MICRONTA MODS

[amtech2005]

BACK IN THE EARLY 1990's , IT WAS ABOUT 1991 OR 1992 . THERE WAS A TREASURE MAGAZINE , IN THE U.S. I BELIEVE THAT POSTED SOME MODIFICATIONS. THEY CHANGED SOME RESISTORS AROUND Q-1 FOR SEARCH COIL'S L-1 , AND ALSO Q-2 FOR THE SEARCH COIL'S L-2. IF YOU HAVE A COPY OF THIS PLEASE POST IT . IT IS A CHEAP DETECTOR , BUT HAS ALOT OF POTENTIAL . AND ALSO A MUCH BETTER SEARCH COIL CAN BE ADDED. AND A NEW MODERN CASE !!!!!BOUNTY HUNTER COILS ARE CHEAP !!!! THANKS AGAIN ...........EUGENE

[Qiaozhi]

BACK IN THE EARLY 1990's , IT WAS ABOUT 1991 OR 1992 . THERE WAS A TREASURE MAGAZINE , IN THE U.S. I BELIEVE THAT POSTED SOME MODIFICATIONS. THEY CHANGED SOME RESISTORS AROUND Q-1 FOR SEARCH COIL'S L-1 , AND ALSO Q-2 FOR THE SEARCH COIL'S L-2. IF YOU HAVE A COPY OF THIS PLEASE POST IT . IT IS A CHEAP DETECTOR , BUT HAS ALOT OF POTENTIAL . AND ALSO A MUCH BETTER SEARCH COIL CAN BE ADDED. AND A NEW MODERN CASE !!!!!BOUNTY HUNTER COILS ARE CHEAP !!!! THANKS AGAIN ...........EUGENE

The detector schematic you posted is for a Micronta 4003.
I've attached the manual which shows some component changes, but don't ask me if they improve anything. I've never tried it.
By the way, I own one of these detectors, and it's next to useless when you try it in the field. The main problem is the unshielded coil, which is severely affected by the ground.

[Fred]

By the way, I own one of these detectors, and it's next to useless when you try it in the field. The main problem is the unshielded coil, which is severely affected by the ground.

Unshielded coils ? That sounds interesting! did you try holding it above your head ?
Regards,
Fred.

[amtech2005]

MICRONTA MODS

THANKS FOR RESPONSES SO QUICK. ANYWAY LIKE I SAID IN MY FIRST POST, IT IS THE LOWEST PRICE DETECTOR YOU CAN BUY !!!!. BUT WITH THE SIMPLE MOD'S AND ADD A MUCH BETTER SEARCH COIL "ONE THATS SHIELDED" . MAY MAKE A SUBSTANTIAL IMPROOVENT, THAT IS IF THE DETECTOR'S FREQUENCY IS STABLE AND YOU DON'T HAVE TO KEEP HITTING THE AUTO TUNE !!!!! IT WOULD BE NICE TO GET SOME SCHEMATIC'S ON THE OTHER MICRONTA AND DELUXE VLF MODELS , OTHER INFORMATION BESIDES THE SCHEMATICS IS POSTED HERE AT http://support.radioshack.com/support_games/3155.htm . I REMEMEMBER THEY HAD SOME HOT DETECTORS BACK THEN , ONE WAS THE "DISCOVERY 3" WHICH WORKED AWESOME AND I THINK IT HAD A 10 INCH SEARCH COIL. I THINK THEY DISCONTINUED IT BECAUSE IT WORKED TOO GOOD FOR THE MONEY !!!!!!!!!! MAYBE WE WILL GET OTHER SCHEMATIC'S TO SEE THE DESIGN'S THEY DISCONTINUED. THANK'S..............EUGENE

[nelson]

Hey amtech2005, i think i have the same detector circuit enclose on a Chinese machine. This cause this MD has the same controls, looks almost identical on the number of controls, S meter, uses three 9 volts batteries, etc.
So i will try to open it to confirm if circuit is the same.
I also noticed that the coil was a vary cheep one and performance wasn´t to good at all.So i open it and i had confirm that it hasn´t any unshielded.
I agree that with a few mods on the circuit and with a new coil, this detector could surprise.
Regards
Nelson

BACK IN THE EARLY 1990's , IT WAS ABOUT 1991 OR 1992 . THERE WAS A TREASURE MAGAZINE , IN THE U.S. I BELIEVE THAT POSTED SOME MODIFICATIONS. THEY CHANGED SOME RESISTORS AROUND Q-1 FOR SEARCH COIL'S L-1 , AND ALSO Q-2 FOR THE SEARCH COIL'S L-2. IF YOU HAVE A COPY OF THIS PLEASE POST IT . IT IS A CHEAP DETECTOR , BUT HAS ALOT OF POTENTIAL . AND ALSO A MUCH BETTER SEARCH COIL CAN BE ADDED. AND A NEW MODERN CASE !!!!!BOUNTY HUNTER COILS ARE CHEAP !!!! THANKS AGAIN ...........EUGENE

[erolunall]

Hello

I used this dedektor I opened its coi about 6-7 years ago

My Coil is shilded with a aliminyum folyo but it is not good at detection.

Regards
Erol

[Qiaozhi]

OK - a slight mistake. The detector I have is a Micronta 4001, not a 4003. The schematic I posted is the correct one though.
Here's a photo of the inside of the 4001 coil. As you can see, it's unshielded.

[amtech2005]

MICRONTA MODS

WOW QIAOZHI, LOOK AT THAT GARBAGE , THEY WENT THROUGH ALL THE TROUBLE TO INSTALL A CX AND RX CAPACITOR BUT THEY COULD NOT AFFORD SOME ALUMINUM FOIL FROM THE GROCERY STORE . WOW , BE CAREFULL THAT SHIELD MODIFICATION MIGHT OVERLOAD THE DETECTOR AND CATCH IT ON FIRE !!!!! . TO EROLUNALL ,ON THIS FORUM WE TRY TO COVER ALL MAKES AND MODEL'S . I HAVE LEARNED AT GEOTECH IN A FEW YEARS , WHAT OTHERS USUALLY LEARN IN A LIFETIME !!! ANYWAY THE OLD SAYING IS "LEAVE NO STONE UNTURNED" ........BECAUSE THERE MIGHT BE GOLD UNDERNEATH ???? I JUST MADE THAT UP. CARL SHOULD COPYRIGHT THAT AS THE GEOTECH SLOGAN !!!!! TAKE CARE EVERYONE .......EUGENE

[Qiaozhi]

WOW QIAOZHI, LOOK AT THAT GARBAGE , THEY WENT THROUGH ALL THE TROUBLE TO INSTALL A CX AND RX CAPACITOR BUT THEY COULD NOT AFFORD SOME ALUMINUM FOIL FROM THE GROCERY STORE . WOW , BE CAREFULL THAT SHIELD MODIFICATION MIGHT OVERLOAD THE DETECTOR AND CATCH IT ON FIRE !!!!! . TO EROLUNALL ,ON THIS FORUM WE TRY TO COVER ALL MAKES AND MODEL'S . I HAVE LEARNED AT GEOTECH IN A FEW YEARS , WHAT OTHERS USUALLY LEARN IN A LIFETIME !!! ANYWAY THE OLD SAYING IS "LEAVE NO STONE UNTURNED" ........BECAUSE THERE MIGHT BE GOLD UNDERNEATH ???? I JUST MADE THAT UP. CARL SHOULD COPYRIGHT THAT AS THE GEOTECH SLOGAN !!!!! TAKE CARE EVERYONE .......EUGENE

A simple fix would be to put some electrostatic sheet in the bottom cover, and attach it to 0V using a simple spring arrangement. That's the way it's done in the Garrett Crossfire coils, and this seems to work ok.

[ivconic]

I have 4003 model. My coil is omega. But what really confuses me is some extra windings over TX and ferrite rod with some windings inside??
What is this? Some old way of balancing? Ha,ha,ha!!!
My coil is shielded.
I intend to change this. Eject and toss this ferrite rod and extra windings.Only shielded TX and RX will remain inside. If not working well than i will make another omega coil.
Very good coil was at MD3007. Same dimensions (TX 165mm and RX 75mm).Also omega. 60 windings for TX and 160 for RX. Right now i dont remember wire gauges...hell, it was 5 years ago! Omega coil is easy to null, not a problem at all.
So...coil is not a problem...question is; is 4003 worth of trying to mod it?
Schematic is pretty simple.
But since i already have it, it will be nice to fix it,mod and "glance" it. Good to have it in collection....sort of vintage! Yup!

[ivconic]

Oh yes....reparation is in progress (dont have anything smarter to do these days). So, components are reslodered out from pcb. PCB is washed and cleaned. All traces are about to be corrected and protected with special resin. New components are being prepared to be put on pcb. Enclosure is in a great shape, almost shiny. In few days i will finish all about detector and than start thinking about coil....
Might look trivial....but it is a hobby, isn't it?

[Qiaozhi]

I have 4003 model. My coil is omega. But what really confuses me is some extra windings over TX and ferrite rod with some windings inside??
What is this? Some old way of balancing? Ha,ha,ha!!!
My coil is shielded.
I intend to change this. Eject and toss this ferrite rod and extra windings.Only shielded TX and RX will remain inside. If not working well than i will make another omega coil.
Very good coil was at MD3007. Same dimensions (TX 165mm and RX 75mm).Also omega. 60 windings for TX and 160 for RX. Right now i dont remember wire gauges...hell, it was 5 years ago! Omega coil is easy to null, not a problem at all.
So...coil is not a problem...question is; is 4003 worth of trying to mod it?
Schematic is pretty simple.
But since i already have it, it will be nice to fix it,mod and "glance" it. Good to have it in collection....sort of vintage! Yup!

Hi Ivconic,

This is very interesting. Are you sure this is the same version of the 4003 as shown in the previous schematic? How is the ferrite connected with the other coils - in series, in parallel??

[ivconic]

Yes it is Micronta 4003... schematic above...

[ivconic]

But.....
your question provoked me to start using my brain for a while....
sheeeshh! This looks like some mod added after a while!?
It seems some "expert" did some mod on it!? Look on photo...
Ferrite rod has 2 coils...one coil connected to one end of RX and other on one end of TX...???? What the hell is that?
I got this detector week or two ago. Didnt payed to much attention on it up to recently. Detector is in working condition now. Detects 1e coin at 15cm in air....disc is working..
But now..."hooked" with you question, i did detailed examination and......bull!
This photo is last of previous coil setup. I just reassembled it and removed that idiotic ferrite rod and some extra added windings....bull!
Tomorrow i will balance it again and use only TX and RX without any extra rods and mods....
TX has faraday cage (Al foil). RX dont.
Exactly same coil i saw at MD3007. Same inductances,resistances,wire gauges, diammeters...only bit different coil housing.If you search pages here, you can find my retrace files of MD3007; pcb and components placement.
Comparing that MD3007 and this 4003...i can conclude that MD3007 actually presents newer and in some details improved version of 4003. Same working frequency, same oscillator stage, same few other stages.....minor differences. At MD3007 audio has 3 pitches. As coil closed to metal pitches are changing from lowest to highest. Generally....both detectors are working in same manner..also same performances - lower class...

[ivconic]

On this photo you can see how that "geniune" mod ended! Not to mention all the smile on my face!
Bull!
And i thought i saw everything...!?!?
I can only assume that this coil will work much better, now when all the scrap removed from it!