Need Help Diagnosing an Error

Litz · Dec 17, 2015

Hello,

I had a crash yesterday with my P3 Pro, but other than a single broken prop there was no apparent damage. I'll mention that the battery popped out upon impact. I took it home and looked everything over carefully. No cracks or damage visible at all.

Powered up, and I am getting a Red-Yellow-Green alternating LED status. This normally just indicates power-up/diagnostic and goes away in a second or two. However, I'm getting this LED pattern continuously--it will not stop. Along with that there is a D-D (two short bursts every second).

Additionally, maybe related, I have a compass error which says to calibrate, but I cannot get it to calibrate. The LEDs continue flashing as described above and no matter what I try I cannot clear the compass calibration error.

On my sensor screen, all my compass values are showing 0.00. Shouldn't there be numbers bouncing in there? I am wondering if my compass cable dislodged, meaning I'll need to open the shell to take a look.

Any ideas? Thank you!

Mark The Droner · Dec 17, 2015

I would definitely open up the top and look everything over carefully.

Meta4 · Dec 17, 2015

Litz said:
Additionally, maybe related, I have a compass error which says to calibrate, but I cannot get it to calibrate. The LEDs continue flashing as described above and no matter what I try I cannot clear the compass calibration error.

On my sensor screen, all my compass values are showing 0.00. Shouldn't there be numbers bouncing in there? I am wondering if my compass cable dislodged, meaning I'll need to open the shell to take a look

That's telling you that the Phantom is getting no input from the compass.
Either a wire is broken or the connection to the mainboard is dislodged.
First place to look is around the compass sensor at the bottom of one of the legs.
You can remove the two tiny screws and expose the sensor - check the 3 grey and 1 black thin cables.

sifu128 · Dec 17, 2015

What caused the crash?

Litz · Dec 17, 2015

Meta4 said:
That's telling you that the Phantom is getting no input from the compass.
Either a wire is broken or the connection to the mainboard is dislodged.
First place to look is around the compass sensor at the bottom of one of the legs.
You can remove the two tiny screws and expose the sensor - check the 3 grey and 1 black thin cables.

Great, that's what I was guessing. I need a longer driver to extract that back screw on each arm to remove the shell top. I'll pick one up. As for inspecting the wires in the landing gear, which leg contains the compass lead? Thank you!

Meta4 · Dec 17, 2015

Litz said:
Great, that's what I was guessing. I need a longer driver to extract that back screw on each arm to remove the shell top. I'll pick one up. As for inspecting the wires in the landing gear, which leg contains the compass lead? Thank you!

Getting the top shell off is a total pain - just check around the sensor first - it's a lot easier.
Bottom of the back right leg - see it has a little covered section with two tiny screws.

Litz · Dec 17, 2015

sifu128 said:
What caused the crash?

Flying inside a large building filming a Christmas tree. There was monofilament lines coming out from the tree which I was not made aware of. Hit the line which slung the aircraft around. The line was cut but it was enough of a disruption that she went down.

Litz · Dec 17, 2015

Meta4 said:
Getting the top shell off is a total pain - just check around the sensor first - it's a lot easier.
Bottom of the back right leg - see it has a little covered section with two tiny screws.

Perfect, thank you. I'll have a look when I get home and will update after. I'm heading out of town tomorrow and was going to do some filming.... Always the way it goes

hunch · Dec 17, 2015

if the compass wire looks good most likely the connector that plugs in the main board broke or the IMU (black box) that has soldered joints on both sides took enough of a hit
that it broke it off. seen it one time too many

sifu128 · Dec 17, 2015

Litz said:
Flying inside a large building filming a Christmas tree. There was monofilament lines coming out from the tree which I was not made aware of. Hit the line which slung the aircraft around. The line was cut but it was enough of a disruption that she went down.

Ouch. I hope its can still fly!

Litz · Dec 17, 2015

I checked the compass connection on the landing gear and it's all solid. I'll have to try opening the shell and see what I can find. It hit with enough force to pop the battery out, so it's possible for a connection or solder joint to have come loose. I'm hoping whatever it is, it's obvious. Thanks for the advice and if anyone else has ideas please chime in and I'll give it a try.