MK tec question!

Discussion in 'Electronics' started by Gustav Raberg, Dec 30, 2012.

  1. Mark Lawson

    Mark Lawson Member

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    Andy, good morning.

    I did the test with all the ribbons connected (it does not let me turn on engines while disconnected, and would not be able to see MK Tools telemetry with the ribbons disconnected).

    Yeah I could borrow one FC from a friend, but you want me to test with it or just swap it? In case it is the FC, how could it be fixed?

    Thanks a million!

    Mark.
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Really? You may have to use MK Tool to disable the GPS functions but you should be able to connect directly to the FC board and still start the motors -- there are some folks who don't even have the GPS and Navigation Control boards.

    That's certainly true.

    It was more a case of trying out a different FC to see if that stops the I2C bus errors. If it does, then I suspect your FC is faulty, if it doesn't then there's something else that's suspect.
    If your FC is faulty, I think you may have to replace it -- I'm not sure if anyone does component-level diagnosis and repair on them -- it would probably cost you more to have it repaired than it would to replace it.

    Andy.
     
  3. Mark Lawson

    Mark Lawson Member

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    So I borrowed an MK GPS, Navi-Ctrl and FC. I swapped each individually and got the same amount of I2C errors on the scope test.

    While doing the tests I found this huge gap on the C D connector on BL #2. I re-solder it, but still have I2C errors.

    [​IMG]

    While testing back each engine with thrust backwards, props on (I connected by mistake the bullet connectors inverted), if I had done without props the amp draw would have not simulated the twitch gimbal effect. I was looking at the gimbal (something I didn't do before, because I was looking at the MK Tool) and by accident replicated my initial problem, after thrusting each engine past 150 out of 255 or so, the gimbal twitched to the left, and also with all engines past 150 the gimbal twitched to the left, so in real flight the rig behaves OK and past 30m or so the gimbal twitches to the left (past certain amount of amp draw), exactly as it happen in my test.

    So my FC, Navi-Ctrl and MK GPS are fine, but the problem might be in the distro board iteself? Or could it be that my bullet connectors have some issues (not likely, I think). What you think Andy, we finally getting somewhere here o_O.

    Thanks!

    Mark.
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Ouch. That gap on C/D (which is the I2C bus incidentally) makes me want to check all of the other connections really, really well.
    And, you've verified that swapping out the FC, NC and GPS are not the issue, therefore, it would appear that it has to be something other than those that is causing the I2C errors.

    Andy.
     
  5. Mark Lawson

    Mark Lawson Member

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    I decided to send the distro board to our friends at Quadrocopter, yesterdey I connected directly the FC to the distro, and it did not resolved the I2C error. Thanks all for the help given!

    Mark.
     
  6. Dave King

    Dave King Well-Known Member

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    Good luck Mark, let us know what happens.
     
  7. Brad Meier

    Brad Meier Active Member
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    Mark,

    I had a short once on my old system that caused some crazy issues.

    After replacing a dead BL-CTRL with a new one I had a scary test flight where luckily I never got above 3 ft. It was doing actions that I wasn't commanding. After looking things over I found that my motor leads going to the new controller were touching the distribution board and shorting out. The easy fix was resoldering them without touching the board. Problem solved... Although the other day while flying this system I got numerous I2C errors and an inflight motor shutdown. I ordered a new distribution board. I figure that will solve the problem.
     
  8. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Brad:
    Do you happen to have a GPX file for that flight with I2C errors and motor shut down? I'm researching such issues for a DVD I'm working on and would love to see it if you have it.

    Andy.
     
  9. Brad Meier

    Brad Meier Active Member
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    Yup.. I'll find it and send it to you.
     
  10. Mark Lawson

    Mark Lawson Member

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    Yeah I also think thats distro board... I sent mine in to Quadro because for something so crucial as it, I wont dare to find out it does not work properly in mid flight, I spent 3 weeks troubleshooting, part of the paid-hobby.

    Mark.
     

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