Updating older components to state of the art

[Woody.au]

Last week I was repairing a Minelab GP Extreme that had 12 volts connected in reverse into the detector. It was not looking good with many ic,s showing brown spots and puncture holes. The only way to get this detector going again was a complete or near complete rechip. Lucky that for some reason the main Hitachi CPU was still ok as well as the A to D and Eprom. So started the rebuild with various 74hct, tle, tlo, adg, bc 547 557 a couple of mosfets and a big load of patience.

In the end the detector started up and after some more components were replaced it was working like a new one, well let me say it was working much better than any other GP Extreme i had ever tested. The stability of the detector was outstanding, the circuit noise was far less than any other extreme. I replaced most ic's with the newest variants of the series that was first used. Most of the performance increase came from the Oscillator, the L/C one, checking the outputs on the cro showed much less hash noise than other detectors that i compared it to.

The integrators were swapped out for some low noise types and the detector is running beautifully. This goes to show that old designs can be greatly improved by swapping the older parts for new.

I did not disclose part numbers as a certain company goes to great trouble to grind the part numbers off.

This was a worthwhile exercise as it allowed the detector to work again and also showed up performance improvements that are straight forward to do.

[detecto]

Last week I was repairing a Minelab GP Extreme that had 12 volts connected in reverse into the detector. It was not looking good with many ic,s showing brown spots and puncture holes. The only way to get this detector going again was a complete or near complete rechip. Lucky that for some reason the main Hitachi CPU was still ok as well as the A to D and Eprom. So started the rebuild with various 74hct, tle, tlo, adg, bc 547 557 a couple of mosfets and a big load of patience.

In the end the detector started up and after some more components were replaced it was working like a new one, well let me say it was working much better than any other GP Extreme i had ever tested. The stability of the detector was outstanding, the circuit noise was far less than any other extreme. I replaced most ic's with the newest variants of the series that was first used. Most of the performance increase came from the Oscillator, the L/C one, checking the outputs on the cro showed much less hash noise than other detectors that i compared it to.

The integrators were swapped out for some low noise types and the detector is running beautifully. This goes to show that old designs can be greatly improved by swapping the older parts for new.

I did not disclose part numbers as a certain company goes to great trouble to grind the part numbers off.

This was a worthwhile exercise as it allowed the detector to work again and also showed up performance improvements that are straight forward to do.

Hi woody
Is it possible that Minelab GP Extreme don't have reverse polarity diode protection for goodness' sake?
I totaly agree with you that changing a components with new one can improwe detector stability and improve performance, best way for that is to discover where is the source of noise and where are weakest points on detector.
BTW you know that!
From my experience metal detector manufacturer don't always use best performance (and quality) components, they use available and cost-effective components.
Conclusion is change each Chinese cheep (and low quality) component in your detector and you are in good way to improve same!
PS. Today almost every single component is Chinese
Cheers
Detecto

[HECTOR]

Thanks for starting this thread detecto!
I've been thinking about this for a while but am having a hard time finding a source of component crossover info. I suppose it might save some time if I just ask if anybody else has upgraded/updated any components in Tesoro Cibola or Vaquero with successful improvements?
Is it normal that my 10 turn GB mod is not centered? Will it work better if it's calibrated to 5 turns? Can this be done with relative ease?
Are there components in particular that would improve performance with closer tolerances? New and improved chips with matching pinouts?

My "techy" knowledge is minimal compared to most of the electronic engineers here but I have some basic troubleshooting and repair knowledge of audio circuits. Very little math and theory but I can repair most audio gear.
If someone can point me to a (specific) source of increased understanding of detector circuits, that would be great! I've spent countless hours reading on this forum but there's much I need to learn before I can be a useful contributor.

I AM the guy who discovered or made public the freq/GB relationship of the Cibola/Vaq. (not monumental but notable) The same one who doesn't like whipped cream and cherries with my MD forum, OR talk about war/religion on a MD forum. That's why I've settled here.
My days of giving free sales pitches for particular brand detectors are DONE. Now I'd like to get some deeper understanding of the tools that I work with, rather than talk about how great my detector is and showing pics of finds. Sales forums seem to have a problem with freedom of speech except when it's working for them.

[Carl-NC]

Most of the performance increase came from the Oscillator, the L/C one, checking the outputs on the cro showed much less hash noise than other detectors that i compared it to.

Did you change out the oscillator? I would not expect that jitter would be severe enough to cause much noise, but in a VLF design I was helping with that turned out to be the case.

I did not disclose part numbers as a certain company goes to great trouble to grind the part numbers off.

You are welcomed to disclose them if you want, but I understand that figuring them out is part of your business.

Sales forums seem to have a problem with freedom of speech except when it's working for them.

My approach with this forum is due to my own frustration with other forums. No sponsors, no sacred cows. Keep it civil, keep it technical.

- Carl

[Jerry]

My approach with this forum is due to my own frustration with other forums. No sponsors, no sacred cows. Keep it civil, keep it technical.

- Carl

That is greatly appreciated.

Jerry

[HECTOR]

That is greatly appreciated.

Jerry

That is greatly, greatly appreciated
May you and Geotech live long and prosper!

[Kjamesgraham]

Geotech Rules

I think this is why all of us are here. Straight tech. I have learned more here than anywhere else. There is a lot of hype out there. It's nice and quiet here.

[satdaveuk]

I think this is why all of us are here. Straight tech. I have learned more here than anywhere else. There is a lot of hype out there. It's nice and quiet here.

Yes its quite here because we all agree to disagree