RELIC HAWK

[Max]

Some idea from where can bay little transformer for audio stage.
I think this maybe is stаndard part.
I put neosid inductor 22 mh with 680 nf but not work

Hi,
that component is not critical.
I made my own using a neosid thing too, and works.

Problem with RH is the dang coil (so far I've not even toiched it anymore...) that if not perfect make you crazy with far iron detection: it disc out iron at near few cms but you can still detect it at 30cm!

Kind regards,
Max

[N@SKO]

The sound is not loud and soft
What is resonance frequency?
1250Hz ????
resistance of coil?I think may be is critical!
May be I can"t find the resonance


I want sound to be same as this

http://www.youtube.com/watch?v=43zVaEbL5Uo

[Ultimate_Haze]

Hi,

Hello,
Recently got modify Minelab relic hawk for repair.
The owner told me that it were modify.Then repair again.
It were hard job.Because battery were inside the unit box.Not much space.Jack for headphones on front panel.
So I first found broken conection on outside part of coil conector.
I thought the it couldn't be so easy.
But when conected all and switch on,there were pip-pip-pip for a few seconds.Then smoke from 15mH inductor(((
I try to switch on again.And got spark near the inductor.
What could be the reason.Everything looks ok with the setup.Then where those smoke and sparks came from.And why?
Shame it looks like nightmare.
I will make some various pictures.

[Ultimate_Haze]

I need some help here.
Will be good to hear Max's or Ivconic opinion on this.
So its burned bsr51.Just replace with closet I found bsr52.
In allm oscillator dont work.When in s,m/disc I read 6,7khz from 4024 pin1.So in those two modes there is some pip-pip-pip sound coming from headphones.
When in L oscillator start and stop after few seconds.What could be wrong here?
Wanna now which IC is concerned in those S/M/L mode change.Because looks like problem might be there.
-2,5V is there.+ and - also OK.
Any help highly welcome.
Thanks

[mesy64]

depth

Hi all


Depth search for this metal detector is much larger coins and goals?

With respect

mesyna

[ivconic]

I need some help here.
Will be good to hear Max's or Ivconic opinion on this.
So its burned bsr51.Just replace with closet I found bsr52.
In allm oscillator dont work.When in s,m/disc I read 6,7khz from 4024 pin1.So in those two modes there is some pip-pip-pip sound coming from headphones.
When in L oscillator start and stop after few seconds.What could be wrong here?
Wanna now which IC is concerned in those S/M/L mode change.Because looks like problem might be there.
-2,5V is there.+ and - also OK.
Any help highly welcome.
Thanks

I had the very same behavior at my first RH, few years ago. But it burned than because battery pin (one of those, which one i am not sure) accidentaly touched earphones socket. As you know; earphone socket is in same cover with power socket and very close to battery pins. There is also foam to prevent shorts there. But at the time my stupid friend removed that foam just for a moment and accident happened.
Also BSR burned. But not only BSR. All 3 ic's bellow BSR burned. 2.5V reference burned also. Also burned one transistor and several diodes....Pitty i don't exactly remember correct list of burned components.
I tried to fix it and after a while i lost my nervs, because i didin't ( and still don't) have tools for SMT.
So after several months i gave it to one friend and he fixed it. Than that RH was sold.
So.... you have tough task there!
I wish you a luck!

[technos]

Problem with RH is the dang coil (so far I've not even toiched it anymore...) that if not perfect make you crazy with far iron detection: it disc out iron at near few cms but you can still detect it at 30cm!

The coil needs to be put on a network analyzer and maybe disassembled. Then once that's understood the circuit can be reworked properly.

In fact, I think that the project needs to start over from scratch. However, I have been unable to buy a relic hawk machine just yet.

[ivconic]

Nothing special in those coils. Last summer i bought several Minelab coils. Some of those made by Minelab and some are Excellerators. Nothing special.
Those ARE exceptionaly good coils, but nothing uncommon or secret at those.
TX=1mH, RX=15mH, TX=2-3ohms, RX=30-40 ohms.
Recently i adapted ordinary handmade ("Serbian Most Wanted") to work very well with those Minelab coils. Nothing specific that i had to do than.
So i think that problem is still in schematic we have here. Still not accurate.
Something is missing or put incorrect in schematic.
Regards!

[Ultimate_Haze]

Hi,
Yes tough task.
Look similar problem.But on this only one wire were broken on outside /coil/connector.Maybe some short there occur.
I can measure that those two diodes in sound stage shows 330!Other pair around 4053 shows 660.Maybe they burn too or took some damage.
The problem is that sometime this bsr52 still get hot.
2,5V ref. is ok.I have it.
I will try to measure those 3 ICs output today.
Thanks

[wam]

Why ?

Hi, I have $100 china metal detector. I have compared its circuit diagram with reworked Relic Hawk schematic and ... it looks very very much the same electrical and even more advance in favor for china. Can You submit any test results for 25c US in air for Relic Hawk. My china detector gets it within 20 cm. I am about to compare some electrical performance with Sterling as well. The curiosity is why detectors with nearly the same schematic and components may differ so much in performance. My bet is the coil and the some 3% difference in schematic. The question is Which part is so critical so it makes that giant difference between metal detectors?
Regards,

[technos]

The question is Which part is so critical so it makes that giant difference between metal detectors?
Regards,

1 to 2% could easily be the difference in coil shielding. What is the brand name/model name of the china detector?

[wam]

1020

I get photo from ebay. It has many names but the model number is 1020
and it has always the same appearance and coil. It has LCD display and it has linear indication for phase shift and depth (signal strength) you can adjust the sensitivity and software filtered discrimination. As I said analog part is very similar to RH. I believe that it is deliberately under design to support 9V battery and due to marketing reasons.

[WM6]

Hi, I have $100 china metal detector. I have compared its circuit diagram with reworked Relic Hawk schematic and ... it looks very very much the same electrical and even more advance in favor for china. Can You submit any test results for 25c US in air for Relic Hawk. My china detector gets it within 20 cm. I am about to compare some electrical performance with Sterling as well. The curiosity is why detectors with nearly the same schematic and components may differ so much in performance. My bet is the coil and the some 3% difference in schematic. The question is Which part is so critical so it makes that giant difference between metal detectors?
Regards,

Can you post schematic (circuit diagram you mentioned) and detailed pcb picture of your China metal detector?

[wam]

I will post some pictures next week (including opened coil).
In have flight to NZ in some hours (I will try to find some gold ...)
Regards,

[ivconic]

Coil and shaft are exactly the same as on "Black Knight". Many simillar models made in China.
However; i am looking forward to see more details on that one.
Regards!