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Need help with compass issue

Discussion in 'General Discussion' started by Hawkeye 1, Jul 29, 2014.

  1. Hawkeye 1

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    My FC40 started drifting to the rear and right on takeoff...after about a minute of jockeying it around, it smooths out and flies normally. Assuming that I had a compass issue, I hooked it up and sure enough, my compass reading was varying between 3900-4400. I did a full re calibration of the IMU, no change......I tried to de-gauss the compass as per instruction and it seems to have made it worse, the readings now varying between 9800 and 11000. I happened to have a brand new compass so I put it on and got the same readings as the old compass which leads me to believe it's not the compass. I'm stumped.....anyone have an idea of what's causing the problem and how to fix it? Any help will be greatly appreciated
     
  2. ProfessorStein

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    Have you done an actual compass calibration (the rotate-the-Phantom-flat-and-again-on-its-face dance)??
     
  3. Hawkeye 1

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    Yes, multiple times, both before and after the IMU re calibration. Funny thing...when trying to de gauss the compass, the values would drop down to normal but pop back up after removing the magnet.
     
  4. EMCSQUAR

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    As frustrating and time consuming as it is, go back and degauss. Yes it's a pain but go in different directions and try multiple times. I had one take almost 45 mins. (I wasn't going to let it kick my A#%) Get it down to between 1200-1800 then you'll be good.
     
  5. Hawkeye 1

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    Thanks, I intended to resume in the morning. The thing that has me puzzled is the fact that I installed a new compass and got the same high readings. This leads me to believe that the problem may be in the cable or inside the Quad. Any thoughts on that?
     
  6. EMCSQUAR

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    Once the Naza has settings loaded it pretty much locks in. So by switching compass' Naza sees same - until you deguass it. Like mentioned it can be really frustrating but keep at it. Usually if there's a problem w/cable you won't have any #s and/or GPS at least in my experience. When I've done these I usually put it on floor away from everything but laptop. With it hooked up to assistant start waving magnet around, up & down even brushing over it until #s get in the ballpark. Even try using stronger magnet.
     
  7. Hawkeye 1

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    Thanks a bunch, your explanation makes perfect sense. I'll resume in the morning and keep at it until one of us gives up.