GPZ 10" Xcoils In USA

[Andyy]

I clip mine to the handle with a plastic dring and a zip tie.

[Jin]

Thanks Rick,

Got to say my first impression was it looks terrible inside compared to the Minelab 14". Real backyard job.

Im surprised as they look professionally made on the outside.

Im told the Russians have sent my 20" coil so looking forward to its arrival. Not doing the 22x21 x-coil now apparently. 

[Jin]

Is that some sort of micro chip inside the gpz14 coil?  Dosnt appear to be one in the x-coil. What would the chip do

[araratgold]

3 hours ago, Jin said:

Thanks Rick,

Got to say my first impression was it looks terrible inside compared to the Minelab 14". Real backyard job.

Im surprised as they look professionally made on the outside.

Im told the Russians have sent my 20" coil so looking forward to its arrival. Not doing the 22x21 x-coil now apparently. 

No worries Rick !

I cancelled my big coil order because 20 inch is not a big enough difference over 17 inch to justify the $$$$. Old mate in Russia wasn't happy with the performance of the 22x21 so has put them on the backburner. 

Cheers, Rick

[Jonathan Porter]

7 hours ago, AlwaysLooking said:

But having the ferrite on the conduit, surely it should not be misplaced, maybe clipping it the shaft/stem will keep it safer ?

[Chet]

On 7/15/2019 at 4:39 PM, araratgold said:

 

Here is a photo of the internals of a 17 inch super D X Coil. Two ferrites included in this coil.

As you can see, vastly different to the Minelab coil !

Cheers, Rick

Hi Rick

In most detector coils there is a conductive coat of black paint that forms a Faraday shield between the coil and the ground to reduce electric capacitance effects. 

Is there some kind of  shield that is not shown in this photo?

I don’t see a shield in the Minelab photo either. Perhaps it is not needed in the GPZ 7000 Zero Voltage Transmission (ZVT) design?

Thank you for this interesting photo and have a good day,
Chet

[araratgold]

No black paint.

Cheers, Rick

[jasong]

It's not really deserving of a thread in of itself, but since I just made a patch cable (and I'm in the US too) I thought I'd illustrate some potential hangups for any of those following after me:

1.) I think Andy already mentioned it before, but I think it's absolutely critical to test for shorts between pins after soldering. It's very easy to make a little solder bridge by accident. Any multimeter can do this. I'm somewhat ok at soldering and I still managed to bridge one connection (I caught it via the multimeter). This could short and kill a control box.

2.) 220 and 320 grit sandpaper worked the best for me to remove the wire epoxy, cleaned off remaining dust residue with acetone for a good solder joint.

3.) The signal RX wire is incredibly thin. Be very careful with stripping this wire, get it right the first time because you don't have enough to correct an error if you remove too much.

4.) "Helping hands" make the job go way easier if this is your first time soldering. Harbor Freight has them for $5, and they have the 3/4" shrink tubing that is about as close as you can get for standard sizing.

5.) A nice small, precision chisel soldering tip works great for soldering those connectors. I use a standard Weller WLC-100 solder station, set to "3" temperature and the chip survived just fine.

6.) This is a fairly easy job for anyone with a little experience in electronics, having all the tools around already saved a lot of money too. However, IMO, if you've never done anything with electronics before you may want to consider paying someone else to do it, there are a lot of little ways to short things out and while some things can be corrected, you only get one chance for some of this stuff.

7.) Hot glue is definitely necessary for physical support of the tiny wires.

So, I made the patch no problems 2 nights ago, turned it on in my yard with no problems other than squeeling like crazy - but no coil errors. I took it out today away from any noise sources and it was still squeeling like crazy. Dissected the patch cable and discovered my signal RX wire had broken at the spot I cut the insulation (this, ironically, does not throw a coil not connected error). Almost certainly I cut it too deep and of course steel will cut copper too. Oddly, I tested continuity after soldering, tested again after shrink wrapping, and all pins had connection. Double checked each phase (so checked 4 times total) and I got it all on vid which I reviewed and it was definitely not broken. So, it must have occured in the process of pushing the coil wire up into the shaft and something bent and snapped - a process which is a bit more difficult because (also as Andy noted) the spiral cable section is wider on the X Coils than the stock coil so it's quite a tight fit. Some are bigger, some are smaller. I made sure to put more hot glue on this time to prevent movement/bending. I still am not quite sure how or why it broke, but it did.

Anyways, just got done remaking the patch cable, all seems to work. It's still quite noisy around my house so I have to wait to go drive some distance away tomorrow to actually see if the 3 X Coils all work now too, but the detector appears to be working with the stock Z14. Just figured I'd pass these lessons learned on to anyone else doing this.

[Jin]

Thanks jasong, Some more helpful information to think about. Ill be more than likely doing my patch lead next week. 

[jasong]

I shot out the prairie real quick because I couldn't stand to wait to see if the coils all worked. Happy to report all 3 are in working order. I'll try to do some controlled testing and depth comparisons on video later next week to verify what I saw tonight before I say much more so I can be certain of the results. Initially, based on a very brief run of all 3, I see some indications of measurable performance gains that go beyond simply size related issues and getting into tighter areas, but I would need to run controlled tests before standing behind that statement.

Unfortunately I realized today that I left my ferrite in my camper in Arizona so I have a 2nd one on order. I ordered a new one from Rob on ebay, if you see the order feel free to overnight it. 

After changing coils quite a lot, one thing I do want to say now in hopes that it can be addressed soon for future coils though is that X Coils absolutely needs to improve their coil cables. 2 of the cables are so wide that you have to "thread" them into the middle shaft, or sometimes cram them in if they get hung and won't rotate anymore. And in fact require me to take the machine apart into 3 pieces just to switch coils, which gets to be incredibly tedious. The 3rd coil cable however goes right in and takes way less time to change.

Also, if there is any way to make the connection in the lower shaft, or lower part of the middle shaft that would be vastly preferable. It would make changing coils a breeze and right now changing coils out is kind of a hassle. If Minelab is considering some gesture of generosity for their lack of follow through by offering a patch cable to customers who already paid a ton for their equipment, this would also be something to consider in design of such a patch cable.