MPP revE need help

[dbanner]

Common (0V) is battery +.

With respect to probing the flyback voltage, would it not be in reference to -Vb or battery negative?

[Albdelafar]

I know that. If I probe everywhere it's because nothing happen on tx on R4 and on the coil.. I tried on my two scopes with diferent probes on different point and i get no flyback voltage signal.

[dbanner]

Anyways, battery+ is the ground. So I'd imagine the scope probe to be grounded at this point and the voltage is measured at the other end of the coil.

[surfdetector]

Disconnect your coil and get an ohm reading on it. It is sounding like you have an open on the coil

[Albdelafar]

I did it with my component tester i received this week and it's all right as you can see here with the coaxial cable.
And here for my second coil alone.

Here you can find link to videos when I tryed to probe flyback voltage. My probes are ground conected to TP5 on first and third video. TP3 is on CH1 as control for coil connection on the three videos and CH2 is connected to damping resistor (R4) on videos 1 and 2 and to coil plug solder pins on video 3.

https://drive.google.com/file/d/1S-H...sp=sharing,%20
https://drive.google.com/file/d/1a1P...sp=sharing,%20
https://drive.google.com/file/d/1ek8...ew?usp=sharing

I do not understand what I did wrong....

[dbanner]

Perhaps you need to disconnect R1 from the circuit.

[Albdelafar]

I tryed to do exactly as surfdetector did on is video https://www.youtube.com/watch?v=6CPgYFwJpTs&t=4s
And I Have no flyback voltage signal ... I took a video here
A strange point is that when I put my probe ground on a side or the other side of the damping resistor tool my TP3 signal is changing. Could someone explain me why ?


I tryed without connexion to R1 too. And guess what stil nothing as you can see here.


I'm lost !! any other ideas to test ?

PS:Only one good thing is changing R35 to a 2k4 resistor gave me a 10.4us minimum sample on TP9 and 10.

[dbanner]

The probe carries some capacitance I guess, so the coil sees this tiny additional capacitance and so the decay curve changes ever so slightly. This will be reflected in the TP3 scope shot.

[dbanner]

Well, after some searching, I think I have found your problem. Seems others have had similar issue trying to scope the flyback with USB scope.
This guy has a hanteck just as you.
Read from post #523
https://www.geotech1.com/forums/show...495#post196495

[dbanner]

Well maybe not the same problem, but perhaps you've got to change the software for 100x probe.I think it could be the software settings.At least he was seeing the flyback pulse, you're getting zilch, nada. It must be something to do with the settings on the software, what else could it be?

[dbanner]

Is it possible that your flyback voltage is above 500volts and the scope is input limited to 5 volts, if exceeded, protection circuit trips and input is disconnected to protect the oscilloscope??

[dbanner]

You hear relays clicking?

[surfdetector]

I tryed to do exactly as surfdetector did on is video https://www.youtube.com/watch?v=6CPgYFwJpTs&t=4s
And I Have no flyback voltage signal ... I took a video here

Where is your jumper connection between PL2 pin 2 and PL3 pin 2?

[Albdelafar]

Is it possible that your flyback voltage is above 500volts and the scope is input limited to 5 volts, if exceeded, protection circuit trips and input is disconnected to protect the oscilloscope??

Thank for your research dbanner !! I don't know how to use the research tool on this forum I had a plenty of thread for each ask and I need to read it in integrality to find the message with the word i asked for ..... I suppose there is a easy way but i did not find it.


About my scope I use the 100X option in the software with the 100X probe and i see nothing not even a light pick. I do not heard cleaping and I tryed to take measurement with my old analog scope and nothing .....
By the way my scope is the 6082BE not the 6022Be it's limited to 35V DC / AC not 5V (I hope my flyback is less than 3500V: D).
What about the IRF840 I saw in the post you mention do you think that could comme from MOSFET or a pulse width not enought longer?!

Thank you very much for your help with surfdetector !!
I hope we will solve this issue.
Alban

[Albdelafar]

Where is your jumper connection between PL2 pin 2 and PL3 pin 2?

As you can see on the first video on post #80 it's on the chassis coil plug.