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P3A gimbal thrashing bouncing (after new OEM ribbon cable)

Discussion in 'Pro/Adv Discussion' started by ody, Mar 17, 2016.

  1. ody

    ody

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    P3A gimbal camera bouncing around like crazy on startup.

    (long post, just trying to be as detailed as possible)

    Have had this P3 since last May. (10 months)

    Gimbal / ribbon cable was damaged in transit to the Caribbean last July. (packed well in a checked suitcase)

    One of the motors separated. Stupid me for not knowing about the clear plastic gimbal guard. Thought I was packed fine, but apparently not.

    Ended up just buying and installing a 2nd complete camera/gimbal at the time.

    (also bought a 3rd camera/gimbal once back home to have as a backup)

    Replaced the ribbon cable last fall sometime with a ATK Drones cable. No video and no gimbal movement after that repair. So the broken unit has just been sitting.

    After seeing several comments about only using the DJI OEM cable, figured I’d give this one last shot. Ordered the ribbon cable from DJA and just installed it.

    Still no video and camera thrashes back and forth and up and down when powered up.

    Don’t remember what firmware I was coming from, but it would have been from Sept sometime. Figured I’d try popping the latest onto the P3A. Did that and all of a sudden the video pops back on. No movement of anything, just firmware. However the gimbal still thrashes all over the place. (gimbal overload of course on the controller) (also strange that a firmware upgrade would result in getting video now)

    Since I have 3 complete camera/gimbals, I then swapped out the main controller board with a known good unit. No improvement. So I’m 99.9% sure I’m not having a controller board issue.

    When the camera is moved up and down, I can see the indicator on the tablet showing movement. So assume no issue with the pitch / roll sensor? (maybe?)
    I’m pretty confident I have the ribbon cables all seated properly.

    The gimbal motors seem to travel from end to end during that thrashing, so the motors are at least working to some extent.

    Is is still possible that I have damaged motors?

    Or maybe the pitch / roll sensors?

    Have searched ebay, and don’t see any sensor boards avail, or any parts for the motors.

    I did see on a video of a gimbal repair process that showed re-gluing a motor shaft back in place and the orientation was important. Could my issue be related to this? When the motor separated way back when, I just pressed it back in place. Maybe the shaft does not have the pot in the right place for the position?

    Looking for suggestions at this point.

    I can just toss this, but would feel better if I could recover it (with reasonable cost) I'm kind of being stubborn and want to "win" on this thing. :)

    And as a very last resort, does anybody know if just the camera/gimbal can be sent to DJI. I don’t really want to send the whole P3A in for service. I have 2 other cameras to put on the P3 to use. Don’t want it to be out of commission for just a camera repair.

    Thanks in advance for any comments / suggestions.
     
  2. Air Ontario

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    The roll shaft does have to be oriented properly for the roll axis to work properly.

    When you replaced the hardware after the trip did it act up? Did/have you done firmware updates, IMU calibration followed by gimbal calibration?

    Is the issue more of a roll problem or a pitch problem.

    Or is is just a continuous rolling and pitching?
     
  3. ody

    ody

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    When the gimbal separated, I was in the Turks & Caicos islands. So I rush purchased another camera / gimbal and my wife brought it to me the following week. That of course worked fine. The problems are just with trying to resurrect the original gimbal.

    The original problem was a separated gimbal motor, (sorry don't remember which one)
    Initially the video still worked, but as I messed with things, I eventually lost video too.
    Replaced the original ribbon cable with that aftermarket cable. Never worked with that at all.

    Now with this new OEM ribbon cable... Initially I didn't have any video, but after the firmware upgrade, video came back, but as above just constant thrashing of the gimbal motors back and forth, (all of them I think)
    Kind of makes sense that the orientation of that shaft needs to be in the proper alignment.
    I'm searching for comments on how each are to be aligned right now. (I know one is commented about in the one video I've seen, but no info on the other one yet) about to search that.

    Seems to be both roll and pitching.
     
  4. Air Ontario

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    Likely the roll shaft flat spot isn't facing up and aligned with the potentiometer when the camera is level. That should help a lot once done.

    Have you verified any orientations yet? Like the one mentioned? Is it the shaft flat spot out of alignment with the circuit board and a level camera?

    The other(camera pitch) is a glue and press fit if I remember correctly.

    Usually fixing the roll/circuit board/potentiometer fixes the constant wobbling unless there is definite physical damage to the pitch area.
     
  5. alokbhargava

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    Anytime connection to gimbal is broken, App doesn't know what kind of P3 is connected. To reestablish it, reinstall App or relink RC to A/C or update any FW. These are my experiences. Hope it gives some clue to you.

    Your problem seems to be misalignment beyond SW corrections
     
  6. ody

    ody

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    thx for the replies
    Busy day,
    Will try to find info on alignment and try to adjust later this evening.
    I'll report back once tried.

    Any info / links on orientation of the flat spots appreciated.
     
  7. Air Ontario

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    Go back into backplate where roll circuit board is located, align flat spot of camera shaft up with a level camera, reinstall circuit board with flat spot on board up, aligned with shaft and level camera. Screw backplate on.

    Double check black ribbon cable connection to verify you didn't loosen them or accidently disconnect any.
     
  8. ody

    ody

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    Had a few min late this afternoon to mess with this...

    As suggested, pulled the back plate, loosened the shaft enough to rotate it so the flat side was level with the camera.
    Bit of pressure to reseat the shaft.
    Assembled enough to test, and the thing powered up, did the happy dance, and leveled out pretty good.
    Did a gimbla calibrate, and from what I can see so far, its near perfect.
    (I'm not sure its pointing 100% straight, could be off to the left a bit)(not sure that is an adjustment?)

    Pick the P3, up shake it around a bit, no weird buzzing as it maintains a level.
    Looks to be fine.
    Have not flown the thing in 3-4 months. Weather is perking up here lately, so will charge a couple batteries and do some testing in the back-yard / field over the next few days. Inspect the video and fingers crossed things look fine.

    I think I was getting to the realization that one pot/shaft was maybe not in the proper range, but just needed confirmation from others that have done this same disassembly / re-assembly to comment. Made me separate the motor shaft again, and get it in the range its suppose to be in.
    Big thanks for the comments.

    On a separate note:
    My 13yr old daughter walks in seeing me messing with all the parts, I explain the situation in detail (she is very tech oriented and loves this stuff), and that the camera / gimbal is now working fine. She sees the other 2 fully functional cameras/gimbals sitting on the desk beside me. She then suggests we mount the other 2, plus purchase and mount a fourth so we can create circle 360 movies. Hum... I like the way she thinks!!!