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P2V+ GPS Module Tests

Discussion in 'Phantom 2 Vision + Help' started by BSquared, Oct 19, 2015.

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  1. BSquared

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    I did have a crash into a tree branch. My own dumb fault. I should have stopped forward motion and climbed, but didn't respond fast enough. I have replaced the upper and lower body shells. All circuit boards were closely examined for any cracks whatsoever using a high magnification LED lamp. None found at all.
    The GPS Module doesn't show any damage at all. Now when I power everything up, there is a very brief flash of the GPS Lock LEDs, then nothing.

    I have looked once more at the main board where this module plugs in. It can't be reversed, but I look underneath and the pins are soldered through the board, and have a dull appearance. My mind wonders if this is an indication of cold solder joints. I've seen this in more equipment than I can remember.

    I have two ways to go. 1) Re-flow the solder on those pins, hoping they are indeed cold solder joints, 2) Attempt to read the data leads with an oscilloscope to see if I can tell if the data is getting in and something else is amiss, 3) Just replace the GPS Module with a new one.

    Suggestions? Other ideas?
     
  2. LuvMyTJ

    LuvMyTJ ADMINISTRATOR
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    Those GPS pucks tend to crack if they crash hard enough. The fact you had to replace the entire shell says your hit hard. Why not try an updated puck? There are a few how-to's here from the past of people replacing their GPS puck with a better version and the upgrade was cheap. I know you said you checked it for damage but in this case it would be upgrading so why not? :)
     
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  3. kirk2579

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    +1

    under $10 and less than an hour , well worth it no matter!
     
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  4. BSquared

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    I did examine the puck just as closely. Admittedly I did not unsolder it and look at the back side. I have looked at just the puck for replacement. That is another option. Jameco has the puck itself at a reasonable cost. I will add that to the list of considerations.
    Do you mind telling me the source of the puck at that cost?
     
  5. kirk2579

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    if by "puck" you mean the whole module it is not.
    The actual ceramic antenna that solders to backside of module is the unit I am referencing and it is :

    http://www.digikey.com/product-detail/en/CGGP.25.4.A.02/931-1126-ND/2690283
     
  6. BSquared

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    That is precisely the part I am referring to. I indeed realize that it is NOT the entire module. I won't go that far until I replace that ceramic part first.
     
  7. kirk2579

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    just wanted to be sure we were both on same page. I am a long time teledata tech and learned not to assume anything, best to ask.
     
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  8. BSquared

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    As you, I have been heavily into data communications. I don't even take a technician's word for how he/she set up a PC on a network! Too many make erroneous assumptions. So I have a habit of double checking things. It is entirely too easy to make an error.
     
  9. BSquared

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    Hello All, Status update on GPS.

    Puck received, installed, GPS still dead!

    I have ordered the entire GPS Module! However, I did NOT go through Amazon NOR DJI!

    I located a source on E-Bay, he is selling these for $68.95. Add shipping and the total is $73.90. The Seller has quite a E-bay Store! RC parts from back to 10th scale R/C car chassis, suspension, bumpers, and pretty much anything!

    Estimated delivery: Tue. Oct. 27 - Fri. Oct. 30.

    Cheers!
     
  10. kirk2579

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    too bad, but good buy on ebay!

    while it is apart fire it up to verify new module is the fix, then if all ok , install the 4mm antenna to the new module.
    save yourself the time from having to do it later again!

    good luck and have fun flying!
     
  11. BSquared

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    I'll install the new GPS Module, and see how good it does before I go and change the puck to the thicker one. My reasoning is simply that the original one worked flawlessly before I crashed. Never had insufficient satellites. If that is how it performs with the new module, then I will most likely leave it that way. I would only go for the thicker puck if I ever get marginal reception.

    Perhaps I am a bit conservative, but I also believe in "Don't fix what isn't broke.". The other one I believe in is: "Don't take it apart to see why it works!". I've seen far to instances of the latter.
     
  12. kirk2579

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    while I agree with don't fix concept. The GPS is a known weakness in the P2 and the upgrade is very common as safety factor. If on average 1 to 3 satelites are added to the matrix from the normal 6 + , the likely hood of dropping below 6 is diminished somewhat.

    I feel doing this has allowed me to reach nearly 500 flights the last 8 months since I updated my 2 phantom 2's
     
  13. kirk2579

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    wifi in quad is also a known weak spot ,
    you may want to research the wifi module fix-- IE open it up and add thermal compound around chips to reduce heat damage and failure(common).

    DJI Forum|Phantom 2
     
  14. BSquared

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    I've not had any heat issues in the WiFi module in the lower body shell. I have had that modules cover off and not found any indications of over heating. I do have the thermal compound, and I always watch for areas that need this applied.
    Actually the last place I found needing it was my Weller W100 soldering pencil. The tip just slides into the heating element barrel. I took out the tip, applied the compound, put it back in and it heats up much quicker.

    I am always looking to find components that either need an additional heat-sink or other methods of reducing heat load to prevent thermal stresses and improve the heat dissipation.

    The biggest issue right now is this FAA issue. I may have to apply for an exemption to the Rules and Regulations. I am 4.6 miles from Class D airspace, which means that I cannot legally lift off whatsoever.

    I'm researching the issue, and looking at perhaps applying for an exemption and becoming a LLC that performs aerial roof surveys for damage/need of repairs due to age.

    Just might manage to achieve this. Just have to add one individual as the Field Observation Spotter. Oh how this has suddenly become a real PIA.
     
  15. BSquared

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    I also have one good reason to NOT put the thicker puck on the new module when I install it. There is the warranty/guarantee issue.

    If I modify it right out of the box, then I void this. I'll go with just putting the new one in. Then run it, and watch the number of satellites I consistently get locked on. I will look inside the WiFi module, and see if it would be beneficial to apply a thermal compound. If there aren't any heat sinks, then it would seem rather pointless. Thermal compound itself won't dissipate heat enough without a mechanism to dissipate it through.
     
  16. BSquared

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    GPS Module received and installed! All successful! Receiving at least SEVEN satellites!

    Cannot test fly - raining all darn day!
     
  17. Mark The Droner

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    Are you sure? It's my understanding that you can launch but you are restricted in height to something less than 400 ft - say 350 ft might be your max.
     
  18. BSquared

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    I am ABSOLUTELY certain! I have ALL documents in hand.
    Now *if* I should happen to lift off and stay below 100 feet, I don't think anyone will even know except for the neighbors.
    The Tower in the Class D airspace won't see it, pick it up on radar or any other means.
    The trees alone between them and I are much taller than that! I saw that when I went up to about 200 feet once.

    It would take a complaint from someone to the FAA before I would encounter ANY issues.
     
  19. Mark The Droner

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    Okay. What is DJI talking about here between the 1:10 mark and the 1:20 mark?



    The map shows the runways at LAX and apparently we can fly a phantom not too far from the end of the runway. We just must limit our height.

    So how is it that you "can't legally lift off?"
     
  20. BSquared

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    Folks, the DJI No Fly is meaningless.

    You need to get THE FAA No Fly Zone map for YOUR area!

    LAX is Class A Airspace!

    Suggest: <https://www.mapbox.com/drone/no-fly/>

    Expand the area where you purport to *attempt* to fly!

    Learn before you have your gear confiscated and you go off in cuffs!

    This is NOT a joke!