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GPS Getting Hot/Phantom Not Starting

Discussion in 'Phantom 2 Discussion' started by chris travels, Nov 5, 2014.

  1. chris travels

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    Hey guys, thanks for checking my post. I had a fly away that did a number on my P2. I am in the process of repairing this phantom as my backup/hard to get spots drone. I have replaced the receiver and now that I have control again the phantom will not spin up. I get the flashing red lights. During said crash the tab on the mother board that the GPS connects to took a beating. I straightened out the metal prongs and the plug fits now. Also, the GPS unit itself gets very warm while I am running the software to see what is going on.

    Is there anyway to fly the phantom without the GPS? Does this sound like a GPS problem to you or a compass problem? Is there a sure fire way to test and see if the GPS is bad?

    Thanks again for your time.

    Chris
     
  2. 4wd

    4wd

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    You should be able to start the motors and fly it without GPS if you are prepared to ignore the red lights.
    It will behave like ATTI mode.
    If you can't start the motors something else is wrong.
    Try calibrating the sticks first, it maybe isn't getting the full CSC signal.

    The GPS antenna is inexpensive and easy to replace.
     
  3. chris travels

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    Thank you for the reply.

    I believe it is the module being I can literally smell it getting hot. I also get 5 flashing red lights when trying to start and the compass will not calibrate. Is there any way to fly the P2 without the module plugged in or operating? At $150 I do not know if it is worth buying as this will be my backup drone when I can buy a new P2 and get the extra battery and other accessories as well.

    Chris
     
  4. RDCF550

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    If it's getting that hot, then it's bad. It failing is what could have caused the fly away also.

    Since FW version 3.0 or so, the Phantom 2 will not spool if it doesn't detect the GPS. You'd have to downgrade it to v1.08 to get it to work with no GPS, and then it would be a completely different animal in the air.

    You're better off replacing the GPS module, even though it's ridiculously expensive compared like modules for other copter setups, it's pretty much the backbone of how the Phantom 2 works.
     
  5. ianwood

    ianwood Taco Wrangler
    Staff Member

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    GPS seldom is the cause for fly aways, if ever. Badly calibrated or malfunctioning compass and IMU are far more likely suspects.

    If the GPS module is getting so hot you can smell it, it is burning and needs to be disconnected and/or removed. It sounds like you may have a wiring issue at the connector and it is possibly shorted out. Disconnect it and see if it works. You will be in ATTI mode.
     
  6. RDCF550

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    Said could be, and it's obviously bad as it doesn't get that hot during normal operation or typically fail even after being knocked around quite a bit.

    If the FW is ~3.0 or higher, then removing the GPS will not let the motors spool up, so it will not work in ATTI mode as it will not start up.


    EDIT:

    [​IMG]


    GPS Connector checks on Central board.

    NOTE: Make sure there is NO battery in the Phantom 2 for these checks, you're testing for Resistance here and want no power going to the board.

    Unplug the GPS module from the Central board.

    Set the DMM to measure Resistance (Ohms).

    Place the Red test lead on TP5 of the Central board. Place the Black test lead on TP1. The reading should be 1.8M or right around there, 1.5M to 2M is fine.

    Place the Red test lead on TP5 of the Central board. Place the Black test lead on TP2. The reading should be 1.8M or right around there, 1.5M to 2M is fine.

    If either of these readings are different, especially if they are a much lower value, then suspect the Central board to be bad and it will need replacing.

    These should be double checked at the GPS connector on the Central board also. The 2 center pins are the same as the TP1 and TP2 spots.

    Place the Red test lead on TP5 again, then check the Resistance on each of the center pins with the Black lead, they should be the same as what was measured on the TP1 and TP2 spots. If they are different, then there is a problem between the connector and the MCU on the Central board.



    Voltage checks. NOTE: Take care not to short out anything with the test leads while poking around in there, as there will be power to the circuits for these tests.

    Unplug the GPS module from the Central board.

    Set the DMM to measure DC Volts.

    Put the battery in the Phantom 2 and power it up.

    Place the Black test lead on TP5 of the Central board. Place the Red Test lead on TP1. It should measure around 2.3v or so.

    Place the Black test lead on TP5 of the Central board. Place the Red Test lead on TP2. It should measure 3.3v.

    Place the Black test lead on TP5. Place the Red test lead on pin 1 of the GPS connector. Pin 1 is the one that it closest to the CAN connector and is the one that the Red wire form the GPS module plugs into. It should read 5.5v.

    Turn the Phantom 2 battery off.



    Really about all you can do for checking the GPS module, without getting extensively into it, is to do some Resistance checks on the GPS module connector.

    Unplug the GPS module from the Central board. At the connector on the GPS module, there are spots where you can probe the connectors for the wires.

    Set the DMM to measure Resistance (Ohms).

    Place the Red test lead on the spot for the red wire. Place the Black test lead on the spot for the Brown wire. You'll get an erratic reading at first, then it will settle down and sit around 200k or so and slowly drop in value. This is normal.

    If you get a fixed Resistance value that is lower right off the bat and see no changing at all, then there is an issue with the GPS module.

    Place the Black test lead on the spot for the Brown wire. Place the Red test lead on one of the Orange wires. It should measure around 3.6M or so. Then move the Red test lead over to the other Orange wire, it also should measure around 3.6M or so.

    If either of those measurements are much lower, then the GPS modules is bad.
     
  7. FedeVision

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    Hi, having this trouble with GPS, viewtopic.php?f=19&t=29973,
    made this checks and I'm getting this same numbers for TP1, TP2 and connector pins, not sure if I did the checks the right way.
    If I'm not wrong, my numbers are over 2M on main board and over 3.6M on module, does that also means these are damaged?
    Voltage values were a little bit low, but battery was around 40%.

    Thank you in advance!
     

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  8. RDCF550

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    Your meter there only measure up to 2000k (that's 2M) so those values are 253k and 475k, far lower than what they should be and would be considered bad, but again, your meter does not measure that high, so you're not getting an accurate measurement and can't go by those numbers.

    The voltage values should be very close, within 0.1v, and if not I'd say that meter is also the cause of that.
     
  9. FedeVision

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    Thank you RDCF500, guess my tester battery must be low, don't know why, but the gps started working again, more details on the post mentioned above.