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Crash from 200 feet - solder joint failure

Discussion in 'Phantom 2 Vision Discussion' started by ronhiner, May 4, 2014.

  1. ronhiner

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    My P2v tumbled from the sky on an otherwise uneventful flight -- except for a bit of a wind.

    The camera is wrecked and one arm gets no power for lights or motor. The other three arms seem to work fine.

    I think I know why it crashed.. the power lead came loose from the central board. See attached photo. It's possible that it broke free when the P2V hit the deck, but the case was undamaged, so I'm inclined to think that bad solder joint caused the crash.

    The question is what to do about it?

    1) I'm not so handy with a soldering iron. And I don't know what that translucent stuff is around the solder joint. I suppose its worth a try to get it flying again.

    2) If I can get it flying again, I still don't have a camera. I can't find a US source for a new camera that had a decent return policy for protection from the many focus and dead pixel issues that this camera has.

    Any other thoughts or ideas?
     

    Attached Files:

  2. RCRookie

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    Re: Crash from 200 feet

    Sorry to hear about your crash. If the pad pulled loose from the pcb as the photo suggests, and caused the crash, rather than the solder being broken as a result of the crash, then DJI should address this as a potential issue.

    Perhaps a rubber isolation washer should be set between the pcb and frame to dampen the effect of vibration, which could be the cause of this. Is "heat" playing a role in the pads seperation from the pcb as well?

    You should search for other identical instances of this, when or if you call DJI

    Good luck,

    The Rookie
     
  3. seajunky

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    Re: Crash from 200 feet

    I used to be in the business of printed ciruits. I would most definatley consider that to be a "dry joint" (a faulty soldering joint) and would contact DJI and send them a copy of the photograph. It's got to be worth trying. Sorry to hear about your crash.
    Steve
     
  4. EMCSQUAR

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    Re: Crash from 200 feet

    +1 - from the picture that looks like bad solder joint (almost no solder to the board itself) as clean as board is. Or the prep before solder was questionable. Usually there would be a small remnant of solder left behind, that looks like silcone seal was only thing holding it. What do the other three look like?
     
  5. ronhiner

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    Re: Crash from 200 feet

    Thanks guys... I'll try calling them tomorrow.

    Here are the other three connections.
     

    Attached Files:

  6. gunslinger

    gunslinger Moderator
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    Re: Crash from 200 feet

    That's at least the third picture I've seen of a broken solder joint, that looked like this. No solder residue on the board to speak of. I'm really starting to think that this is a really serious problem. How would you go about testing your own P2V without trying to physically rip the solder joints off the board...

    Really sorry to hear about your crash and I hope DJI comes through for you...

    -slinger
     
    dirkclod likes this.
  7. Geoelectro

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    Re: Crash from 200 feet

    Certainly shouldn't be seeing this. It does appear to be a bad solder connection. There is no need to pull on solder joints to test them. Rather, reheat the joints (equally board and wire) and reflow the solder. You could even remove much of the old solder with a desoldering tool or braid and flow new solder on. I suspect when initially soldered the board was not heated properly.

    Geo
     
  8. syotr

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    Re: Crash from 200 feet

    That is clearly a manufacturing defect. You can see that the solder did not stick to the pad on the circuit board. If it had, it would have pulled the copper pad off of the board. This is a classic cold solder joint. Do not repair it. Make DJI replace your bird and anything that was attached.
     
  9. gfredrone

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    Re: Crash from 200 feet

    It would be nice if DJI used some sort of terminal in place of soldier on these mission critical connections. It would be easier for users to replace motors as well. Any ideas why they don't? Is it a cost thing or is soldier a better option?
     
  10. syotr

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    Re: Crash from 200 feet

    I would expect a solder joint to be more reliable if it was done correctly. Terminal connectors to conduct this amount of current might take up more space and weigh more.
     
  11. F6Rider

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    Re: Crash from 200 feet

    I as a HAM radio hobbyist who has built many pieces of equipment I can tell you this is some of the worst soldering I have seem coming from a company. It is obvious these connections are being done by hand, and either the poor slob doing the work was not properly trained or he was being forced to hurry as the 'blob' of solder indicates a to cool tip on the iron. It did not 'flow' onto the foil due to the foil being to cool. I checked my bird and 2 of the connections looked suspect, so I de-soldered all of them and re-flowed new 60/40 rosen core solder on the connections. I used a Weller solder station set @ 400ยบ and it worked well.
     
  12. Migmon

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    Re: Crash from 200 feet

    After a real crash you should never post about it and call dji right away. If nothing can be done then post about it.
     
  13. Jezabel

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    Re: Crash from 200 feet

    ronhiner, I am so sorry about your P2's crash. I had the same experience with a P2, H3-2D,GoPro set up where the P2 just "dropped like a brick" without any explanation. I immediately contacted the dealer and sent the malfunctioned unit back and did not inspect the inside of the P2. My hypothesis was some disconnect between the power and the motors,etc. Your pictures of the bad solder joint would confirm this hypothesis and I appreciate that you sent the pictures of all of the solder joints to know what to look for in my new P2V+. This would explain many similar experiences that folks have reported on forums.

    It is hard to regain confidence in the P2 to feel secure in flying a P2 again...I'm working on it but it is taking time to feel a sense of confidence in the system.

    Hope you are able to convey to DJI what you found and that others have had similar experiences so that they need to figure out some quality control in their manufacturing of the P2's.

    Good luck.
     
  14. wkf94025

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    Re: Crash from 200 feet

    Geo,

    Would you mind elaborating a bit on the tools and techniques you would recommend if one wanted to rule out this potential nightmare from one's ship? As you can imagine, there is quite a range of soldering ability/interest/experience on this forum, and for those of us that recently bought a simple pencil iron and are dusting off skills last used in our early teens, it would be great to get a few tips from soldering black belts as it pertains to this specific context. (I am aware there are a gazillion soldering tutorials on youtube.) Also, if one were to go on a cold joint jihad, can someone enumerate the mission critical joints that one should address? Thanks all.

    Kelly
     
  15. ronhiner

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    Re: Crash from 200 feet

    Hmmm.. this isn't good.

    Called DJI today.. ended up on permahold. Posted problem on their web form. No reply. However, the web form said to go to my dealer first. So I tried that. (B&H). Crickets so far.
     
  16. Geoelectro

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    Re: Crash from 200 feet

    The idea of soldering is to heat both elements that are to be soldered together hot enough to melt the solder. So in the case of a wire to a solder pad, the iron would be placed so it touched both the pad and the wire. Add the solder so it flows to both elements. Only enough solder to cover the pad and fills all gaps between the pad and wire. Since this is only a wire and pad rather than electronic components there's little concern for overheating. I use a Weller 33 watt chisel tip soldering iron. Soldering stations are nice but not really needed. You can control temp with time the heat is applied.

    I do recommend practice on surplus boards until comfortable.

    Now in the case of our phantoms, we have suspect solder connections already made rather than making new ones. You can take your solder iron and reheat the joint making sure to heat both the pad and wire. Even better would be to remove the existing solder and add fresh solder. The pics of broken joints posted here represent solder joints where the pads were not heated properly or the overall heat was to low. These kinds of boards are using surface mount components and pads rather than the older solder thru system. This makes the solder joint more critical since there is no mechanical holding action.

    Geo
     
  17. wkf94025

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    Re: Crash from 200 feet

    Thanks Geo. Would you use any flux in re-soldering existing joints? Or just the iron? Any concerns about oxidation in the existing joint or introducing oxidation with the iron?

    Kelly
     
  18. Geoelectro

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    Re: Crash from 200 feet

    I would prefer removing old solder and adding new 60/40 which has flux built in. Just looking at my phantom the joints look like they have too much solder already and no way to know if it flowed onto the pad. Usually when reheating a joint I add fresh solder to it. This introduces the flux for cleaning the surfaces. These joints don't have any room for more solder. That's why I would consider removing some first.

    There are inexpensive solder pumps for removing heated solder or desoldering braid which is what I use. Surface soldering pads are very easy to work with, both removing and adding solder. In some of our work with solder thru on double sided boards we use a vacuum desoldering system. Not necessary on these surface joints.

    Geo
     
  19. wkf94025

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    Re: Crash from 200 feet

    Thank you sir. Sounds like an evening well spent to keep our birds from falling from the sky.

    Kelly
     
  20. KG4MXV

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    Re: Crash from 200 feet

    GEO is correct,

    But it looks like there is a clear sealant that has been applied to the joint.

    The PCB needs to be cleaned very well.
    Flux remover with be a good start and follow up with just plain isopropyl alcohol.

    Please practice a lot first,as ECO suggested.

    A good solder joint will look shiny and smooth, not a bubble but slightly convex.
    Take care not to move the PCB or wire while the joint is cooling.
    Don't blow on the joint to cool it. Let it cool gradually.

    the type of solder you use is important, do not get pumping solder with acid flux.
    got to radio shack and get a medium sized gauge solder that is rosin core.

    good luck.