MPP revE need help

[waltr]

And TADA [ATTACH]50229[/ATTACH]
Big thank you to all of you for your help and your time !! My bad for this stupid mistake.
Polymer elected as winner
If you comme in south of France I give you one of my own brewed beer or two !!

Congrats and good spotting that easy to over look issue.

[Qiaozhi]

[surfdetector]

Glad to see a successful conclusion to this one

[Albdelafar]

And TADA
Big thank you to all of you for your help and your time !! My bad for this stupid mistake.
Polymer elected as winner
If you comme in south of France I give you one of my own brewed beer or two !!

[Albdelafar]

Oh Lord, I waited so long to see that flyback pulse, please let me see it before I die from flybat virus.

Amen.

No more than me I have just finished the work, your relief is near !!

Polymer I use this one
Is a bit thick but they had not thinner wire at store.

[Polymer]

Damn I really need glasses I readed K instead of R....
Thanks Polymer for this !! I think all be better with the good resistor value. I will try to replace it by 4 parrallel resistors 0.5w 3X 12R and 1X 20R to see if I can have a flyback voltage now.

For my solder it is a very simple 30w.

You are welcome! I mean what solder wire do you use. Leaded/Unleaded, brand name or chinese boat?

[Polymer]

Oh Lord, I waited so long to see that flyback pulse, please let me see it before I die from flybat virus.

Amen.

[dbanner]

Oh Lord, I waited so long to see that flyback pulse, please let me see it before I die from flybat virus.

Amen.

[Albdelafar]

Damn I really need glasses I readed K instead of R....
Thanks Polymer for this !! I think all be better with the good resistor value. I will try to replace it by 4 parrallel resistors 0.5w 3X 12R and 1X 20R to see if I can have a flyback voltage now.

For my solder it is a very simple 30w.

[surfdetector]

Well done Polymer

[Qiaozhi]

Albdelafar, in my components parts list R10 should be 3.3 Ohms NOT 3300 Ohms like you have! No wonder you are not getting much flyback.

Solder side, I agree with Qiaozhi - what solder are you using?

Well spotted!
You can actually see the resistor is a 3k3 (instead of 3R3) from the photo of the board.

[Qiaozhi]

I read the document and I follow all the instructions. I just past the damping step because I was waiting for resistors and pot to do the damping resistor tool.
All the steps are working and the only problem I have is that I could measure the flyback voltage anywhere.
I know my soldering is not very good but I checked with multimeter the pads until the pre-amp stage and I get no shorts to the ground.
Another thing is when I change the damping resistor value the saturation time on TP3 change signe to me that my coil is right connected. And it is the same with my two coils.

I think you are making this far too complicated. Simply wind a coil with 22 turns on a 250mm diameter, and connect a fixed resistor of 680 ohms for the damping resistor. This will be suitable for testing. Adjust the main damping delay to 20us and connect a scope to the output of the preamp. Then take snapshots from the scope with and without a target, and post them here.
If you can also post a snapshot of the TX oscillator signal, that would be great.

[Polymer]

Albdelafar, in my components parts list R10 should be 3.3 Ohms NOT 3300 Ohms like you have! No wonder you are not getting much flyback.

Solder side, I agree with Qiaozhi - what solder are you using?

[Albdelafar]

Did you actually read the part in the Build Documents were it says:

"Please do not proceed to the next step until you have solved any problems encountered in the current step. If you get stuck at any stage during the build, then seek help in the Geotech forums before moving on. Do not simply populate the whole board; discover it doesn't work (which will be the most likely result) and then post in the forums: “I've built the Minipulse Plus, and it's not working. What's wrong?” …. as you will receive little sympathy from other Geotech members."

I ask this because it looks to me like you've populated the whole board.
Also, looking at the underside of the PCB, I can see several pads that appear to be shorted to the ground plane. It might be a good idea to tidy up the soldering.

I read the document and I follow all the instructions. I just past the damping step because I was waiting for resistors and pot to do the damping resistor tool.
All the steps are working and the only problem I have is that I could measure the flyback voltage anywhere.
I know my soldering is not very good but I checked with multimeter the pads until the pre-amp stage and I get no shorts to the ground.
Another thing is when I change the damping resistor value the saturation time on TP3 change signe to me that my coil is right connected. And it is the same with my two coils.

[Qiaozhi]

Did you actually read the part in the Build Documents were it says:

"Please do not proceed to the next step until you have solved any problems encountered in the current step. If you get stuck at any stage during the build, then seek help in the Geotech forums before moving on. Do not simply populate the whole board; discover it doesn't work (which will be the most likely result) and then post in the forums: “I've built the Minipulse Plus, and it's not working. What's wrong?” …. as you will receive little sympathy from other Geotech members."

I ask this because it looks to me like you've populated the whole board.
Also, looking at the underside of the PCB, I can see several pads that appear to be shorted to the ground plane. It might be a good idea to tidy up the soldering.