My first alarm was two days ago: starting up for the 2nd flight of the afternoon on Friday I had a “No signal” warning; I restarted the Go App and the warning disappeared. The following 16 minute flight went fine (video OK, no issues).

  

This morning I tried to start up again and the “No signal” warning reappeared and remains. At power up the aircraft does its gimbal “dance”; then suddenly the gimbal goes limp (the RC controller’s green Led indicates connection). Otherwise the overall aircraft status is correct: Firmware Version is latest, Radio channel quality is “Good”, Gimbal status is “Normal”. Multiple tries to restart without success. The motors can be started, so apparently the RC controller has a valid connection to the craft, but the gimbal remains limp (last summer when Go App crashes were common I had no video transmission, but the gimbal control worked and I could film to the SD card).  

I verified that the Lightbridge and Gimbal flat cables are both connected (no signs of damage); camera ribbon cables appear to be in position.

  

My P3P has over 200 flights (131 flights with no issue since a body-shell replacement after a crash). The DJI Go App version is 2.6.1, RC firmware version is 1.5.70, aircraft firmware version is 1.6.40, and my tablet is a Nexus 9 Android version 6.0.1 Marshmallow.

  

Any suggestions?

  

Could it be something as simple (& cheap) as a faulty USB cable.  I'd certainly look there first.

nigelw Posted at 2016-3-13 15:23
Could it be something as simple (& cheap) as a faulty USB cable.  I'd certainly look there first.

Good try Nigel, tried another USB cable, but no change, still "No signal".

johnsr Posted at 2016-3-13 14:51
Good try Nigel, tried another USB cable, but no change, still "No signal".

Well, I hope you get to the bottom of it as I had the same warning last time I flew.  Switched the P3 off & on again & it was all good.  I have noticed the male part inside the USB socket in the RC has moved slightly & appears loose.  Maybe the soldered joints are breaking away.

johnsr Posted at 2016-3-13 07:51
Good try Nigel, tried another USB cable, but no change, still "No signal".

Since you are getting intermittent video loss and you've tried different ribbon cables it may be a hardware issue.
Can you try a different device (borrow a friends iPad or phone) and try deleting and reinstalling the app, Make sure developer options is on on your phone.
If none of those work, then maybe it needs to come in for repair.

nigelw Posted at 2016-3-13 15:57
Well, I hope you get to the bottom of it as I had the same warning last time I flew.  Switched the ...

When did you fly last? Could this be a software bug?

DJI-Ken Posted at 2016-3-13 16:10
Since you are getting intermittent video loss and you've tried different ribbon cables it may be a ...

Thanks Ken. I don't have another tablet handy for now. But will try deleting and reinstalling the app. Incidentally the developer option was on. I have the impression that something is happening a second or so after start up, because the gimbal movement starts out OK.

johnsr Posted at 2016-3-13 15:12
When did you fly last? Could this be a software bug?

Last weekend.  I've not changed any software for about 4 weeks (latest app version).  I flew 3 batteries & only had the problem on the first power-up.

DJI-Ken Posted at 2016-3-13 16:10
Since you are getting intermittent video loss and you've tried different ribbon cables it may be a ...

Removed and reinstalled the Go App as you suggested. The situation is unchanged, still "No signal". However, App not quite normal: the toggle is switching back and forth from camera to video, and I can not modify the menu settings. I'll try removing and reinstalling again later this evening.

johnsr Posted at 2016-3-13 23:48
Removed and reinstalled the Go App as you suggested. The situation is unchanged, still "No signal" ...

Ok, also try another device.

John,  maybe try the Litchi app just to see what happens?

     I  think if you can, I would load the SD card with your current (1.6)  firmware to the aircraft.  It will do its normal dance and maybe a tone or two and after a few minutes power down and remove the SD Card.  Take the SD card over to your PC and View the Hidden File if on lines 0800 and 1500 you have "Device Not Detected" There is a serious problem.  If it  says "How to Connect"  The challenge is more than likely  Transmitte r( USB maybe ) Not seeing the  GO  APP   or Device.  I left the link on" how to view hidden files" below .   
If you have good connection between the Aircraft and RC but the camera is limp, then you have bad wiring  or a cracked circuit board somewhere on the aircraft.   I think I would gently wiggle the wires with everything on and see if camera springs to life, this could narrow things down.

http://forum.dji.com/thread-44544-1-1.html

Hope this helps- donnie

Donnie Posted at 2016-3-13 18:20
I  think if you can, I would load the SD card with your current (1.6)  firmware to the aircraft ...

Many thanks Donnie I will try this tomorrow, and post back.

Donnie Posted at 2016-3-13 18:20
I  think if you can, I would load the SD card with your current (1.6)  firmware to the aircraft ...

Thanks Donnie; I went through your procedure and put the 1.6.40 firmware bin file on the SD card and proceeded as if doing a firmware update on the craft. After the "update" stopped, I removed the card and found the log file to be normal. Now for the big surprise... I then removed the bin file from the SD card, reinserted it and restarted the P3P as normal and all seems to be working again (???).
This looks suspiciously like an intermittent fault, but where? I will try to fly this afternoon, but very nearby...

johnsr Posted at 2016-3-14 05:57
Thanks Donnie; I went through your procedure and put the 1.6.40 firmware bin file on the SD card a ...

     Yes, I agree,  and intermittent failure are the hardest to solve.  Best of Luck, and like you said, "Keep it Nearby....."

All the best to you and yours- donnie

johnsr Posted at 2016-3-14 10:57
Thanks Donnie; I went through your procedure and put the 1.6.40 firmware bin file on the SD card a ...

Did the log file say upgrade successful or not needed?  If it actually did a successful upgrade the problem could well be in the old firmware.  If it wasn't needed because it's the same, you may still get a problem in future.

It's weird how every now & then warnings come & go with no explanation.  There seem to be a lot of bugs.

nigelw Posted at 2016-3-14 14:49
Did the log file say upgrade successful or not needed?  If it actually did a successful upgrade th ...

The log file said update not needed. The "update" affair was very short. That is why I said to Donnie that I suspect an intermittent fault somewhere. As a completeness check I just few 31 minutes; all seemed OK, no issues... for now. I did so gently tapping the aircraft before and the RC controller during the flight (at the start); I also moved USB cable in its socket. Then I progressively flew with faster accelerations, turns & braking. No surprises. So yes, I am afraid that the relief is only temporary. Personally I suspect either the RC controller or an android tablet Go App problem, but that is based on little evidence.