SD2000

[nejdet]

Detecto, which country you

[detecto]

For this i must make a new post just to be more visible!
Yesterday i visited state post website and situation there is dramaticly changed since i last time visited website abouth year ago.
I can send letters and package's pretty cheap all around the world, (law is changed, or something else i don't know)
Also i get a responce from one fabric in my contry for PCB-s.
They charge 30 eur only for documentation ( i think only one time)
and i asked only for 2 PCS (just for me) price will be abouth 30EUR for 1pcs approximate.
For a lot of PCB-s they have second prices.
So if prices is not high i can order a lot of pcbs and supplie it here for all of US if you agree with that!
I don't want to earn money from any of you just to make favor.
Only one problem is to be honest i never send any letter or package enywhere in Europ :P
And i only have moneybookers account LOL (my contry is not covered by paypall)
So i will visit post to get all informations abouth sending and if procedure is not complicated and don't taking me to much time i will do a job:P
If somebody can find manufacturer with better prices feel free to supply it here.
Cheers
Detecto

[detecto]

Modern MOSFETs have lower Rdson by "virtue" of larger capacitances, however, being a low impedance frontend as it is, I guess this Rx could benefit from lower series resistances more than it will be hurt by larger capacitances.

I think the LM13600 has been discontinued. It is usually replaced by LM13700 which has somewhat different output buffers bias (usually not a problem at all) and you better hurry finding some because OTAs in general are a very endangered species. CA3280 is also declared obsolete.

I just wonder whose stupid idea it is to discontinue a whole family of components

Hi Davor
Mechanic is right abouth fet's.
I am wondering to abouth components, i try to reed somewhere why are they doing that.

Hi Davor, Detecto,

There are heaps of better fets than the original ones with lower R and lower C. Look up the datasheets for the originals and see what the on R and the C and the breakdown voltage and the gate source voltage are and then try to find similar fets with better characteristics. About the lowest you should look for on R is about 1R any lower than that the C goes through the roof! Too much capacitance will cause a long large oscillation when the fets are turned on to receive. For the N fet you want a breakdown voltage of > 200v as the flyback is clamped to 180v.

I will have a look tonight and see what I can dig up....

Cheers Mick

I completely agree with you!
It will be nice of you to find something.
Thanks!

Cheers
Detecto

[Mechanic]

Hi Davor, Detecto,

There are heaps of better fets than the original ones with lower R and lower C. Look up the datasheets for the originals and see what the on R and the C and the breakdown voltage and the gate source voltage are and then try to find similar fets with better characteristics. About the lowest you should look for on R is about 1R any lower than that the C goes through the roof! Too much capacitance will cause a long large oscillation when the fets are turned on to receive. For the N fet you want a breakdown voltage of > 200v as the flyback is clamped to 180v.

I will have a look tonight and see what I can dig up....

Cheers Mick

[Davor]

...
Better to say original SD2000 front end recieve fets or modern one?
Also i notice that is dificoult to find LM13600 in SO package, they are more common in DIP packages so in PCB i leave place for both packages.
Cheers
Detecto

Modern MOSFETs have lower Rdson by "virtue" of larger capacitances, however, being a low impedance frontend as it is, I guess this Rx could benefit from lower series resistances more than it will be hurt by larger capacitances.

I think the LM13600 has been discontinued. It is usually replaced by LM13700 which has somewhat different output buffers bias (usually not a problem at all) and you better hurry finding some because OTAs in general are a very endangered species. CA3280 is also declared obsolete.

I just wonder whose stupid idea it is to discontinue a whole family of components

[detecto]

Oh man!, it's the end of GreedLab!!!!


Well done.
Aziz

Hi Aziz
Yep LOL
Cheers
Detecto

[Aziz]

Oh man!, it's the end of GreedLab!!!!


Well done.
Aziz

[detecto]

Hopefully everything goes well.

I think to, i invested a lot of work in it, ~150 hours. Damn he must work well!
Cheers

[eduardo1979]

Hopefully everything goes well.

[detecto]

If that really works I want 5 PCBs. Congratulations for all your effort you've spent this whole project and the good thing is you do not want to publish any information wrong here.

Hi
I alredy say why, i am starting from me I would feel bad to start building such project (with lot of money in) and on the end rotten egg! LOL
If he don't want to work i will connect it to 220V AC! LOL just joking!
I hope everything will be fine!
Cheers
Detecto

[eduardo1979]

If that really works I want 5 PCBs. Congratulations for all your effort you've spent this whole project and the good thing is you do not want to publish any information wrong here.

[detecto]

And one more think for op amps in SD2000 ML used LT1057
LT1057 has some funny pinout (not common) and today we have a lot of better precision op amps with less noise etc etc so i decide to put common pinout for that two op amps.
In schematic and pcb i will mark them and probably make choice for op amp.
But also you can experiment with them, only remember J FET op amps with best quality and characteristics!
Cheers
Detecto

[detecto]

Hi
Thank you all for support.
I contacted several manufacturer of PCB and i am waiting response from them.
I must make a note because now is the best time for all of you who want to build SD2000
LM394 in not any more in production, (but it is not imposibile to find it)
replacement for LM394 is MAT-02,
MAT-02 is even with better caracteristic!
So advice for everyone : Try to find one of that component!
In my contry i only found LM394M (metal package 6 pins)
Also i need one opinion!
In original SD2000 for front end recieve they use 2 type of fets VN2410L, and ZVP4105A they are in T0-92 packages
those two fet dates from 94' and thay both have RDS on <10ohm
In present time we have a whole line of better fets for examle with RDS on abouth 1,5 ohm( and most of them are in SOT-23 packages).
So what are you sugesting TO-92 packages or SOT-23 packages?
Better to say original SD2000 front end recieve fets or modern one?
Also i notice that is dificoult to find LM13600 in SO package, they are more common in DIP packages so in PCB i leave place for both packages.
Cheers
Detecto

[Sean_Goddard]

EXCELLENT work Detecto!

At LAST a project which someone won't release their work until it is tried and tested (and working).

FULL MARKS and respect to you Sir!!

[Bill512]

Hi

Here are my last updates, project is complited, last night i drawed audio board and this is it,
I will spend a couple of hours to check is everything OK.
Afther that i wll send files to local manufacturer and after building one working device, PCB will be able for all of us.
Also i wll make few video's.
Cheers
Detecto

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Nice work Detecto!
The Minelab SD2000 was a milestone on metal detectors evolution.
If your project is going to work, then it will be also a milestone in DIY projects.
Keep going.