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Hi Ivconic, I always follow you, I wanted to ask you if it is possible to replace LF442 with TL082?
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Yes but it will not work as LF442. Try TL062 instead.Originally posted by gallico58 View Post
Or if you can obtain TLC2262.
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Thanks Ivconic, I was wondering if part of the drift depends on the stability of the tx.
in the case of a 4060 with 420khz quartz clock and buffer transistor?
you would also have after the necessary divisions for audio and transistor negative voltage circuit, what do you think?Comment
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I think it is one of the possible solutions, good of course!Originally posted by gallico58 View Post
Yes, I am sure that drift depends on the TX too.
Since the Quest X5 coil is with center tap, I would like to explore the options of such TX and driving such coil with direct square signal.
And to rearrange the RX accordingly.Comment
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I dont think the drift depends on the TX.
It depends of the guality of C7, C20... (C8,C9)Comment
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That too.Originally posted by Xtrem View Post
Low leakage caps will certainly improve stability.
But TX influence on the drifting is present too.
I mentioned square wave signal and direct driving, that's the area i would like to explore more here.
Not because of the present design as it is now, but because of some future upgrades that i am planning.
Step at the time...
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Negative voltage generation improved:
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C7, C20, C8, C9 can be replaced, each by 2x1uF wired parallel.Originally posted by ivconic View Post
That will improve the problem of the leakage.
Also use of film or foil type of capacitors will do. (Plastic film capacitors (Metallized polyester film capacitors)).Comment
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Maybe you need to apply * guard rings * on the PCB (in high resistance areas) , as done in Whites 6000? Then the leakage can be reducedComment
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Reading this thread, I found that some important person's opinion is missing,
which could help significantly, where is Eric? everything is fine?Comment
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My respect for Eric is immeasurable. But there are topics that are not very interesting to everyone.Originally posted by Xtrem View Post
So it does not surprise me that many, who would have something to say on this subject; they are not here.
The Geotech forum has grown into a huge database of various topics, but also many similar topics, even the same ones.
It is becoming increasingly difficult to follow all the topics and especially to separate something that is interesting from something that is not interesting.
And finally, what is interesting to one is not interesting to another.
I received suggestions from a colleague respected by me; to give up this topic because the issue of non motion VLF I/B detectors has long been washed away and
everything that could have been done has been done already in the past.
I would partially agree with that statement.
But the fact that someone has already done everything that could be done on an issue; is the least reason to stop me from trying to do something by myself.
Non motion is an old topic, really quite washed out, the industry has given everything that can be given in the first days of development.
And then it abruptly left and started new principles, new ideas.
With the advent of real motion detectors, with DISC and GEB (the latter more important) functions; somehow everyone rushed to that side.
And non motion has become a "static mode" or in modern times just a "pinpoint" accessory on many detectors.
In most cases, that "pinpoint" remained at a very rudimentary level.
I am not interested in modern market trends, I am a hobbyist above all and I like to "play" with things that interest me ...
or that I feel I have not met enough and that have remained vague.
I've watched recently one video in which a man shows a comparison test between White's Coinmaster 5000 and XP Deus (or it was ORX, I'm not sure).
Of course ... a funny comparison. But ... The 5000CM super simple and old "Methuselah" is almost no worse at detecting some targets.
And if we compare technologies and dates of creation...
The point; metal detectors have not moved away at all in their essence, from 60-70 years ago until today.
That is why it is more interesting for me to deal with the essence and not with "fashion" and modern colorful accessories, packaging, etc ...
Because in 80-90% of cases you will have almost the same results on a real site with a 60-year-old detector as and
a $8-10k priced toy ... by the way, when such one breaks down; the repair will cost you $4k6 ... (taken from another topic).
Of course Eric is welcome, as is everyone else. But I doubt very much that he will be interested in this topic.
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Crazy enough, as I've mentioned many times lately; some "higher power" rules our lives ... or maybe it's still true that
if you "fix" something strong enough in your head; that will happen to you.
So, yesterday, without any prior planning, I stumbled upon White's Coinmaster 5000 ... which is defective, but it will be a pleasure and an easy job to fix.
Someone opened the coil before me, but I don't notice any traces of damage. It seems to me that all the wires are intact.
There are some components that are covered with a dark and strong mass.
Maybe it's some "pre-flood" epoxy! I didn't dare "dig" further, so as not to damage anything. First I will fix the machine and then I will see if the coil is correct.
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I tried to measure the coil on the connector side. But I only get resistance values but not inductances ...
Either something is wrong with the coils, or some internal component prevents the inductance from being measured.
So I could use the help of someone who has information about details at this coil.
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