hi waltr, could you please take a look on these screens schott and advice ?, I m stuck in this result.

Rgds
Anis

Anis, I see you are using Hantek 6022be oscilloscope. How does it perform? Are you pleased with its operation? Can you state what is the timebase range?
The specs on the website do not mention this.
I am thinking of getting one of those 20mHz Hantek scopes for my PC.

[ZED]

Thanks Qiaozhi and dbanner.

So here's the spice file,just unzip it with winrar,hope it answers some of your questions.

Cheers.....

[Anis]

Anis, I see you are using Hantek 6022be oscilloscope. How does it perform? Are you pleased with its operation? Can you state what is the timebase range?
The specs on the website do not mention this.
I am thinking of getting one of those 20mHz Hantek scopes for my PC.

Hi dbanner,
Yep, it performing well, for the timebase range it s operating as follow:
1ns to 9000s, 39 Steps.
See user manual on internet " Annex A: Specification" you will find more details.
For me as beginner it's a nice gage and easy use.

Thx
Anis

[dbanner]

Well, for the price I think it is a good deal. The Hantek 6022 is a very popular model. Seems to work fine.

[ne555]

Has anyone succeeded in compiling this schematic ?

[Anis]

Hi Anis,

You need at least 6v to run properly otherwise the 181v won't be high enough and there are protection circuits that stop the receive fets coming on. That is why you don't hear anything before raising the voltage to 6v.

The IRF710 will need to be mounted to some sort of heatsink as it will get hot. Make sure it is insulated as the tab has 180v on it. It is normally mounted to the case on the sd2000. If your 68r resistors are getting hot then the irf710(or tlc217) isn't working correctly or the resistors current rating are too low.
The tlc271 can easily be damaged, you might need to replace it.
Also make sure your connections are correct to it, that GRND is correct and you have the link to the 2.5v reference from the power supply circuit.

For the coil srf, to measure it I just place the coil(just connected to the scope) near(just close enough to observe decent ringing amplitude) another coil connected to a detector and look at the frequency of the ringing after tx off.
A single strand coil is no good for the sd2000. It takes too long to settle to 0v

Cheers Mick

Hi Mick, again thank you to drive me to the right way,
-Accidently connected pin 6 of TLC271 to GND this caused the blocking of the Fly back, now corrected the circuit is running well and I can see stable 181V in the 100/200V capacitor.



-Coil SRF, I followed your measuring method and below are my results:




-I'm now looking for new litz wire for additionnel coil below are specifications for the wire, please is this a right chois?





-Then I connected the audio board to see if sound response is working, result was:
Sound okay, but there is no change of the tone that mean that there is no coil response to metals.
Attached is screen for N40 & N50 from the front and receive.



Please do you have any advices, you and all genius team of this forum?

Cheers Anis

[Mechanic]

Anis, in N40 N50, where is gnd for each trace? The receive signal should stay very near gnd.

Also if you take a large metal tin, you should see an obvious change in the receive signal.

It is possible that you have damaged the front end fets and 4093 when the 200v circuit was not working correctly.

The srf coil frequency measurement is useless, you need to use a faster timebase.

For the coil wire, you need to search here as there is a lot of good information posted on coil wire specs for Minelab machines. I am no guru of coil building! Check posts by IBgold.

Cheers Mick

[IBGold]

Anis, what size coil are you looking to build the size of Litz depends on the coil size for a coil in the 250 mm range 32/.2 Litz would be around the mark for an 450 mm coil you would need Litz with around 36/.2 strands Litz with .2 mm strands seems to work the best for Minelab PI's and is what most of the commercial coils use this is of course for the TX winding's.

Hi Mick!

Regards, Ian.

[Anis]

Anis, in N40 N50, where is gnd for each trace? The receive signal should stay very near gnd.

Also if you take a large metal tin, you should see an obvious change in the receive signal.

It is possible that you have damaged the front end fets and 4093 when the 200v circuit was not working correctly.

The srf coil frequency measurement is useless, you need to use a faster timebase.

For the coil wire, you need to search here as there is a lot of good information posted on coil wire specs for Minelab machines. I am no guru of coil building! Check posts by IBgold.

Cheers Mick

Hi Mick,
GND is the middle of each wave.

Yep, I v already bought some spares for that as precaution,
Now I think It's working, I will share N40 and N50 waves soon (now I m replaying from my phone).
I tried with some big stainless steel saucepans and it seems that there is some responses, I m not too glad with the results, it my be some errors in the audio board (need to verify wire by wire).

In parallel I started to build an extra audio amplifier for head speakers, in order to have more sound amplitude in the output.

Now I will wait till I receive the new wires, after IBGold's support.

Thx
Anis

[Anis]

Anis, what size coil are you looking to build the size of Litz depends on the coil size for a coil in the 250 mm range 32/.2 Litz would be around the mark for an 450 mm coil you would need Litz with around 36/.2 strands Litz with .2 mm strands seems to work the best for Minelab PI's and is what most of the commercial coils use this is of course for the TX winding's.

Hi Mick!

Regards, Ian.

Hi Ian, thank you for coming to support me with the DIY coil,
Well I m looking for the 18" coil , exactly 457mm coil, (for deep big targets)
as per last attached there is a large choice for wires, please can you specify what would be the good one for this?

Best regards
Anis

[IBGold]

Hi Anis,

Litz made with 36 strands of 0.2 mm enamelled wire would be perfect for what you want for a Mono coil it is what I use.

Regards, Ian.