Garrett Pro Pointer pinpointer can make your GPX5000 unstable even when switched off.

G'day, I've been carrying my Garrett Pro Pointer in its belt loop on my belt <switched off> whilst detecting....and have been having problem getting the GPX to completely settle down because of some interference....be aware from our tests today that even when the Pro Pointer is switched off and from an even greater distance than the belt hanger it can effect/interfere with your GPX5000 stability...we proved it today with two different GPX5000's and each became unstable when the Pro Pointer was brought within their vicinity, switched off, one had the 11" Commander Mono Coil and the other the 11" Commander DD ..each detector had been perfectly stable prior to and immediately after the Pro Pointer had been taken completely away......
I have not removed the 9V battery yet from the Pro Pointer to see if it still has the same effect...but will do and report back....it may be that the Pro Pointer needs to be carried in a back pack whilst detecting <dont even know if that would be too close> or the battery only inserted when about to be used to pin point in the hole <a nuisance>.....I was well aware of the instability/interference caused when digging and switching the Pro Pointer on when even remotely near the GPX5000 coil..<and to be expected> however I was not prepared for the instability and definate interference it caused after it was switched off and had never thought to check that as the source of the interference.<any ideas on how this could be?>....I have found it a great aid in pin pointing for the short time I have been using mine however may have to do a rethink....The Pro Pointer is clearly off with no light on when off,and gives two beeps and light goes on when switched on and otherwise works perfectly....My Walco pick was closer to the GPX than the Prop Pointer and gave no interference whatsoever to either GPX5000....I have always turned off my mobile phone whilst detecting because I am aware it could cause interference when on...maybe I will need to rethink that as well and not carry it due to the ultra sensitivity of the 5000.
Has anyone else identified it as a problem?...give it a go and report back here with your results...Hoo Roo

Bugger it.

I only bought one of them about 2 weeks ago. Sounds as though it could become a real problem with the 5000. Will be intresting to hear whether the problem still exists when the battery is removed from the pinpointer.

Ah... the old Garrett Pinpointer Vs GPX issue.
I've discussed this in detail last year because it can sometimes have the same effect with the GPX-4500 as well. Yours is the first report from a GPX 5000 user. My own 5000s have had no problem with multiple probes... even with coils that were a problem on my 4500. I say "sometimes" because each detector and coil may or may not react to the pinpointer. So far, nobody knows exactly why it happens although Johnathan Porter contacted me on the subject last year when I was writing about how much fun the pinpointer was to use... and suggested it was an issue I should look into with the different coils that I use. It wasn't until I was using a 16" NFA coil that I actually got to experience it myself. Switched on, I could not bring the pinpointer close to the control box without serious reactions from the detector. Switched off produced the same effect though slightly less intense. Since two people can have the same machine and the same coil and still one of them may have a reaction to the pinpointer and the other person may not.... I can only deduce that the detector may be the common cause (see below). Others have used the same pinpointer with the very coils that I seemed to have an issue with yet they experienced no problems.


My Garrett ProPointer pinpointing probe in use.


And, I noticed what you did... that even turned off, the probe caused a reaction from the detector which means that either the circuit on the probe was closing based on the field given off by the detector OR the detector was too sensitive to the link created by the coil (usually a larger coil) and the proximity of the probe. Since each detector from the GPX range is assembled by hand, the possibility exists that it is the shielding that may vary from one detector to another slightly. That might not be the root of the problem but it is the only thing I can draw a link to.

So far I've had no issue with my GPX-5000 and any of my Garrett pinpointers (I have several). In the past, it's only been an issue with particular coils on my GPX-4500. In my case it was the 16" NFA coil.


I wear mine a little lower than it appears in this picture. The new harness I use has a D-Ring located lower down and this allows me to rest my pick handle on my shoulder to counterbalance the detector and keep metal (ie the Pick) further from the larger coils.

My solution? Don't carry it on your damned belt! I carry mine up high on the shoulder strap. The one furthermost from the detector arm. Another alternative is to get your hands on a Coiltek Probe which has 200mm of depth compared to 2cm of depth on the Garrett. Plus it's almost $100 cheaper than the Garrett. It's just a little more involved because you need to connect it to your detector's coil-socket to power it. You can also carry a Coiltek 6" Goldstalker for a pinpointer as this can be useful as a detector mounted sniper coil as well as a handheld pinpointer - especially when it comes to deep holes dug via large coils.


Coiltek's Pinpointer Probe.

G'day Larry and others,

The reason the pinpointer would be effecting your detectors, would be firstly the sensitivity of the newer detectors, but more so the design of the pinpointer itself. The pinpointer has a coil that is in parallel with a capacitor, which will resonate when in the vicinity of a pi detector, due to the pulses, even when the pinpointer is turned off. A simple fix to this would be to put a switch in to disconnect the coil from the rest of the pinpointer when it is turned off and switch a resistor across the coil to prevent oscillations.

Cheers Mick

Mechanic wrote:G'day Larry and others,

The reason the pinpointer would be effecting your detectors, would be firstly the sensitivity of the newer detectors, but more so the design of the pinpointer itself. The pinpointer has a coil that is in parallel with a capacitor, which will resonate when in the vicinity of a pi detector, due to the pulses, even when the pinpointer is turned off. A simple fix to this would be to put a switch in to disconnect the coil from the rest of the pinpointer when it is turned off and switch a resistor across the coil to prevent oscillations.

Cheers Mick

Brilliant solution....
How do I do that though

G'day Brookesy,

First of you will need a soldering iron and a bit of skill soldering. A small switch from jaycar, http://jaycar.com.au/productView.asp?ID=ST0300&keywords=switch+toggle&form=KEYWORD, a 1 k resistor http://jaycar.com.au/productView.asp?ID=RR0572&keywords=1k&form=KEYWORD.

You would have to find the wires that go to the transmit coil and disconnect one which would then go to the centre of the switch. then from one of the side terminals on the switch run a wire to the cct where the original wire came from and on the other side terminal the 1k resistor to the other side of the coil. Refer to the diagram below.


Now if you do choose to try this mod, you do so at your own risk. I would be more than willing to assist anybody who wants to try it. I may need photos of the internals to make some proper instructions.

Cheers Mick

Thanks for your assistance/suggestions Mick.
Would you like to comment on two suggestions just put to me by one of our forum members. I have not tried them yet to see if they have the desired effect.

1. If the battery was removed while its still switched on to discharge all capacitors.
2.alternatively immediately after switching off the propointer if the nose was held for a few seconds on my metal pick which may fully discharge any capacitance?
Thanks.

Hi Larry,

You could try it, but I doubt that it would have any effect. We need to prevent the pinpointer coil from oscillating when the coil on your detector sends out a pulse. The only way I know to do that is to disconnect it from its capacitor and short it out with a resistor. Let me know how you go.

Cheers Mick

Thanks Mechanic,

Will let you know how it goes when I get a spare few hours to try it out.

I have the same one and it only seems to interfere if i swing too close to me. I have it on my belt also. i didnt find it a big issue in my case with my 5000.

If you want to increase depth with the garret pro pointer take a look at this video as this guy tapes a coin to it to extend depth.

I wont be getting a lot of depth out of mine it will stay in my car.....
I detected today in The One Eye State Forrest.
Amazingly when the Pro Pointer is switched off it creates even greater interference on a stable GPX5000 with standard Commander Mono 11" than it does when switched on...
I measured today and cannot bring the Pro Pointer closer than 8' <8 foot!> without considerable interference..take it away and no interference, bring it within 8' and I'm not talking a slight warble I'm talking an unstable detector you could not reasonably detect with...this is exactly the same result as with the other 2 GPX5000's in my above post....
I took out the battery and it made no difference so Mick/Mechanic is absolutely right as he stated in above post....I even touched the nose on my metal pick as suggested by a Forum member to discharge any built up capacitance, and it made no difference whatsoever....
Nero, I put it up where you've got yours which is well within 8' and it could be heard interfering with the GPX...
Someone might have to do a mod in terms of Mechanic's suggestion or Garrett fix the problem as I find it hard to believe that interference will only be caused to some detectors and not others..thats an interesting hypothsis anyone care to comment on...my GPX ran like a dream today with perfect stability <with the Pro Pointer in my car> just like it did before I got my Pro Pointer....I cannot believe this problem is not already known to Garrett in USA......but I dont read the US Garrett Forums...I also believe that Minelab must already know but it is hardly their problem and I guess they would be seen to be opposition bashing if they did point it out to GPX owners....$180 I could have put to better use with a Coiltek pin pointer....I presume they dont have the same problem of causing interference when switched off....I know their selling point is that you have to connect to use but wouldnt it have similar small coil?.....comments? Hoo Roo

G'day Larry,

I think that settings could be the explanation as to why it effects some peoples detectors and not others. Firstly your frequency setting would have a bearing on it. The other settings that would have an effect would be gain and stabiliser settings also deep audio setting would be more vulnerable. If you tend to run low numbers for the stabiliser and gain the effect from the pin pointer would be less and so may your gold finds! Whereas if you run higher stabiliser and gain the detector will be more sensitive to small signals especially those that come from the pinpointer.

As to the coilteck pinpointer not causing interference, that is because it does not have a capacitor in parallel with the coil like the garret pinpointer does. However, what a pain in the butt to be continually changing over from your main coil to the pinpointer all the time, not to mention the wear and tear to your coil plugs and the plug in your detector, don't forget the dirt and dust too! It would be so good if detectors had a second coil port so you could quickly plug in a pinpoint probe for pinpointing a target.

As for the depth increasing trick in the video above, my question is what effect does this have to the pinpointer in mineralised ground? I have a feeling that it would sound off on hotrocks like nobody's business.

Cheers Mick

Mick you know your stuff mate. I was running Factory setting +2 on gain and stabiliser Fs+2 to compensate..however in the mineralised ground I run quiet audio and it filters out the atmospheric inter and cleans up the wobbles nicely....like sitting in a lounge chair..<imagine if I ran in Deep Audio>...providing that pesky Pro Pointer is nowhere near it!...The Pro Pointer does give signals on the ironstone when scraping sideways....quite apart from the target I'm chasing in the hole..however it has saved me heaps of digging larger holes by pin pointing and I would still like to carry it...the concept is great....Garrett just never figured on the sensitivity of the GPX5000 IMO......havnt tested it with my Garrett Infinium that will be interesting exercise as well........
You're not a Minelab test pilot are you??....Hoo Roo

larry303 wrote:
You're not a Minelab test pilot are you??....Hoo Roo

Haha LOL No! I just have a passion for electronics and the internals of detectors and finding gold! I periodically get to use a mates 4500 so I like to know what all of the settings are for and how they work

Cheers Mick

Could it be possible, that what you cant see in the video is his hand on the pin pointer sliding the nickle up the shaft. Giving the effect the pin pointer is achieving more depth to the nickle on the ruler.

G'day Narrawa,

I don't think that that would be the case. Lets say for instance that the pinponter needs 10mv of signal before it makes a response. A nugget close to the tip gives us the 10mv needed for the response but as it is moved away the voltage drops below the 10mv threshold. Now when the nickel is moved up the side this brings the threshold voltage closer to the 10mv, lets say 9mv, now the nugget only has to add 1mv of signal to get a response, which it can do from a greater distance. This 10mv threshold voltage(or whatever it is) is there to stop the pinpointer from sounding off on mineralised ground.
Cheers Mick

Mick, im happy with that.

Just tried that test with the nickel.....But I used a 5 cent coin and YES it does work, you do get about twice the depth

Mick

Very interesting stuff mate,
on the subject of using a coilteks pinpointer probe, this is the best way to save wearing
out your sockets and getting dirt in, also saves you time by allowing you to switch
over from your main coil to the probe, BUT the detector must be powered off
before doing so to save any damage you may cause by disconnecting the coil
via the switch while the detector is still turned on..

Coiltek Switch Block.





Pete in WA

Larry,
How about you take the Garrett To Bendigo Gold and get Ross the techie to do the modification for you as per Mick's schematic?
Nothing to lose mate.

Robert

Hi Guys,
Being a Garrettt Pro Pinponter does that mean that they are made to work well for their own detectors and not others such as Minelab detectors?
uncle bob.

Good tip Robert. Mick has kindly offered to do the mod of a separate switch and I'm sending it to him. This way he and I can report back here......anyone with a GPX5000 that thinks this is not a serious problem should re-test using different settings as Mick suggets...however in Quiet Audio like I run you would think anything else will be chaotic short of dumming down Gain and Stabiliser which is obviously undesirable on small gold...
Beepinpete..your multi point I believe is fraught with danger in that I am reliably informed the surest way to blow up a GPX is to undo and change coils while the machine is still on...immediate spike appearantly....and you only get to make the mistake once...I am told..would be easy to do if not concentrating...Minelab cost to fix about $300 mistake I believe..and a mistake that could not be expected to be covered under warranty as there is a warning in the Manual......Hoo Roo

G'day Pete,

Yes the switch block would be the most convenient way to easily switch between the probe and the main coil, but as Larry and you suggested, the detector must be turned off before switching over. You might be lucky and not blow up your detector by switching with it on at first, but sooner or later it will cause damage. The other thing about the switch is it does add extra capacitance to the coil which in turn will then make the coil take longer to settle before the first sample can be taken. This may not show up as a problem and if it did it would be most noticeable in fine gold on the 5000. If the machine appears to be a little unstable using the switch and nice and stable with the switch removed this would indicate that it is causing problems(with the stabiliser and gain at the same settings, setup with the coil directly connected.).

Cheers Mick

G'day Larry

As i stated above the detector MUST be shut off before actuating the switch
or serious damage could occur.....
The problem could also happen as the switch box is designed to be mounted
on the upper shaft and could very easily be hit on a branch.
Maybe the manufacturing company (coiltek) (not me) could consider
fitting a switch guard so this never happens..

Mick
I have only used the switchblock on SD&GP series machines and havent used
one on my 5000 yet cause i now use a 10x5 mono as a pinpoint probe and dont
find it to much bother to shutdown and fit the small mono to pinpoint with.

All the best on the gold fella's


Pete in WA

I'm not entirely sold on the oscillation theory concerning the Garrett ProPointers. I suggested it last year when people first reported the occasional issue but the number of people using the same coils and detector combinations with only half of those people reporting a problem when all were using an identical coil-detector setup would suggest the issue relates to a random element. Perhaps it is a closing of the circuit (which is what I asked Garrett last year) but there's no confirmation yet.

As for having the ProPointers altered, kiss your warranty goodbye. Note also that they really do vary in sensitivity. No two ProPointers (Garrett) are exactly alike when it comes to sensitivity. Some are duds. Others are prone to reacting if any pressure is brought to bear on the tip by pressing it against the soil. Others are less sensitive than another. Some are hypersensitive.

And when it comes to using "switching boxes", keeping as much metal as possible OFF the shaft and away from the coil is paramount to me. Even if the switching box is clamped to the shaft, it will act as an anchor point for stray strands of energy from the coil's EM field. If you are using a LARGE coil that requires the use of a pinpointer to find those tricky targets, unscrewing your coil cable and attaching a Coiltek Pinpointer Probe (or a small sniper-coil) is not much trouble compared to the time and sheer effort in digging a large, deep hole. Regardless of the amount of effort involved, a coil changeover is a quick and simple process by comparison. For people using a smaller coil, a pinpointer may not be necessary although it does certainly speed up the recovery process in some instances. I like using them. Even with little .22 caliber lead bullets that can be hard to pick out from a handful of dirt. Of course, you can just as easily wave a handful of dirt over the coil and achieve the job without a pinpointer.

Have you tried loading the pin pointer's coil circuit with another coil or a metal object? You could start by wrapping the probe in alfoil or inserting it into a length of small diameter metal tubing. If this works you could then try a half inch long ring of the same tubing (a one turn coil). You would have to slide it along the pin pointer to get the correct position though and then make up something to keep it in position.

Supermarkets use a similar method to counter shop lifting, a small piece of foil containing a flat spiral coil and a capacitor is fitted to vulnerable items but I'm told this can be defeated by placing a small steel washer or a 5 cent coin over the foil.
You can sometimes get a response from a nearby coil with no cappy connected. This occurs occasionally on the work bench.

G'day Nero,

If the pinpointer isn't going to be used because it interferes with the detector, there is not much point to warranty! I will try what Robby has suggested first as that could be a better way to go, we will see. When I'm done I will post the instructions so anybody will be able to fix their own or get a handy friend to do it.

Cheers Mick

If most of the 5000 & 4500 detectors are having a problem with the Garrett Probe why not Gattett or someone else come up with a new rear switch on the probe that would isulate any interferance with the detector. The Garrett Probe would then be able to be use with any detector now or in future models. The probe is the problem, not the detectors. And isn't it the reason why Garrett brought out the Probe in the first place to work hand in hand with detectors. So come on Garret or any of you electronic buffs come up with a one switch only type at the rear of the probe and solve all our problems. I run a Garrett Probe with my 3000 but have no problems, but I'm planning to up grade to a 5000 but still would like to carry my probe as well as I find it saves me a lot of digging. It would be then a matter of sending your probe of to Garrett or a reckonised repairer and getting the switch replaced and Bob's your Uncle, problem solved.

Wombat

hi wombat
don't hold your breath until garret fix the problem as it does not happen with garret detectors

i got a good hand held pin pointer of e-bay it's called a tx 2002 metal detector duel use pin pointer for $49
they are duel use cause you can turn the sound off and it has a led light come on when near
a target
you can also change the sensativaty on them
at the moment they come with a carry pouch to hook on your belt and there still $49
they work realy well
cheers

I have just sent of an E-mail to the Technical boys of Garret with this problem, I don't know what will come from it or there reply. But what I have heard was it may not be the Minelab detector or the pinpointer that is the problem but the different types of coils being used. Nuggetfinder / Coiltec and such with there sensitivity. Has anyone that is having the trouble with the probe and is using a Minelab 4500 or 5000 tried going back to the original coils that came with their machine and seeing if they are still having the same problem

Wombat