Calibration Failed...

[CrashCraft]

Morning Folks - searched for this but didn't find anything in any threads.
Changed my P3P lower shell it was cracked - imagine that - looks worse inside .
After reassembly using the original upper shell with original GPS antennae it powers up like normal, camera works great but it says there is a compass error and to move the AC or re-calibrate.
175 flights from the same location no compass issues - so I go through the process but same result - then take it out to one of our farms pastures - just me the drone and the same issue. "Calibration Failed - Too strong Magnetic Interference Detected. Ensure that there are no magnets or metal objects nearby and hold the AC at least meter off the ground when calibrating"
Only thing I can think is a cable is pinched or - and this is for the chemist/electrical engineer - the paint job on the new lower unit has created a funky magnetic field. Krylon ColorMaster (Acetone, toluene, propane, butane, ethyl 3-ethoxypropionate, dimethyl carbonate). Looks buff hope it's not the issue....want to paint the upper shell to match. Holding pattern on that for now.
DJI Go version 3.1.15 - uninstalled and reinstalled - latest RC and AC firmware versions - have 150 miles of flight on this combination prior to the shell replacement.
Don't like being grounded - help please if you can.

 

[Meta4]

After reassembly using the original upper shell with original GPS antennae it powers up like normal, camera works great but it says there is a compass error and to move the AC or re-calibrate.

It's common to damage one of the fine compass wires when reassembling the legs and antenna.
To check, go to the sensor info in the app and see what it says for your compass.

If there are numbers there, the compass is OK but if it's zero, you've got a broken wire or the compass is disconnected.
It will never calibrate until this is fixed.
You might need to get a new compass that comes with a set of legs.

 

[CrashCraft]

All zeroes on the Compass so likely as you say a wire issue. Thanks so much I'll take it apart and see what I messed up.

 

[Meta4]

All zeroes on the Compass so likely as you say a wire issue. Thanks so much I'll take it apart and see what I messed up.

Just remove the cover plate from the compass and you'll probably see it.

 

[CrashCraft]

Squished the ribbon cable pretty good at both ends where the antennae snaps into the landing gear - monkeyed with the cable but still zeroes on the compass reading.