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Topics - woody

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We have some Enhancement Fets coming out way in a couple of days, lots of testing on the sample devices. These will obtain near zero loss on the signal input side, extremely low capacitance of 28pf ci  22 co 3 tc  R on of less than 100 milli ohm at 5 amps. These fees are in die form, custom made for us. expensive little buggers.  The original standard fets do generate electron mobility noise in the  D-S conduction channel in most fets, also the channel can be modulated with fluctuation of the gate driver. This causes wide bandwidth noise and can obscure small signals.  We are working hard to overcome these issues. More Gold to you.

Information on the new developments / GPZ7000 upgrades...yes yes yes
« on: September 19, 2017, 05:13:27 pm »
We can now upgrade the GPZ-7000 , greater depth, better small gold performance and more stabile and quiet.

(Pity we cannot make it lighter)

Currently carrying out tests on a variety of ground.

General Discussion / If you cannot join the forum..
« on: April 17, 2017, 12:50:05 pm »
We had some issues with the anti spam system , we are told it has been fixed.. So try joining up.

There seems to be a lot of new components being made available that can be used to replace components in old detectors to massively improve the performance, we have been in the lab trying out these new parts and some of the results are mind blowing to say the least.... more to come.

One of the most annoying problems using a P.I detector is that they seem to suffer from a lot of interference, well some new devices have been made available that have anti emissions filters built in, I have tried some of these components and noticed an increase in target response at the same time having a quieter more stabile detector. 

Mods and Price list / Price list and mod info
« on: February 28, 2017, 10:34:19 am »
Price list for upgrades.

The upgrades start at $250 and go up to $2200, all upgrades carry a 5 year warranty.
If there is any problem with your Minelab in the  future we can repair it, we work on Minelab detectors all day long.  Experience is 30 years electronic engineering, 18 years repairing and upgrading Minelab detectors.

We can upgrade the following detectors,

SD2000, SD2100, SD2200 GP Extreme, GP3000, GP3500, GPX4000, GPX4500, GPX4800, GPX5000.

We have done some work on the SDC2300 and the GPZ7000 but have found the design platform is too difficult and too time consuming to work with, when we upgrade the GP and GPX series detectors we have found superior depth and small gold performance than the SDC and GPZ.
As an example, an upgraded and fully modified GPX4500 will detect deeper than the GPZ7000 and will also detect smaller gold deeper than a SDC2300.

 We have carried out testing and found that we can beat these newer detectors in most types of ground. The SDC will detect the most tiny gold, I refer to this as time wasting Gold, spending 10 minutes looking for a fly speck of gold is not prospecting, you are far better off getting half gram or larger bits. Trying to sift out fly specks robs you of productive swinging time and will reduce your chances of shining the coil over a larger piece of gold.

All detectors can have increased performance by replacing the input Field Effect transistors with lower loss types that have recently become available.

The SD2100 to the GPX5000 can have variable frequency added, this makes a very big difference in regards to the size of the gold, the depth and type of coil that you are using.

All detectors can have a variable gain board added that greatly increases the sensitivity and also allows for correct ground mineral reduction so that gold targets can be distinguished in noise ground or in noisy electrical environments. The minelab gain on the GPX does not work the same way as our gain, matching the input stage to the ground is critical to hearing the targets that standard detectors miss.

The upgrades that we carry out allow for optimisation of coil size, ground type and depth.

Our modifications and upgrades allow the operator to be able to control the detector to best suit the multitude of variables so that more gold is won in the field.

The full upgrades on a SD detector $1500 , on a GP is $1800 and GPX is $2200 and all come with a 5 year warranty that is fully transferable. Newest upgrades (mods) include the deep gold low frequency mode that makes a huge difference to being able to find big deep gold in the most noisy ground.

We can just do smaller upgrades starting at $650 but we find that most prospectors want the best and go for the full upgrades.

When these upgrades are carried out it is like using a newer more modern detector, in just about every case our customers have gone over old ground and pulled out more gold after the upgrades.
Yes, I have also pulled out more gold from area’s that have been detected over by lesser technology.

How to repair faulty detectors / Can you trust your detector coil?
« on: February 22, 2017, 07:37:46 pm »
Found a couple of issues with coils, might pay to check them out.

Well guy's, I've been busy soldering components as big as ants and testing a lot of different electronic system to get more smaller gold and also larger gold at depth.  Many of the standard detectors have great difficulty finding simulated 3 oz nuggets at 22 inches, even with a large coil.  I am sure that when we see a lot of big holes and people say they got a 5 gram at 20 inches it is not possible, my hunch is that the nugget was always in the wall higher up and falls in when the  hole is widened out.  Anyway I digress, I have come up with a way to get an honest 30% depth increase on large gold, you know the coke can sized nuggets that everyone just walks over. I think it will marry up perfectly with the new 24 inch evolution coil that is coming out.  Anyway, if you want to hunt for the next hand of faith at greater depth let me know.

Over the years I have had a some very good prospectors doing a fair bit of testing and providing excellent feedback on how to make things better, Big thanks to Bobby White up in Charters Towers, Peter from Melbourne and Matt from Ballarat. Just yesterday Matt came to me with suggestions on gain control and noise, after some discussion i had a brain wave that just had to be tried, I opened up Matt's detector and did a few circuit changes and after initial bench testing we went to the local gold area at Sparrow ground to do some testing. I have never seen Matt with such a big smile on his face, testing the GPX4500 on a 0.2 we could detect it at 8" with "no noise" the most interesting thing was at nearly full gain we were not getting much interference and the ground noise was minimal even using normal timings. It is a fine line designing an input stage that will handle the dynamic range of ground responses and still get maximum performance.  This time I think we nailed it, some more testing will be carried out across the red hot ground of the golden triangle in the next few days.  PS coils used were NF 17" elliptical and 17" Elite flat wound.  The new mods tamed that Elite coil perfectly.

General Discussion / Inside the GPX-4500 andGPX-5000
« on: December 20, 2016, 09:18:39 pm »
Has anyone ever wondered just how they work?  These detectors have 2 main hearts, a CLPD, a complex logic device that is located right next to the Hitachi processor ic, these 2 devices control the timing for various tx and rx functions and general housekeeping as like controlling the electronics when switches are changed. The input stake is much the same as the GP series except they are using a reverse biased n channel mosfet as the second device in the tx on voltage and back emf blocking, a dual gate mosfet is used to hold the input ad797 inputs to ground when not in receive mode. The only difference is that in previous detectors the mosfets were connected to ground but now there are 1k resistors in series to ground. Next in line are the usual bank of 4053 switches and as a slight departure from old designs 10 sets of dual opamps. power supply and feedback is much the same as the old GP design.

General Discussion / DHL and Customs clearance.
« on: December 16, 2016, 06:28:45 pm »
Here, Express service from Kazakstan to Australia......using DHL,   FEDEX......NO PROBLEM    DHL....Always a bloody problem!

If you send me a detector make sure you add "For repair and return" Exempt under section 136.2 of the Australian Customs act.

IT technically is a "Temporary import"  DHL do not do Temporary imports and hand ball it off.   The message is DO NOT USE DHL!

2016   Location   Time   Piece
36   Customs status updated   SYDNEY - AUSTRALIA   14:17   
35   Clearance Delay   SYDNEY - AUSTRALIA   05:33   
Thursday, December 15, 2016   Location   Time   Piece
34   Clearance Delay   SYDNEY - AUSTRALIA   07:11   
Wednesday, December 14, 2016   Location   Time   Piece
33   Clearance Delay   SYDNEY - AUSTRALIA   05:42   
Tuesday, December 13, 2016   Location   Time   Piece
32   Clearance Delay   SYDNEY - AUSTRALIA   05:28   
Monday, December 12, 2016   Location   Time   Piece
31   Clearance Delay   SYDNEY - AUSTRALIA   07:42   
Sunday, December 11, 2016   Location   Time   Piece
30   Clearance Delay   SYDNEY - AUSTRALIA   05:24   
Saturday, December 10, 2016   Location   Time   Piece
29   Clearance Delay   SYDNEY - AUSTRALIA   06:25   
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28   Clearance Delay   SYDNEY - AUSTRALIA   04:59   
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27   Clearance Delay   SYDNEY - AUSTRALIA   07:01   
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26   Clearance Delay   SYDNEY - AUSTRALIA   08:37   
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25   Clearance Delay   SYDNEY - AUSTRALIA   05:24   
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24   Clearance Delay   SYDNEY - AUSTRALIA   02:54   
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23   Clearance Delay   SYDNEY - AUSTRALIA   06:49   
Friday, December 02, 2016   Location   Time   Piece
22   Customs status updated   SYDNEY - AUSTRALIA   09:17   
21   Clearance Delay   SYDNEY - AUSTRALIA   06:38   
Thursday, December 01, 2016   Location   Time   Piece
20   Processed for clearance at SYDNEY - AUSTRALIA   SYDNEY - AUSTRALIA   11:17   
1 Piece
19   Clearance Delay   SYDNEY - AUSTRALIA   11:17   
1 Piece
18   Arrived at Sort Facility SYDNEY - AUSTRALIA   SYDNEY - AUSTRALIA   11:14   
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17   Customs status updated   SYDNEY - AUSTRALIA   06:52   
Wednesday, November 30, 2016   Location   Time   Piece
1 Piece
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12   Customs status updated   INCHEON OUTSKIRT OF SEOUL - KOREA, REPUBLIC OF (SOUTH K.)   01:43   
Tuesday, November 29, 2016   Location   Time   Piece
11   Departed Facility in ALMATY - KAZAKHSTAN   ALMATY - KAZAKHSTAN   18:44   
1 Piece
10   Processed at ALMATY - KAZAKHSTAN   ALMATY - KAZAKHSTAN   16:21   
1 Piece
9   Clearance processing complete at ALMATY - KAZAKHSTAN   ALMATY - KAZAKHSTAN   16:11   
1 Piece
8   Uncontrollable Clearance Delay   ALMATY - KAZAKHSTAN   08:42   
1 Piece
Monday, November 28, 2016   Location   Time   Piece
7   Uncontrollable Clearance Delay   ALMATY - KAZAKHSTAN   18:41   
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Sunday, November 27, 2016   Location   Time   Piece
6   Uncontrollable Clearance Delay   ALMATY - KAZAKHSTAN   23:23   
1 Piece
5   Processed for clearance at ALMATY - KAZAKHSTAN   ALMATY - KAZAKHSTAN   22:57   
1 Piece
4   Arrived at Sort Facility ALMATY - KAZAKHSTAN   ALMATY - KAZAKHSTAN   22:16   
1 Piece
Saturday, November 26, 2016   Location   Time   Piece
1 Piece
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1   Shipment picked up   UST-KAMENOGORSK - KAZAKHSTAN   11:57   
1 Piece

General Discussion / Modification to get rid of power line noise and EMI
« on: December 16, 2016, 06:17:43 pm »
Who would be interested in a mod that totally removes power line noise and 90% of all EMI over 500Khz? 

I have carried out some testing using ADC and DAC with digital filters, seems to work really well but have to sample at very high rates like 5-10 MSPS or it causes signal loss, it may be better to try notching in the time and frequency domain after the 4051

Had a crazy fault today, the detector works without the coil connected but shuts down when a coil is connected, LCD screen stays on and the negative 15 volt rail that supplies the output Fets hits 25 volts and shuts down the negative supply. Hmmm thought it might be in the voltage comparator circuit around the TLE2022 , voltage reference or divider resistors gone high?  No, I made the detector force itself on without the coil and removed the negative tx rail capacitor as it was getting over voltages. then hmmm a burning smell, the second blocking Fet to the AD797 went up in smoke.  Great so I removed it and the input gets as these possibly had gone short and allowed tx voltage to take out the second Fet.  Then hmmm more burning smell , the ADG333 was growing a brown spot in the middle so I put in a new ADG333 and fired the detector up.  Well it worked, there are probably some parts that were stressed out as the ADG333 supplies switching voltages to the damping resistor control Fet, the input protection Fets, the GAas Fet clamps and TX drive.  Why a failure in the ADG333 caused the shutdown was strange as all waveforms were correct before it smoked itself.  So if you get this fault and the detector shuts down it would be wise to think the ADG333 is the problem as trying to find a shutdown problem like this could be a real bastard fault to track out. I did have another customers detector that did a similar fault and came up with the dreaded coil over current problem, it was a sneaky fault as it was a loading problem that only showed when the coil was connected, it turned out to be the FMMT718 pop bipolar that is in part of the 5 volts power supply. These transistors are a low loss switching transistor and if the VCE rises due to thermal issues the detector drops out the +5 volt rail. If you test the transistor it will test fine but the detector will shut down, change the 718 and all is good again.   Anyway it is interesting working on the Minelab detectors, sometimes frustrating but mainly straight forward.

Matt was out using the latest mods for small gold, Variable Frequency set to 50, front gain set to 4 and back gain set to 5. 
This was detected in NORMAL Timings, not enhance and it was on very hot ground not far from Moliagul in Victoria.
The Gold ended up weighing in at 0.2 grams.  Not bad considering the size of the coil and using such a low frequency of 50 and low gain.
Notice how quiet the detector is running, this is exceptional for normal timings, I doubt the SDC2300 would do any better.
All testing and claims are now made with a corresponding video to show it how it is.

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