Critical Problem with #4 motor stopping when Gimble turned on in flight

Discussion in 'Electronics' started by Shane Latham, Mar 20, 2013.

  1. Shane Latham

    Shane Latham New Member

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    Hey guys, I sent this message to Andy per the guys at Quadrocopter but Andy is off traveling today so he wanted me to post it here to see if anyone could help me with my problem. So I will just copy and paste what I wrote last night to him, and thank you guys for any help you can offer on this problem I'm having.


    Andy I have a question thats causing some alarm in my Cinestar 8 if you could be so kind to maybe help me with this.

    I built my Cinestar 8 a few weeks ago with no problems WITH the help of your two awesome DVD sets btw! So first I want to thank you for that!

    Ok so here is the problem I ran across the other day as well as today. I have a Cinestar 8 dual operators and Graupner transmitters/receivers. Pretty much the DIY build from Quadrocopter with all the bells and whistles.

    Yesterday while taking off to fly my number 4 motor stopped spinning and I heard something about something "Sensor over heating" from the voice on the transmitter. Keep in mind this was only after about 45 seconds after take off. After the motor stopped only for a moment it quickly started again and I brought it in for a check. Nothing was hot to the touch and everything felt fine. Restarted the copter and flew with no problems.

    Then today I was flying and the exact same thing happened. We did however notice that this error happened as soon as the camera operator turned on the gimble to get ready to film. Today however I got a different error it said "Data Bus Error". So both of these #4 motor failures happens right after takeoff (First flight) and as soon as camera guy turns on gimble, also starts after giving some throttle.

    So I am completely lost as to what could be happening, I have updated all firmware on my transmitters, flight board, nav board, and this only started happening since yesterday, all other times have been perfect. I haven't changed anything as well so I'm not sure what could be causing it.

    Andy if you can please help me figuring this out it would be really appreciated!

    Thanks in advance Andy!

    Shane
     
  2. Dave King

    Dave King Well-Known Member

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    HI Shane

    It would be very helpful if you could record flight data via a GPX file and post it. I take it you are using the radians? If that is the case then the fact that you get this when the camera operator turns the radians on has to be a fluke or that when you turn on your radians its changing the balancing of the gimble and copter that make your motors work differently. To me, it sounds like you are getting some type of problem on the power distribution board that is effecting your motors. It could be many issues ranging from complex to simple.

    ONe thing you can easily check is to see if you have any IC2 errors with the bird powered up but on the ground. Also let us know if you are seeing any errors in MKtools. You can measure the IC2 parameter through MKtools as its one of the parameters on the left hand side (see pic below). If you don't see it click where it says Anlalog click to switch. I would check the IC2 errors after you hit flight control mode (FliightCrl button under settings button), and also in navigation mode (NaviCtl button under settings).


    MKtooks2a.jpg
     

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  3. Shane Latham

    Shane Latham New Member

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    Hi Dave, thanks for you help on this.

    Here are two GPX files from when it first happened. I believe these are them if not let me know and I can try to find different ones. I believe the smaller size one is it because I landed and unplugged the battery the flew it again.

    I will check the I2C error here on a few mins.

    Let me know if you see anything :) and again thanks for all your help!
     

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  4. Gary Haynes

    Gary Haynes Administrator
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    Shane I would suspect a bad solder joint on the number 4 BL where it attaches the C-D wire jumper from the BL to the power distribution frame. Check those and perhaps re-solder them.
     
  5. Shane Latham

    Shane Latham New Member

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    Gary, thanks I will check the solder points, can you please explain what you mean by BL and C-D jumper however? I am assuming you mean where I attached the three wires from the motors to the power distribution board but before I go in there messing around I don't want to assume.

    Also, I thought about that but why would it only happen when the gimble was turned on then catch itself and fly fine from that point on? Its like the first flight of the day it happens and then it doesn't happen again. Also once it catches itself and runs properly the rest of the flight goes off without a hitch.

    Thoughts?
     
  6. Dave King

    Dave King Well-Known Member

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    I looked over GPS00004.GPX and everything looks very normal. Short flight, you do have IC errrors at the start of the flight but they do not go up in flight. This is the exact condition I see on my bird and I don't think this is anything to worry about since they do not increase in flight. All your BL currents and temps look good, your battery voltage looks good too. I don't see any issues with this file but maybe a more experienced operator can look at it to confirm.
     
  7. Dave King

    Dave King Well-Known Member

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    BL1.jpg

    BL2.jpg


    power distribution board4.jpg

    Shane here's some pics
     

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  8. Shane Latham

    Shane Latham New Member

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    Dave I can't see them
     
  9. Dave King

    Dave King Well-Known Member

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    Sorry, Refresh
     
  10. Shane Latham

    Shane Latham New Member

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    Got them thanks!
     
  11. Dave King

    Dave King Well-Known Member

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    BL4 is highlighted in blue in this picture.
    power_distribution_board4a.jpg
     
  12. Dave King

    Dave King Well-Known Member

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    Can you snap any pictures of your PDB?
     
  13. Shane Latham

    Shane Latham New Member

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    Mine doesn't look like that at all. The only thing I had to solder from the motors were the three wires from the motors. My power board doesn't look like that, its a little different. This was bought not long ago if that helps, its the same board that Andy used in his DVD.
     
  14. Shane Latham

    Shane Latham New Member

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    Sure give me a few moments.
     
  15. Dave King

    Dave King Well-Known Member

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    This is the PDB thats used in the Cinestar 8 Quadrocopter kits and the one Andy uses in the video. Trust me :D It looks a little different because the GPS board is mounted on top of it which is the stock mk location. Most of us have mounted the GPS to boom 1.
     
  16. Shane Latham

    Shane Latham New Member

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    Ok I checked the solder points and they all looked ok and were correctly connected to the power board. Take a look.
     

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  17. Dave King

    Dave King Well-Known Member

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    Shane

    I couple things stick out to me, look at the arrows in this picture. The solder joints could be a lot better and I see a lot of sharp edges especially on the left solder joint. Also when I look at the picture in Photoshop it looks like there is some white substance on the board. If you continue to have the same problem I would remove the PDB and get a very good light and magnifying glass to see if you have anything that can be shorting between any two connections.

    PDB.JPG
     
  18. Shane Latham

    Shane Latham New Member

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    I think the white stuff you are seeing is sand residue as we just flew it out in the California desert. In the process of cleaning it up now.

    I know my solder points could be a lot cleaner however they are all very connected and if it was shorting out wouldn't I constantly have this problem, not just when my camera op turns on the gimble or during the very first flight? If it was a solder problem or a short it would always happen wouldn't it? Thats the only reason I am thinking it is something else
     
  19. Dave King

    Dave King Well-Known Member

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    I would definetely remove the board and clean it up. If you really don't have time to do that I would get compressed air and spray the hell out of it and recheck. I checked the one GPX file and everything seemed good except for the fact that you have IC2 errors like myself. Also for solder joints, if you have one little tiny hairline wire on the board it can cause intermittant issues. If it was my copter I would make sure the board is spic and span clean and clean up the soldering a little better and recheck.
     
  20. Jim Swanson

    Jim Swanson Member

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    Hey Shane,
    I'm no solder expert but yours are not good. Look closely at Dave's picture and you'll see a big difference between the two. Shiny, smooth, completely covering, even, etc. This might not be the cause of your current problem but could cause you problems in the future. Vibration can loosen cold solders and jagged edges can break off and short things out. Don't take this as a criticism...just trying to help.

    Jim
     

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