Tesoro Toltec 100 schematic and adjustment?

[Unregistered]

A very good work Merc , I know the difficulty because I have the toltec 100 and i never want to trace it when i open the case ...too much work...congratulation again
saludos
Alexis

[Merc]

Rev 3

Thanks ApBerg. You are exactly right. I knew the guys here could help spot my mistakes.

Thanks Geo. I'm glad a lot of you can appreciate how difficult it was. It's worth it though if it helps the people of this forum learn something. I'm considering trying to make a surface mount version of this detector, not sure that I have the patience though.

So I have made the changes and here is rev3.

P.S. A funny story on the subject of the Toltec 100. I haven't had a chance to use this detector much since buying it. I bought it just to take apart and study. So I took it out and had lots of false signals. The ID was right but it was way to noisy. Back home, I checked it with a piece of ferrite that I had. It started beeping like crazy. I tried several other detectors I had on the ferrite and they totally ignored it. So I decided to adjust the hot-rock reject. I wore that pot out trying to null out the ferrite but it just didn't seem to help. Not sure why but I decided to check out the notch circuit. THe notch was WAY to wide. What had happened? Hmmmm, wrong pot. I drew the schematic and still turned the wrong dang pot. Anyway after getting on the RIGHT pot, the ferrite nulled right out. Much quieter now.

THE END

[aft_72005]

Hi Merc
Very Thanks Merc for your reverse engineering .
Your drawing for Toltec 100 very useful work because
It is help to people that will be know more about metal
Detectors technology.
Can you revisit Toltec 80 circuit ?
Best regards .

[Merc]

I no longer have a Toltec 80 to examine. I can tell you though that I believe they were identical to the 100 minus the notch disc. circuit.

Merc

[Alexismex]

Toltec-100

Some photos of the TOLTEC-100 to see components ,
Regards to the forums,
Alexis

[Merc]

Looks like the one in the pics has been modified. Is that some type of volume control next to the speaker?

[aft_72005]

more pictures

Hi Alexismex
Thank you ,pictures very useful ,can you upload
More pictures ?
Best regards.

[Alexismex]

Ello forum,
yes is a volume control For the photos i think i show all because to take pictures of the pcb under you must disconnect a bunch of wires and in this moment i can not ok -In the photos you can see the capacidor for the receive coil and for the transmit coil you see a small white mark ... and a 0015 i near LF353 in the last photo, ok
Regards

[dusmenil rocha]

helpme

Please post it anyway.

Help ; Sende-me eschema and ajuste the metal detetor MD-5008
I bought a detecting metal MD-5008 in the china and him it came with defect and it doesn't work ordered an email for it manufactures her/it in Shanghai and them don't want to order me the outline. I ask help the friends and frann.
dusmenil rocha

[Merc]

Revision 4

I had U15 labeled as an LM339 when it was an LM393. Fixed this and decided to repost. I am currently still working on a SMD version of the Toltec 100.

[Merc]

Target ID

I've been studying the target ID of the Toltec 100 and I haven't quite figured out how it works. From what I can tell the RC4200 is being used to do mathematical division. The voltage on pin8 is divided by the voltage on pin5. I think there is also multiplication based on the voltage on pin1. Maybe someone else can tell me if I'm right or wrong. Also, why are 4 sections needed(the bottom 4 on schematic). I can't seem to grasp what's happening there.

Merc

[porkluvr]

Hello Merc.
I thought that RC4200 was unavailable but I found a dealer on ebay selling them. $72.00 apiece.
I refuse to help put that guys kids through school, so, Do you have any thoughts on what could be used in place of RC4200?

I think that the idea around using a divider (pin-4 output = pin-1*pin-8 /pin-5) is that if you divide 'X' by 'Y' you arrive at the tangent of the phase angle. You get high resolution for small amounts of phase shift as you approach tan90 degrees. I have not really analysed the circuit to see if that is what it is doing but it seems plausible.

If on the other hand Y is being divided by X, then the cotangent would give you high resolution as zero degrees is approached.

My math is really rusty and was never that good to begin with so it's a big maybe.

[Merc]

I would think the same thing could be accomplished with 2 or 3 opamps. There may also be a newer chip available that could be used but probably not a drop-in replacement. Still, I'm trying to understand how the ID is working. I thought ID was accomplished by comparing the absolute value of 2 samples. I've been reading through the Tesoro patents on this site trying to understand. I think I'm just missing something. I'll read through again.

Merc

[Merc]

Is it mathematically determining the ratio of the absolute values of two samples?

[porkluvr]

Merc,

I'm wanting to simulate parts of the Toltek 100 circuit to try and figure out why the demodulators are set up like they are but I have a basic problem.
I read in the operators manual tht the operating frequency is 12kHz but when I use the schematic values and the best data I have on the Tesoro coils, LTspice gives me a 14.3kHz output.
I'm assuming that the transmit coil is about 5.6mH (21 ohms) but that is only because most of Tesoro's other IB detectors use that value coil.
Is the Toltek coil any different? And what about the receive coil, is it approximately 6.2uH (23 ohms)? These numbers don't have to be very precise but ballpark figures would sure help. I can't find any information on the search coil in the schematic.