Need help on new GPM

I purchased my SD2000 GPM several weeks ago and want to know as much as possible about it before I take it to the field. My questions are as followes:


1. What are the upper and lower voltage limitations of the GPM?

2. What battery are y'all using? I was going to go LI ION until I saw the price of
$600.00 to power the GPM at 8 amp hours.

3. I have heard that Coiltek recently fixed it's old battery problems and was
wondering if their power supply is sufficient to power the GPM

4. Where can I obtain a copy of the original SD2000 manual? I was a little
surprised that the secretary at Minelab/Nevada never heard of an SD2000. She
said that she would try to send me something if and when she could dig
something up.

5. How are the two small sensitivity knobs just left of the balance controle applied?
No one has had the time or knowledge to answer this seemingly easy
question!

6. I am planning to purchase the 12X24 UFO and 14x12 DD coil by Coiltek unless
y'all have other reccomendations?

I would greatly appreciate any and all info and advice!

Regards,

Donn. C

Dear DonnC

I had a few goes at answering your quieries about the gain controls on the Arizona forum as did Ted.
What aspect of the gain controls are you trying to understand ?

Cheers Billy.z

How about a simple explanation incorporporating all four knobs on the coil side. not just the two directly above and below the switch but the two just two the left as well?

Thanks

It sounds like you haven't used a SD2000 before and are getting confused between the original balance knobs and the new sensitivity knobs of the mod.
For the moment disregard the pics on this site as they show a different face plate with a additional switch used to convert one side of a DD coil to become a mono coil.
Refer instead to page 3 of the GPM mod manual.
The illustration on this page should be exactly what your machine looks like.
The big 3 position toggle switch is the mode switch, (exerpts from the manual are in brackets)
"The Mode Switch is used to select one of the two ground balancing modes or the search mode", "The SD2000 is essentially two detectors in one. Each "half" of the detector must be Ground Balanced seperately. After ground balancing has been completed, prospecting is performed with the Mode Switch in the "Search" position"
The Knobs directly above and below the mode switch are the ten turn potentiometers of Balance I and Balance II and are marked as such. "The Balance Controls allow the detector to be adjusted to suit varying ground mineralisation levels. Each one is adjusted with the Mode Switch in the respective position".
"Ground Balancing. It is important to "Ground Balance" the SD2000 to the local conditions before commencing a search. Assuming that the detector is operating with the Threshold and Tone set, adjust the Balance Controls using the following procedure: Set the Mode Switch to the 'Balance I' setting. Move the coil up and down between 1cm to 15cm(that means up to 6") above the ground. As the coil moves up and down, the volume and the pitch of the Threshold Tone will change if the detector is not ground balanced. Adjust the Balance I Control so that no variation in Volume or pitch is heard as the Coil is moved up and down.
When this is acheived the detector is said to be ground balanced."
"When the detector is balanced with the Mode Switch in the Balance I position, switch to Balance II and using the Balance II Control, repeat the process described above. When the detector is balanced in both positions, switch to Search and commence prospecting."
Thats how you get going with the standard machine, now the modded machine has two additional smaller knobs to adjust the sensitivity of the receive circuit, these are located to the side of and slightly above and below the mode switch. After ground balancing set the mode switch to the Balance I position and adjust the upper small knob as has been described on our posts on other forums, when adjusted to your satisfaction move the mode switch to the Balance II position and adjust the lower small knob, when completed return the mode switch to the central "Search" position and your away.
The whole process is a lot quicker to do than to type.
Hope your finally on the right track.

Sorry guys, I had not seen Billy's last post @ arizonaoutback where the two skinny controles are finally identified as the gain.

Thanks to you to Ted and Billy on your groundbalancing techniques. Ted's last paragraph on this forum was especially helpful.

Any idea of what the upper and lower limit to voltage are on this machine?

Thank you very much!

Cheers

DonnC

Ismael,

I am confused once again. You write that anything above 12 volts is fine and even 14 volts will work but then you also say that any 12 volt battery with more than 10.5 volts output is probably to much? The reason I ask this is because I am thinking about using a 14 volt lithium ion laptop battery (2 ponds by the way) on my gpm but I think that the the battery's output may actually be more than 14 volts. come to think about it my 12v/18 Ah (13 pounds) gell cell may also have more than 12volts of output. I realize that the regulator will bring the out put down but how do I know if it will bring it down enough. Maybe I should just play it safe and use a weeker 12 volt gell cell of say just 7Ah. I can't seem to find any LI ion batteries under 14 volts that have sufficient Ah and so am very interested in how and when yours is coming along. I do see alot of little cylinderical 3.5 V/2Ah LI Ion batteries and was thinking of connecting three of them but don't know if that will work.

i am realy concerned about batteries because where I am planning to go there are no power sources not even automobile access to charge them. Any solar panel suggestion would also be helpful.

Regards,

DonnC