Pulling Chip Out Of 6000 Coil

[phrunt]

This is how X-coils did it, they removed the chip from the coil, and made the adapter then put a patch over the coil so it could still be used off the adapter.

 

[Chet]

On 2/28/2024 at 2:45 PM, Chet said:

A few days ago I salvaged the cable and module from a defective GPX 6000 14” Double D coil. I have wired it up to a standard 5 pin connector to adapt to the X-Coil connectors. I also rewired a ML GPX 5000 Commander 11” DD coil to the same pin connections as the X-Coils. In testing there are no coil faults and it appears to be working. But with both a GPZ 14 coil and the modified 11” DD coil there is very low sensitivity. I will do some troubleshooting to find out what is wrong.

I think I found the problem with the GPX 6000 not working well with the 5000 and 7000 coils. The 6000 14” DD receiver coil measures 300uH, 4.0 ohms. The other 5000 DD and 7000 DOD receiver coils measure more than 400uH and much higher resistances. This indicates that the GPX 6000 DD coil has fewer receiver coil wire turns than the other DD coils. The GPX 6000 GeoSense function/operation probably needs close to 300uH for both mono and DD modes.    

[phrunt]

Yes, X-coils did these experiments early on and told me the 5000 coils will not work well with the 6000.   Sounds like a problem with no solution, Chet? 

 

[Chet]

4 minutes ago, phrunt said:

Yes, X-coils did these experiments early on and told me the 5000 coils will not work well with the 6000.   Sounds like a problem with no solution, Chet? 

 

Not for us coil winders.lol But you are right for standard available coils.

[jasong]

9 hours ago, phrunt said:

 

Nice find, the weird connector alone is worth that since it's not easy to replicate. At least I couldn't find any when the 6000 first came out.

I'm unconvinced those chips aren't hackable too, with a little sideways thinking on what they are. Not that I would ever do such a thing. But I have thought of some ways it could be done if the world ended and zombies raided my place and my life depended on me hacking that stupid chip to create a super anti-zombie weapon in order to escape. 😛

[Aureous]

14 hours ago, Chet said:

If you look closely at the photo with the green toothpick; the bare wire that is looped back into the white plastic goop is the shield/ground wire. It should have been connected to the graphite shield inside the coil housing

I dont quite follow you Chet, is the shield wire supposed to be connected the same way as legacy GPX coils and this one was a 'fail' at the factory? Or is the actual method for the screen wire on the 6000 coils totally different?

[phrunt]

I'm sure that shield wire is meant to be connected as it was just a mistake on that coil, perhaps that's why some get worse coils than others for noise, their shielding method at the factory might be a bit questionable with attachment of that wire, and in this case went missed entirely.  I hope they're not just masking taping it on.  That's designed to fail, might last the warranty period but not a long-life product.

There was rumour floating around the chip in some way configures the detector to the coil, and that rumour was only enhanced by the fact in the info section on the GPZ it displays the coil you've got connected.  Then again, probably more than half of the X-coil users had their adapter made out of 19" coils, as they never intended to use it so didn't care about getting it cut, and their coils of all shapes and sizes work fine off the 19" coil plug.  I did the same, mine was made out of a 19" coil, and I run the 8" coil the most and it works a real treat.  As I bought the 12" Z-Search and didn't like it I also got an adapter from its cord, this was going to be the big test for me, will my 8" work differently off a 12" coils cord than it does a 19" coils cord.  Absolutely no difference! 

With the 6000 though, the DD chips are different to the mono chips, that makes complete sense.  I have my doubts the Mono chips are different between coils sizes when it comes to "calibrating" the detector, I think the only detector doing that so far is the Algoforce and it makes good sense for it to do it with the large range of GPX coils from various manufacturers it supports, may as well get the best out of the coils.

[Chet]

8 hours ago, Aureous said:

I dont quite follow you Chet, is the shield wire supposed to be connected the same way as legacy GPX coils and this one was a 'fail' at the factory? Or is the actual method for the screen wire on the 6000 coils totally different?

Yes, this was a factory defect. Yes, the GPX 6000 screen wire is wired differently. It is carried on separate/isolated wire within the coil cable and terminated on the printed circuit board within the control box. 

The standard GPX 5000 Mono coil uses a single coax cable with a single transmit/receive wire inside a braided coax shield. 
Inside the coil housing the graphite coil shield drain wire is soldered to the braided coax shield.

 Most GPX 5000 Double D coils use two coax cables one for a D shaped transmit/receive coil, the other for a D shaped receive coil with a single wire inside each braided coax shield. 

The transmit coax shield is required since the GPX 5000 uses the transmit coil as an additional receive coil when a Double D coil is used in Mono or Cancel modes. 

Inside the coil housing the graphite coil shield drain wire is normally soldered to the receiver braided coax shield. In some incidents this drain wire to coax shield connection is done with a jumper wire inside the five pin cable connector.

In summation the GPX 6000 graphite coil shielding requires an isolated ground/drain wire. Standard GPX 5000 coils cannot be easily adapted to the GPX 6000 because the ground/drain wire is internally connected to a cable coax shield. Also the GPX 6000 appears to be finicky if the shielding, inductance, capacitance and resistance of the coils are not just right.

Attached photo shows the drain wire after I heated up the plastic and pulled out the loose end. Inside the coil housing I can see where it was broken from the graphite shield.

[phrunt]

That's a very thin wire! 

[Chet]

1 minute ago, phrunt said:

That's a very thin wire! 

Yes, the other end is embeded into the graphite paint. Better than painters tape LOL.