P3 Adv disconnects and stays disconnected in flight

[PilotM]

I have had P3 Adv for several months and it is has been fine. About 6 weeks ago I upgraded to the V1.8.8 and then this problem started. It is still there with the latest firmware upgrade 1.9.6

I fly and at short range (few hundred meters) the craft will go from full signal strength (control & video) to disconnected and then continually cycle in this disconnected state. By cycle I mean 1 red bar for control; and then video goes from 5 bars to none and back again. Repetitive disconnect messages.
It will stay in this state for minutes. Rarely might recover. Then eventually do a RTH. While in this state I have checked remote antennas (good position); turned each way; moved left and right - nothing helps.
After the RTH, at the time the props stop it will connect with 5 bars on each. once it reconnected a few meters off the ground.
This behaviour is fairly typical - but doesn't always happen. I might then fly a km away without problems.

My analysis:
-The areas I am flying in on beaches and it has happened in several locations so I don't think this is RF interference. It would reconnect faster at closer range if it was and it doesn't...
- direct LOS. no trees. Over water off beach in every case so shouldn't be these issues.
- why it reconnects when motors shut down may be a hint?
- no physical damage or reason to suspect damage to antennas (I did have a cracked base on one remote antenna but I fixed it and all looked fine).
- the nature of this looks like a software bug in not reconnecting and just cycling..... my suspicion... but have no idea why it would just crop up. Does anyone know if this is indicative of a control link problem which causes the video to drop in and out?

deathly drones log below. In this case it did recover a couple of times in flight but then eventually did an RTH.

 

[tberton]

I am having the same problem with my p3s. The RTH will not function on mine. I really don't loose control, even when display shows disconnected. It started right after the firmware update about the same time. I installed a new battery last night and it required a firmware download. I downloaded firmware 1.6.8. Now I am keeping track of numbers. Flew it and it was worse then before, however lost control, while showing not connected. I am sending it in for repairs, I think it is controller.

 

[Vertigo]

- why it reconnects when motors shut down may be a hint?

Might be a big hint. Sounds like a loose connector, broken wire or something else giving intermittent contact. Id begin by double checking all connectors, see that they are firmly inserted and that you can see no blank wires coming loose from the connector.

When I recently replaced an antenna on my P3A, I was surprised to see the ULF connectors from the antenna wires to the light bridge controller are not fixed with some goo/glue/whatever as they normally are on just about any RC equipment Ive ever used. You might want to check that too.

Of course, the problem might also be with the controller.

 

[PilotM]

Might be a big hint. Sounds like a loose connector, broken wire or something else giving intermittent contact. Id begin by double checking all connectors, see that they are firmly inserted and that you can see no blank wires coming loose from the connector.

When I recently replaced an antenna on my P3A, I was surprised to see the ULF connectors from the antenna wires to the light bridge controller are not fixed with some goo/glue/whatever as they normally are on just about any RC equipment Ive ever used. You might want to check that too.

Of course, the problem might also be with the controller.

Did you have to take the P3A apart to check these antennas?
I have externally checked cables to see they exist but I believe I would have to take the drone and remote apart to check anything .... and I haven't been sure this is worth it.

 

[Vertigo]

You can access the ULF connectors by just opening the vision controller unit at the bottom. All 4 antenna's connect there. But TBH, as I understand, those 4 antenna's are 2x video and 2x control and they are redundant. It doesnt seem likely all 4 would have the same intermittent contact.

If its not the remote control, then its more likely one of the connectors between the lightbridge/VPS module and the mainboard. You can check one side by opening the VPS unit:

IMG_20160614_111528_HDR

• Vertigo
• Jun 14, 2016

IMG_20160614_112223_HDR

• Vertigo
• Jun 14, 2016

To check the one on the mainboard, you need to take the shell apart.

 

[PilotM]

advising the problem turned out to be a faulty OFDM receiver board. i got an as new one on eBay and this fixed it. Only though after buying a 2nd hand remote control an seeing if that fixed it (it didn't)