Tesoro Toltec 100 schematic and adjustment?

[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

[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.

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

[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

[aft_72005]

more pictures

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

[Merc]

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

[Alexismex]

Toltec-100

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

[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

[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]

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

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

[Geo]

Hi Merc .
Congratulation for your hard work.
Greate
Regards

[ApBerg]

Toltec power

Hello Merc.

Thanks for the circuit ! Can you check the 47k resistors in the volt.conv. think it must be 4k7 ?
I have send you a mail, it came beck, is your mailadres correct ?

Best regards.

Ap

[Merc]

Thanks guys

Thanks Max for pointing that out. I have corrected this. I double checked and the bypass capacitor across the feedback resistor in the receive circuit is an 8pF.

Northerntrowel you are also correct. I have corrected and here is rev2.

Keep'em coming!

[Northerntrowel]

Hi! Merc

That's a big work!
Thanks! a lot!

On your Rev1 drawing, check at the control wires of U18A and U18D.They are not connected.If you look at pin 2 of U18A,the first wire connected is the one who should be conneted to the control wires of U18A/U18D.(in according of your previous drawing).

Best regard.
JF