Tesoro Lobo news

[porkluvr]

What exactly is wrong with the DISC operation? I should have asked you that at the beginning but I won't wait for your answer since all I have is a guess, anyway.

Why don't you try replacing C7 in your preamp with 10nF. That would delay the rx signal ~40 degrees relative to what you have now (using 10pF according to your schematic). You may also need to re-adjust your ground balance trimmer pot to accommodate the new phase delay.

[marcellotronic]

Hi, the pointer of the knob of Time is 10us.

U7 pin1 RX



U6-1 GB min


U6-1 GB max


U5-7 DISC min


U5-7 DISC max


search head 9x8 silver umax


thank's

[porkluvr]

Seeing the transmitter waveform is good but it would be helpful to see the rx channel output (U7-1) and compare that with the DISC ZCD output (u5-7). By your using a non-standard Lobo coil is very likely causing your rx signal to be out of optimal phase for the disc Zero Crossing Detector to work correctly.

Also, your time base setting is ambiguous; the pointer of the knob is hidden making it difficult to detemine your tx frequency. Help us out here?

[marcellotronic]

Excuse me, the trace on channel one is the collector of 2N2907 of TX (Q1).

[porkluvr]

Why don't you tell us where the other test point is connected? You have only listed one connection for each of your photos but we can plainly see two scope traces. What is the other test point ?

[marcellotronic]

I made the Tesoro lobo.
For testing I connected the search head of 9x8 silver umax.
for the moment it detects 1 euro to 15cm.
GB works well.
Disc does not work well.
I'm working on.

Pin1 U7A


Pin1 U6A GBmin


Pin1 U6A GBmax


Pin7 U5B DISCmax


Pin7 U5B DISCmin

[marcellotronic]

lobo original

Good morning, I'm making the LOBO and I redesigned the original scheme (attachment). For the tests will use the search head of the silver umax (10kHz), then I'll make one manually.
What are the best values of capacitors and resistors you just found?
thank you for the help!

[Derx]

I solved more troublesa my lobo
all work very stable and sensetivity
build in "original" pcb

[amtech2005]

I have everything else but the LM358 !! Just wanted to get some opinions on a perfect substitution .
It should turn out good , I am checking the schematic as I go and making a new parts list .

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

[homefire]

Cool Beans! Looking Good.

Why Sub the LM358?

[amtech2005]

I finally got started on the Lobo Project, its a miracle !! Just need to find a substitute for LM358. The next step is to solder the caps and resistors .
One thing I learned the hard way so far is "always make circuit boards with silkscreen for super fast parts placement !! I now use sprint layout with "x-ray view" image to help place the parts .

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

[Derx]

Hi friends
I have a problem with my Lobo from Foma sheet and original PCB

If you turn on the device without the coil and set the control to minimum SENS the unit starts to howl
If you turn the handle SENS then disappears howling

Another problem with the coil when tuned GB and 10 minutes to work, and again there is howling again need to turn the handle GB
And so some times little by little until it stops.

It must be so?

[amtech2005]

Need to finish drilling my boards

Hi, has anyone built with this board?, unfortunately it only beep at me.

I made 4 or 5 single sided boards for Lobo , but I broke a few drill bits and did not finish the boards because the drill press I used was very un-stable !! I need a better drill press . The coated drill bits are 2 dollars a piece from Jameco over priced "High Profit" for cobalt-coated !!!

But I just found 10 drill bits for 10 dollars advertised at "Electronic Goldmine"

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

[Legaucho]

What is correct tri-state switchs connect?
Version 1 left or version 2 right?

Hi
Please see my post 103 on this topic page 7, the version is left one corresponding with my PCB connections ( 01 - 02 - 03 -04- 05 ).

Regards

[herpes]

Hello Eugene

The Lobo with a single sided PCB is a modified versus ( in relation with yopur comment ).

Why the double side: I did it to simplify wiring, I gathered the various connections on both sides of the card and also there is less bridges in the middle of the circuit.

But if you want to make a single side PCB use this one.

Hi, has anyone built with this board?, unfortunately it only beep at me.