Hi all,

Last year I had a crash that cracked the shell of my Phantom 3 Pro. I finally got around to dismantling the innards and rebuilding them into a new shell. Everything boots up fine, gimbal works, etc. etc. However, I cannot calibrate the compass. I've tried in a number of locations including an open field. I never had this much trouble previously which leads me to believe a component was broken or not rebuilt properly.

My question is, how can I start the process of elimination to narrow in on the issue / solution? Is there a way I can test compnents individually? Or something obvious I'm missing? Any help / insight appreciated!

The most common cause of persistent failure to calibrate is a disconnected compass.
Go into your app settings and check the Sensors page.
What does it show for the compass?
If you see numbers, the compass is OK, if you see zero, the compass is disconnected.

If the compass is plugged into the mainboard, the cause is likely to be a fine wire at the bottom of the landing gear.
It's probably easier to buy new landing gear than to fix.