I had a broken center support post and while I had the copter apart I upgraded the center frame support board with an after market anti-vibration board. Nothing electronic has changed - but now that I have the unit back together the BTU flashes green/yellow constantly. I tried everything and yesterday I thought I had fixed when it suddenly acted like normal - I was able to do a compass calibration, locked GPS and flew for ten minutes. Today, it's back to green/yellow flash.

I can go into compass calibration but it fails every time (red LED until I either try to calibrate again or reset power). Immediately on power up, it's flashes green and yellow. I've done an IMU calibration and reset every connection on board. I can't think of what else to try and I've changed nothing since the brief, successful flight yesterday.

After about the fifth time connecting it to the computer the LEDs suddenly began to work as expected and now it's flying like normal. Strange and very frustrating for several days. Especially frustrating not knowing what the issue was and if it could pop up again without warning!

Scratch that success from yesterday - today I'm back to four green/yellow LED and a dead UAV.  I carefully moved the position of my A2 components as they were not fixed in temporary positions and now it won't do anything but four green/yellow flashes.

I did notice this - in the A2 assistant software the GPS is not highlighted on the tools panel. If I reroute the connections so the GPS is tapped in through another connection - it lights up as if connected but still gives me the same LED - indicating compass issue. Anyone know if you have to use the connections exactly as show in the instructions or if it's like computers on a simple network, as long as everything is connected it works?

Anyone have anything I can try to resolve my compass issue? I was thinking maybe the compass is bad but then it will suddenly work for a couple flights. This inconsistency with no information more than four flashing LEDs is very frustrating.

Well if anyone comes across this post and is having the same issue - I discovered that there is a nick in the cable from the gps-compass, which makes sense. Now I'm just hoping I can repair it and avoid a $500-$600 replacement part.

dylan@dylangloc Posted at 2015-4-29 10:25
Well if anyone comes across this post and is having the same issue - I discovered that there is a ni ...

Yeow..not much wire to work with...what do you think caused the nick?