GPS problem - always switching to attitude mode after liftoff

[Moonfox]

Phantom 4 Pro been flying good for about a year but now seems like my GPS module is bad - have reinstalled latest firmware with DJI assistant 2, reinstalled DJI Go 4 app, calibrated IMU, still have same problem - flying in P mode. Even did factory reset and reinstalled firmware.

Also did reset of Nexus 7 that has always worked well with the aircraft.

GPS can be picking up 15 satellites but soon after takeoff drops to zero and attitude mode kicks in. If I land and idle GPS usually goes green again after a bit of time and then same problem after takeoff again. Happens at different locations.

About a month ago bird would start kicking into attitude mode while flying and then back to GPS. This happens in clear area with plenty of satellites.

Also getting popup that says NFZ database needs to be updated but I have current version. DJI support said to ignore all is fine.

Any suggestions on what to try or check before I send for repair? Anyone have this type of issue that might be firmware bug?

 

[N017RW]

Any crashes?
Possibly a cracked antenna or other intermittent issue aggravated in flight by vibration.
Just a guess.

 

[Moonfox]

No crashes.

 

[snabie]

Strange, i can tell i installed a fpvlr boossted antenna and afterwards the flymode switch button did not work, it stayed on ATT mode nomatter what mode was selected?

 

[Moonfox]

Sent in for repair to drone nerds, took 25 days to receive diagnosis, 30 days to repair and ship:

I have inspected and diagnosed your Phantom 4 Pro aircraft. I went to take your aircraft out for a flight test but immediately got a known error about the GPS being disconnected. This identifies that there is a hardware corruption in the 3 in 1 board module as well as the GPS unit itself. Both of these parts would have to be replaced to remedy the problem. I understand that the aircraft may be out of the warranty period which is unfortunate. In this case the cost to repair the aircraft replace the parts is $457.00.

• 1x P4 PRO Compass Part#1 for $38.00 each
• 1x P4 PRO 3in1 board Part#15 for $419.00 each