Nevada Nugget Hunters

Everett

This is to explain how to add the button on the top of the hand grip on a Minelab GP 3000. This will convert the ground balance action of switching from Fixed to Tracking and back to Fixed by a push of the button instead of flipping the toggle switch.

Normally if you are running in fixed as many suggest is the best position under normal conditions. It takes two hands and some award body movement to pump the coil with one hand as you switch from fixed to tracking and back to the fixed setting with the other.

When the GP 3500 came out it incorporated this handy fix / upgrade. The whole process can be done with your main grip hand with out missing a beat by depressing the button on the top of the grip. You set the switch to Fixed and leave it, then simply push the button down as you pump the coil a few seconds, then release the button, and your machine is balanced.

Being able to re-balance on the fly can be of great importance on ground that changes fairly rapidly. This helps insure you are getting maxim depth and sensitivity as you cover the area you in. I call this the GP 3250 fix as it is kind of half of the GP 3500 upgrade.

So here are some pictures, a common parts list of the items required, and a description of how to do it. Tools required are; Phillips screwdriver, soldering iron / gun, rosin core solder, electrical tape, pocket knife, 3/16th & 1/2" or larger metal drill bits.

The 3250 fix; All parts are from Radio Shack. Total cost $12 +-

Parts required are;
1 x 3A 125VAC SPST "2 Press" Off-(On) momentary switch.

6' Shielded cable 1/8" phone jack to stripped end.

1/8 Inch Mono Panel-Mount Audio Jack 2-conductor.

Here is a picture of the front end of my 3250 after the fix.

First, making the hole. I used a 3/16" or 1/4" drill bit "I'm going by memory as I did this fix in the field in Nevada on the tailgate of my truck" and most likely had my good friend's BUD & Cuervo helping". So you should;
Check the diameter of the Panel-Mount Audio Jack. You just want the barrel shaft to make it into the face cover and leave enough meat to seat the locking ferrel nut. "measure twice, drill once"

Closeup of the installed Panel-Mount Audio Jack, front side.

This is the prime location so as to clear the connectors mounted to the inside of the face, and not mar the lettering on the face. Drill from the face inward. Use a nail or what ever to create a seat for the bit. The face is made of hard plastic and will drill real easy. I twisted a 16p nail with my hand to start the seat / pilot hole. I had to use a 1/2 inch drill bit to recess the inside of the hole to give me enough thread on the outside to connect the nut. There is a heavy foil shield on the inside that should be carefully cut back so that it does not contact the Audio Jack.

Here is a picture of the inside of the face with the Panel-Mount Audio Jack installed.

A closeup view.

These pictures show a 3 connection Panel-Mount Audio Jack, they where out of the 2 connector type. You only need 2 connections as you are tyeing into the 2 wires coming from the Fixed / Tracking switch. I used a extra piece of the Shielded cable to make this internal connection from the switch to the audio jack connectors. It only needs to be about 3 to 3 1/2 inches long.

A picture of the connection.

There are two wires coming from the fixed / tracking switch, mine are yellow & orange. Allow about 1 1/2 inches away from the switch connectors and then gently remove the sheathing from the two wires for about 1/4 inch to expose the copper wire inside. Do not cut the copper wire. It can be fixed if you do though. Once you can see the bare copper, use a small knife blade to separate the wire in the center, half the wire bows one way the other half bows the other. This is where you will stick your wires from the 3 inch Shielded cable into this oval opening you have just made. Insert one of your wires into one of the oval wires and then wrap them around the to make a good contact connection. This way you do not cut the detectors wires and can still use the Fixed / Tracking switch in the normal manner.

Solder the connections from the Fixed / Tracking switch and the Panel-Mount Audio Jack. It does not really make a difference left / right positive / negative. What you are doing is simply connecting / breaking the contact as you push th button. This is the same thing that happens when you flip the switch.

Now the wire to the handle;

The wire connection is made by 1/8 Inch Phone Jack. It will simply plug into the 1/8 Inch Mono Panel-Mount Audio Jack and can be disconnected if you need to remove the main unit from the upper shaft. There is a previous picture of the phone jack coming out of the face connection. Do not cut this cable until you have coiled and threaded it into the grip handle on the shaft.

Make 3 or 4 wraps from the plug-in around the shaft to the base of the handle. The wire will need to be snaked under the foam grip if the handle. I used a piece of tie wire and ran in in from the top, under the foam until it came out the bottom. Then I looped it around the cut end of the Shielded cable and pulled it through and out the top. This was the hardest part of the whole operation. Smear some liquid dish soap on the wire and the cable to help it slide past the foam grip.

One you have the wire out and still have the wraps around the shaft then you can cut the wire and solder the 2 connectors on 1 x 3A 125VAC SPST "2 Press" Off-(On) momentary switch to the two wires on the shielded cable. Then wrap all the soldered connections with a little electrical tape. Pull the wire and button down into the foam grip and secure with tape or what ever.

I did have to remove the red button it's self and shave the corners and bottom edges because it binded up from dust. It just pulls off and the real button is under it.

This is a real handy modification for the GP 3000 and the SD 2200 that I know of.

I do not take any credit for this fix. I first read about it in a post from Gary aka Grubstake when he did it to his Minelab. Then we refined the idea at Rye Patch when Shep & Grubstake further explained it and showed me both of their modifications. Shep has a GP 3000 and Grubstake has either a SD 2000 or a 2200 he bought from Jim Straight.

So this fix will work on several different models and maybe many others. It is a prime example of ingenuity and the prospector helping his fellow prospectors when they have a wild idea about something.

Enjoy, and please post any questions or different ideas you might have about this or any other mod's or projects.

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Everett

kbaltz · Posted: Mon Jul 31, 2006 8:31 pm Post subject:

Thanks Everett!

I have wanted this information and didn't know where to look!

You are the MAN!

Thanks

Karl
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Karl Baltz
Spring, Texas-just a little bit north of Houston
aka:
kbaltz; scorpion
I work so I can play and what I play at is also work so that I can have fun all the time!

RexB · Site Admin Joined: 21 Jun 2006 Posts: 563

Wow, I have a GP3000 this sounds like it could be a nice project, quite informative.

RCB
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If first you don't succeed...

wes · Joined: 14 Jul 2006 Posts: 75 Location: Placerville,CA

Looks good Everett, When I did mine I used the soft touch pushbutton they had at radio shack. It had a nicer feel than the standard switch and you don't have to mash it down very hard to make the contact. Just a slight pressure switches it on.
Here's a pic of my setup. I kept it a little simpler and just ran the cable through the cover, but the removable jack looks good too.

Everett · Posted: Wed Aug 02, 2006 4:23 pm Post subject:

Wes,
I think that is the same button I used.
I did the phone jack connection on the outside face after talking to Shep.
Grubstake did his like you did, a more of a hardwired connection. With the jack, you can disconnect the main's from the shaft and leave the button as is.

Have you had the button kind of lock up sometimes? That is when I pulled the red button cover off and kind of shaved the corners and button edge.

But in whole no matter which way it is a great mod. I will ground balance now about every 10 minutes or anytime I notice the ground change. Before I would get a cramp in my side doing the twist & bounce.
_________________
Everett

wes · Joined: 14 Jul 2006 Posts: 75 Location: Placerville,CA

Everett, No problems with the swx yet. But I bet eventually I'll have to clean out the dust, and maybe sand it like you did. I'v had it on the detector for about 6 months now. So far so good.

I wonder if minelab would just sell the 3500 handle and swx combo. That would be the ticket.