Delta Pulse

[Geo]

Big mistake

Hi 1843. It was a bag with foil near the coil so the waveforms are not ok. I attach you 4 photos. The first 2 are with power at min and max. The other 2 are with gain at max and min (there is a change at the down place of waveform.

[Geo]

I forgot something

Ohh i forgot...... My DP works at 350Hz and the coil (10 in) has 8.5 ohm resistor (without resistor in series), i don't remember about turns and wire diameter.

[Geo]

Hi 1843.
I opened my DP and i took 3 photos that i attach here. The first is with the power at midle, the second with power at max and the other with power at min. The photow are with a 955 mH coil connected to the detector. It is absolute stable .
Sorry for the bad quality of photos but they are with mobile phone

[1843]

I don't know why it has a such waveform:

[1843]

My coil is 4" (35 Turns) and the test got done indoor since it is free from most indoor noise. (bbsailor suggested to me)
I tested different coils (350uH,750uH,1mH... also with resistor in series them) and I found that instability doesn't depend on the coil.
I think that problem is around D4, but I want to know your opinion...
I also tried with different frequencies. (100Hz,450Hz...)
Thanks for reply Geo

[Geo]

Instability increases when the Gain pot be set to max...
What is your opinion about the D4 waveform?

Hi. I will try to open my DP and to see the waveforms.
1. What is the frequency of your DP?
2. Do you try it on the Lab or at the field
3. What coil do you use. As i remember when i made some tests with different coils, when the coil had little impedance the DP was unstable.

(I read your message)

[1843]

Instability increases when the Gain pot be set to max...
What is your opinion about the D4 waveform?

[1843]

LF357 Output

Hi all,
My DP works very unstable....
I looked at the waveform of D4 pin6; It looks bad, Doesn't it?



Thanks for any help.

[kt315]

thanks lots, Geo! ... have a nice day!

[Geo]

anybody can give me speedy reply? where is a correct polarity of VD12 and VD13 - on the PCB or on the schematic? (because the connections are mirrorly different). sorry I have see this question in forum, but I can not find up again the answer via Search
tia.

The schematic is sorrect. Both XR71 and Delta-Pulse schematics are the same and correct with R35..VD12 and R36 VD13. I have the original XR71 so i am sure.

[kt315]

anybody can give me speedy reply? where is a correct polarity of VD12 and VD13 - on the PCB or on the schematic? (because the connections are mirrorly different). sorry I have see this question in forum, but I can not find up again the answer via Search
tia.

[1843]

hi 1843, good job. which are the performance and which type of coil you used. thx

Hi dan129,
It has a problem and its detection is poor...
I shall repair it next week since I haven't oscilloscope now.
My coil is 70 x 70cm.

cheers

[dan129]

good job

Here is my Delta Pulse:
[ATTACH]1551[/ATTACH]

hi 1843, good job. which are the performance and which type of coil you used. thx

[1843]

Soldered IC sockets photo

[1843]

Here is my Delta Pulse: