Minelab GPX4500 tips, settings, questions

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Hi all,

I'm from France, working with a GPX4500 of 2003.

Yesterday when I started this old guy, I was afraid by this problem.

- Sound when the threshold start is strange.

- The auto tune (research for free frequency) is a stable sound, with no variation.

- And no power ! about 5 inch max for my metal digging pick-axe.

I tried some factory resets, but the problem is always the same...

I tried this one with another disc, tracking button, cable, headphone, battery, the problem come from the main box...

Anyone know of this problem?

Thank you and have a nice day.

Luis
 
Hi Luis , this does sound like a strange problem . If you have checked all your connections, cables and have tried another coil , battery ,headphones . I think you should look into sending the main box to minelab to be looked at .
Not sure if you have a minelab dealer there in France . You may have to send it to an Australian minelab dealer or somewhere closer . Good luck with this problem. Let us know how it gos.
Cheers Booney.
 
Hi mate,
firstly the GPX came out in 2008 not 2003, so unless that was a typo or misunderstanding that might be the first clue.
Where did you buy it?
Can you post some close up pictures of the control box and a picture of the harness if it came with one?
 
Hi !

Greaaat neeews here !!

A friend come at home today, we worked on the GPX.

The Ribbon cable cleaning have not resolve the problem...

After made some test with each elements from his GPX on mine, we find the problem comes from a bad contact in the disc.

A simple solder should resolve the problem for sure !

Thank's to everybody for your help.

Best regards from France.

Luis.

PS : The GPX birth date is 2009 ! I was sure about 2003 but the PCB date is June 2009 ! And it's a real one for sure !
 
Incase you all didnt get my reply , I would just like to say thankyou all for your input that has helped me tremendously ty again cheers kenlily18
 
Ok here's my take.

Running the stabiliser within 2 -3 of RX gain is a myth that who knows where it came from. If you stick with this mantra, then you are not getting the best out of your machine.

I always used to run the stabilser high on the dial (its counter intuitive as the higher the number, the less 'damping' it has on the signal) and then run the RX as high as I could without too much instability.

Lately though I've changed things a little. I run the RX Gain almost flat out all the time and have stabiliser down between 2 - 4. I'm digging much deeper targets and miss very little. I'm generally using a 15" Evo and my enhancer of course. But these settings seem to work well for me with any coil. I may be loosing sensitivity to the fly-poo size shallow bits but I never dig those anyway so I dont mind. But I am now consistently digging targets at the depth of my pick (around 900mm deep).
If its quiet ground I may raise the stabiliser a little. If its too noisy, weather a bit stormy, too much emi, I may drop the RX a little but never get below about 12 or 13.

Best thing I can suggest is to get a small test target and try your settings on it. If nothing else it will reassure you that your machine is working.

regards Pat

1582404592_img_5148.jpg
 
Been using the 15 spoked evo nugget finder on my gpx4500 and so far it seems great (no gold yet). But Ive noticed a couple things. 1. It seems to pick up hot ground lots more than my 11 commander did, this leaves me digging holes and pulling my hair out wondering what it is but never getting to the source, They seem to be inverted soft sounds. I have my rx gain generally around 7-10 I change it depending on how noisy it is. Another thing is how incredibly hard it is to pinpoint a target with. Any ideas to make this easier?

Thanks Vicgoldhunter
 
Pin pointing is a matter of practice with the right method and becomes accurate and simple with practice.
1: If you don't have a full manual, download one free from the Minelab site. Read it back to front, over and over.
2: Draw a plus sign on the ground and place a target on the cross hairs. Now approach low and slow from each direction and note where on the coil you receive a signal. (It won't be at the tip of the coil.) Bury a target a foot or so deep and once again mark the exact spot with a cross and again use detector noting the position on the coil where you receive the signal.
3: Back in the real world. When you get a target, step back and move forward low & slow until you get the signal. (You can draw a line in the dirt until you get used to it)
Step around 90 and once again low & slow as you move in along the line you have drawn until you get the signal draw another line across the original.. (Naturally you don't need to draw the lines when you have mastered it) Have seen many instances where prospectors have mistaken target point at the rear of the coil.
Also with mono coils the deeper the target the signal is more to the centre of the coil. (Send & receive in cone shape)
4: Don't waste your money on a pinpointer, you master this method and you will be on the gold with a minimum diameter hole. (Hopefully deep for larger gold. :money: )
**Many of the videos out there have you telling the operator, as you watch screen, (maybe a sign of madness. :lol: )they are digging in the wrong spot. No they stop fiddle and fart around with a pinpointer then back to their machine, dig some more, pinpointer again......... Finally when the pinpointer goes off, low and behold they're digging in wrong position. :lol: :lol:

Good luck VicGoldHunter, practice makes perfect.
 
Nightjar said:
Pin pointing is a matter of practice with the right method and becomes accurate and simple with practice.
1: If you don't have a full manual, download one free from the Minelab site. Read it back to front, over and over.
2: Draw a plus sign on the ground and place a target on the cross hairs. Now approach low and slow from each direction and note where on the coil you receive a signal. (It won't be at the tip of the coil.) Bury a target a foot or so deep and once again mark the exact spot with a cross and again use detector noting the position on the coil where you receive the signal.
3: Back in the real world. When you get a target, step back and move forward low & slow until you get the signal. (You can draw a line in the dirt until you get used to it)
Step around 90 and once again low & slow as you move in along the line you have drawn until you get the signal draw another line across the original.. (Naturally you don't need to draw the lines when you have mastered it) Have seen many instances where prospectors have mistaken target point at the rear of the coil.
Also with mono coils the deeper the target the signal is more to the centre of the coil. (Send & receive in cone shape)
4: Don't waste your money on a pinpointer, you master this method and you will be on the gold with a minimum diameter hole. (Hopefully deep for larger gold. :money: )
**Many of the videos out there have you telling the operator, as you watch screen, (maybe a sign of madness. :lol: )they are digging in the wrong spot. No they stop fiddle and fart around with a pinpointer then back to their machine, dig some more, pinpointer again......... Finally when the pinpointer goes off, low and behold they're digging in wrong position. :lol: :lol:

Good luck VicGoldHunter, practice makes perfect.
Click to expand...

Thanks a lot, thats a great idea Ill try it. Didnt really have a problem pinpointing with the 11 mono but the 15 is a bugger to pinpoint atm for me.
 
u find 11 always to more stable ,because bigger coil more ground it accessing, the machine working harder as the day get on ,hotter the ground heats up more the chances of false signals some days ive pull out at 9.30 in the morning because of ground noise and false signals if u going to walk over ground u got to have the machine at its best other wise u missing gold yes u wind the machine back but u r losing depth , settings r important rx gain ,stability can,t think the other one they run to compliment each other ive jump from the 5000 to 7000 for less false signals ground noise
 
Hi Pat, do you set your detector up , then plug in and switch the Spo1 on to boost the signal?
I did this the other day and run the Threshold down very low, plugged in the Spo1 and boosted the signal; very smooth signal, except for the odd emi spike.
 
limpalot said:
Hi Pat, do you set your detector up , then plug in and switch the Spo1 on to boost the signal?
I did this the other day and run the Threshold down very low, plugged in the Spo1 and boosted the signal; very smooth signal, except for the odd emi spike.
Click to expand...

No I turn everything on and then make adjustments. To be honest most of my other settings are pretty much standard - I've highlighted the ones I change.
General
Enhance
Fixed, Mono
Volume limit 14
Motion Very Slow or Slow
Audio Normal
Tone FP
Signal FP
Target Volume 12
Response Normal
and of course Iron Reject Off.

Then gain and stabiliser as per previous post.

Now personally I like a little bit of a noisy threshold. It becomes almost as though the ground talks to you. Targets always seem to come through the noise easily and I'm sure if I didnt run like this, those very faint deep targets may not be heard. But this is personal preference and some people dont like it and still find gold. Are they missing any? No sure but no one gets it all ;)

regards
Pat
 
Without being in situ I cant really offer any advice other that stick with it and learn how it behaves. 12 evo was my favourite but lately have been using the 15 a lot more. I think it will now stay on. If hot grounds a issue quiet audio can help. You might loose a little depth but to me its negligible. Get out and try different settings .
 
VicGoldHunter said:
Been using the 15 spoked evo nugget finder on my gpx4500 and so far it seems great (no gold yet). But Ive noticed a couple things. 1. It seems to pick up hot ground lots more than my 11 commander did, this leaves me digging holes and pulling my hair out wondering what it is but never getting to the source, They seem to be inverted soft sounds. I have my rx gain generally around 7-10 I change it depending on how noisy it is. Another thing is how incredibly hard it is to pinpoint a target with. Any ideas to make this easier?

Thanks Vicgoldhunter
Click to expand...

Vicgoldhunter, I think you'll find all of these fancy aftermarket coils will give you that trouble. The Commander is an excellent coil and certainly more stable when the going gets tough. Most of us get used to the extra noise picked up by these coils and sometimes it's not just ground noise. That bit of extra sensitivity can also find you a nugget that you might have walked right past swinging the Commander coil.

I had difficulty carrying the heavy 14" Coiltec Elite one year so I went back to the much lighter Commander for the whole season. That year I came home with the same amount of gold even though I may have walked over a few. The quieter more stable Commander probably found me a few extra ones that were hiding in difficult ground.
 

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