Full m/lab SD2000 schematics

[Woody.au]

Oh what a wonderful thread, this is making its way onto just about every forum associated with metal detecting. I have also made some inroads into doing more mods for the 2000 and 2100. Keep up the good work.

[ZED]

Unregistered

Thanks for your input dude,much appreciated.

Zed

Spot the Goof

They must of thought that it brings good luck to add 2 X 4148 diodes as a protection feat. Pity that these diodes are never exactly the same as each other and if a big spike came down the lower voltage drop of the two will conduct and be converted into a tiny little bit of conductive slag. My advise is to get rid of the diodes as we can do without the extra 10pf of capacitance at that part of the circuit. The Goof is in the bias setup of the 2 transistors, the set point is wrong and upsets the noise figure and the available low signal gain. There are other technical (not quite right) components in other parts of the circuit, especial on the gain settings on some opamps. Some of the stages should have rc networks rather than a straight resistor to cut out a lot of artifact noises being generated by the detector itself when the input signal causes problems with the slew rate of some components.

Anyway, thanks to Zed for putting up a decent schematic, much better than the hotch potch of drawings from past contributors.

Other ML things that we have at our disposal is circuits for the 2100 2200 but not the later ones (being worked on) Source code for the above two and I think the code has been cracked for the 3000 series.

We do not want to post too much at this time as ML will go into meltdown and the stock options will go to zero. They just need to be slowly softened up like the old SD2000 popping up and saying "Hello Boys".

Just think that if Eric Foster or Corbyn patented their work then we would not have a M/L.

[ZED]

bets

So who wants to place bets ?

I bet ya the next model m/lab detector gets filled up with military grade concrete.

Zed

[ZED]

this is fun

Mr WY unregistered

Looking at a photo of the 2100 boards,the 2100 appears to have the same or similer front end receive as the 2000,does the 2100 also have this as you suggest engineering goof.

Zed

[ZED]

curious

G`day AzNuggetBob

Just a little curious about your mods,what do the 4 channels do,can you describe it.

Zed

[bugwhiskers]

Spot the Goof

Hi unregistered,

Is it the 2 parallel diodes (unreversed) on the junction of the 2 input blocking fet's ?

regards
bugwhiskers

[bugwhiskers]

Hi unregistered,

Thanks for your contribution. I do hope this serial has lots of episodes.

regards
bugwhiskers

Still lol.... I was told by a good source that David Murphy was doing the ring around to see what they could do to have this schematic removed. Seems like Graham Walters did not give a rats posterior as they are being paid out of their stock holdings by Codan. I wonder if Codan took into account the up and coming expiration of Candy's patents? By the way there is an engineering Goof on the circuit of the front end that holds back some depth performance..any takers? This not a copy Goof but a Goof when this thing was designed by that marvelous engineer Bruce (do the maths) (again) Baby.

On that topic, if the overall input resistance on the front end is halved then we have 6db better noise performance. This is an old but good overall design that leaves the later machines for dead if a few modifications are carried out to the unit. By the way if you want a psuedo sensitive smooth mode on a SD2000 add a larger capacitor to the r/c network on the on the (or lower the R) collectors on the input transistor pair.

Enough from me today..

P.S When can I publish the 4000 circuit? It is 90% the same as a 2000 bar the stepped pulse voltage circuit and the micro. No wonder they grind the part numbers off, must be pretty scared of being copied..lol

Enough from me today..lol

[ZED]

WOW !!!

Bloody amazing! I never figured minalab would agree,i have to say that i am some what touched by minelabs change of heart.

It feels like christmas, geez.
I feel much better posting the schematics with this current resolution.

I would like to give a big THANK YOU to minelab for giving us the green light even though they may have agreed begrudgingly.
And that yobbo with the cigar hanging out his gob,Carl thank you for allowing
me to post the schematics on your forum,sorry for the rough ride.

Cheers Zed....

[bugwhiskers]

Hi Carl,

Thankyou for your negotiations, it's nice to know we can rely on you to not "roll over".

regards
bugwhiskers

[Carl-NC]

I am pleased to say that I have reached an agreement with Minelab in which the schematics will remain. A new notice has been placed in the first post:

"These schematics may contain design elements which are protected by US and/or Australian patents. Reproducing all or parts of this circuit may violate those patents. Any use of these schematics beyond the purposes of education or modifications to an existing SD2000 should be discussed with Minelab."

- Carl

lol... ML are cracking the ****s over this big time.. I posted as unregistered for a reason. I checked the schematics and can say they are 100% accurate. Wont be long until we see micro controlled ML machines coming out of Bulgaria. As a side note the SD2000 is the best detector thar ML have ever made, with a few modifications it beats all their latest offerings.
To make the detector more sensitive the timings can be changed and the recieve side can be modded easily to give 25% more sensitivity. Just ask woody about it.

uspt5576624

Hi Carl,
Take a look at US patent 5576624, The timing pattern and demodulator is almost identical to the Sd2000.
Also see 5537041, fig 9 show a similar demodulator which combines short, medium and long ground balanced signals, then selects the strongest signal.
Also see 5506506.
These three patents cover the SD's, Gp's, soverign and explorer. In my opinion all three patents are linked and must be considered, when developing new or novel approaches.

Thanks Zed and Carl

Mark

[AzNuggetBob]

Hey Guys, The way I see it, Its "my" detector. Its bought and payed for. If I want to hang christmas lights on it, and show off my work,That is my prerogative. That does not mean Im selling anything. Patents were intended to protect people from others profiting from their ideas. If you try to write any more than that into it, thats the work of over paid lawyers. I dont see anyone selling anything here. If someone out their starts cloneing one of these detectors and selling them, Minelab can wast their time hassling them. AzNuggetBob