RESOLVED: Worsening disconnections from AC => Overheating RC
2168 12 2018-6-13
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KeithLa
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UPDATED 6/25/2018:  I ascertained my RC was faulty and overheating, causing this problem. Details in my post below in this thread.

------------------ ORIGINAL POST -----------------

Although there are already many other threads reporting close range mid-flight disconnections with MP, MPP, and MA, I'm creating my own post about my own recent experiences.
  
I'm fearing a physical hardware defect in either RC or MPP, given what I've witnessed and am reading on these forums. I plan to do some test flights in WiFi mode, without RC, to see if it's isolated to RC/Ocusync.

Narrated video of yesterday's latest incident:
  
Problem: Repeated, increasing occurrences of MPP disconnects from both DJI Go 4 app and RC, at very close range and low altitudes within minutes of takeoff, in multiple locations. In yesterday's incident, MPP lost connection only ~100ft immediately overhead from takeoff point, then unable to reconnect only feet away from the RC after its auto land descent.
  
RC has been unresponsive each time, so I only watch auto RTH and attempts to land. In attached video, yesterday it was stuck hovering over the ground due to false obstacle detection, see video.

RC showed full signal strength at all times, antennae correctly aimed, no signal interference warnings in the app.
  
Some very brief reconnects, updating RC status to "Landing", creating multiple cached video clips on my phone, and a second distinct flight record in DJI Go, even though there was only one takeoff.
  
Yesterday, power cycling RC reconnected the app and AC, enabling Forced Landing (whew). But in prior incidents, neither restarting DJI Go 4 nor RC worked, MPP only reconnected after it landed and was itself power cycled.
  
No apparent consistency on flight time, distance, or altitude when these disconnections occur.
  
Was unit in a crash? No
   
What have you tried so far?: Prior to takeoff, restarted phone and set airplane mode. Used high quality USB-C cable to bottom RC port. Restarted DJI Go 4 app after disconnect, did not help.
   
What device are you using? Moto Z2 Force: Very fast device (current flagship), Android Oreo
  
What firmware are you running (aircraft, remote controller)? Latest as of 6/11/2018
  
What Go app version are you using? Whatever version preceded this morning's auto-update, currently 4.2.20 on my phone.
  
Any modification? No
  
Did you change anything or install any apps? No.

2018-6-13
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Optimus Prime-Mavic Air
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May i know your RC connect to your MP through 2.4 or 5.8?
2018-6-14
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WebParrot
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Hopefully you've landed by now.  And if you haven't already done so, go to online Support, start a "Chat" session.  You can link the video to the chat and get a Case#.  Be prepared to answer all the basic questions.  Be to sure to let us know of progress.
2018-6-14
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KeithLa
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WebParrot Posted at 2018-6-14 03:56
Hopefully you've landed by now.  And if you haven't already done so, go to online Support, start a "Chat" session.  You can link the video to the chat and get a Case#.  Be prepared to answer all the basic questions.  Be to sure to let us know of progress.

Thanks WebParrot, I'll give that a shot.
2018-6-14
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KeithLa
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Optimus Prime-Mavic Air Posted at 2018-6-14 00:54
May i know your RC connect to your MP through 2.4 or 5.8?

Hi Optimus Prime-Mavic Air, my RC and goggles were connected with OcuSync, not WiFi, so frequency is selected automatically for minimum interference.
2018-6-14
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KeithLa
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Just had a positive, albeit ultimately not particularly enlightening, hour+ online chat with DJI Support. The tech did not seem to have a lot more knowledge about remote controller disconnect scenarios than what's in DJI's written troubleshooting steps. As expected, he went straight to questioning my smartphone compatibility, which I consider irrelevant to loss of downlink between the aircraft and remote controller.

That said, he did identify several further troubleshooting steps I'm directed to try, before they'll open an official support case:  1) Reinstall DJI Go 4 app, 2) recalibrate IMU, 2) relink remote controller to aircraft.

I'm reluctant to reinstall DJI Go 4, since that will purge my cache and editor files (or so he says). So I'll first try the other two steps, and see if anything improves. I'm dubious IMU calibration affects downlink signal, but who knows. I've also refreshed the firmware on the aircraft using DJI Assistant 2 desktop app.

All that said, there's another hypothesis, though one that seems like a stretch:  Could my Verizon Wear 24 smartwatch be interfering with the remote controller? It contains wifi, BT, and cellular radios, though only BT is enabled on it. Further, it has a lot of metal, so much so that it doesn't get through TSA airport metal detectors. I'm dubious of this since I've been wearing that watch during nearly all my prior successful flights, with no signal interference warnings or disconnects. But still, I'll isolate it as a factor and see what happens.

2018-6-14
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paul2660
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I would also consider, refreshing firmware on both Mavic and controller.  You can do this from the Assistant 2 software or djigo4.  The assistant software gives you a menu.

With DJIgo4, on the main screen, when the app loads, look to the top right for 3 bars, hold that down for about 5 to 10 seconds, you should get a new menu asking if you want to load a new firmware or downgrade the firmware.

The mavic is only 2.4 on it's connection, does not have the 5.8 option even though it's occusync.  (at least that is how I understand it), so you are are always on 2.4 with a Mavic.

I would try these steps only if the re-linking of the controller doesn't work.   

You have just started having the problems as I recall so going back to an older firmware may help.   

Also, last thought, try flying without the googles, just to see if you still get the disconnection?  I can't see why they would cause it, but just a thought.

Paul Caldwell
2018-6-14
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Optimus Prime-Mavic Air
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KeithLa Posted at 2018-6-14 09:44
Hi Optimus Prime-Mavic Air, my RC and goggles were connected with OcuSync, not WiFi, so frequency is selected automatically for minimum interference.

Oh, I am sorry. Hope you can get it fix soon.
2018-6-14
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KeithLa
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paul2660 Posted at 2018-6-14 12:22
I would also consider, refreshing firmware on both Mavic and controller.  You can do this from the Assistant 2 software or djigo4.  The assistant software gives you a menu.

With DJIgo4, on the main screen, when the app loads, look to the top right for 3 bars, hold that down for about 5 to 10 seconds, you should get a new menu asking if you want to load a new firmware or downgrade the firmware.

@paul2660, thanks for the suggestions. I was able to refresh the MPP firmware using Mac desktop DJI Assistant, but that app doesn't seem to recognize the RC, so perhaps I'll try the other method you describe from Djigo4. Strangely, though, I once again saw an "update required" notice in Djigo4, even though MPP, RC, and goggles are all current. Mysteriously, it seemed to disappear on my next flight.

Happily, though, after refreshing the firmware, IMU and compass recalibration, and RC and goggles relink, I had three nearly flawless flights today, with no disconnects on what are now my furthest distances, altitudes, and duration, and my most enjoyable flights yet.

However, I say "nearly" flawless as I'm investigating two new glitches:  My 5+ minute video recording didn't cache to my mobile phone. Instead, I see multiple zero length videos in Djigo4 album, groan. The 4K video file is on the Mavic SD, and I can view it using the goggles.

The second problem I noticed is I can now not get into Fixed Wing Mode, even with the tutorial enabled, it's not detecting my 3 second forward flight and prompting to press C1 to enter Fixed Wing Mode. Need to spend more time on this tomorrow.

2018-6-14
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paul2660
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Glad to see the main issue appears to be fixed.

Paul C
2018-6-15
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KeithLa
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paul2660 Posted at 2018-6-15 06:39
Glad to see the main issue appears to be fixed.

Paul C

Discovered last night that my DJI Goggles firmware wasn't current, likely explaining why I sometimes saw update warnings in Djigo4, depending on whether or not goggles were connected at the time. Confusingly, I don't recall the Djigo4 warnings identifying the goggles, specifically, plus the display in the goggles themselves indicated current firmware installed.

More important question is whether goggles firmware mismatch could have caused the RC disconnects. It seems plausible, although my three successful flights yesterday were still with the old firmware on the goggles. I'll be doing more goggles flying shortly today.
2018-6-15
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KeithLa
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KeithLa Posted at 2018-6-15 09:14
Discovered last night that my DJI Goggles firmware wasn't current, likely explaining why I sometimes saw update warnings in Djigo4, depending on whether or not goggles were connected at the time. Confusingly, I don't recall the Djigo4 warnings identifying the goggles, specifically, plus the display in the goggles themselves indicated current firmware installed.

More important question is whether goggles firmware mismatch could have caused the RC disconnects. It seems plausible, although my three successful flights yesterday were still with the old firmware on the goggles. I'll be doing more goggles flying shortly today.

Big let down today:  After two successful flights in the same location, I had a remote control disconnect again, MPP immediately overhead at about 190ft, after a 5-10 minute flight in Fixed Wing Mode that traveled hundreds of feet away. Failsafe RTH with precision landing occurred successfully, but my confidence is shattered again.
2018-6-15
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KeithLa
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RESOLVED: Worsening disconnections from AC => Overheating RC

Happy to update here that after further troubleshooting of these close range aircraft disconnections, I ascertained my RC was faulty, seemingly overheating ten or so minutes into flights in warm outdoor temps (80-85F). My several observations that led to this:

- Immediately after random aircraft disconnects, Djigo4 reported RC firmware as 00.00.0000
- Power cycling RC would reconnect to AC and Djigo4, but only sporadically, just enough time to force land
- RC fan noise not present as usual, quieter or not running at all, and felt hotter to touch than normal.
- After power off and cool down, RC would connect to AC, and Djigo4 showed RC version 01.04.0300, but firmware refresh would fail. (Interestingly, it downgraded ok to 01.04.0200, but wouldn't go back up to 0300.)

After an hour online chat with DJI Support describing these conditions, they concluded RC must be faulty and should be returned for diagnosis and repair. Instead, I took advantage of Costco's 90-day satisfaction guarantee, returning the entire MPP/Goggles bundle for a brand new one, no questions asked.

I've had no RC aircraft disconnects with the new gear, and am now flying much greater distances without incident. Well, almost no incident: On one recent flight, my new DJI Goggles disconnected and Djigo4 reported 00.00.0000 for *their* firmware version, but the RC performed flawlessly. Not sure what happened with these goggles, hasn't happened since.

No idea what might have caused the RC to become faulty, but I'm taking care to only charge the new RC with the Mavic AC adapter, for starters.



2018-6-25
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