lobo improved

[maxbiri]

I found a new error in disc stage, this time it's a my error!
I will correct it and than post what i presume will be the definitive schematic.
At moment device is not too performing, but i need again well test for tx- rx phase.
The strange thing is that i have a double ritarded ring with non ferrous target and a single well centered ring with ferrous target, this happen in all metal and disc mode.
I presume this is a phase problem.

Bye Max

[aft_72005]

and now it's working

Hi Maxbiri
Very good ,please more inform us .
Best regards.

[maxbiri]

Yes, the problem was the incorrect connession of e10 k and 1n4148, i wired them as 1 and now it's working, i dont use the 3.6 M resistor in parallel at 1n4148.
Now i have problem with oscope, after 1-2 minutes it go on strike!
I need fix problem on oscope or find a new oscope!


Bye Max

[aft_72005]

Hi Maxbiri
Please see attached pictures .my opinion schematic 1 correct. Try
It.
Best regards.

[maxbiri]

I aft72005

Sorry now i havent photos of signal, after i will try with a digital camera, never tryed before take a picture from oscope tube.
It seem that W.L. schematic of year 1990 have sames errors around last 393 comparator .
I need more time for investigate but if is what i suspect it will be a big problem because i designed a very compact ss pcb and i need change a lot of tracks!

Bye Max

[aft_72005]

Hi Maxbiri
It is good news, that your homemade lobo running .congratulate.
Can you upload waveforms pictures?
Best regards.

[maxbiri]

Hi all

Finally copper wire arrived! it's 0.22 mm.
I started same fast test and seem i have same problem around disc channel.
All metal seem working in good way.
In disc and gb channel i can follow signals with oscope on second lm358 and they are good but i lost them around 308 and 393, it seem i have same problem in this part of schematic.
I hope solving problem in the next days.
Bye Max

[Eugene52]

lobo improoved

Yes Maxbiri , LS204 is the correct opamp to use . W. Lahr did excellent reverse engineering work , Always !!!! He was very correct and accurate . Use his LOBO schematic on your first prototype , then test your new Lobo circuit. And if it works great , make a case for the circuit board , and seal the search coil and put it away !!! And then if you want to improove or modify the lobo circuit design , build a second lobo circuit board for experimenting !!!! And your first Lobo will always be working for test points , and a reference for comparison ..........Regards.........Eugene

[maxbiri]

I' m thinking change lm 358 with ls204 in first filter's stage.
What do you think about?

Bye Max

[Eugene52]

lobo improoved

Maxbiri , when this project finally gets going , it will become one of the top projects to build on this forum . Here are the Top Projects to build from Geotech , and each are almost ready for that final schematic posting !! And also the "Engineering Members" who highly contributed :

1. Tesoro Golden Sabre Light from "Ivconic"
2. Tesoro Lobo "1989 VLF version"
3. Minelab Relic Hawk from "Max & Fred"
4. Hammerhead P.I. latest version from "KingJL"
5. Delta Pulse P.I. latest version from "KT315"

Regards.............Eugene

[maxbiri]

Hi Eugene

I started from second schematic but i do same changes.
Project at moment is stopped, I'm very busy and i have no time for hobby.
I'm waiting copper wire for coils.

Bye Max

[Eugene52]

lobo improoved

Maxbiri , how is your progress on this project ??? Which schematic are you using ??? Thanks.................Eugene

[maxbiri]

Hi Max

No i havent still built coil, i need copper wire and need found my old template for ellitical coil's shell for cheking exat dimension.
It look nice but usually when a board look too nice dont work !
When a board look terrible usually work in a beatifull way!
I hope this time theory will be not confirmed!
All component are recicled, only LS204 are new.
I need even change ceramic NP0 with polistirene type, very difficult find value < 500 pf.

Bye Maxbiri

[Max]

Hi all

This is the new version for Newlobo, the board is populated about 95%.
After testing the tx + power supply i preferred design a single board and not a splitted board.
After test if all is ok i will post pcb design.

Bye Maxbiri

Hi,
seems good work.

Have you made the coil ?

Kind regards,
Max

[maxbiri]

Hi all

This is the new version for Newlobo, the board is populated about 95%.
After testing the tx + power supply i preferred design a single board and not a splitted board.
After test if all is ok i will post pcb design.

Bye Maxbiri