Full m/lab SD2000 schematics

[Bill512]

http://youtu.be/DsBiPSUTwjw

nice work!
thanks for the video...

[serci78]

detector great looks bravo Finderskeepers

[serci78]

Hi Finderskeepers what type of capacitor

[Mechanic]

Hi Serci,

The 10uf cap is a tantallum, the 2.2uf is polypropylene, for the 2.2, choose as high as possible voltage as they normally have less leakage. You want a low loss tangent.

Finderskeepers, nice job on your 2000, well done! I notice that your GB control sounds a bit touchy, are you using a 10 turn pot for the adjustment?

Cheers Mick

[serci78]

Hi Serci,

The 10uf cap is a tantallum, the 2.2uf is polypropylene, for the 2.2, choose as high as possible voltage as they normally have less leakage. You want a low loss tangent.

Finderskeepers, nice job on your 2000, well done! I notice that your GB control sounds a bit touchy, are you using a 10 turn pot for the adjustment?

Cheers Mick

thank you for answer Mechanic

[Finderskeepers]

Each channel has to be ground balanced seperately and when complete the switch is then set to search mode (middle/off position). The schematic shows an on-on switch but should be an on-off-on switch. The dds unit works fantastic and is a substantial improvement over the quartz crystals. I don't have a scope so I cant answer how the timings are affected.

The ground balance pots are Bourns 100k 10 turn. When adjusting the knobs they do sound off slighty and as I have never used or seen a sd2000 in action, thought this was normal. The ground at that location is pretty nasty with a mono coil, the balance knobs were set to fully clock wise for this video to give people an idea of the mineralised ground in Australia. You become pretty quick at learning how to ground balance by listening to the tone when the coil is lowered, turn clockwise when low and counter clockwise when high.

Good quality parts should be used, such as polypropylene capacitors, low esr capacitors and 0.1% resistors. Unused pins of the cd4000 series i.c.'s should be tied down to -5volt (if chip has -5/+5volt supply) or - battery (if chip has single volt supply). Best to read manuf. data sheets for appropriate tiedown. If your using a dip version of the lt1057, beware that the pinouts are different to the smd version. Bypass caps are to be used for all i.c.'s. Keep the circuit as original as posible, I have used a ssm2210 in lieu of lm394.

There is alot of helpful information on the web thats been posted by Zed, Mechanic, Woody, Ismael and Mario on the sd2000 and a big thanks goes out to them.

[Ronk]

Wow what a read !!! it has taken me several hours over last couple of days reading and looking at all the attachments truly amazing thread and I am surprised at the lack of attacks on other peoples views , so many forums end up in **** fights over who know more , I also have probably learn enough to fix my sd2100 , It is great to be a member and i hope i can not only learn a whole more, and that i can give some back in the future if anyone need a pcb made I am more than happy to do it it wont be drilled but it will good quality and cheap other than that not much to offer at this stage
wondering if there is any circuits out there for my 2100 although I think i have enough from what has been presented here
Thanks to you all for your inputs and discussion

Ronk

[greylourie]

Hi Ronk,
You might glean some info in this thread : http://www.geotech1.com/forums/showt...my-Minelab-PCB

[Ronk]

looks great thanks

[Ronk]

hi guys well there is not enough about the 2100 to be of much help so many featurs are different my 2100 is the first model so even all the posts from Mario while they give me the idea they are different and right at the frontend to the reciever there is a fet and my 2100 doesnt have it. it has an ic in the same spot 8 pin dil
the running of the detector with the yellow wire cut gives a low tone that is constant and pure , reconnect the yellow wire and there is a warbelling noise that cannot be cancelled tried a different coil and same noise . the level of the warbel did change up and down and that is the fault it has always had so it is possibly a design fault , hence the V2 or sometinhg is varying in the circuit but i havnt found out what yet .

[N@SKO]

it has an ic in the same spot 8 pin dil .

Two fet in Dip8 maybe.

[Ronk]

thanks N@asko I have been trying to remove some paint with little results but that might explain the difference i will check into it and see if i can sort it out

[Ronk]

that ic is a lm394 matched pair transistors

[kato]

hello, ı want to ask you somethıng.do you have sd2000 unılateral pcb on your websıte ?
ıf you have this product on your site,do you publısh it?

[Ronk]

there are quite s few sd2000 circuits published on this site
there are photos of the pcb but not a full layout to build your own