Mean machine

[Max]

And...why i named this thread "Mean machine" but not "Minelab Musketeer.." or simillar?
There is more...
This Minelab Musketeer (Colt,XS and Advantage) and Minelab Relic Hawk are sharing exactly the same platform. Exactly the same. With additon on Relic Hawk as S M L modes followed by proper electronics.
So...this machine is really mean!
Right now it is much occupied - i am going almost every day on various terrains...prospecting and coinshooting. But when winter comes i am planning to reassemble it and retrace whole schematic. Than we will have complete datas for our new handmades!
Also, than we wil have chance to suggest some more serious modifications and improvements.
Come to think...actually this machine has no drawbacks at all. Very hard to improve.
Only thing i would like to improve ....could be to achieve multitone audio.

Hi Ivconic,
nice mod , I see you made it with ease cause they already made pcb with control in mind... marketing issue then having such choke there for AUS soil... but also for middle/average users there... cause that way they have don't mess with manual control.

Now... I would like to ask you about iron... what about far iron ?

In the range say of 30cm is e.g. a big hammer detected or not ?

I guess not... but will be nice hear from you... cause when made RH had that problem with my homemade coil...

Kind regards,
Max

[ivconic]

I just saw your question.
Disc at Colt is different than at TGSL. At TGSL even when Disc pot is at "1" large iron is still rejected. But here at Colt, Disc pot must be turned more....maybe at "7" or "8" to totally reject large iron.
So it is fully rejected in air on any distance.
In soil situation is a bit different. Mostly depends of soil type.
But Colt is real bijou - even if it makes sound on large iron, it is easy to distinguish it. Cose sound on large iron in soil is much different than on coloured metal. Sounds is noticeable "spitting" on large iron, while on coloured metal is smooth.
Respecting Disc pot position sound is more "spitting" and if iron item is not to large, it is possible to totally reject it by turning Disc pot clockwise.
Other hand; if Disc pot is adjusted to lower value and iron item is not to large than you can also hear cracked, spitting sound on it. More you turn Disc clockwise - more cracks and spitts in audio (on large and extra large iron objects).
On meduim and small iron items Colt is acting pretty simillar as TGSL or any other simillar detector (can reject totally if desired).

So everything is in audio here. Shape, smoothness,lasting, decay, "spitting"...
To be succesfull with Colt on the field, operater must have certain experience first. Or to dig every suspectable target.

[ivconic]

One more reason to like this machine lays just in what i explained in last post. It is good that it is producing various combinations of cracks and spitts respecting size and purity of detected iron object. Why? Cose it could be adjusted very easy to accept (cracking and spitting with beeps) only pure iron alloys such are usually met in nice arrows and spears and at the same time to totally reject iron junk and trash such are nails and simillar.
I was very happy with TGSL cose it is real master of coins and also at the same time very unhappy with it cose i missed so much arrows and spears at the same terrains.
Now with Colt i can get those all! Usually it is adjusted to produce smooth and pleasant audio on coloured items and nice clear audio on pure iron with additon of spitt before audio and spitt after. Ha,ha,ha!! I dont know how to explain this!???

Let me try this way:

* good coloured targets = "bleeeeeeeeeeeep"
* pure iron alloys = "spitt beeeep spitt" (can be totally rejected if Disc adjusted higher)
* junk and bad iron = "spitt beep crack crack beep spitt" (can be totally rejected if Disc adjusted higher)
* extra large iron = " spitt plonk beeeeeeep plonk spitt" (can produce more cracks if Disc adjusted higher)
*Foil & pull tabs = "beep crack beep crack beep crack" (can be rejected in high percentage if Disc adjusted higher)

[ivconic]

Hi Ivconic,
I like to see this kind of mods, where a not-very-nice marketing option is bypassed
Something intersting here to learn about the RH famous oscillator transistor ?

Fred....say "CHEESE" !

Dont ask me how i know this!

It should be BC857c....but small "p" is confusing me. Also that "54" number?? What the heck this stands for?

[erolunall]

[IMG]file:///D:/Documents%20and%20Settings/O%C4%9ELUM/Desktop/Pano-1.jpg[/IMG]

[Fred]

Hi Ivconic
Great! a secret revealed !
I confirm this must be a BC857, very common one...
Here an excellent database for SMD´s :
http://tkb-4u.com/codes-and-markings...kings/database
And here the datasheet:
http://www.tkb-4u.com/SMDcode2/PDF_D..._BC858_Phi.pdf

Thanks!
Regards,
Fred.

[Max]

One more reason to like this machine lays just in what i explained in last post. It is good that it is producing various combinations of cracks and spitts respecting size and purity of detected iron object. Why? Cose it could be adjusted very easy to accept (cracking and spitting with beeps) only pure iron alloys such are usually met in nice arrows and spears and at the same time to totally reject iron junk and trash such are nails and simillar.
I was very happy with TGSL cose it is real master of coins and also at the same time very unhappy with it cose i missed so much arrows and spears at the same terrains.
Now with Colt i can get those all! Usually it is adjusted to produce smooth and pleasant audio on coloured items and nice clear audio on pure iron with additon of spitt before audio and spitt after. Ha,ha,ha!! I dont know how to explain this!???

Let me try this way:

* good coloured targets = "bleeeeeeeeeeeep"
* pure iron alloys = "spitt beeeep spitt" (can be totally rejected if Disc adjusted higher)
* junk and bad iron = "spitt beep crack crack beep spitt" (can be totally rejected if Disc adjusted higher)
* extra large iron = " spitt plonk beeeeeeep plonk spitt" (can produce more cracks if Disc adjusted higher)
*Foil & pull tabs = "beep crack beep crack beep crack" (can be rejected in high percentage if Disc adjusted higher)

Uhm... maybe is better, if you have time and an mp3 recorder, to capture that sounds (even better if on soil, during real search) and post here!

Cause I'm going crazy trying to understand the sound... adding spittings etc

So, the transitor issue was solved !? BC857C... fine! Very good!

Kind regards,
Max

[ivconic]

Max i will do that. I dont have any mobile mp3 recorder right now. But i will prepare some condenser microphone and attach to sound card and use Sound Forge. Must be done indoor...at least for now. Can you beleive...all those electronics...blah..blah... and i never had good will or a bit interest for such gadgets?
My older son do have some midget mp3 player, recorder, radio...blah..blah... but he is on studies right now, far away from home...so no deal with that.
So i will do that in old fashion way - mic and Sound Forge...
I presume it will be certain difference in air ... but hopefully enough good as an example. Give me day or two...need to get rid of present responsibilities...

[ivconic]

Hi Ivconic
Great! a secret revealed !
I confirm this must be a BC857, very common one...
Here an excellent database for SMD´s :
http://tkb-4u.com/codes-and-markings...kings/database
And here the datasheet:
http://www.tkb-4u.com/SMDcode2/PDF_D..._BC858_Phi.pdf

Thanks!
Regards,
Fred.

* High current gain

* Low collector-emitter saturation voltage

* Low noise between 30 Hz and 15 kHz

Huh!!! It is not just "any" common transistor. Right now i am thinking about conventional (non smt) substitution.....for our future handmades...

[Fred]

* High current gain

* Low collector-emitter saturation voltage

* Low noise between 30 Hz and 15 kHz

Huh!!! It is not just "any" common transistor. Right now i am thinking about conventional (non smt) substitution.....for our future handmades...

BC548
Every manufacturer will claim they are selling the best component...actually the bc548 has more gain and more current , just less voltage:
http://www.philohome.com/sensors/gp2...eets/bc548.pdf
And about the collector-emitter saturation voltage, the´857 phillips datasheet shows variations that are so large, i think the ´548 is a good candidate for equivalent.
Maybe there is another important characteristic on the 857 ...

[ivconic]

Even so...BC548 is NPN !?

[ivconic]

I also searched through several cross references....hmmm... According to what i saw; BC557c should be pretty good replacement???
But we already have one BC557c there on ocb?????
So....why oh why they put one conventional BC557c there and than put also BC857c ????? Why they dont used also BC557c if it can successfully replace BC857c????
Can anybody explain this? I do not understand this at all!
Maybe 3Gp (54) is not just ordinary BC857c....maybe have some speacial features?


Carl...Sean...you are having experiences in this. C'mon help here about this !

[Qiaozhi]

I also searched through several cross references....hmmm... According to what i saw; BC557c should be pretty good replacement???
But we already have one BC557c there on ocb?????
So....why oh why they put one conventional BC557c there and than put also BC857c ????? Why they dont used also BC557c if it can successfully replace BC857c????
Can anybody explain this? I do not understand this at all!
Maybe 3Gp (54) is not just ordinary BC857c....maybe have some speacial features?


Carl...Sean...you are having experiences in this. C'mon help here about this !

The BC857 is an SMD with a total power dissipation (Ptot) of 200mW, whereas the BC557 (TO-92F) has a Ptot of 500mW.

It looks like the designer was trying to use SMD components wherever possible, but a higher power device was required in this instance.

[ivconic]

Very good point! That really could be right answer! Actually 3g is last in TX "chain" and i guess it was desirable to reduce power disipation as much as possible. Seems pretty logical.
So... what we gonna loose on performances if BC557c is used...in our handmades? I guess not much....yet!?
This need to be explored...

[Qiaozhi]

Very good point! That really could be right answer! Actually 3g is last in TX "chain" and i guess it was desirable to reduce power disipation as much as possible. Seems pretty logical.
So... what we gonna loose on performances if BC557c is used...in our handmades? I guess not much....yet!?
This need to be explored...

In a handmade clone I would think that the BC557 is a perfect replacement for the BC857, if you don't want to use SMDs.